The detection of clinically significant erythrocyte alloantibodies using a human mononuclear phagocyte assay.

Red blood cell (RBC) allo- or autoantibodies, which markedly reduce the survival of transfused or autologous RBC, are considered to be clinically significant antibodies. The occurrence of antibodies against high-incidence antigens, which are occasionally associated with clinically significant RBC destruction or are of unknown clinical significance, often creates delays in providing blood to patients. In the majority of cases these antibodies are benign; however, clinically significant examples of these antibodies have been reported. An in vitro homologous human mononuclear phagocyte assay (MPA) was used to study antibodies directed against specificities associated with variable clinical significance. Two antibodies reported to be clinically significant and 25 antibodies known to be clinically insignificant were tested by MPA. The results indicate that clinically significant antibodies have a significantly higher score than do clinically insignificant antibodies, with no overlap observed between the two groups. An additional eight antibodies with unknown clinical significance were tested. None of these antibodies had scores in the clinically significant range.