Low frequency of cytomegalovirus infection during exacerbations of inflammatory bowel diseases

Although numerous reports have described inflammatory bowel diseases (IBDs) complicated with cytomegalovirus (CMV) infection, the virus participation as an exacerbating factor remains unclear. The aim of this study was thus to clarify the clinical significance of CMV infection complicating exacerbation and to correlate CMV detection with various characteristics in IBD patients. Sixty-seven colonic biopsies obtained from 53 patients admitted for IBD exacerbation were retrospectively analyzed by real-time PCR assay. The CMV genome was detected in seven (10.4%) colonic biopsies related to seven patients (three ulcerative colitis and four Crohn's diseases). Among the patients with IBD studied, patients with evidence of CMV infection were older (P = 0.047), were more likely male gender (relative risk [RR] 4.48; 95% confidence interval [CI] 0.94-21.36), received corticosteroids (RR 3.2; CI 0.79-13.02) or azathioprine (RR 3.17; CI 0.80-12.57) treatments, presented more extended lesions (RR for rectum-sigmoid-left colon 3.75 (0.0-69.37) and for pancolitis 2.45 (0.36-16.23)), and had a more severe disease (RR 3.3; CI 0.87-12.48) than those without CMV infection. Viral loads measured in the colonic mucosa of infected patient ranged from 5 to 236961 genome copies by microgram of total extracted DNA. No relationship was observed between the severity of the disease and the viral load level. Furthermore, CMV disappeared in five infected IBD patients in remission without antiviral agents. In conclusion, these results showed infrequent CMV detection in colonic biopsies of IBD patients during exacerbation leaving open the question of the relationship between CMV reactivation and the onset or the severity of IBD exacerbation.