CHT Transplant Immunology

Question 1

Which type of rejection occurs within minutes to hours after transplantation and is mediated by preformed donor-specific antibodies?

Accepted Answer

Hyperacute rejection

Answer

Hyperacute rejection is caused by preformed donor-specific antibodies that immediately activate complement and cause thrombosis of graft vasculature.

Question 2

Which immune cells are primarily responsible for acute cellular rejection?

Accepted Answer

CD4+ and CD8+ T lymphocytes

Answer

Acute cellular rejection is driven predominantly by host CD4+ and CD8+ T cells that recognize donor alloantigens as foreign.

Question 3

What is the 'indirect pathway' of allorecognition?

Accepted Answer

Host T cells recognize donor peptides presented by self HLA on host APCs

Answer

In the indirect pathway, donor HLA proteins are processed into peptides and presented by recipient APCs on self-HLA molecules to recipient T cells.

Question 4

Chronic allograft nephropathy is most closely associated with which long-term immunological mechanism?

Accepted Answer

Persistent donor-specific antibody (DSA)-mediated injury

Answer

Chronic antibody-mediated rejection driven by DSA leads to progressive microvascular injury, transplant glomerulopathy, and eventual graft loss.

Question 5

Which complement pathway is most directly activated by donor-specific antibodies (DSA) bound to graft endothelium?

Accepted Answer

Classical complement pathway

Answer

DSA bound to donor endothelial HLA antigens activate the classical complement pathway via C1q, leading to C4d deposition.

CHT - Certified Histocompatibility Technologist Practice Test