Synergism and gene dose effect in HLA-DR serology

By mixing HLA-DR antisera of different specificities and testing them against B lymphocytes carrying the corresponding antigens, a synergistic action of HLA-DR antibodies was revealed. Furthermore, it was demonstrated that HLA-DR and HLA-ABC antibodies may act synergistically against appropriate B cells. HLA-DR homozygous B lymphocytes were found to react more strongly with HLA-DR specific antisera than heterozygous cells, thus revealing a gene dose effect in HLA-DR serology. ABO antibodies were found not to react against B lymphocytes, either alone nor in concert with HLA-DR antisera. The practical implications of synergism and gene dose effect in HLA-DR serology are discussed.