Cytomegalovirus Infection in Ulcerative Colitis is Related to Severe Inflammation and a High Count of Cytomegalovirus-positive Cells in Biopsy Is a Risk Factor for Colectomy

Abstract

Background and aims: Cytomegalovirus [CMV] infection often reactivates in the course of inflammatory bowel disease, but the significance of this remains disputable. Our aim was to evaluate whether severity of CMV colitis is associated with colectomy risk in ulcerative colitis [UC] patients. The secondary aim was to evaluate agreement between immunohistochemistry [IHC] and blood CMV polymerase chain reaction [PCR].

Methods: UC patients with CMV assessment of the colon, hospitalised in a referral unit between 2005 and 2012 were retrospectively identified. The course and severity of the disease were analysed, with inflammation graded histologically across the range 0-3. The numbers of CMV IHC-positive cells per biopsy section were counted, and results for blood CMV PCR were also retrieved. Data on colectomies were also collected.

Results: Of 141 patients, 95 were analysed, with 33 found to be CMV IHC-positive and 62 negative. The colectomy risk was significantly higher in patients with ≥ 5 IHC-positive cells, as opposed to those with none or less than 5 [p = 0.014] with median follow-up of 1.9 and 3.2 years, respectively. The CMV IHC-positive patients had lower haemoglobin [median 11.0g/dl vs 12.0; p = 0.028] and albumin [median 29.5g/l vs 33.1; p = 0.038] levels and more intense histological inflammation [p = 0.020] compared with CMV IHC-negative patients. There was substantial agreement between IHC and blood PCR [Cohen's kappa coefficient 0.72].

Conclusions: Five or more CMV IHC-positive cells per biopsy section were indicative of a greater colectomy risk. CMV infection was related to more severe inflammation. Blood CMV PCR is a useful tool in UC.

Keywords: Ulcerative colitis; colectomy risk; cytomegalovirus; immunohistochemistry; polymerase chain reaction.