[Cytomegalovirus and its relationship to chronic inflammatory bowel diseases and tumors]

Human cytomegalovirus (hCMV), a member of the Betaherpesvirinae subfamily, was long considered an important pathogen especially in immunocompromised hosts, mainly in post-transplant patients receiving immunosuppressive therapy. Results of many studies from the last decade suggest that cytomegalovirus is a very important pathogen having a greater association with many other diseases. The relationship of hCMV to chronic inflammatory bowel diseases, ulcerative colitis and Crohn's disease, has been long studied but results of the studies have been rather inconclusive. Interestingly, hCMV was found to be more prevalent in lesions of severe ulcerative colitis, in particular ulcerative colitis refractory to immunosuppressive therapy (40-57% in results from clinical studies) than in mild or moderate colitis (up to 5% in most studies). Another group of diseases possibly related to hCMV is tumors. Numerous studies discuss the oncomodulatory role of hCMV in malignant glioblastoma, colorectal adenocarcinomas, prostate cancer and lymphomas. Despite extensive evidence suggesting a possible relationship of hCMV to some tumors, such as successful induction of malignant carcinoma by hCMV latent infection in animal models, hCMV has not been classified as an oncovirus. However, its potential in this respect is apparent.