CMV Disease in IBD: Comparison of Diagnostic Tests and Correlation with Disease Outcome

Significance of cytomegalovirus (CMV) in inflammatory bowel disease (IBD) is unclear due to pathobiology, numerous CMV tests, and disparate treatment outcomes.

Retrospective chart review was done on patients with positive qualitative CMV tissue polymerase chain reaction (PCR) from 2005-2013 at a tertiary referral hospital. Frequency of PCR+, hematoxylin and eosin staining(HE)+, histopathology and immunohistochemistry (IHC)+ was assessed. IHC was assessed on a sample of PCR- tissues. Surgery rates were correlated with CMV testing and treatment.

PCR was done on 310 samples from 180 patients. Thirty-seven samples were PCR+ (51.4% PCR+ only, 35.1% IHC/PCR+, 13.5% HE/IHC/PCR+). The H&E frequently failed to detect CMV identified on extensive IHC. Of 13 PCR- samples tested with IHC, 100% were negative. Twenty-five patients were CMV+ (40% PCR+, 40% IHC/PCR+, 20% HE/IHC/PCR+). Surgery rates increased with number of positive tests: 60% in IHC/PCR+ and 80% in HE/IHC/PCR+, compared to 26.8% in PCR- or PCR+ (P = 0.03, P = 0.02, respectively). There were 20/25 PCR+ patients who received CMV treatment. Surgery occurred in 80% of HE+ patients despite treatment and 100% of IHC+ patients without treatment.

Rates of CMV+ testing and surgical risk varied by test modality. PCR+ results were most frequent but alone did not detect clinically significant CMV. HE+ testing was least frequent and associated with highest surgical rate, despite treatment. CMV treatment may benefit IHC+ patients most, supporting immunostaining as optimal diagnostic test for clinically significant CMV in IBD. In PCR+ samples, HE frequently did not detect CMV identified on extensive IHC. In PCR- samples, data suggest IHC is likely negative. Consider using qualitative PCR to guide extensive immunostaining.