Immunology of Transplantation — MCQs
Which of the following drugs shows nephrotoxicity during administration?
Choose the correct option regarding graft rejection.
Which of the following can be prevented by transfusing irradiated RBCs?
Antigen presented along with HLA-II stimulates
t(2,8) is associated with:
Which immunosuppressant blocks IL-2 production?
If mother is donating the kidney to her son, this is an example of:-
Dr. Christiaan Barnard performed the 1st heart transplant in the year -
Graft taken from identical twin is called as:
If a mother is donating her kidney to son, this is an example of which of the following?
Immunology of Transplantation Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following drugs shows nephrotoxicity during administration?
- A. Azathioprine
- B. Tacrolimus (Correct Answer)
- C. Mycophenolate mofetil
- D. Leflunomide
Explanation: ***Tacrolimus*** - **Tacrolimus** is a calcineurin inhibitor and a well-known cause of **nephrotoxicity**, which can manifest as acute kidney injury or chronic renal dysfunction [1], [4]. - Its mechanism involves vasoconstriction of afferent arterioles and direct tubular toxicity, leading to reduced glomerular filtration. *Azathioprine* - **Azathioprine** is an immunosuppressant primarily associated with **bone marrow suppression** (leukopenia, thrombocytopenia) and **hepatotoxicity**, not typically nephrotoxicity [2]. - While it can cause renal impairment in rare cases, it is not a primary mechanism of action. *Mycophenolate mofetil* - **Mycophenolate mofetil (MMF)** is an immunosuppressant that primarily causes **gastrointestinal side effects** (diarrhea, nausea) and **myelosuppression**. - It is generally considered **renal-sparing** and is often used in situations where calcineurin inhibitors are contraindicated due to nephrotoxicity. *Leflunomide* - **Leflunomide** is an immunosuppressant used in rheumatoid arthritis, known for causing **hepatotoxicity**, **hypertension**, and **teratogenicity** [3]. - While it can affect various organ systems, direct and significant nephrotoxicity is not a prominent adverse effect.
Question 2: Choose the correct option regarding graft rejection.
- A. CD4 and CD8 both play a role in graft rejection (Correct Answer)
- B. None of the options
- C. CD8 only plays a role in graft rejection
- D. CD4 only plays a role in graft rejection
Explanation: ***CD4 and CD8 both play a role in graft rejection*** - **CD4+ T cells** (helper T cells) recognize donor MHC class II molecules and differentiate into effector cells that produce cytokines, promoting inflammation and activating other immune cells involved in rejection - **CD8+ T cells** (cytotoxic T lymphocytes, CTLs) recognize donor MHC class I molecules and directly kill donor cells in the graft, leading to tissue destruction - Both T cell subsets are crucial for initiating and mediating different aspects of the immune response against transplanted organs *CD8 only plays a role in graft rejection* - This is incorrect because while **CD8+ T cells** are vital for direct cytotoxicity, **CD4+ T cells** are also essential for orchestrating the overall immune response - **CD4+ T cells** provide help to B cells and CD8+ T cells, and their cytokines can also directly injure graft tissue *CD4 only plays a role in graft rejection* - This is incorrect because although **CD4+ T cells** are critical for initiating and amplifying the immune response through cytokine production and activation of other cells, **CD8+ T cells** are directly responsible for killing graft cells - Both cell types contribute significantly to the complex pathophysiology of graft rejection
Question 3: Which of the following can be prevented by transfusing irradiated RBCs?
- A. Graft versus host disease (Correct Answer)
- B. HLA Alloimmunization
- C. Transfusion Related Acute Lung Injury (TRALI)
- D. Immunomodulation
Explanation: Graft versus host disease - **Irradiation** of red blood cell (RBC) products inactivates proliferating donor **T-lymphocytes**, which are responsible for mediating transfusion-associated **graft-versus-host disease (TA-GVHD)**. - TA-GVHD is a severe and often fatal complication where donor immune cells attack recipient tissues. *HLA Alloimmunization* - **HLA alloimmunization** is prevented by **leukoreduction**, which removes donor leukocytes expressing HLA antigens, not by irradiation. - Irradiation targets the proliferative capacity of T-lymphocytes, but does not remove the cells themselves or prevent the presentation of HLA antigens. *Transfusion Related Acute Lung Injury (TRALI)* - **TRALI** is primarily associated with **donor antibodies** (anti-HLA or anti-HNA) in plasma that react with recipient neutrophils, leading to lung injury. - It is prevented by selecting plasma donors who have not been pregnant or by using male-only plasma, not by irradiating RBCs. *Immunomodulation* - **Transfusion-related immunomodulation (TRIM)** is a broad effect associated with multiple blood components, including cytokines and biological response modifiers in the transfused products. - While leukoreduction may reduce some aspects of TRIM, irradiation is not specifically used to prevent or reduce this phenomenon.
Question 4: Antigen presented along with HLA-II stimulates
- A. CD2 cells
- B. CD8 cells
- C. CD4 cells (Correct Answer)
- D. CD19 cells
Explanation: ***CD4 cells*** - Antigen presented with **MHC class II molecules** (formerly HLA-II) on antigen-presenting cells (APCs) is recognized by the **T-cell receptor (TCR)** on **CD4+ T helper cells**. - This interaction is crucial for the activation and differentiation of CD4+ T cells, leading to cytokine production and the coordination of the adaptive immune response. *CD2 cells* - **CD2** is a surface molecule found predominantly on T cells and NK cells, involved in cell adhesion and co-stimulation but not directly in the primary antigen recognition with MHC class II. - While CD2 plays a role in T cell activation, it does not directly recognize antigen presented via MHC class II. *CD8 cells* - **CD8+ T cells** (cytotoxic T lymphocytes) primarily recognize antigens presented by **MHC class I molecules**, which display intracellular (endogenous) antigens. - MHC class I presentation signals to CD8 cells to induce apoptosis in infected or cancerous cells. *CD19 cells* - **CD19** is a cell surface marker found on **B lymphocytes** and is involved in B cell activation and signaling. - B cells can act as APCs and present antigen, but their primary recognition of antigen is typically through their B-cell receptor (BCR), and they are not themselves stimulated by MHC class II in the same manner as T cells.
Question 5: t(2,8) is associated with:
- A. T cell ALL
- B. CML
- C. B cell ALL (Correct Answer)
- D. CLL
Explanation: ***B cell ALL*** - The translocation **t(2;8)(p11;q24)** is a **variant cytogenetic abnormality** specifically associated with **Burkitt lymphoma/leukemia**, a highly aggressive form of mature B-cell neoplasm, which can present as B-cell ALL. [1] - This variant translocation (occurring in ~15% of Burkitt lymphoma cases) leads to the **dysregulation of the MYC oncogene** on chromosome 8q24 due to its juxtaposition with the **kappa (κ) immunoglobulin light chain gene (IGK)** on chromosome 2p11. [1] - The most common translocation in Burkitt lymphoma is **t(8;14)(q24;q32)** involving MYC and the immunoglobulin heavy chain gene IGH (~80% of cases), while **t(8;22)** involving the lambda light chain occurs in ~5% of cases. [1] *T cell ALL* - T-cell ALL is primarily associated with translocations involving **T-cell receptor genes (e.g., TCRα/δ on 14q11, TCRβ on 7q34)** and various oncogenes like *TAL1*, *LMO1*, *LMO2*, *HOXA*, and *NKX2-5*. - It does not typically involve the **t(2;8) translocation**. *CML* - **Chronic Myeloid Leukemia (CML)** is classically defined by the presence of the **Philadelphia chromosome**, an acquired reciprocal translocation **t(9;22)(q34;q11)**. - This translocation results in the formation of the **BCR-ABL1 fusion gene**, which encodes a constitutively active tyrosine kinase. *CLL* - **Chronic Lymphocytic Leukemia (CLL)** is most frequently associated with cytogenetic abnormalities such as **deletions of 13q14, 11q22-23 (ATM gene), and 17p13 (TP53 gene)**, and **trisomy 12**. - The **t(2;8) translocation** is not characteristic of CLL. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 324-325.
Question 6: Which immunosuppressant blocks IL-2 production?
- A. Sirolimus
- B. Methotrexate
- C. Tacrolimus (Correct Answer)
- D. Mycophenolate
Explanation: ***Tacrolimus*** - Tacrolimus is a **calcineurin inhibitor** that works by binding to **FKBP-12**, forming a complex that inhibits calcineurin. - This inhibition prevents the dephosphorylation of **NFAT**, thereby blocking its translocation to the nucleus and subsequent **IL-2 gene transcription**. *Sirolimus* - Sirolimus is an **mTOR inhibitor** that works downstream from the IL-2 receptor, blocking **T-cell proliferation** in response to IL-2, rather than blocking IL-2 production itself. - It binds to **FKBP-12** but targets the **mTOR complex**, which is crucial for cell growth and division. *Methotrexate* - Methotrexate is an **antimetabolite** that inhibits **dihydrofolate reductase**, interfering with **DNA synthesis** and thus suppressing the proliferation of rapidly dividing cells, including lymphocytes. - Its primary action is not directly blocking IL-2 production but rather reducing the overall immune cell expansion. *Mycophenolate* - Mycophenolate mofetil is a **reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH)**, an enzyme critical for the *de novo* synthesis of guanosine nucleotides. - This preferentially inhibits the proliferation of **lymphocytes**, which are highly dependent on the *de novo* pathway for purine synthesis, but does not directly block IL-2 production.
Question 7: If mother is donating the kidney to her son, this is an example of:-
- A. Autograft
- B. Allograft (Correct Answer)
- C. Isograft
- D. Xenograft
Explanation: ***Correct: Allograft*** - An **allograft** involves the transplantation of organs or tissues between **genetically different individuals of the same species** - In this scenario, a mother donating a kidney to her son is a classic example, as they are genetically distinct (share approximately 50% DNA) but belong to the same human species - This is the **most common type of transplant** performed in clinical practice *Incorrect: Autograft* - An **autograft** involves transplanting tissues or organs from one part of the body to another in the **same individual** - Examples include skin grafts from a patient's thigh to an injured area on their arm, or using saphenous vein for coronary artery bypass grafting - This does not apply to mother-son transplantation as two different individuals are involved *Incorrect: Isograft* - An **isograft** refers to a transplant between **genetically identical individuals**, such as monozygotic (identical) twins - The mother and son are not genetically identical (they share only ~50% of their DNA), thus precluding an isograft - Isografts have minimal risk of rejection due to genetic identity *Incorrect: Xenograft* - A **xenograft** is a transplant of organs or tissues **from one species to another** - Examples include transplanting a pig heart valve into a human or using bovine pericardium - Mother and son are both humans (same species), so this is not a xenograft
Question 8: Dr. Christiaan Barnard performed the 1st heart transplant in the year -
- A. 1962
- B. 1965
- C. 1969
- D. 1967 (Correct Answer)
Explanation: ***1967*** - Dr. Christiaan Barnard performed the **first human heart transplant** on December 3, 1967, at Groote Schuur Hospital in Cape Town, South Africa. - The recipient, Louis Washkansky, lived for 18 days after the surgery. *1962* - While significant advancements in medicine occurred in 1962, the **first heart transplant** had not yet been performed. - This year saw the approval of the **measles vaccine** and the publication of Rachel Carson's "Silent Spring," but not the seminal heart transplant. *1965* - The year 1965 was a period of continued research and experimentation in organ transplantation, but the **first successful human heart transplant** took place later. - Prior to 1967, xenotransplantation experiments in humans involving animal hearts were attempted, but a human-to-human transplant was still pending. *1969* - By 1969, **several hundred heart transplants** had already been performed worldwide following Barnard's pioneering surgery. - Dr. Denton Cooley performed the **first implantation of a total artificial heart** in a human in 1969, indicating that heart transplantation was already established.
Question 9: Graft taken from identical twin is called as:
- A. Autograft
- B. Allograft
- C. Isograft (Correct Answer)
- D. Xenograft
Explanation: ***Isograft*** - An isograft (or syngeneic graft) is a transplant of tissue or organs between **genetically identical individuals**, such as identical twins. - Due to their identical genetic makeup, there is **no immune response** or rejection of the transplanted tissue. *Autograft* - An autograft is a graft of tissue from **one's own body** to another site on the same individual. - Examples include a skin graft from the thigh to the hand, or a saphenous vein used for coronary artery bypass. *Allograft* - An allograft is a transplant of an organ or tissue from one individual to another individual of the **same species** but with a **different genetic makeup**. - These grafts typically require **immunosuppressive therapy** to prevent rejection. *Xenograft* - A xenograft is a transplant of tissue or organs between individuals of **different species**. - These grafts face a very strong immune response and are typically used in experimental settings or for temporary support.
Question 10: If a mother is donating her kidney to son, this is an example of which of the following?
- A. Autograft
- B. Xenograft
- C. Isograft
- D. Allograft (Correct Answer)
Explanation: ***Allograft*** - An **allograft** involves the transplantation of organs or tissues between genetically different individuals of the **same species**. - In this scenario, a mother donating a kidney to her son is a classic example of an allograft since they are human (same species) but **genetically distinct** individuals. - Although mother and son share approximately 50% of their genetic material, they are **not genetically identical**, which distinguishes this from an isograft. *Autograft* - An **autograft** involves transplanting tissues from one site to another within the **same individual**. - Examples include skin grafts from one part of a patient's body to another or coronary artery bypass grafts using a patient's own veins. *Xenograft* - A **xenograft**, also known as a xenotransplantation, involves transplanting tissues or organs between individuals of **different species**. - An example would be the transplantation of a heart valve from a pig to a human. *Isograft* - An **isograft** refers to a transplant between **genetically identical individuals**, such as identical twins. - In such cases, there is typically no immune rejection because the donor and recipient share the same genetic makeup.
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