Immunopathology: mixed cryoglobulinaemia: practice question

A Pathology 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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Pathology · Immunopathology: mixed cryoglobulinaemia

Sample item

A 55-year-old woman with chronic hepatitis C has palpable purpura, arthralgia, low C4 and membranoproliferative glomerulonephritis. The serum precipitates in the cold. What are the cryoglobulins?

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

The answer and the reasoning

B. Polyclonal IgG bound by monoclonal IgM rheumatoid factor

In mixed (type II) cryoglobulinaemia a monoclonal IgM with rheumatoid factor activity binds polyclonal IgG, forming immune complexes that precipitate in the cold and deposit in small vessels. Hepatitis C is the commonest cause, and the picture is a type III hypersensitivity vasculitis.

Option by option

  • A. Monoclonal IgM only

    Monoclonal IgM alone is type I cryoglobulinaemia, as in Waldenstrom macroglobulinaemia.

  • B. Polyclonal IgG bound by monoclonal IgM rheumatoid factor (correct)

    Correct. IgM rheumatoid factor complexed with polyclonal IgG defines the mixed type II form.

  • C. Polyclonal IgA with secretory component

    Secretory IgA is found in mucosal secretions and is not a cryoglobulin.

  • D. Monoclonal IgG light chains only

    Light chains alone are Bence Jones protein and do not precipitate in the cold.

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.

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Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is B, Polyclonal IgG bound by monoclonal IgM rheumatoid factor. In mixed (type II) cryoglobulinaemia a monoclonal IgM with rheumatoid factor activity binds polyclonal IgG, forming immune complexes that precipitate in the cold and deposit in small vessels.

Why is "Monoclonal IgM only" not the answer?

Monoclonal IgM alone is type I cryoglobulinaemia, as in Waldenstrom macroglobulinaemia.

Why is "Polyclonal IgA with secretory component" not the answer?

Secretory IgA is found in mucosal secretions and is not a cryoglobulin.

Why is "Monoclonal IgG light chains only" not the answer?

Light chains alone are Bence Jones protein and do not precipitate in the cold.

What concept does this question test?

It tests Immunopathology: mixed cryoglobulinaemia in Pathology. Hepatitis C is the commonest cause, and the picture is a type III hypersensitivity vasculitis.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Immunopathology: mixed cryoglobulinaemia?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.