Six weeks after allogeneic bone marrow transplantation for leukemia, a patient develops a maculopapular rash over palms and soles, watery diarrhea, and rising bilirubin with cholestatic hepatitis. Which cellular event initiates this complication?
- A Recipient CD8+ T cells destroying donor hematopoietic cells
- B Donor mature T cells recognizing recipient alloantigens as foreign and mounting a response ✓
- C Preformed donor antibodies binding recipient endothelium and fixing complement
- D Recipient B cells producing autoantibodies against donor HLA molecules
Explanation
Graft-versus-host disease occurs when immunocompetent mature T cells contained in the donor graft recognize recipient HLA and minor histocompatibility antigens as foreign. These donor T cells proliferate and injure host tissues, targeting skin, gastrointestinal tract, and liver, producing the rash, diarrhea, and cholestatic jaundice described. It requires three conditions: a graft containing immunocompetent T cells, a recipient unable to reject them, and histoincompatibility, hence its association with bone marrow and liver transplantation. Option C describes hyperacute rejection, which is antibody-mediated and occurs within minutes.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.