HLA antigens on red blood cells. Two donors with extraordinarily strong reactivity

We have shown exceptionally strong HLA reactivity of the red blood cells (RBC) of two healthy blood donors, concerning several HLA antigens. HLA antigens not usually detectable on RBC are also expressed on the RBC of these donors. The RBC show a broad spectrum of reactivity with sera containing HLA antibodies. Absorption/elution experiments with these RBC and HLA antisera proved successful. Absorption studies with leucocytes showed that HLA-A2 and A28 behaved as separate specificities also on RBC, even though antisera always seem to contain heamagglutinins that react with both specificities. We found no evidence that HLA is associated with beta2-microglobulin on the RBC membrane.