Diagnostic utility of quantitative cytomegalovirus DNA polymerase chain reaction in intestinal biopsies from patients with inflammatory bowel disease.

OBJECTIVES: Diagnostic utility of cytomegalovirus (CMV) DNA quantitative polymerase chain reaction (qPCR) in inflammatory bowel disease (IBD) has not been established. We aimed to compare diagnostic utility of qPCR for CMV in biopsy specimens with blood, serology, and histopathology.

MATERIALS AND METHODS: A total of 132 patients were included (92 ulcerative colitis [UC], 9 Crohn's disease, and 31 unclassified IBD). Comparison between CMV IgM, CMV DNA qPCR in biopsy, in blood and histopathology was done. Positive result in any of the test was considered as CMV infection. Various risk factors for CMV association with IBD were analyzed.

RESULTS: Confirmed CMV infection was seen in 41 (31.1%) patients. Diagnostic sensitivity of different assays was: DNA in biopsy seen in 37 (90.2%), DNA in blood in 19 (46.3%), CMV IgM in 15 (36.5%), and histopathology in 8 (19.5%). Thirty-two UC cases were further followed up for a median time of 14.0 ( R : 3-31) months. They were grouped as group I - biopsy and blood DNA both positive (14, 43.7%), Group II - biopsy positive and blood negative (17, 53.1%), and Group III - biopsy negative but blood positive (1, 3.1%). CMV DNA viral load in Group I was significantly higher (mean: 4.2 ± 1.0 log10 copies/mg) than Group II (mean: 3.2 ± 0.6 copies/mg) and Group III (viral load: 2.69 log10 copies/ml), P < 0.001. Steroid refractoriness was seen more in Group I cases ( n = 9) P < 0.001. A cutoff of ≥2.5 log10 copies/mg of DNA in tissue was predictive for steroid refractoriness (AUROC = 0.84).

CONCLUSIONS: Quantitation of CMV DNA in intestinal biopsy is a useful diagnostic tool and can predict response to steroid treatment in patients with UC.