People with both type‑2 diabetes and gum disease have much higher levels of the antimicrobial peptide LL‑37 (and also HNP 1‑3) in their saliva. These peptide levels are linked to the severity of gum disease and to blood‑sugar measures, suggesting they rise as part of the body’s inflammatory response.

The aim of this study was to evaluate the interrelationship between salivary levels of human neutrophil antimicrobial peptides (AMP) 1-3 (HNP 1-3), LL-37 and periodontitis in individuals with and without type 2 diabetes (T2DM). Eighty individuals were enrolled and grouped as follows: Group I: 20 healthy individuals, Group II: 20 systemically healthy individuals with chronic periodontitis (CP), Group III: 20 individuals with T2DM only and Group IV: 20 individuals T2DM and CP. Plaque index, probing pocket depth, bleeding on probing and clinical attachment levels were evaluated. The diabetic status was established by assessing the levels of fasting plasma glucose and HbA1c. Salivary levels of HNP 1-3 and LL-37 were assessed by ELISA. The present study demonstrated that individuals with T2DM and CP had significantly higher salivary levels of LL-37 (443.00 ±221.52 ng/ml) and HNP 1-3 (149.52 ± 35.07 ng/ml) (p less than 0.001) compared to other groups. Additionally, salivary LL-37 and HNP 1-3 were significantly correlated with clinical and laboratory parameters (p less than 0.001). A significant positive correlation was seen between salivary levels of LL-37 and HNP 1-3 (r=0.69; p less than 0.001). LL-37 concentrations were highest in patients with T2DM+CP when compared with controls. LL-37 was positively correlated with age. HNP 1-3 levels were increased in groups with DM when compared to the groups without periodontitis. The role of AMPs is vital in the immunoinflammatory response in the pathogenesis of periodontitis and DM.