Herpesviruses in human periodontal disease

Recent studies have identified various herpesviruses in human periodontal d isease. Epstein-Barr virus type 1 (EBV-1) infects periodontal B-lymphocytes and human cytomegalovirus (HCMV) infects periodontal monocytes/macrophages and T-lymphocytes. EBV-1, HCMV and other herpesviruses are present more fr equently in periodontitis lesions and acute necrotizing ulcerative gingivit is-lesions than in gingivitis or periodontally healthy sites. Reactivation of HCMV in periodontitis lesions tends to be associated with progressing pe riodontal disease. Herpesvirus-associated periodontitis lesions harbor elev ated levels of periodontopathic bacteria, including Actinobacillus actinomy cetemcomitans, Porphyromonas gingivalis, Bacteriodes forsythus, Prevotella intermedia, Prevotella nigrescens and Treponema denticola. It may be that a ctive periodontal herpesvirus infection impairs periodontal defenses, there by permitting subgingival overgrowth of periodontopathic bacteria. Alterati on between latent and active herpesvirus infection in the periodontium migh t lead to transient local immunosuppression and explain in part the episodi c progressive nature of human periodontitis. Tissue tropism of herpesvirus infections might help explain the localized pattern of tissue destruction i n periodontitis. Absence of herpesvirus infection or viral reactivation mig ht explain why some individuals carry periodontopathic bacteria while still maintaining periodontal health. Further studies are warranted to delineate whether the proposed herpesvirus-periodontopathic bacteria model might acc ount for some of the pathogenic features of human periodontal disease.