Background To evaluate the NETosis biomarkers citrullinated histone H3 (citH3), neutrophil elastase (ELA), calprotectin (CALPRO), and myeloperoxidase (MPO) as indicators of inflammation in the severe stages of periodontitis III and IV in both (smokers and nonsmokers) patients, and to determine the correlation between NETosis biomarkers and clinical periodontal parameters. Methods This study recruited male subjects with an age range of (20-60) years; 60 were stage III and stage IV periodontitis patients, 30 were cigarette smoker, and 30 were nonsmokers. After applying the inclusion and exclusion criteria to evaluate their eligibility for recruitment, 25 control subjects with a healthy periodontal status and good oral hygiene maintenance were included. Unstimulated saliva was obtained and evaluated using an enzyme-linked immunosorbent assay, and the following periodontal parameters were documented: [plaque index, bleeding on probing, periodontal pocket depth, and clinical attachment loss]. Results The mean levels of all salivary NETosis biomarkers citH3, ELA, CALPRO, and MPO were elevated in the periodontitis groups (smokers and nonsmokers) than in controls. Moreover, the mean NETosis biomarker‘s mean levels were significantly higher in smoker than in nonsmokers. In addition, the correlations were significant between CALPRO and CitH3 in smokers and between ELA and CitH3 in nonsmokers. Conclusions The results of this study showed that the chosen salivary biomarkers of NETosis revealed elevated clinical accuracy in differentiating the studied periodontitis groups (smokers and nonsmokers) from controls. In addition, cigarette smoking increases the risk of periodontitis, and neutrophils in smokers with periodontitis exhibited more susceptibility to form neutrophil extracellular traps when compared with nonsmokers.
