Questions and Answers
What is the primary function of cytokines in the immune system?
Which cells are known for their role in cell-mediated immunity?
What type of immunity is characterized by the active production of antibodies after exposure to an antigen?
What is the primary role of plasma cells in the immune response?
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Which immunoglobulin is the most abundant in the bloodstream?
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What are the three stages of HIV infection?
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Which enzyme is responsible for converting HIV RNA into DNA?
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What distinguishes active acquired immunity from passive acquired immunity?
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Which test gauges immunocompetence by observing skin reactions to common antigens?
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Which of the following groups is considered high-risk for HIV transmission?
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What is the role of major histocompatibility complex (MHC) in the immune system?
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What is a significant characteristic of sickle cell anemia?
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In which type of hypersensitivity reaction do allergies primarily fall?
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What is the expected outcome when a person with secondary polycythemia is treated for their underlying hypoxia?
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What type of vaccine formulation typically includes live but inactivated virus?
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What condition is caused by autoimmune disease disrupting intrinsic factor, impacting vitamin B12 absorption?
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What is a common clinical presentation of hemolytic anemias?
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What psychological symptom may arise from the chronic blood loss associated with anemia?
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What is the role of macrophages in HIV infection?
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Which of the following is a common sign of hemolytic anemia?
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What is the initial step in the process of Type I hypersensitivity?
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Which of the following is a common symptom of allergic rhinitis?
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What is the primary treatment for anaphylaxis?
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In Type II hypersensitivity, what is the primary cause of cell lysis?
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Which of the following is a characteristic of Systemic Lupus Erythematosus (SLE)?
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What mediates the acute inflammatory response in Rheumatoid Arthritis (RA)?
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Which condition is characterized by an abnormal accumulation of fibrous tissue?
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What is a common nonpharmacological recommendation for patients with Systemic Lupus Erythematosus (SLE)?
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What defines Selective IgA Deficiency?
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In Sarcoidosis, what is the most frequent site of organ involvement?
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What is the primary mechanism involved in Type I hypersensitivity?
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Which is a common clinical manifestation of Systemic Lupus Erythematosus (SLE)?
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In autoimmune disorders, what is meant by molecular mimicry?
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Which condition is characterized by a chronic inflammatory response with the presence of granulomas?
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What is the main pharmacological treatment for the systemic manifestations of Systemic Lupus Erythematosus (SLE)?
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Which symptom is typical for Type IV hypersensitivity reactions?
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In the context of rheumatoid arthritis, what role do T-cells play?
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A 45-year-old female presents with dry eyes and mouth, possibly indicating which disorder?
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What is the common treatment strategy for managing rheumatoid arthritis?
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Which of the following triggers can exacerbate Systemic Lupus Erythematosus (SLE)?
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What is a key feature of hypersensitivity Type II reactions?
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Which of the following is an autoimmune disorder associated with systemic manifestations?
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Which mechanism is primarily responsible for autoimmune diseases through the mimicry of molecular structures?
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What clinical manifestation is commonly associated with Sickle Cell Anemia during a vaso-occlusive crisis?
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In Pernicious Anemia, what key component is disrupted, leading to vitamin B12 deficiency?
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What is a common symptom of hemolytic anemia?
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Which of the following describes the expected laboratory finding in a patient with Vitamin B12 deficiency?
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Which treatment is commonly used to manage hemolytic transfusion reactions?
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Following a reaction to a blood transfusion, which of the following symptoms might indicate a severe response?
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What is the typical presentation of autoimmune hemolytic anemia?
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Which type of hypersensitivity reaction is characterized by an immediate response, such as an allergy to pollen?
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Which of the following best describes an autoimmune disorder?
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In Systemic Lupus Erythematosus (SLE), what is a common clinical presentation?
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What is molecular mimicry in the context of autoimmune disorders?
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Which type of hypersensitivity is characterized by a delayed response, such as contact dermatitis or graft rejection?
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In the context of autoimmune disorders, which factor plays a significant role in triggering immune responses?
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Which symptom is most commonly associated with Systemic Lupus Erythematosus (SLE)?
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Which type of hypersensitivity reaction involves antibody-mediated cell destruction, as seen in some blood transfusion reactions?
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What is a common treatment strategy for autoimmune disorders such as Systemic Lupus Erythematosus?
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What mechanism explains the occurrence of joint inflammation in autoimmune conditions?
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What is a characteristic symptom of anaphylaxis?
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In Type III hypersensitivity reactions, what causes tissue damage?
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Which of the following is an example of a localized presentation of Type III hypersensitivity?
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What is a common clinical manifestation of Systemic Lupus Erythematosus (SLE)?
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Which factor is identified as a trigger for Systemic Lupus Erythematosus (SLE)?
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What immediate treatment is recommended for anaphylaxis?
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Which mechanism is primarily involved in molecular mimicry leading to autoimmune disorders?
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Which treatment strategy is typically recommended for managing Rheumatoid Arthritis?
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What is a clinical feature associated specifically with Sjögren's Syndrome?
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Which condition involves the formation of granulomas due to chronic inflammation?
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What is a common clinical presentation of Severe Anemia due to Chronic Blood Loss?
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Which of the following statements accurately describes molecular mimicry in autoimmune disorders?
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What type of hypersensitivity is primarily mediated by IgG antibodies?
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In the context of Systemic Lupus Erythematosus (SLE), what is the significance of antinuclear antibodies (ANA)?
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What is a potential treatment strategy for managing Sickle Cell Anemia?
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Which of the following best describes the delayed-type hypersensitivity reaction?
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Which of the following treatments is commonly prescribed for managing autoimmune hemolytic anemia?
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What is a significant clinical feature present in patients with pernicious anemia?
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What risk does primary polycythemia pose due to overproduction of blood cells?
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Which type of hypersensitivity reaction is characterized by a delayed immune response occurring hours to days after exposure to an allergen?
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What autoimmune disorder is characterized by the production of autoantibodies against various antigens in the body, leading to diverse clinical manifestations?
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In the context of autoimmune disorders, what is molecular mimicry?
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Which clinical manifestation is commonly associated with Systemic Lupus Erythematosus?
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What is the expected laboratory finding in a patient with an autoimmune disorder like Systemic Lupus Erythematosus?
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In which type of hypersensitivity disorder does the body produce IgE antibodies that lead to an immediate allergic reaction?
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Which treatment is commonly utilized to manage an acute allergic reaction in a patient with hypersensitivity?
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A patient with Systemic Lupus Erythematosus may experience joint pain. Which of the following is the primary mechanism underlying this symptom?
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Which type of hypersensitivity is triggered by the formation of immune complexes that lead to tissue damage?
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What is the hallmark of Type II hypersensitivity reactions?
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Study Notes
Immune System Overview
- Cytokines: Signaling proteins that regulate inflammation and immune responses; excessive cytokines can cause unhealthy inflammation.
- Natural Killer Cells: Granular lymphocytes that attack tumor cells and virus-infected cells.
- Monocytes-Macrophages: Critical immune cells that phagocytize pathogens and debris.
- B and T Lymphocytes: Key players in adaptive immunity; T cells manage cell-mediated responses, while B cells focus on antibody production.
- CD4 and CD8 Cells: CD4 (helper T cells) are targeted by HIV, while CD8 (cytotoxic T cells) destroy infected cells.
- Antigen Presenting Cells: Include macrophages and dendritic cells; they present antigens to T cells to trigger adaptive immunity.
- Immunoglobulins: Antibodies produced by B cells that bind to specific antigens.
Immune System Components
- Innate Immunity: Present at birth, involves physical barriers like skin and mucus membranes.
- Adaptive Immunity: Developed through exposure (e.g., vaccines), involves specific responses to antigens.
Types of Immune Responses
- Immunodeficiency: Weak or underactive immune system, leading to increased susceptibility to infections.
- Autoimmunity: Immune system mistakenly attacks “self” cells.
- Hypersensitivity: Exaggerated immune response; symptoms can range from mild allergies to severe anaphylaxis.
Immunoglobulins (Igs)
- Classifications of antibodies:
- IgM: First antibody produced in response to an antigen; pivotal in the primary immune response.
- IgG: Most abundant antibody, effective in long-term immunity.
- IgA: Found in mucosal areas, breast milk, saliva, contributing to mucosal immunity.
- IgD: Associated with hypersensitivity and found in respiratory and gastrointestinal tracts.
- IgE: Primarily involved in allergic reactions.
Immunity Types
- Active Acquired Immunity: Results from exposure to pathogens or vaccines; involves production of antibodies and memory cells.
- Passive Acquired Immunity: Involves receiving pre-made antibodies, providing short-term protection (e.g., maternal antibodies).
Vaccination
- Designed to provoke immune response without causing disease; long-lasting effects often require boosters.
- mRNA Vaccines: Utilize messenger RNA to prompt cells to produce antigens, eliciting an immune response.
Anergy and Antibody Testing
- Anergy Panel: Tests immune competence; positive reaction indicates immunity, lack suggests immunodeficiency.
- Antibody Titer: Measures levels of antibodies to assess immunity to specific diseases.
Allergy Testing
- Skin Tests: Evaluate immediate reactions to allergens.
- Serology Testing: Measures IgE antibody levels against specific allergens.
Immune Disorders
-
Hypersensitivity Types:
- Type I: Immediate reactions (e.g., allergies).
- Type II: Cytotoxic reactions (e.g., transfusion reactions).
- Type III: Immune complex-mediated.
- Type IV: Delayed T-cell mediated responses.
- Autoimmune Disorders: Result from the immune system targeting self-cells; molecular mimicry is a potential trigger.
Common Autoimmune Disorders
- Systemic Lupus Erythematosus (SLE): Multi-system autoimmune disease with characteristic butterfly rash; affected by genetic, hormonal, and environmental factors.
- Rheumatoid Arthritis (RA): Chronic inflammatory disorder affecting joints, possibly systemic.
- Sjögren's Syndrome: Autoimmune disorder marked by dry eyes and mouth due to destruction of exocrine glands.
- Scleroderma: Characterized by skin and organ fibrosis; variants include diffuse and limited forms.
Immunodeficiency Disorders
- Primary Immunodeficiency: Congenital defects leading to weakened immune response.
- Secondary Immunodeficiency: Acquired through factors like HIV, chemotherapy, or infections.
HIV Specifics
- Targets CD4 T helper cells, disrupting cell-mediated immunity and increasing vulnerability to opportunistic infections.### Human Immunodeficiency Virus (HIV)
- Affects CD4 and T helper cells, crucial components of the immune system.
- Three stages of HIV infection: Acute, Chronic, and AIDS (Acquired Immunodeficiency Syndrome).
Transmission Routes
- Sexual activity involving semen and vaginal secretions.
- Blood exposure, transplacental transmission, and breast milk.
- Organ transplants and saliva (in open mouth wounds) can also be routes of transmission.
High-Risk Individuals
- Unsafe sexual practices increase risk.
- Men who have sex with men (MSM) and young Black/African American gay and bisexual men are particularly affected.
- IV drug users are at higher risk for HIV infection.
Viral Characteristics
- HIV is a retrovirus, specifically an RNA virus that utilizes reverse transcriptase to convert its RNA into DNA.
- Targets cells with CD4 receptors and the CCR5 chemokine receptor; individuals without CCR5 exhibit resistance to HIV.
Infection Progression
- Initial HIV infection may cause flu-like symptoms, followed by a period of asymptomatic dormancy.
- HIV can remain inactive in CD4 cells and macrophages, while infected CD4 lymphocytes lose functionality, leading to increased risk of opportunistic infections.
Seroconversion
- Detectable antibody levels can develop within 2 weeks to 6 months post-infection.
- Early stages may be asymptomatic but infectious; this is termed the "latent period."
- CD4 cell levels decline while HIV RNA levels rise over time.
Anemia Caused by Chronic Blood Loss
- Possible causes include gastrointestinal bleeding, menstrual blood loss, and medication side effects (e.g., NSAIDs leading to GI bleeding).
- Symptoms may not be noticeable initially, but patient condition may deteriorate over time.
Hemolytic Anemias
- Results from erythrocyte destruction exceeding replacement.
- Primary causes include hemoglobinopathies, autoimmune disorders, alloimmune hemolysis (e.g., blood transfusion reactions), hereditary spherocytosis, and lead poisoning.
Signs and Symptoms of Hemolytic Anemias
- Includes typical anemia symptoms along with jaundice, dark urine, and splenomegaly due to RBC breakdown.
- Diagnosis may show elevated reticulocytes and misshapen RBCs on peripheral smear.
Hemoglobinopathy
- Inherited disorder resulting in abnormal hemoglobin structure, impairing oxygen transport and causing RBC destruction.
- Examples include Sickle Cell Anemia (SCA) and Thalassemia.
Sickle Cell Anemia (SCA)
- Autosomal hemoglobinopathy, includes homozygous and heterozygous forms with varying severity.
- Sickle-shaped RBCs result from hypoxia, dehydration, and stress, with symptoms appearing post-fetal hemoglobin decline.
- Increases malaria resistance through genetic expression.
Clinical Presentation of SCA
- Typical anemia symptoms, hyperbilirubinemia, and splenomegaly may be present.
- Vaso-occlusive crises occur due to sickle-shaped RBCs lodging in capillaries, causing tissue hypoxia and severe pain, resulting in chronic organ damage.
Diagnosis and Treatment of SCA
- Diagnosis involves electrophoresis revealing HbS.
- Treatment strategies include avoiding triggers for crises, folic acid supplementation, blood transfusions, and possible bone marrow transplants.
Blood Transfusion Reactions
- Known as hemolytic transfusion reactions where recipient antibodies attack transfused cells.
- Type and crossmatch must be double-checked by clinicians before transfusions.
Presentation and Manifestations of Reactions
- May include nonhemolytic febrile reactions, mild allergies, or severe anaphylactic reactions.
- Symptoms range from fever, chills, joint pain to severe hypotension, bleeding, and renal failure in acute cases.
Vitamin B12 Deficiency
- Characterized by impaired absorption due to intrinsic factor disruption (e.g., pernicious anemia), leading to macrocytic anemia and neurological issues.
- At-risk groups include those with malnutrition, vegans, the elderly, and individuals post-bariatric surgery.
Pernicious Anemia
- Autoimmune disruption of intrinsic factors leads to Vitamin B12 absorption issues, resulting in megaloblastic anemia.
- Associated neurological symptoms may include glossitis, numbness, and unsteady gait.
Lack of Bone Marrow Production
- Erythropoietin (EPO) deficiency typically from kidney failure or hypothyroidism; recombinant EPO may be prescribed.
Primary Polycythemia (Polycythemia Vera)
- Overproduction of all blood cells, increasing clot risk; CBC may reveal hematocrit (HCt) >60%.
- Etiology remains unclear, but may involve chromosomal abnormalities.
Secondary Polycythemia (Erythrocytosis)
- More common than primary, often due to prolonged hypoxia (e.g., COPD).
- Symptoms develop gradually, and EPO levels are typically elevated.
Type I: Immediate Hypersensitivity
- Also called allergy or atopic disorder; involves rapid immune response.
- Allergen interacts with antigen-presenting cells (APCs), activating B cells to produce IgEs.
- IgEs bind to mast cells, triggering degranulation and release of chemicals that induce allergy symptoms.
- Common local/systemic responses include hives, nasal discharge, bronchial asthma, and allergic gastroenteritis.
- Allergic rhinitis affects 50% of U.S. population, characterized by histamine release causing mucus hypersecretion and respiratory symptoms.
- Anaphylaxis is severe and life-threatening, requiring emergency treatment with epinephrine (EpiPen).
Type II Hypersensitivity: Cytotoxic
- Involves antibodies (IgG, IgM) attacking antigens on cells, leading to cell lysis.
- Blood transfusion reactions occur within the first 15 minutes.
Type III Hypersensitivity: Immune Complex
- Antigen-antibody complexes deposit in tissues, causing tissue damage.
- Associated with systemic conditions like lupus and localized conditions like rheumatoid arthritis.
Type IV Hypersensitivity: Delayed
- T-cell mediated response; occurs days post-exposure.
- Examples include poison ivy and transplant rejection.
- Mantoux test used for tuberculosis detection indicates Type IV hypersensitivity.
Autoimmune Disorder Overview
- Body attacks its own "self" cells through Ig-mediated (autoantibodies) or T-cell mechanisms.
- Can be organ-specific or systemic; etiology often unknown.
- Molecular mimicry noted in conditions like rheumatic fever (autoantibodies target heart valves).
Systemic Lupus Erythematosus (SLE)
- Multisystem disorder with antinuclear antibodies (ANA) present.
- Triggered by hormonal factors (estrogen), genetics (X chromosome), and environmental factors (EBV, UV light).
- Clinical manifestations include butterfly rash, joint inflammation, kidney damage, and vasculitis.
- Treatment involves hydroxychloroquine, NSAIDs, corticosteroids, and immunosuppressants.
Rheumatoid Arthritis (RA)
- Chronic joint inflammation potentially leading to systemic effects.
- Causes remain unknown; genetic and environmental factors play roles.
- Causes synovial hypertrophy (pannus) and can affect organs like the lungs and heart.
- Treatment includes NSAIDs, DMARDs, and immunosuppressants.
Sarcoidosis
- Chronic multi-system disorder with T cell and macrophage accumulation, leading to granulomas.
- Lung involvement is common; skin lesions (erythema nodosum, lupus pernio) are diagnostic.
- Treatment typically includes glucocorticoids and immunosuppressive agents.
Sjögren's Syndrome
- Characterized by dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) due to immune destruction of glands.
- Women are more commonly affected; associated with RA.
- Diagnosis involves ANAs and specific antibodies (anti-Ro/SSA, anti-La/SSB).
Scleroderma
- Known as systemic sclerosis; results in fibrous tissue accumulation in skin and organs.
- Associated with inflammation and gene mutations; affects skin appearance significantly.
- Diagnosis through elevated ANAs and imaging for lung changes; treatments include NSAIDs, corticosteroids, and immunosuppressants.
Immunodeficiency Disorders
- Primary immunodeficiency is congenital or genetic.
- Secondary immunodeficiency is acquired (e.g., HIV, chemotherapy).
Selective IgA Deficiency (sIgAD)
- Common primary immune deficiency; often asymptomatic.
- Increased risk for atopic and autoimmune diseases.
- Monthly Ig injections can be administered as needed.
Human Immunodeficiency Virus (HIV)
- Attacks CD4 T-helper cells, compromising cell-mediated immunity.
Overview of the Immune System
- Comprised of innate (born with) and adaptive (acquired) components.
- Recognizes self vs. non-self; immunodeficiency indicates weakened immunity, while autoimmunity indicates an attack on self-cells.
Cellular Components of the Immune System
- Cytokines are key signaling proteins regulating immune responses.
- Natural Killer (NK) cells destroy tumor and virus-infected cells.
- B and T lymphocytes are vital for both antibody-mediated and cell-mediated immunity.
Immunoglobulins (Igs)
- Produced by B cells; bind to specific antigens.
- Five subtypes: IgM (earliest), IgG (most abundant), IgA (mucosal), IgD (hypersensitivity), IgE (allergies).
Active vs. Passive Immunity
- Active acquired immunity develops from exposure to an antigen.
- Passive acquired immunity involves receiving premade antibodies, providing short-term defense.
Vaccines
- Designed to provoke immune response without causing disease.
- Primary response to vaccines is long-lasting; boosters enhance immunity.
Anergy Panel
- Tests immunocompetence by injecting common antigens and observing skin reactions.
Antibody Screening and Titer
- Assesses presence and levels of antibodies; indicates previous exposure or immunity to diseases.
Allergy Testing
- Skin tests and serology testing measure IgE levels in response to allergens.
Basic Immune Disorders
- Overreaction responses categorized as hypersensitivity (Types I-IV) and autoimmune disorders; underreactions result in immunodeficiency.### Human Immunodeficiency Virus (HIV)
- Affects CD4 and T helper cells, crucial components of the immune system.
- Three stages of HIV infection: Acute, Chronic, and AIDS (Acquired Immunodeficiency Syndrome).
Transmission Routes
- Sexual activity involving semen and vaginal secretions.
- Blood exposure, transplacental transmission, and breast milk.
- Organ transplants and saliva (in open mouth wounds) can also be routes of transmission.
High-Risk Individuals
- Unsafe sexual practices increase risk.
- Men who have sex with men (MSM) and young Black/African American gay and bisexual men are particularly affected.
- IV drug users are at higher risk for HIV infection.
Viral Characteristics
- HIV is a retrovirus, specifically an RNA virus that utilizes reverse transcriptase to convert its RNA into DNA.
- Targets cells with CD4 receptors and the CCR5 chemokine receptor; individuals without CCR5 exhibit resistance to HIV.
Infection Progression
- Initial HIV infection may cause flu-like symptoms, followed by a period of asymptomatic dormancy.
- HIV can remain inactive in CD4 cells and macrophages, while infected CD4 lymphocytes lose functionality, leading to increased risk of opportunistic infections.
Seroconversion
- Detectable antibody levels can develop within 2 weeks to 6 months post-infection.
- Early stages may be asymptomatic but infectious; this is termed the "latent period."
- CD4 cell levels decline while HIV RNA levels rise over time.
Anemia Caused by Chronic Blood Loss
- Possible causes include gastrointestinal bleeding, menstrual blood loss, and medication side effects (e.g., NSAIDs leading to GI bleeding).
- Symptoms may not be noticeable initially, but patient condition may deteriorate over time.
Hemolytic Anemias
- Results from erythrocyte destruction exceeding replacement.
- Primary causes include hemoglobinopathies, autoimmune disorders, alloimmune hemolysis (e.g., blood transfusion reactions), hereditary spherocytosis, and lead poisoning.
Signs and Symptoms of Hemolytic Anemias
- Includes typical anemia symptoms along with jaundice, dark urine, and splenomegaly due to RBC breakdown.
- Diagnosis may show elevated reticulocytes and misshapen RBCs on peripheral smear.
Hemoglobinopathy
- Inherited disorder resulting in abnormal hemoglobin structure, impairing oxygen transport and causing RBC destruction.
- Examples include Sickle Cell Anemia (SCA) and Thalassemia.
Sickle Cell Anemia (SCA)
- Autosomal hemoglobinopathy, includes homozygous and heterozygous forms with varying severity.
- Sickle-shaped RBCs result from hypoxia, dehydration, and stress, with symptoms appearing post-fetal hemoglobin decline.
- Increases malaria resistance through genetic expression.
Clinical Presentation of SCA
- Typical anemia symptoms, hyperbilirubinemia, and splenomegaly may be present.
- Vaso-occlusive crises occur due to sickle-shaped RBCs lodging in capillaries, causing tissue hypoxia and severe pain, resulting in chronic organ damage.
Diagnosis and Treatment of SCA
- Diagnosis involves electrophoresis revealing HbS.
- Treatment strategies include avoiding triggers for crises, folic acid supplementation, blood transfusions, and possible bone marrow transplants.
Blood Transfusion Reactions
- Known as hemolytic transfusion reactions where recipient antibodies attack transfused cells.
- Type and crossmatch must be double-checked by clinicians before transfusions.
Presentation and Manifestations of Reactions
- May include nonhemolytic febrile reactions, mild allergies, or severe anaphylactic reactions.
- Symptoms range from fever, chills, joint pain to severe hypotension, bleeding, and renal failure in acute cases.
Vitamin B12 Deficiency
- Characterized by impaired absorption due to intrinsic factor disruption (e.g., pernicious anemia), leading to macrocytic anemia and neurological issues.
- At-risk groups include those with malnutrition, vegans, the elderly, and individuals post-bariatric surgery.
Pernicious Anemia
- Autoimmune disruption of intrinsic factors leads to Vitamin B12 absorption issues, resulting in megaloblastic anemia.
- Associated neurological symptoms may include glossitis, numbness, and unsteady gait.
Lack of Bone Marrow Production
- Erythropoietin (EPO) deficiency typically from kidney failure or hypothyroidism; recombinant EPO may be prescribed.
Primary Polycythemia (Polycythemia Vera)
- Overproduction of all blood cells, increasing clot risk; CBC may reveal hematocrit (HCt) >60%.
- Etiology remains unclear, but may involve chromosomal abnormalities.
Secondary Polycythemia (Erythrocytosis)
- More common than primary, often due to prolonged hypoxia (e.g., COPD).
- Symptoms develop gradually, and EPO levels are typically elevated.
Type I: Immediate Hypersensitivity
- Also called allergy or atopic disorder; involves rapid immune response.
- Allergen interacts with antigen-presenting cells (APCs), activating B cells to produce IgEs.
- IgEs bind to mast cells, triggering degranulation and release of chemicals that induce allergy symptoms.
- Common local/systemic responses include hives, nasal discharge, bronchial asthma, and allergic gastroenteritis.
- Allergic rhinitis affects 50% of U.S. population, characterized by histamine release causing mucus hypersecretion and respiratory symptoms.
- Anaphylaxis is severe and life-threatening, requiring emergency treatment with epinephrine (EpiPen).
Type II Hypersensitivity: Cytotoxic
- Involves antibodies (IgG, IgM) attacking antigens on cells, leading to cell lysis.
- Blood transfusion reactions occur within the first 15 minutes.
Type III Hypersensitivity: Immune Complex
- Antigen-antibody complexes deposit in tissues, causing tissue damage.
- Associated with systemic conditions like lupus and localized conditions like rheumatoid arthritis.
Type IV Hypersensitivity: Delayed
- T-cell mediated response; occurs days post-exposure.
- Examples include poison ivy and transplant rejection.
- Mantoux test used for tuberculosis detection indicates Type IV hypersensitivity.
Autoimmune Disorder Overview
- Body attacks its own "self" cells through Ig-mediated (autoantibodies) or T-cell mechanisms.
- Can be organ-specific or systemic; etiology often unknown.
- Molecular mimicry noted in conditions like rheumatic fever (autoantibodies target heart valves).
Systemic Lupus Erythematosus (SLE)
- Multisystem disorder with antinuclear antibodies (ANA) present.
- Triggered by hormonal factors (estrogen), genetics (X chromosome), and environmental factors (EBV, UV light).
- Clinical manifestations include butterfly rash, joint inflammation, kidney damage, and vasculitis.
- Treatment involves hydroxychloroquine, NSAIDs, corticosteroids, and immunosuppressants.
Rheumatoid Arthritis (RA)
- Chronic joint inflammation potentially leading to systemic effects.
- Causes remain unknown; genetic and environmental factors play roles.
- Causes synovial hypertrophy (pannus) and can affect organs like the lungs and heart.
- Treatment includes NSAIDs, DMARDs, and immunosuppressants.
Sarcoidosis
- Chronic multi-system disorder with T cell and macrophage accumulation, leading to granulomas.
- Lung involvement is common; skin lesions (erythema nodosum, lupus pernio) are diagnostic.
- Treatment typically includes glucocorticoids and immunosuppressive agents.
Sjögren's Syndrome
- Characterized by dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) due to immune destruction of glands.
- Women are more commonly affected; associated with RA.
- Diagnosis involves ANAs and specific antibodies (anti-Ro/SSA, anti-La/SSB).
Scleroderma
- Known as systemic sclerosis; results in fibrous tissue accumulation in skin and organs.
- Associated with inflammation and gene mutations; affects skin appearance significantly.
- Diagnosis through elevated ANAs and imaging for lung changes; treatments include NSAIDs, corticosteroids, and immunosuppressants.
Immunodeficiency Disorders
- Primary immunodeficiency is congenital or genetic.
- Secondary immunodeficiency is acquired (e.g., HIV, chemotherapy).
Selective IgA Deficiency (sIgAD)
- Common primary immune deficiency; often asymptomatic.
- Increased risk for atopic and autoimmune diseases.
- Monthly Ig injections can be administered as needed.
Human Immunodeficiency Virus (HIV)
- Attacks CD4 T-helper cells, compromising cell-mediated immunity.
Overview of the Immune System
- Comprised of innate (born with) and adaptive (acquired) components.
- Recognizes self vs. non-self; immunodeficiency indicates weakened immunity, while autoimmunity indicates an attack on self-cells.
Cellular Components of the Immune System
- Cytokines are key signaling proteins regulating immune responses.
- Natural Killer (NK) cells destroy tumor and virus-infected cells.
- B and T lymphocytes are vital for both antibody-mediated and cell-mediated immunity.
Immunoglobulins (Igs)
- Produced by B cells; bind to specific antigens.
- Five subtypes: IgM (earliest), IgG (most abundant), IgA (mucosal), IgD (hypersensitivity), IgE (allergies).
Active vs. Passive Immunity
- Active acquired immunity develops from exposure to an antigen.
- Passive acquired immunity involves receiving premade antibodies, providing short-term defense.
Vaccines
- Designed to provoke immune response without causing disease.
- Primary response to vaccines is long-lasting; boosters enhance immunity.
Anergy Panel
- Tests immunocompetence by injecting common antigens and observing skin reactions.
Antibody Screening and Titer
- Assesses presence and levels of antibodies; indicates previous exposure or immunity to diseases.
Allergy Testing
- Skin tests and serology testing measure IgE levels in response to allergens.
Basic Immune Disorders
- Overreaction responses categorized as hypersensitivity (Types I-IV) and autoimmune disorders; underreactions result in immunodeficiency.### Human Immunodeficiency Virus (HIV)
- Affects CD4 and T helper cells, crucial components of the immune system.
- Three stages of HIV infection: Acute, Chronic, and AIDS (Acquired Immunodeficiency Syndrome).
Transmission Routes
- Sexual activity involving semen and vaginal secretions.
- Blood exposure, transplacental transmission, and breast milk.
- Organ transplants and saliva (in open mouth wounds) can also be routes of transmission.
High-Risk Individuals
- Unsafe sexual practices increase risk.
- Men who have sex with men (MSM) and young Black/African American gay and bisexual men are particularly affected.
- IV drug users are at higher risk for HIV infection.
Viral Characteristics
- HIV is a retrovirus, specifically an RNA virus that utilizes reverse transcriptase to convert its RNA into DNA.
- Targets cells with CD4 receptors and the CCR5 chemokine receptor; individuals without CCR5 exhibit resistance to HIV.
Infection Progression
- Initial HIV infection may cause flu-like symptoms, followed by a period of asymptomatic dormancy.
- HIV can remain inactive in CD4 cells and macrophages, while infected CD4 lymphocytes lose functionality, leading to increased risk of opportunistic infections.
Seroconversion
- Detectable antibody levels can develop within 2 weeks to 6 months post-infection.
- Early stages may be asymptomatic but infectious; this is termed the "latent period."
- CD4 cell levels decline while HIV RNA levels rise over time.
Anemia Caused by Chronic Blood Loss
- Possible causes include gastrointestinal bleeding, menstrual blood loss, and medication side effects (e.g., NSAIDs leading to GI bleeding).
- Symptoms may not be noticeable initially, but patient condition may deteriorate over time.
Hemolytic Anemias
- Results from erythrocyte destruction exceeding replacement.
- Primary causes include hemoglobinopathies, autoimmune disorders, alloimmune hemolysis (e.g., blood transfusion reactions), hereditary spherocytosis, and lead poisoning.
Signs and Symptoms of Hemolytic Anemias
- Includes typical anemia symptoms along with jaundice, dark urine, and splenomegaly due to RBC breakdown.
- Diagnosis may show elevated reticulocytes and misshapen RBCs on peripheral smear.
Hemoglobinopathy
- Inherited disorder resulting in abnormal hemoglobin structure, impairing oxygen transport and causing RBC destruction.
- Examples include Sickle Cell Anemia (SCA) and Thalassemia.
Sickle Cell Anemia (SCA)
- Autosomal hemoglobinopathy, includes homozygous and heterozygous forms with varying severity.
- Sickle-shaped RBCs result from hypoxia, dehydration, and stress, with symptoms appearing post-fetal hemoglobin decline.
- Increases malaria resistance through genetic expression.
Clinical Presentation of SCA
- Typical anemia symptoms, hyperbilirubinemia, and splenomegaly may be present.
- Vaso-occlusive crises occur due to sickle-shaped RBCs lodging in capillaries, causing tissue hypoxia and severe pain, resulting in chronic organ damage.
Diagnosis and Treatment of SCA
- Diagnosis involves electrophoresis revealing HbS.
- Treatment strategies include avoiding triggers for crises, folic acid supplementation, blood transfusions, and possible bone marrow transplants.
Blood Transfusion Reactions
- Known as hemolytic transfusion reactions where recipient antibodies attack transfused cells.
- Type and crossmatch must be double-checked by clinicians before transfusions.
Presentation and Manifestations of Reactions
- May include nonhemolytic febrile reactions, mild allergies, or severe anaphylactic reactions.
- Symptoms range from fever, chills, joint pain to severe hypotension, bleeding, and renal failure in acute cases.
Vitamin B12 Deficiency
- Characterized by impaired absorption due to intrinsic factor disruption (e.g., pernicious anemia), leading to macrocytic anemia and neurological issues.
- At-risk groups include those with malnutrition, vegans, the elderly, and individuals post-bariatric surgery.
Pernicious Anemia
- Autoimmune disruption of intrinsic factors leads to Vitamin B12 absorption issues, resulting in megaloblastic anemia.
- Associated neurological symptoms may include glossitis, numbness, and unsteady gait.
Lack of Bone Marrow Production
- Erythropoietin (EPO) deficiency typically from kidney failure or hypothyroidism; recombinant EPO may be prescribed.
Primary Polycythemia (Polycythemia Vera)
- Overproduction of all blood cells, increasing clot risk; CBC may reveal hematocrit (HCt) >60%.
- Etiology remains unclear, but may involve chromosomal abnormalities.
Secondary Polycythemia (Erythrocytosis)
- More common than primary, often due to prolonged hypoxia (e.g., COPD).
- Symptoms develop gradually, and EPO levels are typically elevated.
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Description
Test your knowledge on key concepts of immunology, including cytokines, cell-mediated immunity, and the stages of HIV infection. This quiz will cover various components of the immune response, from plasma cells to antibodies. Perfect for students looking to reinforce their understanding of immunological principles.
