Immunosuppression — MCQs
Which of the following drugs shows nephrotoxicity during administration?
Choose the correct option regarding graft rejection.
Monoclonal antibodies to the CD25 (IL-2α) receptors are used for the treatment of:
The hypersensitivity reaction involved in the hyperacute rejection of a renal transplant is:
After a renal transplant, what is the most common opportunistic infection?
Which type of graft provides the best immunological outcome for renal transplantation?
Which of the following statements about heart transplantation is false?
What type of graft has the best immunological outcome for renal transplantation?
If a mother is donating her kidney to son, this is an example of which of the following?
After the first postoperative year of cardiac transplantation, what is the most common cause of death?
Immunosuppression 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: Monoclonal antibodies to the CD25 (IL-2α) receptors are used for the treatment of:
- A. Kidney transplant rejection (Correct Answer)
- B. Hematological malignancies
- C. Autoimmune disorders
- D. Bone marrow transplant complications
Explanation: ***Kidney transplant rejection*** - Monoclonal antibodies targeting **CD25 (IL-2α receptor)** interfere with T-cell activation and proliferation, which are critical in mediating transplant rejection [1], [2]. - Examples include **basiliximab** and **daclizumab**, which are used as induction therapy to prevent acute rejection in organ transplantation [2]. *Hematological malignancies* - While some monoclonal antibodies are used for hematological malignancies (e.g., rituximab for CD20), those targeting **CD25** are not primary treatments for most hematological cancers. - **CD25** can be expressed on some leukemias (e.g., hairy cell leukemia), but the main use of CD25 antibodies is in immunosuppression. *Autoimmune disorders* - Although immune activation is central to autoimmune diseases, specific **CD25-targeting antibodies** are not widely established as frontline treatments for most autoimmune disorders. - Other immunomodulators and biologics are more commonly used in this context. *Bone marrow transplant complications* - While some immunosuppressants are used to manage complications like **graft-versus-host disease (GVHD)**, agents specifically targeting **CD25** are not primary treatments for these complications. - GVHD treatment often involves corticosteroids and other broad immunosuppressants.
Question 4: The hypersensitivity reaction involved in the hyperacute rejection of a renal transplant is:
- A. Type I
- B. Type III
- C. Type IV
- D. Type II (Correct Answer)
Explanation: ***Type II*** - Hyperacute rejection is primarily mediated by **antibody-mediated mechanisms**, indicative of Type II hypersensitivity [2]. - It involves pre-existing **IgG antibodies** that react against donor renal graft antigen, leading to rapid graft destruction [1]. *Type I* - Type I hypersensitivity is associated with **allergic reactions** involving **IgE antibodies**, not relevant to transplant rejection [2]. - Typically involves conditions like **anaphylaxis** or **asthma**, which are unrelated to hyperacute rejection scenarios. *Type IV* - Type IV hypersensitivity is cell-mediated and typically manifests as **delayed-type hypersensitivity**, not acute rejection. - It involves **T cells** and does not play a role in the immediate immune response seen in hyperacute rejection. *Type III* - Type III hypersensitivity involves the formation of immune complexes, leading to conditions like **serum sickness**, not hyperacute rejection. - This type of reaction is usually more relevant in **chronic inflammatory conditions** rather than immediate transplant rejections. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 241-242. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 208-210.
Question 5: After a renal transplant, what is the most common opportunistic infection?
- A. Varicella Zoster Virus (VZV)
- B. Coxsackie Virus
- C. Epstein-Barr Virus (EBV)
- D. Cytomegalovirus (CMV) (Correct Answer)
Explanation: ***Cytomegalovirus (CMV)*** - **CMV** is the most common opportunistic infection after renal transplantation, particularly in the first 6 months due to immunosuppression [1]. - It can cause a range of clinical syndromes, including **fever**, **leukopenia**, **gastroenteritis**, **pneumonitis**, and **hepatitis**, and can also have indirect effects that increase the risk of graft rejection. *Varicella Zoster Virus (VZV)* - While VZV can cause opportunistic infections in transplant recipients (e.g., **shingles**), it is less common than CMV [1]. - VZV typically occurs later post-transplant and is characterized by a **vesicular rash** in a dermatomal distribution. *Coxsackie Virus* - **Coxsackie virus** infections are less frequently reported as significant opportunistic infections in renal transplant recipients compared to other viral pathogens. - They are generally associated with hand-foot-and-mouth disease, herpangina, or myocarditis, which are not the most common post-transplant complications. *Epstein-Barr Virus (EBV)* - **EBV** can cause post-transplant lymphoproliferative disorder (PTLD), which is a serious complication, but EBV infection itself is not the most common opportunistic infection overall [1]. - PTLD is more common in the first year after transplant and often presents with **lymphadenopathy**, **fever**, or **graft dysfunction**.
Question 6: Which type of graft provides the best immunological outcome for renal transplantation?
- A. Allograft
- B. Xenograft
- C. Autograft
- D. Isograft (Correct Answer)
Explanation: ***Isograft*** - An **isograft** is a transplant between genetically identical individuals, such as identical twins, minimizing immune rejection. - While rare, if an identical twin is available, an **isograft** is the best option for renal transplantation due to superior long-term outcomes and minimal need for immunosuppression. *Allograft* - An **allograft** is a transplant between genetically non-identical individuals of the same species and is the most common type of renal transplant. - Despite being the most frequent, it still requires significant **immunosuppression** to prevent rejection, which is not ideal compared to an isograft. *Xenograft* - A **xenograft** involves transplantation of tissues or organs between different species (e.g., pig to human). - This type of graft currently faces significant challenges with **hyperacute rejection** and ethical considerations, making it unsuitable for routine clinical renal transplantation. *Autograft* - An **autograft** is a transplant of tissue from one part of a person's body to another part of the same individual. - This is not applicable for renal transplantation, as a failing kidney cannot be replaced by a portion of itself or another non-renal tissue.
Question 7: Which of the following statements about heart transplantation is false?
- A. High pulmonary arterial resistance is a contraindication
- B. It is only orthotopic and not heterotopic (Correct Answer)
- C. Immunosuppression is started preoperatively
- D. A beating heart cadaver/donor is not always needed.
Explanation: ***It is only orthotopic and not heterotopic*** - This statement is **FALSE**, making it the correct answer to this question asking for the false statement. - While **orthotopic transplantation** (replacing the recipient's heart with the donor heart in its normal anatomical position) is the overwhelmingly predominant method, **heterotopic transplantation** (leaving the recipient's heart in place and implanting the donor heart as an auxiliary "piggyback" pump) has been performed as an alternative technique. - Heterotopic transplantation, though rarely used in modern practice, was described and performed in select cases, particularly when the donor heart is undersized or when severe pulmonary hypertension is present. Therefore, the claim that heart transplantation is "only orthotopic" is incorrect. *Immunosuppression is started preoperatively* - This statement is **TRUE**. - **Immunosuppressive therapy** is typically initiated intraoperatively or in some protocols may begin preoperatively to prevent hyperacute and acute rejection. - Induction immunosuppression aims to suppress the recipient's immune response before it can react to the transplanted organ, improving early graft survival. *High pulmonary arterial resistance is a contraindication* - This statement is **TRUE**. - **Fixed pulmonary hypertension** with elevated pulmonary vascular resistance (PVR >4-5 Wood units or transpulmonary gradient >15 mmHg unresponsive to vasodilators) is a **contraindication** for isolated heart transplantation. - The donor right ventricle may not be able to pump against high pulmonary pressures, leading to acute right heart failure. - Such patients may require combined heart-lung transplantation or medical optimization to reduce pulmonary vascular resistance before transplantation can be considered. *A beating heart cadaver/donor is not always needed* - This statement is considered **TRUE**, though with important caveats. - Traditionally, heart transplantation has relied almost exclusively on **beating-heart donors** (brain-dead donors with maintained cardiac function) to ensure organ viability. - The statement acknowledges that in rare circumstances or with advanced preservation techniques, the absolute requirement for a beating heart might be questioned, though in practical terms beating-heart donation remains the standard for heart transplantation.
Question 8: What type of graft has the best immunological outcome for renal transplantation?
- A. Isograft (Correct Answer)
- B. Allograft
- C. Xenograft
- D. Autograft
Explanation: ***Isograft*** - An **isograft** is a transplant from a **genetically identical donor**, such as an identical twin. - This type of graft has the **lowest risk of immune rejection** because the recipient's immune system recognizes the donor tissue as "self." *Allograft* - An **allograft** is a transplant from a **genetically non-identical donor** of the same species. - While commonly used in renal transplantation, it always requires **immunosuppressive therapy** to prevent rejection, unlike an isograft. *Xenograft* - A **xenograft** is a transplant from a donor of a **different species**. - These grafts face **severe immune rejection** due to significant genetic differences and are not currently viable for whole organ transplants like kidneys. *Autograft* - An **autograft** is a transplant of tissue from **one part of an individual's body to another part of the same individual**. - This is not applicable for renal transplantation, as a failing kidney cannot be replaced by a healthy kidney from the same individual.
Question 9: 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.
Question 10: After the first postoperative year of cardiac transplantation, what is the most common cause of death?
- A. Infection
- B. Arrhythmia
- C. Accelerated graft arteriosclerosis (Correct Answer)
- D. Acute rejection episode
Explanation: **Explanation:** The survival of cardiac transplant recipients is divided into two distinct phases: the early postoperative period (within the first year) and the late postoperative period (after one year). **Why 'Accelerated Graft Arteriosclerosis' is correct:** Also known as **Cardiac Allograft Vasculopathy (CAV)**, this is a unique, progressive form of chronic rejection. Unlike typical atherosclerosis, CAV is characterized by diffuse, concentric intimal proliferation affecting the entire length of the coronary arteries. It remains the leading cause of late mortality (after 1 year) because the denervated heart does not experience typical angina, often leading to silent myocardial infarction, heart failure, or sudden death. **Why the other options are incorrect:** * **Infection:** This is the **most common cause of death within the first year** (specifically the first 30 days to 6 months) due to intense induction immunosuppression. * **Acute Rejection:** This typically occurs within the first 3–6 months. While it remains a risk, its incidence decreases significantly after the first year due to maintenance therapy. * **Arrhythmia:** While arrhythmias can occur due to surgical trauma or acute rejection in the early phase, they are rarely the primary cause of late-term mortality unless secondary to CAV. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common cause of death (<1 year):** Infection. 2. **Most common cause of death (>1 year):** Cardiac Allograft Vasculopathy (CAV) / Graft Arteriosclerosis. 3. **Gold Standard for CAV diagnosis:** Annual coronary angiography with **Intravascular Ultrasound (IVUS)**, as angiography alone may underestimate the diffuse narrowing. 4. **Malignancy:** The risk of lymphomas (PTLD) and skin cancers increases significantly in the late phase due to long-term immunosuppression.
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