The role of natural killer cells in periodontitis

Periodontitis is the most common chronic inflammatory disease of humans. The microbial etiology of the disease is well documented, as is the major role of the host response in disease pathogenesis. As natural killer cells are one of the most important components of innate immunity against bacteria and viruses, they can be expected to act as major players in the development of the disease. Through direct interaction with periodontal pathogens, natural killer cells produce pro-inflammatory cytokines that subsequently may lead to tissue destruction. Indeed, using a murine periodontitis model, such mechanisms have been shown to be involved in bacterial-induced alveolar bone loss. In the present review we document the available literature and evidence base regarding the origin, biology and characteristics of natural killer cells, and their interactions with periodontal pathogens. The potential role of natural killer cells in periodontal pathogenesis and the mechanisms involved are discussed.