TNFSF11 and periodontitis: Porphyromonas gingivalis contributes to the pathogenesis of aggressive periodontitis by inducing high levels of proinflammatory cytokines, such as IL-1β and IL-6 by peripheral CD4+ T helper cells [9]. Porphyromonas gingivalis serotypes K1 and K2 but not others are associated with an increased production of the osteoclastogenesis-related factor RANKL.