Distinct functional profiles of oral neutrophils in molar incisor pattern periodontitis, generalized periodontitis and periodontal health.

This study aimed to compare oral neutrophil (oNeut) functions in molar-incisor pattern periodontitis (MIPP), generalized periodontitis (GP), and periodontally healthy subjects, and to explore how biofilm exposure shapes these functions. oNeut were isolated from healthy, GP, and MIPP volunteers (n = 10 per group) and challenged ex vivo with Aggregatibacter actinomycetemcomitans JP2. Reactive oxygen species (ROS) production, cell viability, and cytokine release were quantified post-infection. Separately, healthy oNeut were exposed to de novo biofilms modeling healthy, GP, or MIPP microbiomes, and their functional responses were assessed. Results showed that periodontitis patients (GP and MIPP) had higher baseline oNeut counts but exhibited reduced resistance to necrosis and lower ROS output after JP2 challenge than controls; JP2-stimulated ROS was significantly lower than both HOCl-treated and naïve controls. MIPP oNeut secreted more TNFα, CCL2, OPG, and RANKL than GP, whereas GP displayed a higher OPG/RANKL ratio. Except for TNFα and IL-1β, all measured mediators were elevated in healthy oNeut compared with those from periodontitis groups. Under dysbiotic versus symbiotic biofilm challenge, healthy oNeut produced less ROS but secreted higher levels of TNFα, OPG, and RANKL. Overall, oNeut from periodontitis patients exhibited distinct oxidative and cytokine responses to JP2, reflecting both host-specific and biofilm-driven priming.