Alterations in the immunohistochemical expression of Das-1 and CG-3 in colonic mucosal biopsy specimens helps distinguish ulcerative colitis from Crohn disease and from other forms of colitis.

Distinction between ulcerative colitis (UC) and Crohn disease (CD) in mucosal biopsies is often difficult. Das-1 and CG-3 are monoclonal antibodies directed against an unknown colonic epithelial protein and human tropomyosin isoform-5, respectively, both show altered expression in patients with UC. In this study, we evaluated the utility of Das-1 and CG-3 in distinguishing UC from CD and from other types of colitis. One colonic biopsy specimen from each of 85 patients with confirmed UC (n=25), CD (n=15), lymphocytic (n=15), collagenous (n=15), and ischemic (n=15) colitis, and also 10 samples from normal controls, were stained for Das-1 and CG-3 using standard techniques. Reactivity for Das-1 and CG-3 was noted to be absent or present, and the location (ie, surface+/-crypt epithelium) and degree (weak or strong) of CG-3 staining was recorded. Loss of Das-1 staining occurred more frequently in UC (96%) compared with CD (20%), lymphocytic (20%), collagenous (13%), and ischemic colitis (0%) cases, as well as controls (10%, P<0.001 for all comparisons). CG-3 positivity in crypt epithelium was significantly more common in UC (52%) compared with the other groups (P< or =0.02 for all comparisons). The combination of strong crypt CG-3 staining and loss of Das-1 staining was noted in 44% of UC cases, but not in any other type of colitis (P=0.003 for all comparisons). We conclude that the patterns of Das-1 and CG-3 staining in colonic mucosal biopsies may be clinically useful in distinguishing UC from CD and from other colitidies.