Immunopathology Practice Questions

Q: All of the following statements regarding Antineutrophil Cytoplasmic Antibodies (ANCA) are true, EXCEPT:

There are three principal classifications of ANCA.. **Explanation:** The correct answer is **D** because there are only **two** principal classifications of ANCA based on immunofluorescence patterns: **cANCA** (cytoplasmic) and **pANCA** (perinuclear). While a third pattern, xANCA (atypical), is sometimes described in inflammatory bowel disease, it is not considered a "principal" classification in the context of systemic vasculitis. **Analysis of Options:** * **Option A (Incorrect):** This is a true statement. **Proteinase-3 (PR3)** is the major antigen for cANCA. It is located in the azurophilic granules of neutrophils. cANCA is highly specific (approx. 90%) for **Granulomatosis with Polyangiitis (Wegener's)**. * **Option B (Incorrect):** This is a true statement. **Myeloperoxidase (MPO)** is the primary target for pANCA [1]. It is associated with Microscopic Polyangiitis (MPA), Churg-Strauss Syndrome (EGPA), and Pauci-immune Crescentic Glomerulonephritis [1]. * **Option C (Incorrect):** This is a true statement. Unlike cANCA, which is highly specific for vasculitis, **pANCA** can be found in non-vasculitic conditions such as Primary Sclerosing Cholangitis (PSC), Ulcerative Colitis, and Rheumatoid Arthritis. **High-Yield Clinical Pearls for NEET-PG:** * **cANCA/PR3-ANCA:** Associated with Granulomatosis with Polyangiitis (GPA). * **pANCA/MPO-ANCA:** Associated with Microscopic Polyangiitis (MPA) and Eosinophilic Granulomatosis with Polyangiitis (EGPA) [1]. * **Diagnostic Gold Standard:** The current recommendation is to use **ELISA** to confirm the specific antigen (PR3 or MPO) after an initial screening with **Indirect Immunofluorescence (IIF)**. * **Monitoring:** ANCA titers often correlate with disease activity; a rise in titers may predict a relapse. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 917-918.

Question 1

What is amyloidosis?

Accepted Answer

Protein misfolding

Answer

RNA misfolding

Answer

DNA repair defect

Answer

Mitochondrial defect

Question 2

ABO incompatibility is an example of which hypersensitivity reaction?

Accepted Answer

Type-II hypersensitivity reaction

Answer

Type-I hypersensitivity reaction

Answer

Type-III hypersensitivity reaction

Answer

Type-IV hypersensitivity reaction

Question 3

Which of the following is an immune privilege site?

Accepted Answer

Seminiferous tubule

Answer

Optic nerve

Answer

Area postrema

Answer

Spinal canal

Question 4

Hyperacute rejection is due to:

Accepted Answer

Preformed antibodies

Answer

Cytotoxic T-lymphocyte mediated injury

Answer

Circulating macrophage mediated injury

Answer

Endothelialitis caused by donor antibodies

Question 5

A 30-year-old man presents with fever, chills, and neck stiffness. Cerebrospinal fluid analysis reveals gram-negative diplococci. The patient has a history of sepsis with meningococcemia. Which immunologic deficiency is most likely responsible?

Accepted Answer

Complement deficiency C5-C9

Answer

Post-splenectomy status

Answer

Drug-induced agranulocytosis

Answer

Interleukin-12 receptor deficit

Question 6

C-ANCA positivity indicates antibody formation against which antigen?

Accepted Answer

Proteinase 3

Answer

Myeloperoxidase

Answer

Cytoplasmic antinuclear antibody

Answer

Anti centromere antibody

Question 7

Necrotizing arteritis with fibrinoid necrosis is mediated by which of the following?

Accepted Answer

Antigen-antibody complex

Answer

Immediate hypersensitivity

Answer

Cell-mediated immunity

Answer

Cytotoxic cell-mediated

Question 8

All of the following statements regarding Antineutrophil Cytoplasmic Antibodies (ANCA) are true, EXCEPT:

Accepted Answer

There are three principal classifications of ANCA.

Answer

Proteinase-3, found in neutrophil azurophilic granules, is the primary antigen for cANCA.

Answer

Myeloperoxidase is the main target antigen for pANCA.

Answer

A pANCA staining pattern is linked to nonvasculitic conditions, including rheumatic and other autoimmune diseases.

Question 9

Which of the following tests should be done to optimize graft uptake in bone marrow transplant?

Accepted Answer

HLA matching

Answer

Blood grouping

Answer

Culture for infection

Answer

All of the above

Question 10

Which HLA association is seen with Myasthenia gravis?

Accepted Answer

HLA-B8

Answer

HLA-B27

Answer

HLA-B51

Answer

HLA-B47

Immunopathology — MCQs

Immunopathology — MCQs

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