Human Leukocyte Antigen (HLA) part 10

During infection, microbial antigens are processed by APC and presented via HLA molecules to T cells that elicit cytotoxic and delayed-type hypersensitivity-like inflammatory reactions in the allograft. The so-called HLA restricted mechanisms are more effective if the relevant HLA antigens are shared between recipient T cells  and donor APC  or target cells. For example, an HLA-DR1,2 patient shares HLA-DR1  with an HLA-DR1,3  donor; if the patients has produced T cells that react with  an antigenic peptide presented by HLA-DR1 on their own APC, the T cells might also react with the same peptide presented by HLA-DR1 on donor cells.