Expression of Epstein-Barr virus in children with sacrococcygeal pilonidal sinus determined by immunohistochemical methods.

In this study, we probed whether chronic infections of skin such as pilonidal sinus could be a potential site of Epstein-Barr virus (EBV) replication. Pilonidal sinus is associated with a high recurrence rate. Therefore, we decided to determine the role of EBV's presence to explain whether it is correlated with the recurrence of pilonidal sinuses. This study was conducted on 36 patient samples with sacrococcygeal pilonidal sinus. Samples were immunohistochemically stained for EBV, CD3 and CD20 expression. Thirty-six adolescents with pilonidal disease were evaluated. EBV-positive cells were located in dermis with high inflammatory activity. EBV-positive cells stained positive for the B-cell antigen CD20 and were detected in 10 of 36 (27%) pilonidal sinus specimens. Among those who had experienced a relapse, three were positive for EBV expression. In addition, EBV expression was detected in eight cases with severe inflammation, and in two with minimal or moderate inflammation. Our study advances the field by demonstrating that similar to gastrointestinal mucosa, skin could be a reservoir for EBV. EBV was found to be restricted to B cells in skin lesions, and it was found that skin lesions with severe inflammation showed higher frequency of EBV expression in comparison to minimal or moderately inflammed skin lesions. Additionally, recurrence was more frequently observed among EBV-positive cases. These findings point out for a role of EBV infection in the recurrence of pilonidal sinuses.

High frequency of Epstein-Barr virus-infected lymphocytes in pilonidal cysts.

Circulating memory B cells are considered as the main reservoir for Epstein-Barr virus. Several studies identified the presence of Epstein-Barr virus-infected B cells in the lesions of Crohn disease and ulcerative colitis suggesting that colon mucosa with chronic inflammation could be a potential site of Epstein-Barr virus replication. However, whether skin could be also an Epstein-Barr virus reservoir has not yet been investigated. We used pilonidal cysts as a model of skin chronic inflammation, and we found in 20 (55.6%) of 36 cases variable amounts of Epstein-Barr virus-infected cells as assessed by in situ hybridization using Epstein-Barr virus-encoded RNA probe and immunostainings. Most (95%) of the Epstein-Barr virus-positive cells were of B-cell phenotype, whereas scattered cells were double stained with Epstein-Barr virus-encoded RNA probes and T-cell markers. Epstein-Barr virus-encoded RNA+ cell density correlated with the intensity of inflammation. This density was similar to that observed in chronic diverticulitis but higher when compared with appendicitis, suggesting that chronic rather than acute inflammation facilitates the recruitment of Epstein-Barr virus-infected cells in diseased tissues. Altogether, these data suggest that, in immunocompetent patients, skin inflammatory lesions contain Epstein-Barr virus-infected cells exhibiting latency type I. Moreover, skin-like gastrointestinal mucosa is a potential site of Epstein-Barr virus replication and spreading. Our results may explain the pathogenesis of the Epstein-Barr virus-positive mucocutaneous ulcer.