Abstract
Detection of anti-class II antibodies by panel response assay (PRA) and flow crossmatch techniques carries an important value in terms of graft function. Even low levels of preformed alloantibodies to HLA class II antigens represent a risk of rejection. We present here a method for blocking non-specific flow crossmatch reactions using pooled, heat-inactivated rabbit serum. This method shows very low background and minimal non-specific reactions. In addition, it avoids the use pronase enzyme that can non-specifically digest different cell surface proteins.