Blood and immunity: hyperacute graft rejection: practice question

A Physiology 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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Physiology · Blood and immunity: hyperacute graft rejection

Sample item

Within minutes of revascularisation, a transplanted kidney becomes mottled and cyanotic. Which mechanism is responsible?

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

The answer and the reasoning

C. Pre-formed recipient antibodies against donor ABO or HLA antigens

Hyperacute rejection occurs within minutes to hours when pre-formed antibodies, for example anti-ABO or anti-HLA, bind to graft endothelium, activate complement and cause thrombosis. It is prevented by ABO matching and a negative cross-match.

Option by option

  • A. Graft T cells attacking host tissues

    Graft T cells attacking the host describes graft-versus-host disease.

  • B. Donor-reactive CD8 T cells infiltrating over several weeks

    T-cell infiltration is acute cellular rejection, which takes days to weeks.

  • C. Pre-formed recipient antibodies against donor ABO or HLA antigens (correct)

    Correct. Pre-formed antibodies act as soon as blood flow is restored.

  • D. Slow arteriolar fibrosis from chronic alloimmune injury

    Fibrosis from chronic injury develops over months to years.

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 Physiology question

What is the answer to this Physiology question?

The best answer is C, Pre-formed recipient antibodies against donor ABO or HLA antigens. Hyperacute rejection occurs within minutes to hours when pre-formed antibodies, for example anti-ABO or anti-HLA, bind to graft endothelium, activate complement and cause thrombosis.

Why is "Graft T cells attacking host tissues" not the answer?

Graft T cells attacking the host describes graft-versus-host disease.

Why is "Donor-reactive CD8 T cells infiltrating over several weeks" not the answer?

T-cell infiltration is acute cellular rejection, which takes days to weeks.

Why is "Slow arteriolar fibrosis from chronic alloimmune injury" not the answer?

Fibrosis from chronic injury develops over months to years.

What concept does this question test?

It tests Blood and immunity: hyperacute graft rejection in Physiology. It is prevented by ABO matching and a negative cross-match.

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 Blood and immunity: hyperacute graft rejection?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.