Detection of urothelial Lewis antigens with monoclonal antibodies

The detectability of Lewis a and b antigens (Lea, Leb) was examined in the normal urothelium of 28 human subjects whose red blood cells (RBCs) were also tested for Lea and Leb. Mouse monoclonal antibodies as well as goat and human antisera were used on paraffin-processed and fresh-frozen tissues. Multiple biopsy specimens from the same individual were studied in order to evaluate temporal as well as topographic consistency of the results. In addition, the expression of the Lewis antigens in the appendiceal mucosa was investigated in 9 of these patients. The antibodies against Lea reacted with the urothelium of all patients with either Lea+b- or Lea-b+ RBC phenotype. None of the 5 patients with Lea-b- RBCs had Lea urothelial reactivity. The antibodies against Leb reacted with the urothelium of all patients with Lea+b- or Lea-b+ RBCs and with 2 of the 5 patients with Lea-b- RBCs. The mucin in the goblet cells of the appendiceal mucosa was positive only for the Lewis antigen that was also detectable of the individual's RBCs. These findings indicate that the expression of Lewis antigens in nonsecretory epithelia may not follow the same principles as in the blood and secretions.