Retrospective investigation of the diagnostic value of CMV DNA positivity in intestinal biopsy specimens

Cytomegalovirus remains latent after primary infection, causing secondary infections in stem cell and solid organ recipients, Human immunodeficiency virüs (HIV) infected individuals, those with hematological malignancies, and those with inflammatory bowel disease. The disease can be seen in pneumonia, retinitis, and colitis. Pathological detection of CMV in tissue is recommended for diagnosing CMV colitis. Our study aims to examine the diagnostic value of CMV DNA detection in intestinal biopsies of patients with suspected CMV colitis. Biopsy samples sent to Bursa Uludağ University Health Center Medical Microbiology Laboratory between January 2019 and March 2022 with the suspicion of CMV colitis were analyzed retrospectively in this study. Simultaneously, 96 samples which CMV DNA was investigated in intestinal tissue by polimerase chain reaction (PCR) method, and CMV was searched by immunohistochemistry (IHC) method in the Medical Pathology Laboratory were included in the study. IHC examination was accepted as the gold standard, and the place of CMV DNA detected in tissue and blood in the diagnosis was investigated. Of the samples, 81 belonged to patients with ulcerative colitis (UC), six with stem cell and solid organ transplants, four with hematological malignancies, two with Crohn's, one with chronic renal failure, one with Behçet's, and one with diabetes mellitus. Statistical analyses were performed for the UC patients' data, which constitute the largest group. Positivity was detected in 10 tissues by IHC method, in 61 tissues by PCR method, and in 25 of 43 plasmas for which CMV DNA was investigated. Based on the IHC examination, the sensitivity of plasma CMV DNA was 100%, the specificity was 48.64%, the positive predictive value (PPD) was 24%, and the negative predictive value (NPD) was 100%. The sensitivity of tıssue CMV DNA method was 100%, specificity was 41.9%, PPD was 15.68%, and NPV was 90.12%. With ROC analysis, values above 392 copies/mg in tissue and 578 copies/ml in plasma were found as important clues for diagnosis. It was observed that the CMV DNA PCR test in tissue and blood samples has high sensitivity and low specificity. Standardized methods are needed for the quantification of CMV DNA in tissue.