THE DIFFERENTIAL EXPRESSION OF A NOVEL INTESTINAL EPITHELIAL GLYCOPROTEIN IN VARIOUS FORMS OF INFLAMMATORY BOWEL-DISEASE

A13D8 is a monoclonal IgM antibody that identifies an as yet unknown a ntigen that is expressed intensely and ubiquitously in enterocytes. Im munohistochemically, it was shown that A13D8 has a granular supranucle ar staining pattern in columnar epithelial cells of normal small intes tine and the colon, In ulcerative colitis, this staining pattern was r etained. However, during active inflammation, staining also was eviden t in goblet cells, To test whether this feature of goblet cell stainin g was unique to ulcerative colitis, tissue sections from a variety of colitides were examined. Crohn's disease, infections colitis, and isch emic colitis had similar staining patterns to that seen with ulcerativ e colitis. There was significantly more inflammation in the biopsies f rom patients with ulcerative colitis and Crohn's disease with positive goblet cell staining than in the biopsies from those patients with ne gative goblet cell staining, Almost all positive goblet cell staining in ulcerative colitis and Crohn's disease occurred in biopsies that we re actively. inflamed, whereas there was rare staining in biopsies tha t were noninflamed (regardless of whether or not there was active infl ammation elsewhere in the colon). Ileal goblet cells stained positivel y with A13D8 only in cases of active ileitis. In cases of collagenous colitis, with comparable degrees of inflammation to that seen in ulcer ative colitis and Crohn's disease, there was rarely goblet cell staini ng and in graft-versus-host disease goblet cell staining of A13D8 was not observed, The binding of A13D8 to tissue sections was completely i nhibited by N-acetyl-D-galactosamine. These results, in conjunction wi th immunochemical studies, suggest that the antibody recognizes an N-a cetyl-D galactosamine-containing epitope on a glycoprotein(s). In conc lusion, these data suggest that A13D8 recognizes a glycoprotein expres sed by intestinal columnar epithelial cells and during specific inflam matory states, particularly those associated with a neutrophilic infil trate, becomes evident in goblet cells, Further work is required to es tablish the exact nature of this molecule and whether it is a pro- or anti-inflammatory factor.