Podcast
Questions and Answers
What services are available for telemedicine at the MWU Multispecialty Clinic?
What services are available for telemedicine at the MWU Multispecialty Clinic?
What is the cost for student acute care visits at the MWU Acute Care Clinic?
What is the cost for student acute care visits at the MWU Acute Care Clinic?
When can students schedule a telehealth appointment?
When can students schedule a telehealth appointment?
What should students do to access the free counseling service mentioned?
What should students do to access the free counseling service mentioned?
Signup and view all the answers
What is the coupon code for student appointments starting August 1st?
What is the coupon code for student appointments starting August 1st?
Signup and view all the answers
Which type of graft involves transplantation between genetically identical individuals?
Which type of graft involves transplantation between genetically identical individuals?
Signup and view all the answers
Which of the following is correctly ordered according to the degree of immune response elicited during transplantation?
Which of the following is correctly ordered according to the degree of immune response elicited during transplantation?
Signup and view all the answers
What mechanism is primarily responsible for hyperacute graft rejection?
What mechanism is primarily responsible for hyperacute graft rejection?
Signup and view all the answers
Which type of graft rejection typically occurs days to weeks after transplantation?
Which type of graft rejection typically occurs days to weeks after transplantation?
Signup and view all the answers
In direct recognition of allogeneic MHC, which cells are directly involved in presenting peptides to activate T cells?
In direct recognition of allogeneic MHC, which cells are directly involved in presenting peptides to activate T cells?
Signup and view all the answers
What is the primary function of HLA typing in transplantation?
What is the primary function of HLA typing in transplantation?
Signup and view all the answers
Which statement accurately describes the role of MHC molecules in transplantation?
Which statement accurately describes the role of MHC molecules in transplantation?
Signup and view all the answers
What distinguishes an autologous graft from an allogeneic graft?
What distinguishes an autologous graft from an allogeneic graft?
Signup and view all the answers
What is the primary reason for the significance of crossmatching in transplants?
What is the primary reason for the significance of crossmatching in transplants?
Signup and view all the answers
What is one characteristic of chronic inflammation following a transplant?
What is one characteristic of chronic inflammation following a transplant?
Signup and view all the answers
What is the time frame for chronic inflammation to develop after a transplant?
What is the time frame for chronic inflammation to develop after a transplant?
Signup and view all the answers
Which of the following best describes the approach to managing acute and chronic graft-versus-host disease (GvHD)?
Which of the following best describes the approach to managing acute and chronic graft-versus-host disease (GvHD)?
Signup and view all the answers
What role do growth factors play in chronic inflammation post-transplant?
What role do growth factors play in chronic inflammation post-transplant?
Signup and view all the answers
What is a potential method for preventing acute GvHD?
What is a potential method for preventing acute GvHD?
Signup and view all the answers
How does the immune response in chronic inflammation compare to acute inflammation?
How does the immune response in chronic inflammation compare to acute inflammation?
Signup and view all the answers
Why is it essential to only focus on covered figures and tables in the material provided?
Why is it essential to only focus on covered figures and tables in the material provided?
Signup and view all the answers
What is a key difference between the induction and maintenance phases in transplant scenarios?
What is a key difference between the induction and maintenance phases in transplant scenarios?
Signup and view all the answers
What resource can a student access for immediate mental health crises?
What resource can a student access for immediate mental health crises?
Signup and view all the answers
Which method is not advised for improving transplant outcomes?
Which method is not advised for improving transplant outcomes?
Signup and view all the answers
What is primarily responsible for acute rejection in transplant recipients?
What is primarily responsible for acute rejection in transplant recipients?
Signup and view all the answers
What mechanism characterizes hyperacute rejection?
What mechanism characterizes hyperacute rejection?
Signup and view all the answers
Which of the following statements about chronic rejection is true?
Which of the following statements about chronic rejection is true?
Signup and view all the answers
Which type of graft has the highest likelihood of experiencing immune rejection?
Which type of graft has the highest likelihood of experiencing immune rejection?
Signup and view all the answers
What is the role of alloantibodies in transplant rejection?
What is the role of alloantibodies in transplant rejection?
Signup and view all the answers
What is the principal purpose of HLA typing prior to transplantation?
What is the principal purpose of HLA typing prior to transplantation?
Signup and view all the answers
Which immune response mechanism is associated with graft vs host disease (GvHD)?
Which immune response mechanism is associated with graft vs host disease (GvHD)?
Signup and view all the answers
What outcome follows the activation of preexisting antibodies in hyperacute rejection?
What outcome follows the activation of preexisting antibodies in hyperacute rejection?
Signup and view all the answers
Which immunosuppressive drug inhibits IL-2 synthesis?
Which immunosuppressive drug inhibits IL-2 synthesis?
Signup and view all the answers
What is associated with acute antibody-mediated rejection?
What is associated with acute antibody-mediated rejection?
Signup and view all the answers
What is the major factor in determining graft survival in transplant recipients?
What is the major factor in determining graft survival in transplant recipients?
Signup and view all the answers
What is one consequence of chronic rejection in transplanted tissues?
What is one consequence of chronic rejection in transplanted tissues?
Signup and view all the answers
In which type of rejection do antibodies play a significant role shortly after transplantation?
In which type of rejection do antibodies play a significant role shortly after transplantation?
Signup and view all the answers
How is smooth muscle cell proliferation related to chronic rejection?
How is smooth muscle cell proliferation related to chronic rejection?
Signup and view all the answers
Study Notes
Graft Types
- Autograft: Transplant from one individual to the same individual.
- Isograft: Transplant between two genetically identical individuals.
- Allograft: Transplant between two genetically different individuals of the same species.
- Xenograft: Transplant between individuals of different species.
Alloantigens
- Alloantigens are foreign antigens found on the surface of transplanted cells/tissues.
- They are usually protein antigens encoded by polymorphic genes, which differ among individuals.
- Alloreactive T and B cells are lymphocytes that react against alloantigens.
Histocompatibility Antigens
- MHC (Major Histocompatibility Complex) molecules: These are responsible for strong immune responses and mismatches in MHC lead to allograft rejection.
- Minor histocompatibility antigens: Various molecules that induce weaker or slower rejection reactions.
Histocompatibility and HLA Typing
- Histocompatibility type: An individual's unique set of MHC glycoproteins.
-
Haplotype: A set of MHC alleles on a chromosome. Each person inherits two haplotypes.
- Identical twins are haploidentical (100% HLA-matched).
- Parents have a 50% HLA match with their children (if they are heterozygous).
- HLA (Human Leukocyte Antigen) typing is a vital part of transplant assessment to minimize rejection.
Recognition of Allogeneic MHC
- Direct Recognition: Donor dendritic cells (cDCs) present alloantigens to recipient T cells, activating them and leading to graft cell destruction by CTLs (Cytotoxic T Lymphocytes).
- Indirect Recognition: Recipient cDCs phagocytose graft cells and present peptides derived from donor MHC molecules in class II MHC, activating Th cells, and leading to antibody-mediated injury and inflammation.
Host vs. Graft Rejection
-
Types of Host vs. Graft Rejection:
- Hyperacute rejection: Occurs within minutes to hours post-transplant. Mediated by pre-existing antibodies against alloantigens on endothelial cells of the graft.
- Acute rejection: Usually occurs within the first two months post-transplantation. Primarily mediated by T cells responding to alloantigens on endothelial and parenchymal cells.
- Chronic rejection: Develops months to years post-transplantation. Characterized by increased fibrosis due to chronic inflammation and vascular smooth muscle cell proliferation.
Preventing Rejection
- ABO Blood Typing and Crossmatching: Essential to prevent hyperacute rejection.
- HLA Typing: Important for minimizing acute rejection; the fewer mismatches, the better the chance for graft survival.
Graft vs. Host Disease (GvHD)
- A serious complication of HSC transplantation (and occasionally other transplants). Occurs when donor T cells from the graft recognize alloantigens on recipient tissues and attack host tissues.
- Can be acute or chronic, commonly affecting the skin, liver, and gastrointestinal tract.
Immunosuppressive Therapies
-
General Immunosuppressive Agents:
- Corticosteroids: Inhibit inflammation, decrease IL-1 and IL-2 production, and reduce MHC expression on APCs.
- Mitotic inhibitors: Inhibit nucleic acid synthesis.
- Examples: Azathioprine (Aza), Mycophenolate mofetil (MMF)
-
T Cell Specific Immunosuppressive Agents:
- Tacrolimus: Inhibits IL-2 synthesis.
- Basiliximab: Anti-CD25 antibody that blocks IL-2 binding to IL-2R.
- Sirolimus: Inhibits IL-2R signaling (mTOR inhibitor).
Summary Table of Rejection
- Type: Hyperacute, Acute, Chronic
- Mechanism: Pre-existing antibodies, T cell activation, Th1-mediated inflammation, vascular smooth muscle proliferation
- Time Frame: Minutes to hours, 7-10 days to 2-3 months, Months to years
- Prevention: ABO typing, Crossmatching, HLA typing
- Therapy: Varies, General and specific immunosuppressive therapy
Resources
- MWU Student Support: Counseling, Academic Support, Multispecialty Clinic
- Teletherapy: Academic Live Care (ALC), 24/7 In the Moment Counseling
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the different types of grafts, alloantigens, and histocompatibility antigens. This quiz covers key concepts relevant to transplantation biology, including MHC molecules and HLA typing. Perfect for students in immunology or medical fields.