Cytomegalovirus Infection in Idiopathic Inflammatory Bowel Disease: Clinicopathologic Analysis of 6 Cases

ABSTRACT

Cytomegalovirus (CMV) infection is an uncommon association with idiopathic inflammatory bowel disease (IBD) often leading to a variety of serious complications. A total of 41 resected cases of IBD were examined to elucidate the pathologic features of intestinal CMV infection which was assessed by histologic examination and confirmed by immunohistochemistry with CMV antibody. Six cases were positve for CMV antibody; five cases in 19 ulcerative colitis (UC, 26.3%) and one case in 22 Crohn's disease (CD, 4.5%). Of 7 cases of the steroid-treated UC group, five cases were superinfected with CMV (71.4%) but none in 12 cases of the steroid-untreated UC group. All of the five CMV-positive cases in UC showed deep ulceration and transmural inflammation, while none of 10 UC cases without above features were CMV positive. Fibrinoid necrosis and thrombi were found in 83.3% of the CMV infected group, while none in the CMV-negative group of UC cases (p=0.01). We conclude that IBD, particularly UC, is susceptible to the CMV infection when steroid hormone is administered, and that deep colonic ulceration, transmural inflammation and fibrinoid necrosis of vasculature may suggest superinfection of CMV in UC patients. It seems that deep colonic ulceration may be the consequence of an ischemic change following vascular luminal occlusion or vasculitis by CMV infection.