Figure 814

Crossmatch methods. Early reports correlating a positive crossmatch between recipient serum and donor lymphocytes with hyperacute rejection of transplanted kidneys led to establishing tests of recipient sera as the standard of practice in transplantation. However, controversy remains regarding 1) the level of sensitivity needed for crossmatch testing; 2) the relevance of B-cell crossmatches, a surrogate for class II incompatibilities; 3) the relevance of immunoglobulin class and subclass of donor-reactive antibodies; 4) the significance of historical antibodies, ie, antibodies present previously but not at the time of transplantation; 5) the techniques and type of analyses to be performed for serum screening; and 6) the appropriate frequency and timing of serum screening. Despite a number of variables, when the data from reported studies are considered collectively, several observations can be made. Human leukocyte antigen-donor-specific antibodies present in the recipient at the time of transplantation are a serious risk factor that significantly diminishes graft function and graft survival. Antibodies specific for human leukocyte antigen class II antigens (HLA-DR and -DQ) are as detrimental as are those specific for class I antigens (HLA-A, -B, and -C). The degree of risk resulting from HLA-specific antibodies varies among immunoglobulin classes, with immunoglobulin G antibodies representing the most serious risk. AHG—antiglobulin-augmented lymphocytotoxicity.

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