Immunosuppressants and immunostimulants: pharmacology MCQs With Answer

Introduction:

This set of MCQs on Immunosuppressants and Immunostimulants is tailored for M.Pharm students preparing for Advanced Pharmacology-II exams. The questions emphasize mechanisms, clinical uses, pharmacokinetics, monitoring parameters, adverse effects and key drug interactions—bridging basic pharmacology with therapeutic decision-making. Emphasis is given to biologics (monoclonal antibodies and fusion proteins), small-molecule immunomodulators, and clinically important immunostimulants. Each item tests applied knowledge important for safe and effective drug therapy, therapeutic drug monitoring and patient counselling. Use these questions to gauge readiness, focus revision on knowledge gaps, and deepen understanding of immunomodulatory pharmacotherapy in modern clinical practice.

Q1. Which of the following best describes the primary mechanism of action of tacrolimus?

• Inhibits inosine monophosphate dehydrogenase, reducing guanosine nucleotide synthesis
• Binds FKBP and inhibits calcineurin, reducing IL-2 transcription
• Blocks mammalian target of rapamycin (mTOR) to arrest T-cell proliferation
• Alkylates DNA leading to lymphocyte apoptosis

Correct Answer: Binds FKBP and inhibits calcineurin, reducing IL-2 transcription

Q2. Which monitoring parameter is most important for dose adjustment of cyclosporine in transplant patients?

• Serum creatinine alone without drug level monitoring
• Therapeutic drug trough level and renal function tests
• Complete blood count and liver enzymes weekly
• Plasma uric acid and electrolyte panel

Correct Answer: Therapeutic drug trough level and renal function tests

Q3. Mycophenolate mofetil exerts selective immunosuppression mainly through inhibition of which enzyme?

• Dihydrofolate reductase
• Inosine monophosphate dehydrogenase (IMPDH)
• Thymidylate synthase
• Topoisomerase II

Correct Answer: Inosine monophosphate dehydrogenase (IMPDH)

Q4. Which adverse effect is most closely associated with sirolimus (rapamycin) therapy?

• Nephrotoxicity as a primary dose-limiting toxicity
• Severe hyperglycemia and pancreatitis
• Hyperlipidemia and impaired wound healing
• Cardiotoxicity leading to heart failure

Correct Answer: Hyperlipidemia and impaired wound healing

Q5. Azathioprine toxicity is markedly increased when co-administered with which drug due to xanthine oxidase inhibition?

• Allopurinol
• Rifampicin
• Carbamazepine
• Probenecid

Correct Answer: Allopurinol

Q6. Belatacept (CTLA-4-Ig) reduces T-cell activation primarily by interfering with which interaction?

• IL-2 binding to IL-2 receptor
• CD28 co-stimulatory signaling via CD80/CD86
• TNF-alpha binding to TNF receptor
• CD20-mediated B-cell activation

Correct Answer: CD28 co-stimulatory signaling via CD80/CD86

Q7. Which immunosuppressive drug is activated intracellularly to 6-mercaptopurine and its metabolism is affected by TPMT polymorphism?

• Mycophenolate mofetil
• Azathioprine
• Cyclosporine
• Sirolimus

Correct Answer: Azathioprine

Q8. Which monoclonal antibody targets CD20 and is used to deplete B cells in autoimmune diseases and lymphomas?

• Rituximab
• Alemtuzumab
• Infliximab
• Basiliximab

Correct Answer: Rituximab

Q9. Which immunostimulant is an approved recombinant cytokine used to treat neutropenia by stimulating granulocyte production?

• Filgrastim (G-CSF)
• Interferon-alpha
• Interleukin-1
• Thrombopoietin receptor agonist

Correct Answer: Filgrastim (G-CSF)

Q10. A patient on azathioprine develops severe myelosuppression after starting allopurinol. What is the best pharmacological explanation?

• Allopurinol induces hepatic enzymes increasing azathioprine clearance
• Allopurinol inhibits xanthine oxidase, decreasing 6-MP catabolism and increasing toxicity
• Allopurinol competes for TPMT, reducing azathioprine activation
• Allopurinol increases renal excretion of azathioprine metabolites

Correct Answer: Allopurinol inhibits xanthine oxidase, decreasing 6-MP catabolism and increasing toxicity

Q11. Which of the following agents acts by blocking TNF-alpha and carries a risk of reactivation of latent tuberculosis?

• Etanercept and infliximab
• Belatacept
• Sirolimus
• Mycophenolate mofetil

Correct Answer: Etanercept and infliximab

Q12. Which statement best describes the immunosuppressive action of corticosteroids at the molecular level?

• They irreversibly inhibit DNA replication in lymphocytes
• They enhance NF-κB activity to suppress cytokine production
• They modulate gene transcription to reduce pro-inflammatory cytokine synthesis
• They selectively deplete B cells via complement activation

Correct Answer: They modulate gene transcription to reduce pro-inflammatory cytokine synthesis

Q13. Which drug is a JAK inhibitor used as an oral immunomodulator in rheumatoid arthritis with risk of cytopenias and thromboembolism?

• Tofacitinib
• Infliximab
• Basiliximab
• Rituximab

Correct Answer: Tofacitinib

Q14. Which immunostimulant acts as a TLR7 agonist and is used topically for certain viral and neoplastic skin lesions?

• Imiquimod
• Interferon-gamma
• IL-2 (aldesleukin)
• Bacillus Calmette–Guérin (BCG)

Correct Answer: Imiquimod

Q15. Which agent is an IL-2 receptor (CD25) antagonist used to prevent acute rejection immediately post-transplant?

• Basiliximab
• Rituximab
• Mycophenolate mofetil
• Sirolimus

Correct Answer: Basiliximab

Q16. Which drug’s immunosuppressive effect is primarily due to inhibition of pyrimidine synthesis by blocking dihydroorotate dehydrogenase?

• Leflunomide
• Methotrexate
• Azathioprine
• Cyclophosphamide

Correct Answer: Leflunomide

Q17. Which complication is most closely associated with long-term high-dose systemic corticosteroid therapy?

• Aplastic anemia
• Opportunistic infections, osteoporosis, hyperglycemia
• Renal tubular acidosis
• Severe peripheral neuropathy

Correct Answer: Opportunistic infections, osteoporosis, hyperglycemia

Q18. Which of the following immunosuppressive drugs is most associated with nephrotoxicity and hypertension due to vasoconstriction of renal arterioles?

• Cyclosporine and tacrolimus
• Mycophenolate mofetil
• Rituximab
• Belatacept

Correct Answer: Cyclosporine and tacrolimus

Q19. Aldesleukin (recombinant IL-2) is used therapeutically to stimulate which immune cell population for antitumor effect?

• Neutrophils
• Natural killer cells and cytotoxic T lymphocytes
• B lymphocytes producing antibodies
• Eosinophils

Correct Answer: Natural killer cells and cytotoxic T lymphocytes

Q20. Which precaution is essential when administering live attenuated vaccines to patients receiving significant immunosuppression?

• Live vaccines are safe and should be given routinely regardless of therapy
• Defer live attenuated vaccines until immunosuppression is reduced or stopped
• Increase vaccine dose to overcome immunosuppression
• Combine with rituximab to enhance response

Correct Answer: Defer live attenuated vaccines until immunosuppression is reduced or stopped

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