Autoimmune disorders: types and mechanisms MCQs With Answer

Autoimmune disorders: types and mechanisms MCQs With Answer

This question set is designed specifically for M.Pharm students studying Immunotechnology. It covers fundamental and advanced concepts of autoimmune diseases, including classifications (organ-specific vs systemic), cellular and molecular mechanisms (central and peripheral tolerance, molecular mimicry, epitope spreading, Treg and Th17 roles), diagnostic markers and assays (ANA patterns, anti-dsDNA, Coombs test), genetic and environmental risk factors (HLA associations, epigenetics, checkpoint inhibitors), and therapeutic strategies (B‑cell depletion, biologics). Each MCQ is intended to deepen mechanistic understanding and prepare students for clinical-pharmacological problem solving and exams. Answers are provided for self-assessment and focused revision.

Q1. What best distinguishes an organ-specific autoimmune disease from a systemic autoimmune disease?

• Autoimmune response is limited to innate immunity only
• Autoantibodies circulate widely causing multi-organ damage
• The immune attack is primarily directed at antigens in a single organ or tissue
• It is always mediated by immune complexes

Correct Answer: The immune attack is primarily directed at antigens in a single organ or tissue

Q2. Which mechanism predominantly explains the pathogenesis of myasthenia gravis?

• Immune complex deposition in neuromuscular junctions
• CD8+ T cell–mediated lysis of motor neurons
• Autoantibodies bind and functionally block the acetylcholine receptor
• Th17-driven neutrophil infiltration of muscle

Correct Answer: Autoantibodies bind and functionally block the acetylcholine receptor

Q3. Molecular mimicry as a mechanism of autoimmunity is best exemplified by which disease association?

• Anti-CCP antibodies in rheumatoid arthritis
• Cross-reactivity between streptococcal M protein and cardiac tissue in rheumatic fever
• Anti-TSH receptor antibodies in Graves’ disease
• Immune complexes containing nucleic acids in SLE

Correct Answer: Cross-reactivity between streptococcal M protein and cardiac tissue in rheumatic fever

Q4. Which HLA genotype is most strongly associated with increased risk of type 1 diabetes mellitus?

• HLA-B27 homozygosity
• HLA-DR3 and HLA-DR4 heterozygosity
• HLA-DR2 homozygosity
• HLA-A2 allele presence only

Correct Answer: HLA-DR3 and HLA-DR4 heterozygosity

Q5. What is the primary outcome of negative selection during T cell development in the thymus?

• Generation of memory T cells
• Positive selection of T cells recognizing self-MHC
• Deletion of strongly self-reactive T cells to prevent autoimmunity
• Differentiation into regulatory B cells

Correct Answer: Deletion of strongly self-reactive T cells to prevent autoimmunity

Q6. Regulatory T cells (Tregs) primarily maintain peripheral tolerance by which mechanism?

• Producing proinflammatory cytokines IL-17 and IFN-γ
• Presenting self-antigen to naïve T cells for activation
• Suppressing autoreactive T cells via IL-10 and TGF-β secretion
• Generating autoantibodies to neutralize self-antigens

Correct Answer: Suppressing autoreactive T cells via IL-10 and TGF-β secretion

Q7. Which definition best describes epitope spreading in autoimmune disease progression?

• Mutation of autoantigens to evade immune detection
• Primary immune response narrows to a single epitope over time
• Immune response expands from the initial epitope to target additional epitopes on the same or different antigens
• Loss of B cell receptor diversity

Correct Answer: Immune response expands from the initial epitope to target additional epitopes on the same or different antigens

Q8. The predominant pathogenic mechanism in systemic lupus erythematosus (SLE) is:

• CD8+ cytotoxic destruction of endocrine cells
• Immune complex deposition with complement activation and inflammation
• Direct blockade of neurotransmitter receptors by IgG
• Granulomatous inflammation driven by Th1 cells

Correct Answer: Immune complex deposition with complement activation and inflammation

Q9. What is the most appropriate initial laboratory test to screen for suspected systemic lupus erythematosus?

• Anti-dsDNA ELISA alone
• Direct Coombs test
• Antinuclear antibody (ANA) by indirect immunofluorescence on HEp-2 cells
• Serum protein electrophoresis

Correct Answer: Antinuclear antibody (ANA) by indirect immunofluorescence on HEp-2 cells

Q10. Which antibody isotype is most efficient at fixing complement via the classical pathway?

• IgA
• IgG4
• IgE
• IgM

Correct Answer: IgM

Q11. Antibody-dependent cellular cytotoxicity (ADCC) is primarily mediated by which effector cell type recognizing IgG-coated targets?

• Neutrophils via complement receptors
• Natural killer (NK) cells via FcγRIII (CD16)
• CD4+ T helper cells through TCR recognition
• Eosinophils via IgA Fc receptors

Correct Answer: Natural killer (NK) cells via FcγRIII (CD16)

Q12. Neonatal lupus is most commonly caused by transplacental transfer of which maternal autoantibodies?

• Anti-centromere antibodies
• Anti-neutrophil cytoplasmic antibodies (ANCA)
• Anti-Ro/SSA and anti-La/SSB antibodies
• Anti-mitochondrial antibodies

Correct Answer: Anti-Ro/SSA and anti-La/SSB antibodies

Q13. Immune-related adverse events, including new-onset autoimmunity, can be caused by cancer immunotherapy targeting which molecules?

• CTLA-4 and PD-1 checkpoint inhibitors that relieve peripheral tolerance
• CD20-targeting antibodies that deplete B cells exclusively
• TNF-α inhibitors that suppress inflammation
• Antifolate chemotherapeutics

Correct Answer: CTLA-4 and PD-1 checkpoint inhibitors that relieve peripheral tolerance

Q14. Which epigenetic change is commonly implicated in the pathogenesis of autoimmune diseases?

• Increased genomic DNA methylation of cytokine genes
• DNA hypomethylation leading to overexpression of immune-related genes
• Permanent histone deletion
• Loss of all non-coding RNAs

Correct Answer: DNA hypomethylation leading to overexpression of immune-related genes

Q15. A peripheral (rim) nuclear pattern on HEp-2 ANA immunofluorescence is most suggestive of which autoantibody?

• Anti-centromere
• Anti-Scl-70 (topoisomerase I)
• Anti-dsDNA
• Anti-RNP

Correct Answer: Anti-dsDNA

Q16. Th17 cells contribute to autoimmune pathology primarily by producing which cytokine that recruits neutrophils and sustains inflammation?

• IL-4
• IL-10
• IL-17
• IFN-α

Correct Answer: IL-17

Q17. Which size of circulating immune complexes is most likely to deposit in tissues and trigger complement-mediated damage?

• Very large complexes that are rapidly cleared by phagocytes
• Intermediate to small complexes that escape efficient clearance
• Monomeric antigen alone
• Soluble cytokine complexes

Correct Answer: Intermediate to small complexes that escape efficient clearance

Q18. Rituximab, used to treat several autoimmune diseases, exerts its therapeutic effect by targeting which molecule?

• CD3 on T cells
• CD20 on B cells
• TNF-α cytokine
• CTLA-4 on regulatory T cells

Correct Answer: CD20 on B cells

Q19. The direct antiglobulin (Coombs) test is used clinically to detect which of the following in autoimmune hemolytic anemia?

• Circulating immune complexes in serum
• Complement split products in plasma
• Autoantibodies or complement bound directly to patient red blood cells
• Anti-platelet antibodies only

Correct Answer: Autoantibodies or complement bound directly to patient red blood cells

Q20. Which autoimmune disease shows the strongest association with HLA-B27?

• Systemic lupus erythematosus
• Hashimoto’s thyroiditis
• Ankylosing spondylitis
• Myasthenia gravis

Correct Answer: Ankylosing spondylitis

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