Published online Feb 14, 2016. doi: 10.3748/wjg.v22.i6.2030
Peer-review started: September 10, 2015
First decision: October 14, 2015
Revised: November 19, 2015
Accepted: December 19, 2015
Article in press: December 19, 2015
Published online: February 14, 2016
Processing time: 136 Days and 12.5 Hours
The link between cytomegalovirus (CMV) infection and inflammatory bowel diseases remains an important subject of debate. CMV infection is frequent in ulcerative colitis (UC) and has been shown to be potentially harmful. CMV reactivation needs to be diagnosed using methods that include in situ detection of viral markers by immunohistochemistry or by nucleic acid amplification techniques. Determination of the density of infection using quantitative tools (numbers of infected cells or copies of the genome) is particularly important. Although CMV reactivation can be considered as an innocent bystander in active flare-ups of refractory UC, an increasing number of studies suggest a deleterious role of CMV in this situation. The presence of colonic CMV infection is possibly linked to a decreased response to steroids and other immunosuppressive agents. Some treatments, notably steroids and cyclosporine A, have been shown to favor CMV reactivation, which seems not to be the case for therapies using anti-tumor necrosis factor drugs. According to these findings, in flare-ups of refractory UC, it is now recommended to look for the presence of CMV reactivation by using quantitative tools in colonic biopsies and to treat them with ganciclovir in cases of high viral load or severe disease.
Core tip: There is increasing evidence for the deleterious effect of in situ cytomegalovirus (CMV) reactivation in flare-ups of refractory ulcerative colitis. In patients aged > 30 years with a high density of infection in the colonic tissue, or with stigmata of severe disease associated with colonic markers of CMV reactivation (whatever the density of infection), treatment with ganciclovir is highly recommended, together with anti-tumor necrosis factor monoclonal antibody therapy in the absence of any contraindication to these drugs. For validating the present strategy based on our experience and the in-depth analysis of the available literature presented in this review, prospective randomized controlled studies are urgently needed.