Lewis antigens in normal and neoplastic urothelium.

The Lewis (Lea and Leb) antigens are closely related to the A, B, H blood group antigens and have been demonstrated in several secretory epithelia, but their expression in nonsecretory cells has not been studied systematically. This report provides detailed data on the expression of Lea and Leb in normal and neoplastic urothelium. The authors have examined multiple biopsy specimens of normal bladder mucosa and transitional cell carcinomas (TCCs) from 74 patients whose red blood cells (RBCs) were also typed for A, B, H, Lea, and Leb antigens and have correlated tissue antigen detectability with the RBC phenotype and the cytologic grade of malignancy. Antisera of human and animal sources were used in a modified red cell adherence test (RCA), and multiple controls were employed for determination of the specificity of the reactions. Both fresh-frozen and paraffin-processed tissues were examined from each patient. Paraffin processing as well as treatment with ethanol significantly suppressed the tissue reactions. Ninety-four percent of normal mucosa specimens and 73% of TCCs gave positive reactions with both anti-Lea and anti-Leb sera. Abnormal patterns of Lewis reactivity were observed in 43% of Grade III or IV and in 14% of Grade I or II TCCs. Although there was no direct correlation between A, B, H reactivity and Lewis reactivity, all TCCs which had abnormally low reactivity for both the expected Le and A, B, or H antigens were of high grade and invasive.