Immunology: hypersensitivity type II: practice question

A Microbiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Microbiology · Immunology: hypersensitivity type II

Sample item

A 24-year-old smoker has haemoptysis and rapidly rising serum creatinine. Renal biopsy immunofluorescence is performed. Which finding is expected if anti-glomerular basement membrane disease is the cause?

ADominant mesangial deposits of IgABSmooth linear deposits of IgG along the glomerular basement membraneCScanty or absent immunoglobulin depositsDCoarse granular deposits of IgG and C3 along the basement membrane

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Smooth linear deposits of IgG along the glomerular basement membrane

In Goodpasture (anti-GBM) disease, autoantibodies target the non-collagenous domain of the alpha-3 chain of type IV collagen in glomerular and alveolar basement membranes. This type II reaction gives continuous linear IgG staining, in contrast to the granular pattern of immune complex disease.

Option by option

A. Dominant mesangial deposits of IgA
Mesangial IgA is the pattern of IgA nephropathy, which does not cause haemoptysis.
B. Smooth linear deposits of IgG along the glomerular basement membrane (correct)
Correct. Antibody bound along a basement membrane antigen gives a linear pattern.
C. Scanty or absent immunoglobulin deposits
Pauci-immune staining is typical of ANCA-associated vasculitis such as granulomatosis with polyangiitis.
D. Coarse granular deposits of IgG and C3 along the basement membrane
Granular deposits indicate immune complex disease such as post-streptococcal glomerulonephritis.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Smooth linear deposits of IgG along the glomerular basement membrane. In Goodpasture (anti-GBM) disease, autoantibodies target the non-collagenous domain of the alpha-3 chain of type IV collagen in glomerular and alveolar basement membranes.

Why is "Dominant mesangial deposits of IgA" not the answer?

Mesangial IgA is the pattern of IgA nephropathy, which does not cause haemoptysis.

Why is "Scanty or absent immunoglobulin deposits" not the answer?

Pauci-immune staining is typical of ANCA-associated vasculitis such as granulomatosis with polyangiitis.

Why is "Coarse granular deposits of IgG and C3 along the basement membrane" not the answer?

Granular deposits indicate immune complex disease such as post-streptococcal glomerulonephritis.

What concept does this question test?

It tests Immunology: hypersensitivity type II in Microbiology. This type II reaction gives continuous linear IgG staining, in contrast to the granular pattern of immune complex disease.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Immunology: hypersensitivity type II?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.