Histocompatibility antigens (HLA-A,B,C) are not detectable in molar villous fluid.

Cell-free villous fluid from healthy and necrotic molar villi did not contain detectable soluble HLA Class I (HLA-A,B,C) antigens; therefore, HLA sensitization of the maternal host is probably not attributable to shedding of HLA antigens by viable or degenerating HLA-positive stromal cells. The method developed for this study, a combination of immunoprecipitation and Western blot techniques, employed specific antibodies for positive identification of the HLA heavy chain. The pathogenesis of complete molar pregnancy may be better understood through further study of the mechanisms of HLA sensitization of the maternal host and the host's response to these foreign antigens.