CD79A and periodontitis: Although P. gingivalis is considered a keystone pathogen of periodontal dysbiosis, it is possible that other microorganisms also involved in the pathogenesis of periodontitis may also reflect differences between the groups; (2) residual confounders, such as genetic factors and cell mediated immunity were not investigated; (3) total anti - P. gingivalis IgA antibody was measured and it is unknown how much of this was actual secretory - IgA.