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. This evidence concerns the gene MPO and periodontitis.