Cellular localization of blood group antigens (including HLA markers) in human bladder urothelium.

Expression of A, B, H, Lewis, I, i, HLA class I and class II antigens was studied on 81 urinary bladder samples. Striking variation in the expression of HLA class II and to a lesser extent of HLA class I determinants was observed. Expression of at least five distinct A (or B) determinants, the synthesis of which is controlled by H, A, B, secretor and Lewis genes, was demonstrated by using a panel of reagents directed against different A, B and H epitopes. These results suggest that evaluation of blood group changes during tumoral processes requires the precise determination of the specificity of reagents used and the knowledge of ABO, Lewis and secretor phenotypes for each patient. ABH and related antigens should now be regarded as tissue antigens with a complex genetic regulation and expression.