Disparity in HLA-DR typing and mixed lymphocyte culture reactivity

Prospective HLA-DR matching has been shown to enhance renal graft survival. It has also been demonstrated that the major stimuli in the one-way mixed lymphocyte culture reaction (MLR) are the DR rather than DQ class II histocompatibility antigens. A two antigen DR match between the potential recipient and donor is usually associated with a negative MLR. The findings of two family studies are reported in which HLA-DR identity between the potential recipient and donors did not correlate with the MLR reactivity. These findings further strengthen the need for performing the MLR in conjunction with DR/DQ typing since splits have been described for some of the DR antigens which may not be detected using the currently available commercial typing trays.