Human Stem Cells and Organ Regeneration
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Questions and Answers

What is the main function of histocompatibility molecules in graft rejection?

  • To facilitate grafterecipient compatibility
  • To distinguish between self and non-self tissue
  • To prevent the activation of the complement system
  • To evoke both cellular and humoral immune responses (correct)

    • What is the consequence of ABO blood group incompatibility in graft rejection?

  • Acute rejection
  • Hyperacute rejection (correct)
  • Graft acceptance
  • Chronic rejection

    • What is the primary target of the recipient's immune system in graft rejection?

  • The graft vasculature
  • The graft histocompatibility molecules
  • The graft parenchyma
  • The graft endothelium (correct)

    • What is the role of preformed antibodies in graft rejection?

    <p>To cause hyperacute rejection</p> Signup and view all the answers

    What is the term for the molecules that evoke an immune response in graft rejection?

    <p>Histocompatibility molecules</p> Signup and view all the answers

    What is the consequence of histocompatibility molecule recognition by the recipient's immune system?

    <p>Graft rejection</p> Signup and view all the answers

    What is the name of the complex responsible for evoking an immune response in graft rejection?

    <p>Major histocompatibility complex (MHC)</p> Signup and view all the answers

    What is the term for the process of graft rejection caused by preformed antibodies?

    <p>Hyperacute rejection</p> Signup and view all the answers

    What is the primary mechanism by which CD40L promotes cancer therapy?

    <p>By stimulating the immune system to suppress cancer cells</p> Signup and view all the answers

    What is the primary cell type that CD40 is expressed on?

    <p>B cells and macrophages</p> Signup and view all the answers

    What is the main consequence of CD40L deficiency in lower-income countries?

    <p>Increased risk of infections, particularly HIV</p> Signup and view all the answers

    What is the primary cause of immune suppression in children suffering from acquired immunodeficiency syndrome?

    <p>Infections by pyogenic and intracellular bacteria</p> Signup and view all the answers

    What is the term for the condition characterized by a weakened immune system?

    <p>Immunodeficiency syndrome</p> Signup and view all the answers

    What is the primary role of CD40L in the immune response?

    <p>To activate B cells and macrophages</p> Signup and view all the answers

    What is the main consequence of CD40L-mediated immune responses in cancer therapy?

    <p>Stimulation of the immune system to suppress cancer cells</p> Signup and view all the answers

    What is the primary mechanism by which CD40L promotes immune responses against cancer cells?

    <p>By stimulating the production of pro-inflammatory cytokines</p> Signup and view all the answers

    Which of the following cells are directly involved in the killing of graft cells in acute cellular rejection?

    <p>CD8+ T cells</p> Signup and view all the answers

    What is the primary role of CD4+ T cells in acute cellular rejection?

    <p>Producing cytokines that contribute to inflammation</p> Signup and view all the answers

    Which of the following is NOT a direct consequence of CD4+ T cell activity in acute cellular rejection?

    <p>Direct killing of graft cells</p> Signup and view all the answers

    How do macrophages and neutrophils contribute to the damage of parenchymal cells in acute cellular rejection?

    <p>By engulfing and destroying the cells</p> Signup and view all the answers

    What is the role of alloantigen-specific T cells in acute cellular rejection?

    <p>To recognize and attack the graft cells</p> Signup and view all the answers

    Which of the following best describes the relationship between CD8+ T cells and CD4+ T cells in acute cellular rejection?

    <p>CD4+ T cells provide support and amplify the activity of CD8+ T cells</p> Signup and view all the answers

    Why is the destruction of parenchymal cells considered a hallmark of acute cellular rejection?

    <p>It directly leads to the loss of function of the transplanted organ</p> Signup and view all the answers

    Which of the following would be considered a potential therapeutic target for preventing or treating acute cellular rejection?

    <p>Blocking the production of cytokines by CD4+ T cells</p> Signup and view all the answers

    Which of the following organs is most commonly transplanted in the United States?

    <p>Kidney</p> Signup and view all the answers

    What is the primary purpose of organ transplantation?

    <p>Replace damaged or impaired organs</p> Signup and view all the answers

    What is the estimated annual number of organ transplants performed?

    <p>30,000</p> Signup and view all the answers

    Which glands are commonly involved in transplantation practices?

    <p>Pancreatic endocrine glands</p> Signup and view all the answers

    In the context of organ transplants, what is meant by 'transplanting from other individuals'?

    <p>Standardizing organ sources among living and deceased individuals</p> Signup and view all the answers

    Which organ follows the kidney in terms of commonality in transplantation?

    <p>Liver</p> Signup and view all the answers

    What type of T cells are referenced in relation to organ transplant density rates?

    <p>CD4+ T cells</p> Signup and view all the answers

    Which of the following is true regarding the practice of organ transplantation?

    <p>It has become a standard medical practice</p> Signup and view all the answers

    What is the main function of pre-B cell receptors?

    <p>To receive signals necessary for the maturation of B cells.</p> Signup and view all the answers

    How do primary immunodeficiency diseases arise?

    <p>From genetic mutations affecting the immune system.</p> Signup and view all the answers

    What is the consequence of a lack of pre-B cell receptor signaling?

    <p>Impaired development of B cells beyond the pre-B stage.</p> Signup and view all the answers

    What are plasma cells responsible for?

    <p>Producing antibodies in response to antigens.</p> Signup and view all the answers

    What is a potential outcome of a deficiency in antibody-producing B cells?

    <p>Increased susceptibility to bacterial and viral infections.</p> Signup and view all the answers

    Why are children with primary immunodeficiency diseases more prone to infections?

    <p>They lack the necessary components for a robust immune response.</p> Signup and view all the answers

    What is the meaning of the term "congenital immunodeficiency"?

    <p>An immune system deficiency present at birth.</p> Signup and view all the answers

    What is the main difference between primary and secondary immunodeficiency diseases?

    <p>Primary immunodeficiencies are caused by genetic mutations, while secondary immunodeficiencies are caused by other disorders.</p> Signup and view all the answers

    Hyperacute rejection is caused primarily by the deposition of antibody on the endothelium.

    <p>True</p> Signup and view all the answers

    The pathophysiology of hyperacute rejection involves the activation of platelets and fibrin thrombi formation.

    <p>True</p> Signup and view all the answers

    Hyperacute rejection is characterized by a gradual process leading to chronic ischemia in the transplanted organ.

    <p>False</p> Signup and view all the answers

    Neutrophil infiltration is an early event in hyperacute rejection of transplanted organs.

    <p>False</p> Signup and view all the answers

    Thrombosis during hyperacute rejection leads to severe ischemic injury in the transplanted organ.

    <p>True</p> Signup and view all the answers

    The hyperacute rejection of an allograft is primarily mediated by T cells.

    <p>False</p> Signup and view all the answers

    SS-A and SS-B are specific for dryness of the nose (xerostomia).

    <p>False</p> Signup and view all the answers

    Perforation of the septum is known to occur in some cases of this disease.

    <p>True</p> Signup and view all the answers

    The disease in question is primarily triggered by bacterial infections.

    <p>False</p> Signup and view all the answers

    More than half of the patients exhibit rheumatic arthritis as a secondary condition.

    <p>True</p> Signup and view all the answers

    Dryness of the epithelial tissues can lead to ulceration.

    <p>True</p> Signup and view all the answers

    CD4 T cells do not play a role in vessel occlusion during chronic inflammatory reactions.

    <p>False</p> Signup and view all the answers

    Chronic inflammatory reactions can lead to intimal smooth muscle proliferation.

    <p>True</p> Signup and view all the answers

    Neuropsychiatric symptoms are common in all patients with this disease.

    <p>False</p> Signup and view all the answers

    Antibody binding to endothelial antigens is unrelated to chronic inflammatory reactions.

    <p>False</p> Signup and view all the answers

    Autoimmune diseases can lead to lung fibrosis in affected individuals.

    <p>True</p> Signup and view all the answers

    Cytokines play a central role in modulating immune responses in vessel wall inflammation.

    <p>True</p> Signup and view all the answers

    This condition is solely characterized by excessive saliva production.

    <p>False</p> Signup and view all the answers

    Vascular smooth muscle cells are typically inhibited during chronic inflammatory processes.

    <p>False</p> Signup and view all the answers

    Alloantigen-specific CD4 T cells do not contribute to chronic inflammatory reactions.

    <p>False</p> Signup and view all the answers

    The presence of CD4 cells and cytokines in the vessel wall is indicative of chronic inflammation.

    <p>True</p> Signup and view all the answers

    Blood vessel injury results exclusively from external trauma and is not influenced by immune responses.

    <p>False</p> Signup and view all the answers

    Adenosine deaminase is only expressed in low levels in recipients of HSC transplants.

    <p>False</p> Signup and view all the answers

    Granulocytes and T lymphocytes are involved in the accumulation of toxic purine metabolites.

    <p>True</p> Signup and view all the answers

    Recovery of immune competence can happen rapidly after HSC transplantation.

    <p>False</p> Signup and view all the answers

    Adenosine deaminase deficiency does not affect T cell development in the thymus.

    <p>False</p> Signup and view all the answers

    The immune competence influenced by adenosine deaminase levels is crucial for effective graft acceptance.

    <p>True</p> Signup and view all the answers

    T cells can recover completely without any influence from adenosine deaminase.

    <p>False</p> Signup and view all the answers

    Severe immune deficiency can result from inadequate production of adenosine deaminase after HSC transplantation.

    <p>True</p> Signup and view all the answers

    The expression levels of adenosine deaminase have no impact on the effectiveness of immune responses.

    <p>False</p> Signup and view all the answers

    CD40L is involved in promoting immune suppression in the context of autoimmune diseases.

    <p>True</p> Signup and view all the answers

    Children affected by acquired immunodeficiency syndrome (AIDS) are less likely to suffer from immune deficiency due to enhanced immune activity.

    <p>False</p> Signup and view all the answers

    CD40 is primarily expressed on T cells and plays a role in B cell activation.

    <p>False</p> Signup and view all the answers

    In lower-income countries, malnutrition significantly contributes to immune deficiencies and related diseases.

    <p>True</p> Signup and view all the answers

    The primary function of CD40L is to bind to B cells and enhance antibody production.

    <p>True</p> Signup and view all the answers

    Acquired immunodeficiency syndrome primarily results from infections by opportunistic pathogens and does not affect immune function.

    <p>False</p> Signup and view all the answers

    Macrophage activation is an indirect consequence of CD40L engagement on B cells.

    <p>True</p> Signup and view all the answers

    Pyogenic bacteria and some viruses can lead to acquired immunodeficiency syndrome.

    <p>True</p> Signup and view all the answers

    Explain the two primary mechanisms by which CD8+ T cells contribute to the destruction of graft cells during acute cellular rejection, as depicted in Figure 4.12.

    <p>CD8+ T cells directly kill graft cells through cytotoxic mechanisms. They also release cytokines, further promoting inflammation and attracting other immune cells.</p> Signup and view all the answers

    Describe the role of CD4+ T cells in acute cellular rejection, highlighting their specific contributions to the overall process.

    <p>CD4+ T cells release cytokines that promote inflammation and recruit macrophages and neutrophils. They also activate CD8+ T cells, amplifying the cytotoxic response against graft cells.</p> Signup and view all the answers

    Based on Figure 4.12, explain how parenchymal cell damage and interstitial inflammation are interconnected in acute cellular rejection.

    <p>Parenchymal cell damage is a direct consequence of CD8+ T cell killing, while interstitial inflammation is driven by cytokines released from CD4+ T cells. This inflammation further exacerbates parenchymal cell damage by attracting more immune cells.</p> Signup and view all the answers

    Discuss the specific roles of macrophages and neutrophils in the progression of acute cellular rejection, as illustrated in Figure 4.12.

    <p>Macrophages and neutrophils are recruited to the site of rejection by cytokines released from CD4+ T cells. They further contribute to the inflammatory response and tissue damage through the release of inflammatory mediators and phagocytosis.</p> Signup and view all the answers

    Explain how alloantigen-specific T cells contribute to the initiation of acute cellular rejection.

    <p>Alloantigen-specific T cells recognize and bind to foreign antigens expressed on the graft cells. This recognition activates these T cells, leading to their proliferation and differentiation into effector T cells that mediate the rejection response.</p> Signup and view all the answers

    Describe the relationship between CD8+ T cells and CD4+ T cells in acute cellular rejection, highlighting their interdependence.

    <p>CD4+ T cells play a crucial role in activating CD8+ T cells by providing them with essential signals. In turn, CD8+ T cells directly kill graft cells, contributing to the overall rejection process. Their actions are interconnected and contribute to the progression of the disease.</p> Signup and view all the answers

    Why is the destruction of parenchymal cells considered a hallmark of acute cellular rejection? How does this process contribute to the overall rejection response?

    <p>Parenchymal cell destruction is a hallmark of acute cellular rejection because it represents the direct impact of the immune response on the functional tissue of the transplanted organ. This damage disrupts organ function and ultimately leads to the rejection of the graft.</p> Signup and view all the answers

    Based on the information presented in Figure 4.12, identify potential therapeutic targets for preventing or treating acute cellular rejection. Explain your reasoning.

    <p>Potential therapeutic targets could include blocking the activation of CD4+ or CD8+ T cells, inhibiting cytokine production or signaling, or preventing the recruitment of macrophages and neutrophils. These strategies could help to reduce the inflammatory response and decrease parenchymal cell damage.</p> Signup and view all the answers

    What is the primary cause of acute graft-versus-host disease (GVHD) and what is its major consequence?

    <p>Acute GVHD is primarily caused by T cell-mediated killing of host cells, and its major consequence is severe tissue damage and organ dysfunction.</p> Signup and view all the answers

    What is the role of the c receptor in interleukin signaling, and how does its deficiency lead to X-linked severe combined immunodeficiency (X-SCID)?

    <p>The c receptor is a common subunit of several interleukin receptors, including IL-2 and IL-7, and is essential for T cell development and function. Deficiency of c leads to X-SCID, characterized by impaired T cell development and function, and increased susceptibility to infections.</p> Signup and view all the answers

    What is the mechanism by which histocompatibility molecules trigger an immune response, and what are the consequences of this response in the context of organ transplantation?

    <p>Histocompatibility molecules trigger an immune response by presenting peptides to T cells, which recognize them as foreign, leading to activation of immune cells and subsequent rejection of the transplanted organ. This response can lead to acute rejection, chronic rejection, or graft-versus-host disease.</p> Signup and view all the answers

    What is the role of MHC molecules in T cell development and function, and how do defects in MHC expression lead to immunodeficiency?

    <p>MHC molecules play a crucial role in T cell development and function, as they present peptides to T cells, allowing for the selection and activation of T cells. Defects in MHC expression lead to impaired T cell development and function, resulting in immunodeficiency.</p> Signup and view all the answers

    What is the mechanism by which immunodeficiency can lead to increased susceptibility to infections, and what are the consequences of repeated infections in individuals with immunodeficiency?

    <p>Immunodeficiency can lead to increased susceptibility to infections due to impaired immune function, allowing for the proliferation of pathogens. Repeated infections in individuals with immunodeficiency can lead to chronic inflammation, organ damage, and increased mortality.</p> Signup and view all the answers

    What is the role of alloantigens in graft rejection, and how do they trigger an immune response?

    <p>Alloantigens are foreign proteins present on the surface of donor cells, which trigger an immune response by being recognized as non-self by the recipient's immune system, leading to the activation of immune cells and the rejection of the transplanted organ.</p> Signup and view all the answers

    What is the consequence of a lack of immune tolerance to donor antigens in the context of organ transplantation, and how can this be overcome?

    <p>A lack of immune tolerance to donor antigens can lead to graft rejection, which can be overcome through the use of immunosuppressive medications, which suppress the immune response, or through the induction of tolerance, which allows for the acceptance of the transplanted organ.</p> Signup and view all the answers

    What is the role of cytokines in the immune response to transplanted organs, and how do they contribute to graft rejection?

    <p>Cytokines play a crucial role in the immune response to transplanted organs, as they promote the activation and proliferation of immune cells, leading to the rejection of the transplanted organ. Pro-inflammatory cytokines, such as IL-2 and TNF-, are particularly important in this process.</p> Signup and view all the answers

    What is the primary consequence of a lack of antibody-producing B cells in immunodeficiency diseases?

    <p>Increased susceptibility to bacterial and viral infections.</p> Signup and view all the answers

    How do mutations affect the development of primary immunodeficiency diseases?

    <p>Mutations can affect the development of B cells, leading to a lack of antibody-producing cells and a weakened immune system.</p> Signup and view all the answers

    What is the role of pre-B cell receptors in B cell development?

    <p>Pre-B cell receptors are required for the maturation of B cells and the production of antibody-producing plasma cells.</p> Signup and view all the answers

    What is the difference between primary and secondary immunodeficiency diseases?

    <p>Primary immunodeficiency diseases are caused by genetic mutations, while secondary immunodeficiency diseases are caused by other disorders or factors.</p> Signup and view all the answers

    How do immunodeficiency diseases affect the immune system?

    <p>Immunodeficiency diseases lead to a weakened immune system, making individuals more susceptible to infections.</p> Signup and view all the answers

    What is the role of plasma cells in the immune response?

    <p>Plasma cells produce antibodies, which help to neutralize pathogens and protect against infection.</p> Signup and view all the answers

    What is congenital immunodeficiency?

    <p>Congenital immunodeficiency refers to immunodeficiency diseases that are present at birth, often caused by genetic mutations.</p> Signup and view all the answers

    What is the main characteristic of primary immunodeficiency diseases?

    <p>Primary immunodeficiency diseases are characterized by a defect in the immune system that is present from birth.</p> Signup and view all the answers

    What role do CD4+ T cells play in the process of acute graft rejection?

    <p>CD4+ T cells secrete cytokines that induce inflammation and activate other immune cells.</p> Signup and view all the answers

    Describe the impact of antibodies during chronic rejection of solid-organ allografts.

    <p>Antibodies target blood vessels and contribute to ischemia and tissue injury.</p> Signup and view all the answers

    What is the relevance of CD8+ CTLs in the rejection of allografts?

    <p>CD8+ CTLs directly kill graft cells, leading to cell-mediated rejection.</p> Signup and view all the answers

    Explain how cytokines contribute to vascular injury during graft rejection.

    <p>Cytokines secreted by CD4+ T cells lead to vascular inflammation and damage to endothelial cells.</p> Signup and view all the answers

    Identify the three mechanisms through which chronic rejection can occur.

    <p>Chronic rejection may involve T cell-mediated injury, antibody-mediated responses, and chronic inflammation.</p> Signup and view all the answers

    How does prolonged ischemia affect the graft over time?

    <p>Prolonged ischemia can induce fibrosis and ultimately lead to graft failure.</p> Signup and view all the answers

    What is the consequence of vascular injury caused by antibodies in grafts?

    <p>Vascular injury leads to thrombosis, reduced blood supply, and infarction of the graft.</p> Signup and view all the answers

    What is the significance of the endothelium in the context of graft rejection?

    <p>Endothelium is the primary target for circulating antibodies, making it vulnerable to immune attack.</p> Signup and view all the answers

    What role do MHC proteins play in the context of transplant rejection?

    <p>MHC proteins display peptide antigens for recognition by T cells, which can lead to the rejection of foreign graft tissue.</p> Signup and view all the answers

    How does the presence of preformed antibodies affect graft acceptance?

    <p>Preformed antibodies can recognize donor antigens, leading to immediate hypersensitivity reactions and graft rejection.</p> Signup and view all the answers

    What distinguishes acute cellular rejection from other types of rejection?

    <p>Acute cellular rejection is primarily mediated by T cells recognizing foreign MHC molecules on donor cells, leading to cellular infiltration and tissue damage.</p> Signup and view all the answers

    In what ways can careful blood group matching influence transplant outcomes?

    <p>Careful blood group matching reduces the risk of immunological reactions, thereby decreasing the chances of graft rejection.</p> Signup and view all the answers

    What is the significance of the CD8+ T cells in the context of graft rejection?

    <p>CD8+ T cells are cytotoxic and specifically target and kill graft tissue that is recognized as foreign.</p> Signup and view all the answers

    What consequence does the expression of different MHC molecules on donor graft tissue have during transplantation?

    <p>Different MHC molecules may trigger a stronger immune response from the recipient, leading to a heightened risk of acute rejection.</p> Signup and view all the answers

    How is acute cellular rejection typically diagnosed post-transplant?

    <p>Acute cellular rejection is diagnosed through monitoring clinical symptoms and histopathological examination of the graft tissue.</p> Signup and view all the answers

    What can lead to graft failure following transplantation due to immune responses?

    <p>Graft failure can occur when the recipient's immune system robustly targets the graft as foreign, resulting in tissue damage and loss of function.</p> Signup and view all the answers

    The ______ and salivary glands are the major targets of organ transplantation.

    <p>heart</p> Signup and view all the answers

    Organ transplants help replace ______ or dysfunctional impaired organs.

    <p>damaged</p> Signup and view all the answers

    Transplants can be used to treat ______, but other exogenous glands, including those for the nose, can also be transplanted.

    <p>disease</p> Signup and view all the answers

    The transplantation of organs from other ______ has become standard medical practice.

    <p>individuals</p> Signup and view all the answers

    About 30,000 organ ______ are performed yearly in the United States.

    <p>transplants</p> Signup and view all the answers

    The most common organ transplanted in the United States is the ______, accounting for almost half of all transplants.

    <p>kidney</p> Signup and view all the answers

    The ______, liver, lung, and pancreas are also commonly transplanted.

    <p>heart</p> Signup and view all the answers

    High densities of CD4+ T cells are found in ______ of the body.

    <p>tissues</p> Signup and view all the answers

    Rejection of allografts is mediated by ______ cells and antibodies.

    <p>T</p> Signup and view all the answers

    Chronic rejection is characterized by vascular ______ and inflammation.

    <p>injury</p> Signup and view all the answers

    Antibodies bind to graft tissues, notably the ______ because it is the most accessible to circulating antibodies.

    <p>endothelium</p> Signup and view all the answers

    Three mechanisms may be involved simultaneously, but they play dominant roles in different types of ______.

    <p>rejection</p> Signup and view all the answers

    CD4+ T cells specific for graft antigens secrete ______ that induce inflammation in the graft.

    <p>cytokines</p> Signup and view all the answers

    CD8+ CTLs kill graft ______.

    <p>cells</p> Signup and view all the answers

    Hyperacute rejection is caused primarily by the deposition of ______ on the endothelium.

    <p>antibody</p> Signup and view all the answers

    The pathophysiology of hyperacute rejection involves the activation of ______ and fibrin thrombi formation.

    <p>platelets</p> Signup and view all the answers

    The ______ molecules may be taken up by the recipient's APCs and presented to T cells.

    <p>MHC</p> Signup and view all the answers

    In both cases, the recipient's CD4+ and CD8+ T cells specific for donor antigens are produced, bind to graft endo- or graft antigens, are activated, migrate back into the ______, and cause damage.

    <p>transplant</p> Signup and view all the answers

    Recipient B cells also recognize molecules in the graft as foreign, resulting in the production of ______ specific for these molecules.

    <p>antibodies</p> Signup and view all the answers

    Immunosuppressive therapy has been more successful in treating acute ______ than any other form.

    <p>rejection</p> Signup and view all the answers

    The recipient's immune system recognizes graft antigens as ______, triggering an immune response.

    <p>foreign</p> Signup and view all the answers

    The immune response against graft antigens can be either ______ or humoral.

    <p>cellular</p> Signup and view all the answers

    The recipient's immune system can directly recognize graft antigens (direct recognition) or indirectly recognize them through the presentation of graft antigens by recipient ______ cells.

    <p>antigen-presenting</p> Signup and view all the answers

    The rejection of a graft is a complex process involving both the ______ and humoral immune systems.

    <p>cellular</p> Signup and view all the answers

    Hyperacute rejection is primarily mediated by __________.

    <p>antibodies</p> Signup and view all the answers

    The immune responses to organ allografts are influenced by the presence of __________.

    <p>antigens</p> Signup and view all the answers

    Grafts exchanged between non-identical individuals are known as __________.

    <p>allografts</p> Signup and view all the answers

    Hyperacute rejection is characterized by the deposition of antibodies on the __________.

    <p>endothelium</p> Signup and view all the answers

    The pathophysiology of hyperacute rejection involves the activation of __________ and fibrin thrombi formation.

    <p>platelets</p> Signup and view all the answers

    Same species are referred to as __________.

    <p>syngeneic</p> Signup and view all the answers

    The immune system's __________ type is responsible for graft rejection.

    <p>immune</p> Signup and view all the answers

    Rejection mechanisms in organ transplantation are mediated by __________ specific for donor antigens.

    <p>antibodies</p> Signup and view all the answers

    X-linked ______ syndrome was originally identified by the ______.

    Signup and view all the answers

    X-linked ______ syndrome was originally identified by Patient.

    <p>agammaglobulinemia</p> Signup and view all the answers

    Patients typically present with recurrent infections in the absence of class-switched IgG and IgA ______, and, hence, the infancy or early childhood.

    <p>antibodies</p> Signup and view all the answers

    This is usually associated with a profound ______ of the humoral immune system.

    <p>deficiency</p> Signup and view all the answers

    The ______ receptor is a transmembrane protein that plays a critical role in the development of B cells.

    <p>pre-B cell</p> Signup and view all the answers

    Primary immunodeficiency diseases arise from genetic defects that affect the development or function of the ______ system.

    <p>immune</p> Signup and view all the answers

    A lack of pre-B cell receptor signaling results in the failure of B cells to mature and differentiate into ______ cells.

    <p>plasma</p> Signup and view all the answers

    Hyperacute rejection is caused primarily by the deposition of ______ on the endothelium.

    <p>antibody</p> Signup and view all the answers

    The pathophysiology of hyperacute rejection involves the activation of platelets and ______ thrombi formation.

    <p>fibrin</p> Signup and view all the answers

    Match the following terms related to immunodeficiency with their corresponding descriptions:

    <p>Secondary immunodeficiencies = Immune deficiencies arising from external factors like infections or medications. Primary immunodeficiencies = Immune deficiencies caused by genetic mutations. CD40L = A protein crucial for activating B cells and macrophages. Pre-B cell receptor = A receptor on immature B cells essential for their development and differentiation.</p> Signup and view all the answers

    Match the following conditions related to immunodeficiency with their primary causes:

    <p>Acquired Immunodeficiency Syndrome (AIDS) = Infection with the Human Immunodeficiency Virus (HIV) Common Variable Immunodeficiency (CVID) = Genetic mutations affecting B cell development and function. Severe Combined Immunodeficiency (SCID) = Severe defects in both T cell and B cell development. X-linked Agammaglobulinemia (XLA) = Genetic mutations affecting B cell development and function.</p> Signup and view all the answers

    Match the following mechanisms related to immune system dysfunction with their corresponding effects:

    <p>CD40L deficiency = Reduced activation of B cells and macrophages, leading to impaired immune responses. Pre-B cell receptor signaling deficiency = Impaired B cell development and antibody production. Therapy targeting the immune system = Suppression of immune responses, potentially increasing susceptibility to infections. Mutations in genes involved in immune system development = Disruption of normal immune cell development and function, leading to immunodeficiency.</p> Signup and view all the answers

    Match the following terms related to graft rejection with their corresponding definitions:

    <p>Hyperacute rejection = Rapid rejection of a graft within minutes or hours, mediated by preformed antibodies. Acute cellular rejection = Rejection occurring within days or weeks, primarily mediated by T cells. Chronic rejection = Gradual and irreversible rejection occurring over months or years, characterized by fibrosis and vascular damage. Graft-versus-host disease (GVHD) = Immune reaction of donor T cells against recipient tissues, occurring after bone marrow transplantation.</p> Signup and view all the answers

    Match the following terms related to the immune system with their corresponding functions:

    <p>CD4+ T cells = Helper T cells that activate other immune cells, like B cells and macrophages. CD8+ T cells = Cytotoxic T cells that directly kill infected or cancerous cells. Macrophages = Phagocytic cells that engulf and destroy pathogens and cellular debris. B cells = Cells responsible for producing antibodies, which target specific antigens.</p> Signup and view all the answers

    Match the following statements related to immunodeficiency with their corresponding categories:

    <p>Secondary immunodeficiency resulting from HIV infection = Acquired immunodeficiency Primary immunodeficiency caused by genetic mutations = Congenital immunodeficiency Immune deficiency caused by medications = Acquired immunodeficiency Immune deficiency arising from malnutrition = Acquired immunodeficiency</p> Signup and view all the answers

    Match the following types of rejection with their characteristics:

    <p>Acute rejection = Mediated by CD4+ and CD8+ T cells Chronic rejection = Develops over months to years Hyperacute rejection = Occurs almost immediately after transplantation Antibody-mediated rejection = Involves preformed antibodies attacking grafts</p> Signup and view all the answers

    Match the following immune cells with their roles in graft rejection:

    <p>CD4+ T cells = Secrete cytokines to recruit other immune cells CD8+ T cells = Kill graft cells directly B cells = Produce antibodies against graft antigens Macrophages = Engulf and destroy graft debris</p> Signup and view all the answers

    Match the rejection mechanisms with their descriptions:

    <p>Cell-mediated immunity = Involves direct attack on graft cells by T cells Humoral immunity = Involves antibodies binding to graft antigens Chronic inflammation = Causes long-term damage due to sustained immune response Vascular damage = Results from antibody-mediated injury to blood vessels</p> Signup and view all the answers

    Match the following types of T cells with their specific roles in graft rejection:

    <p>CD4+ helper T cells = Assist in activating other lymphocytes CD8+ cytotoxic T cells = Directly kill infected or transplanted cells Regulatory T cells = Help suppress the immune response Memory T cells = Provide long-term immunity against previously encountered antigens</p> Signup and view all the answers

    Match the following types of graft rejections with their timelines:

    <p>Hyperacute rejection = Seconds to minutes after transplant Acute rejection = Days to weeks after transplant Chronic rejection = Months to years after transplant Antibody-mediated rejection = Can occur at variable times but often after acute rejection</p> Signup and view all the answers

    Match the following factors with their impact on graft rejection:

    <p>Mismatch of major histocompatibility complex (MHC) = Increases risk of acute rejection Presence of pre-existing antibodies = Leads to hyperacute rejection Delayed graft function = Can indicate acute rejection Inadequate immunosuppressive therapy = Elevates the risk of chronic rejection</p> Signup and view all the answers

    Match the following clinical signs with their associated rejection type:

    <p>Fever and malaise = Acute rejection Vascular occlusion = Hyperacute rejection Fibrosis and narrowing of blood vessels = Chronic rejection Increased creatinine levels = Can indicate all types of rejection</p> Signup and view all the answers

    Match the following graft types with their definitions:

    <p>Allograft = Transplant from a genetically non-identical donor Xenograft = Transplant from a different species Autograft = Transplant from one's own body Isograft = Transplant between genetically identical individuals</p> Signup and view all the answers

    Match the immune response components to their functions:

    <p>Cytokines = Facilitating communication between immune cells CD4 T cells = Helping other immune cells respond to antigens Vascular smooth muscle cell = Contributing to vessel occlusion Antibody binding = Recognizing and neutralizing pathogens</p> Signup and view all the answers

    Match the conditions to their descriptions:

    <p>Chronic inflammatory reaction = Prolonged and persistent immune response Intimal smooth muscle proliferation = Thickening of vessel walls due to cell growth Vessel occlusion = Blockage of blood flow through a blood vessel Alloantigen-specific response = Immune reaction against transplanted tissue</p> Signup and view all the answers

    Match the term to its relevant characteristic:

    <p>Cytokines = Molecules that can enhance immune responses CD4 T cells = A type of helper T cell involved in adaptive immunity Antibody binding = Specific interaction between an antibody and an antigen Vascular smooth muscle cell = Cell type involved in maintaining vessel structure</p> Signup and view all the answers

    Match the immune processes to their outcomes:

    <p>Chronic inflammatory reaction = Tissue damage and dysfunction Intimal smooth muscle proliferation = Narrowing of blood vessels Vessel occlusion = Reduction or cessation of blood flow Antibody binding to endothelial antigens = Initiation of graft rejection reactions</p> Signup and view all the answers

    Match the cytokine-related effects to their corresponding actions:

    <p>Cytokines = Mediate inflammatory responses CD4 T cells = Regulate other immune cells Vascular smooth muscle cell activation = Promotes intimal hyperplasia Alloantigen-specific response = Triggers graft-versus-host reactions</p> Signup and view all the answers

    Match the immune system components to their associated effects:

    <p>Cytokines = Stimulating immune cell proliferation CD4 T cells = Activation of B cells and macrophages Antibody binding = Formation of immune complexes Vascular smooth muscle cell changes = Contributing to obstructive vascular disease</p> Signup and view all the answers

    Match the anatomical elements with their relevant immune reactions:

    <p>Endothelial antigens = Targets of antibody binding during rejection Cytokines = Triggers for vascular inflammation Smooth muscle proliferation = Regulates arterial response to injury Alloantigen-specific T cells = Mediators of transplant rejection</p> Signup and view all the answers

    Match the terms to their functions or characteristics in graft rejection:

    <p>CD4 T cells = Coordinate adaptive immunity Antibody binding = Mediate humoral immune response Cytokines = Modulate immune and inflammatory responses Vascular smooth muscle cells = Influence graft survival rates</p> Signup and view all the answers

    Match the following medical terms with their definitions:

    <p>Immunodeficiency = A condition characterized by a weakened immune system. Histocompatibility = The compatibility of tissues and organs for transplantation. Transplantation = The process of transferring cells, tissues, or organs from one site to another. Allograft = A graft of tissue taken from a donor of the same species.</p> Signup and view all the answers

    Match the following diseases with their characteristics:

    <p>AIDS = A disease caused by the HIV virus affecting immune system function. Diabetes = A chronic condition that affects the body's ability to utilize sugar. Hypertension = A condition where blood pressure is consistently too high. Asthma = A respiratory condition marked by spasms in the bronchi.</p> Signup and view all the answers

    Match the following types of graft rejection with their descriptions:

    <p>Hyperacute rejection = Occurs immediately after transplantation due to pre-existing antibodies. Acute rejection = Occurs days to weeks after transplantation and involves immune response. Chronic rejection = A slow, progressive loss of graft function occurring over months to years. Graph-to-host disease = A condition where transplanted immune cells attack the host's tissues.</p> Signup and view all the answers

    Match the following immune cells with their roles:

    <p>T cells = Cells that play a central role in cell-mediated immunity. B cells = Cells responsible for antibody production. Macrophages = Cells that engulf and digest pathogens and debris. Natural Killer cells = Cells that provide rapid responses to virally infected cells.</p> Signup and view all the answers

    Match the following genetic technologies with their applications:

    <p>DNA sequencing = Determining the exact sequence of nucleotides in a DNA molecule. Gene therapy = Introducing genetic material into a person's cells to treat disease. CRISPR = A technology used for editing genomes by introducing, removing, or altering DNA. PCR = A technique used to amplify small segments of DNA.</p> Signup and view all the answers

    Match the following symptoms with their respective conditions:

    <p>Xerostomia = Dryness of the mouth often associated with autoimmune diseases. Joint Pain = A common symptom in autoimmune and inflammatory conditions. Fatigue = A prevalent symptom in chronic infections and immune disorders. Skin Rash = Frequently seen in a variety of allergic reactions and autoimmune conditions.</p> Signup and view all the answers

    Match the following factors with their implications in immunology:

    <p>Cytokines = Proteins that mediate and regulate immunity and inflammation. Antibodies = Proteins produced by B cells that neutralize pathogens. Pathogens = Microorganisms that can cause disease. Vaccines = Prepared substances that stimulate the body's immune response.</p> Signup and view all the answers

    Match the following types of immunity with their characteristics:

    <p>Innate immunity = The body's first line of defense against pathogens, non-specific. Adaptive immunity = Immunity that develops over time and is specific to certain pathogens. Passive immunity = Immunity acquired through the transfer of antibodies. Active immunity = Immunity that develops as a result of exposure to a pathogen.</p> Signup and view all the answers

    Match the following diseases with their characteristics:

    <p>SCID = Severe combined immunodeficiency presenting in infancy GVHD = Graft-versus-host disease related to immune response Leukemia = Cancer associated with blood cell abnormalities HSC Transplantation = Procedure involving hematopoietic stem cells</p> Signup and view all the answers

    Match the following immune system issues with their implications:

    <p>Tumor cells = Major problem during transplantation Infections = Diverse range that grafts can be susceptible to Bone marrow failure = Condition leading to impaired blood production Immunocompromised host = Increased infection risk post-transplant</p> Signup and view all the answers

    Match the following aspects of immune response with their definitions:

    <p>Adaptive immunity = Specific response against pathogens or grafts Innate immunity = Non-specific first line of defense Humoral immunity = Response involving antibodies Cell-mediated immunity = Involvement of T cells in the immune response</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>CD40L = Molecule promoting immune responses against cancer B cells = Cells responsible for antibody production T cells = Lymphocytes critical for cellular immunity Plasma cells = Specialized B cells that secrete antibodies</p> Signup and view all the answers

    Match the following types of grafts with their definitions:

    <p>Autograft = Graft from the same individual Allograft = Graft between genetically non-identical individuals Xenograft = Graft from a different species Isograft = Graft between genetically identical individuals</p> Signup and view all the answers

    Match the following immune deficiencies with their causes:

    <p>Primary immunodeficiency = Genetic defects in the immune system Secondary immunodeficiency = Acquired conditions leading to immune dysfunction Humoral deficiency = Lack of antibodies Cellular deficiency = Insufficient T cell function</p> Signup and view all the answers

    Match the following transplant-related terms with their implications:

    <p>Hyperacute rejection = Immediate rejection due to preformed antibodies Acute rejection = Rejection occurring days to months post-transplant Chronic rejection = Long-term gradual loss of graft function Transplant tolerance = State where the recipient accepts the graft without immune response</p> Signup and view all the answers

    Match the following immune conditions with their treatment options:

    <p>SCID = Bone marrow transplant GVHD = Immunosuppressive therapy Leukemia = Chemotherapy Allergic rhinitis = Antihistamines and corticosteroids</p> Signup and view all the answers

    Study Notes

    Organ Transplantation

    • Replacement of damaged or nonfunctional organs through transplantation has become standard medical practice.
    • About 30,000 organ transplants occur annually in the United States.
    • Commonly transplanted organs include kidneys, followed by the heart, liver, lungs, and pancreas.

    Graft Antigens and Immune Response

    • Graft antigens recognized by the recipient's immune system are primarily histocompatibility molecules.
    • Preformed antibodies can trigger rapid immune responses when they bind to graft endothelium, activating both cellular and humoral responses.
    • Major Histocompatibility Complex (MHC) is crucial for determining tissue compatibility; incompatible tissue can lead to hyperacute rejection.

    Acute Cellular Rejection

    • Acute cellular rejection involves direct destruction of graft cells by CD8+ cytotoxic T lymphocytes (CTLs) and inflammation by cytokines from CD4+ T cells.
    • B cells require specific signals for proliferation and maturation, which may be disrupted in certain immunodeficiencies.

    Types of Immunodeficiencies

    • Immunodeficiencies can be primary (due to genetic mutations) or secondary (resulting from other disorders).
    • Children with congenital immunodeficiencies are susceptible to various infections due to ineffective antibody-producing B cells.

    Impact of External Factors

    • Chemotherapy and radiation can compromise the immune system, increasing the risk of graft rejection and autoimmune diseases.
    • In lower-income countries, malnutrition significantly contributes to immunodeficiency.

    Acquired Immunodeficiency Syndrome (AIDS)

    • AIDS is a notable cause of worldwide immunodeficiency, leading to increased vulnerability to opportunistic infections from bacteria, viruses, and fungi.
    • Involves various autoimmune bodies targeting the cornea; leads to keratoconjunctivitis sicca (dry eyes).
    • Lack of saliva causes dryness in the mouth, known as xerostomia; associated antibodies include SS-A and SS-B.
    • Nasal dryness can lead to ulceration and complication of the disease.
    • Triggers for antibody formation are not identified; in some cases, perforation of the septum can occur.
    • Lesions can develop outside of the glands, with possible viral infection involvement in over half of patients.

    Autoimmune Conditions

    • Sjögren's is linked to other autoimmune diseases, most commonly rheumatoid arthritis.
    • Patients often face complications related to autoimmune disorders, requiring careful management.

    Rejection of Transplants

    • Classifies rejection types based on mechanisms involved:
      • Hyperacute Rejection: Antibody deposition on endothelial cells activates complement, resulting in thrombosis and severe ischemic injury (e.g., in kidney transplants).
      • Chronic Rejection: Features chronic inflammatory reactions in blood vessels, including intimal smooth muscle proliferation and vessel occlusion caused by cytokine activity.

    Immune System Considerations

    • Adenosine deaminase deficiency can lead to immunocompromised conditions, impacting transplanted cells' effectiveness and potentially resulting in toxic purine metabolite accumulation.
    • Recovery of immune competence after damage can take months, complicating patient outcomes and immune system functionality.

    Infections and Immunodeficiency

    • Acquired Immunodeficiency Syndrome (AIDS) is a major global cause of immunodeficiency, related to infections by various pathogens, including pyogenic bacteria and viruses.
    • In lower-income countries, lack of access to treatments can lead to severe immune dysfunctions, impacting children significantly.

    Recipients of Organ Transplants

    • Organ transplant recipients possess polymorphic MHC (Major Histocompatibility Complex) genes that influence immune response.
    • Previous blood transfusions or transplants can sensitize recipients to specific MHC proteins, impacting acceptance of new grafts.
    • MHC proteins display peptide antigens for recognition by T cells, leading to potential rejection of donor tissue.

    Types of Rejection

    • Acute rejection occurs when recipient T cells recognize graft MHC molecules as foreign, leading to immune response within days to weeks.
    • Chronic rejection develops over months to years, often caused by T cells and antibodies, resulting in gradual graft failure.

    Mechanisms of Rejection

    • CD4+ T cells secrete cytokines that cause inflammation and vascular injury, leading to interstitial fibrosis and narrowing of blood vessels in grafts.
    • CD8+ cytotoxic T lymphocytes (CTLs) directly kill graft parenchymal cells, contributing to tissue damage.
    • Three mechanisms may work concurrently in causing graft injury.

    Treatment of Graft Rejection

    • Treatment often involves managing T cell activity to prevent or minimize rejection.
    • Alloantigen-specific CD8 and CD4 T cell activation leads to direct cell killing and recruitment of immune cells like macrophages and neutrophils.

    Graft Versus Host Disease (GVHD)

    • Acute GVHD is characterized by T cell-mediated killing of epithelial cells, often seen post-bone marrow transplantation, driven by activated T cells.
    • Immune dysregulation in the absence of specific cytokine signals can complicate B cell maturation and antibody production.

    Immunodeficiency Disorders

    • Can be primary (due to genetic mutations) or secondary (resulting from other diseases).
    • Primary immunodeficiencies arise from mutations affecting immune cell function, leading to an increased susceptibility to infections.
    • Signs may include recurrent bacterial and viral infections due to lack of functional B cells and plasma cells.

    Importance of MHC in Transplantation

    • MHC molecules are critical for the success of organ transplants as they are pivotal in mediating immune recognition and tolerance.
    • Proper matching of MHC between donor and recipient is essential to reduce the risk of acute and chronic rejection.

    Organ Transplantation Overview

    • Replacement of damaged or non-functional organs through transplantation is a critical aspect of modern medicine.
    • Standard practice includes organ donation from living and deceased individuals, with around 30,000 organ transplants performed annually in the U.S.
    • Common transplant organs include kidneys, heart, liver, lungs, and pancreas; kidneys are the most frequently transplanted.

    Immune Responses and Rejection Mechanisms

    • Immune rejection is mediated by T cells and antibodies, varying with types of rejection that may occur.
    • Hyperacute rejection occurs due to pre-existing antibodies against donor antigens present in the recipient before transplantation.
    • Acute rejection involves CD4+ and CD8+ T cells which recognize graft antigens, leading to inflammation and tissue damage.
    • Chronic rejection can develop over months to years and is characterized by gradual deterioration of graft function, primarily caused by vascular injury and inflammation.

    Types of Rejection

    • Hyperacute Rejection: Type of rejection that occurs immediately due to pre-existing antibodies in the recipient.
    • Acute Rejection: Involves T cell-mediated immune responses, with inflammation and injury to the graft.
    • Chronic Rejection: Gradual response marked by CD4+ T cell activity, cytokine secretion, and tissue fibrosis leading to loss of graft function.

    Factors Influencing Transplant Success

    • The success of organ transplants heavily relies on immunosuppressive therapy to prevent rejection and enhance graft survival.
    • The recognition of grafts as foreign prompts immune-mediated destruction, causing a critical issue in the long-term maintenance of transplanted organs.
    • The immune system uses specific patterns and markers to distinguish between self and foreign tissues, which can result in various response levels.

    Treatment Approaches

    • Effective immunosuppressive treatments have improved the management of acute rejection compared to chronic rejection, which remains challenging.
    • Chronic rejection is often complicated by progressive damage that involves multiple immune mechanisms working together over time.

    Summary of Rejection Mechanisms

    • Both humoral (antibody-mediated) and cellular (T cell-mediated) components contribute to the rejection.
    • Recognition of grafts by the recipient's immune system is influenced by the degree of histocompatibility between donor and recipient tissues.
    • Monitoring and modifying immune responses are crucial for the success of organ transplantation and prolonged graft survival.

    Mechanisms of Rejection of Solid-Organ Allografts

    • Rejection is primarily mediated by T cells and antibodies.
    • Chronic rejection develops over months to years and is a leading cause of graft failure.
    • CD4+ T cells target graft antigens and release cytokines that contribute to vascular injury and intimal fibrosis.
    • CD8+ cytotoxic T lymphocytes (CTLs) are responsible for killing graft cells.
    • Antibodies can target vessel cells, leading to ischemia and intimal fibrosis due to prolonged binding.
    • Three mechanisms of rejection can occur simultaneously: inflammatory damage, antibody-mediated injury, and CD8+ T cell activation.

    Treatment of Graft Rejection

    • Treatment approaches vary based on the type of rejection.
    • Antibodies bind to endothelial antigens, triggering a chronic inflammatory reaction in the vessel wall.
    • Cytokines are secreted by CD4+ T cells, promoting smooth muscle cell proliferation and vessel occlusion.

    Severe Combined Immunodeficiency (SCID)

    • SCID is characterized by severe immune deficiencies, often presenting in infancy.
    • Grafts in SCID patients may lead to graft-versus-host disease (GVHD) due to the presence of T cells and other immune cells.

    Secondary Immunodeficiencies

    • More common than primary immunodeficiencies due to disorders like infections or therapeutic interventions.
    • Common causes include chemotherapy and the use of immunosuppressive drugs.

    Gene Mutations

    • CD40 ligand mutations can lead to various immunodeficiencies.
    • CD40L plays a significant role in T cell activation, influencing immune responses.

    Up-to-Date Genetic Insights

    • Advances in DNA sequencing have enhanced the understanding of primary immunodeficiencies.
    • Genetic basis for over 90% of cases of certain immunodeficiencies is now known.
    • Emerging insights showcase diverse pathways impacted by immunodeficiencies, leading to varied clinical outcomes.

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