The association between antigenemia, histology with immunohistochemistry, and mucosal PCR in the diagnosis of ulcerative colitis with concomitant human cytomegalovirus infection

BACKGROUND: Human cytomegalovirus (HCMV) colitis can be involved in active ulcerative colitis (UC) in patients refractory to steroid and immunosuppressive drugs. Histological examination with colonic biopsy specimens and antigenemia assays are the standard tests for diagnosing HCMV enterocolitis, and we have previously reported the usefulness of mucosal polymerase chain reaction (PCR) methods. However, the associations among histopathological tests, antigenemia assays, and mucosal PCR are unknown. METHODS: We retrospectively analyzed 82 UC patients who underwent mucosal biopsy from inflamed colonic tissues for histological evaluation and mucosal PCR to detect HCMV. We analyzed the relationships between the HCMV-DNA copy number in colonic mucosa and other HCMV tests. RESULTS: In total, 131 HCMV mucosal PCR tests from 82 UC patients were positive. The HCMV-DNA copy number was significantly higher in patients with positive immunohistochemistry (IHC) (p < 0.01) and was correlated with the number of positive cells for the antigenemia (C7-HRP, p < 0.01; C10/11, p < 0.01). Receiver operating characteristic curve analysis confirmed 1300 copies/μg of HCMV-DNA as the best diagnostic cut-off value to predict positive results of antigenemia (area under the curve = 0.80, 95% CI 0.68–0.93). HCMV-DNA copy number also correlated with the total UCEIS score (p = 0.013) and the bleeding score (p = 0.014). For each individual patient, a positive correlation between the change in total UCEIS score and HCMV-DNA copy number was observed (p = 0.040). CONCLUSION: The antigenemia assay and histopathological test with IHC were significantly associated with the HCMV-DNA copy number in colonic tissues. Moreover, endoscopic examination with the UCEIS can help diagnose the HCMV colitis in UC patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00535-022-01931-2.