Prevalence of Epstein-Barr Virus in Periapical Granulomas from Japanese Patients

Methods: Surgically removed periapical lesions were analysed by haematoxylin-eosin stains using the paraffin section. Healthy gingival tissues were obtained as a healthy control. EBV DNA and inducible nitric oxide synthase (iNOS) mRNA were detected using real-time polymerase chain reaction. Immunohistochemistry using human iNOS monoclonal antibody was also performed. This study was approved by an ethics committee in our university, and written consent was obtained from patients prior to the collection of the lesions.

Results: Of 35 specimens, 27 specimens were histologically determined as periapical granulomas. The rest of the specimens showed epithelial cell layer and cholesterol crystal; therefore, these were diagnosed as radicular cysts. EBV DNA was detected from 22 out of 27 periapical granulomas, whereas none of healthy gingival tissues showed EBV DNA detection. Expression of iNOS mRNA was also detected from all periapical granulomas, whereas none of healthy gingival tissues expressed iNOS mRNA. Inflammatory cells in periapical granulomas expressed iNOS, as determined immunohistochemically.

Conclusion: The data suggested the possibility that EBV could be associated with the periapical inflammation, and periapical granulomas could be the reservoir for systemic infection of EBV.