The distribution of type 1 chain ABH and related histo-blood group antigens in normal cycling human endometrium.

Cycling endometrial tissue was examined immunohistochemically for blood group antigens using a panel of monoclonal antibodies with specificity to type 1 chain carbohydrates. Staining was evaluated against the genetic background (ABO, Lewis, and saliva-secretor status) and the subphase of the menstrual cycle. Expression of type 1 chain antigens in most cases correlated with the genetic background; however, Le(a) and Le(b) antigens were in a few cases demonstrated in endometria with the erythrocyte Le(a-b-) phenotype and Le(b) antigen in erythrocyte Le(a + b-) endometria also. In addition, Le(b) antigen was preferentially expressed in endometria from blood group O individuals. Type 1 chain antigens were, in general, maximally demonstrated in the surface epithelium. Chain 1 A, H, ALe(b), Le(a), and disialosyl-Le(a) (dsLe(a)) determinants were demonstrated only sporadically in functionalis and basalis glands of cycling endometria. Staining for most type 1 chain antigens showed variations that were related to the histomorphology (layer and menstrual phase), and monosialosyl-Le(a) (msLe(a)) seemed to be a marker of secretory differentiation in the endometrium. Our results support the view that synthesis and expression of type 1 chain antigens in human endometrium is influenced by the genetic background and is modulated by the hormonal environment.