Clinicopathologic characteristics of clinically relevant cytomegalovirus infection in inflammatory bowel disease

Background. In this study we aimed to identify clinically relevant patterns of cytomegalovirus (CMV) infection in inflammatory bowel disease. Methods. Twenty-two patients with severe ulcerative colitis (UC), 12 with moderate UC, and 16 with Crohn's disease were studied retrospectively. We confirmed CMV infection immunohistochemically. The patients were classified into three groups according to the density of CMV-infected cells. Clinicopathologic features were compared between the groups. Results. Dense CMV infection was found only in five patients with severe UC. Scattered CMV infection was found in nine patients with severe UC, three with moderate UC, and one patient with Crohn's disease, and in three controls (normal mucosa from early colorectal cancer specimens). For patients with severe UC, severity of CMV infection tended to correlate with older age and more rapid deterioration, including toxic megacolon and panperitonitis. The dense CMV group took significantly higher final daily doses of steroids before the operation, and showed steroid resistance. The frequency of emergency surgery was higher and postoperative hospital stay was significantly longer in the dense CMV group. No significant differences were observed in sex, disease duration, steroid administration (total amount or duration), or frequencies of other therapies among the three groups. Immunohistochemically, CMV positivity in endothelial cells around the ulcer base was a significant feature in dense CMV infection, compared with scattered CMV infection. Conclusions. Older patients with severe steroid-resistant UC may be at particular risk for CMV infection. Dense CMV infection, especially when it occurs predominantly in endothelial cells, may be a useful marker for clinically relevant CMV infection.