Effects of Herpesviruses on Proinflammatory Cytokines in Chronic Periapical Lesions

BACKGROUND Apical periodontitis is caused by infected dental pulp and may be associated with dental caries or trauma, which can destroy periradicular tissues. This study included periapical tissue of patients with chronic apical periodontitis and aimed to evaluate the presence of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) using polymerase chain reaction (PCR), and to determine the levels of inflammatory cytokines using enzyme-linked immunoassay (ELISA). MATERIAL AND METHODS A total of 79 patients participated in this study. Periapical lesions were taken from the tooth roots indicated for extraction, and were divided into 2 groups: symptomatic and asymptomatic. PCR was used to identify HCMV and EBV. Interleukin 6 (IL-6), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor beta-1 (TGFß-1) were determined using ELISA. RESULTS The occurrence of HCMV (P<0.05) and dual HCMV/EBV infection (P<0.05) was significantly more frequent in symptomatic lesions compared to asymptomatic. The concentrations of IL-6, IL-8, and TNF-alpha were significantly higher in virus-positive lesions compared to virus-negative ones (P<0.05); especially high cytokine levels were found in lesions with dual HCMV/EBV infection (P<0.05). The level of TGF-ß1 was higher in virus-positive compared to virus-negative lesions, but the difference was significant only in lesions with dual HCMV/EBV infection (P<0.05). CONCLUSIONS The higher prevalence of herpesviruses in symptomatic lesions compared to asymptomatic ones indicates their important role in pathogenesis of periapical lesions. Expression of TNF-alpha, IL-6, and IL-8 may be of importance in the development and clinical features of herpesvirus-infected lesions, while TGF-ß1 appears to be of no significance.