Peripheral Neutrophil Phenotypes During Management Of Periodontitis

Background and Objectives Neutrophils are emerging as a key player in periodontal pathogenesis. The surface expression of cellular markers enables functional phenotyping of neutrophils which have distinct roles in disease states. This study aimed to evaluate the effect of periodontal management on neutrophil phenotypes in peripheral blood in periodontitis patients over one year. Materials and Methods Peripheral blood and the periodontal parameters, mean probing depth and percentage of sites with bleeding on probing (%BOP), were collected from 40 healthy controls and 54 periodontitis patients at baseline and 3-, 6- and 12- months post-treatment. Flow cytometry was used to identify CD11b(+), CD16b(+), CD62L(-)and CD66b(+)expression on neutrophils, neutrophil maturation stages as promyelocytes (CD11b(-)CD16b(-)), metamyelocytes (CD11b(+)CD16b(-)) and mature neutrophils (CD11b(+)CD16b(+)), and suppressive neutrophil phenotype as bands (CD16(dim)CD62L(bright)), normal neutrophils (CD16(bright)CD62L(bright)) and suppressive neutrophils (CD16(bright)CD62L(dim)). Results CD62L(-)expression decreased with treatment. No differences were observed in neutrophil maturation stages in health or disease upon treatment. Suppressive and normal neutrophils showed a reciprocal relationship, where suppressive neutrophils decreased with treatment and normal neutrophils increased with treatment. In addition, %BOP was associated with suppressive neutrophils. Conclusion This study demonstrates that management of periodontitis significantly modifies distinct neutrophil phenotypes in peripheral blood. Suppressive neutrophils may play a role in the pathogenesis of periodontitis. However, their exact role is unclear and requires further investigation.