Blood group ABO and Lewis antigens in fetal and normal adult bladder urothelium: immunohistochemical study of type 1 chain structures.

Five monoclonal antibodies specific for structural variants of type 1 chain blood group antigens (H, Lea, Leb, A, ALeb) were used to study the distribution of these particular antigens in normal bladder urothelium. The urothelium samples were taken from seven human fetuses (aged seven to 21 weeks) and 19 adults. The adults were blood group A and O individuals, and their antigen expression was compared to ABO, secretor, and erythrocyte Lewis status. Detailed data on the histological location of the antigens were obtained by means of immunohistochemical methods. In fetuses expression of Lewis a and A antigens was stage-dependent, whereas the Lewis b and H antigens were consistently present at all stages. In adults the urothelial blood group antigen expression seemed to be correlated to ABO and secretor status, but not to erythrocyte Lewis type. Secretors expressed primarily ABO isoantigens on their cell membranes, whereas non-secretors (four individuals) expressed inappropriate Lewis antigens. Examination of the histological distribution of the antigens showed results different from earlier examined epithelia. In adult bladder urothelium from A secretors, only the most complex antigens (Leb, A, ALeb) were present in the basal germinative cell layer, whereas the luminal umbrella cell layer expressed both these antigens and showed a unique expression of less complex precursor antigens (H, Lea), as well as sialylated Lewis a antigens.