TNF and periodontal disorder: In addition, in vitro experiments showed that F. alocis could induce apoptosis in gingival epithelial cells (GECs) and stimulate pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α secreted by GECs45, supporting the notion that F. alocis may be an important pathogen in the formation of subgingival biofilm and the onset of periodontal diseases.