last updated 25-09-2022

HLA class I and II antigens

HLA matching

The human leukocyte antigens (HLA) have been defined by serological methods. There exist two kinds of receptor classes for major histocompatibility complexes (MHC): MHC class I and MHC class II. The class I antigens are HLA-A, HLA-B, and HLA-C and the class II are HLA-DR-, HLA-DQ, and HLA-DP. By determining HLA type an assessment of histocompatbility is made.

It is thought that HLA-A, HLA-B and HLA-DR are the most relevant for graft outcome. CD4 Th1 and CD8 T cells recognize the graft’s MHC class I and II. Most transplants are performed across some HLA class I and/or II difference, and thus generate T-cell mediated allo-reactions. This is called acute rejection, it takes days to develop and can be prevented.

1

Which one of the following interactions between surface molecules must take place for a T-cytotoxic cell to be stimulated to begin to destroy a virus-infected cell? (assume that the antigen and the receptor are also interacting correctly) 

2

A man (50) with end stage renal disease from long-standing diabetes mellitus receives a cadaveric renal transplant. A month later, he has increasing malaise. Findings: urine output decreases, rising serum urea nitrogen and creatinine. The allograft is biopsied and seen microscopically to be undergoing destruction by cells which are recognizing graft cells expressing class I HLA antigens. Which of the following cells is most likely to mediate this response?