Usefulness of quantitative real-time PCR assay for early detection of cytomegalovirus infection in patients with ulcerative colitis refractory to immunosuppressive therapies

Background: Studies suggest that cytomegalovirus (CMV) infection exacerbates ulcerative colitis (UC) refractory to immunosuppressive therapies. Early and accurate diagnosis of CMV infection is important for the treatment of UC. We evaluated the usefulness of quantitative real-time polymerase chain reaction (PCR) for detecting CMV infection in inflamed colonic mucosa of patients with UC refractory to immunosuppressive therapies. Methods: From 2003 to 2006, 30 patients (mean age: 41 +/- 18 years: 14 men, 16 women) with UC refractory to immunosuppressive therapies were enrolled in the study. We evaluated CMV infection by CMV antigenemia, histologic examination, and quantitative real-time PCR for CMV using colonic mucosa and investigated the clinical outcomes of antiviral therapy. Results: CMV-DNA was detected only in the inflamed colonic mucosa in 17 (56.7%) of 30 patients. Of the 17 CMV-DNA-positive patients, 4 were positive for CMV antigenemia or inclusion bodies on histologic examination; of the 13 CMV-DNA-negative patients none was positive for CMV antigenemia or inclusion bodies. Of the 17 CMV-DNA-positive patients, 12 (70.6%) were treated with ganciclovir for 2 weeks and 10 patients went into remission. Two other patients required colectomy after antiviral therapy. In contrast, of the 13 CMV-DNA-negative patients 12 (92.3%) achieved remission after intensifying their immunosuppressive therapies. Conclusions: Quantitative real-time PCR assay for detecting CMV-DNA is useful for early, accurate diagnosis of CMV infection in patients with UC refractory to immunosuppressive therapies, enabling prompt and appropriate treatment.