Features of mucosal immunity in the development of periodontal diseases in patients with type II diabetes mellitus

Chronic generalized periodontitis takes one of the leading places in the structure of dental diseases. Inflammatory periodontal disease is one of the most common complications of diabetes. An important role in the progression of periodontitis in type II diabetes mellitus (T2DM) belongs to disorders of the immune system that affect the supportive/retaining complex of the tooth. Inflammation of periodontal tissues which occurs in the patients with carbohydrate metabolism disorders is characterized by a more severe course, which worsens the condition and quality of life of patients with T2DM thus leading to tooth loss. In this regard, the immunological aspects of developing periodontal pathology under conditions of carbohydrate metabolism disorders are of great interest. Purpose of our study included comparative assessment of local TNF, TNF, IFN, IL-1, IL- 12, IL-17A levels in patients with periodontitis with and without carbohydrate metabolism disorders (type II diabetes mellitus), as well as in patients with type II diabetes mellitus without signs of periodontitis. 
127 patients were examined, aged 30 to 59 years. The patients were divided into 3 groups, i.e., group I included patients suffering from periodontitis of varying severity without known comorbidities (47 persons); Group II consisted of patients with T2DM and periodontitis of varying severity (49 persons); Group III included patients with T2DM without symptoms of periodontitis (30 persons). The control group consisted of 30 practically healthy volunteers, matched to the patients for age and sex. Saliva specimens were used for laboratory studies. The levels of TNF, TNF, IFN, IL-1, IL-12, IL-17А were determined by ELISA sandwich technique, with specific reagents purchased from RD Diagnostics Inc (USA). 
A significant increase in the IL-1, TNF, IFN and IL-17A levels was found in patients of all groups compared with controls. At the same time, the increased concentrations of IFN, IL-1, IL-17A correlated with increase in periodontitis severity in the patients of both groups. Decreased TNF levels in saliva samples were revealed in the patients from almost all groups, regardless of the periodontitis severity. Significantly increased levels of IL-12 (p40 subunit) were recorded in saliva of the persons from group II and III when compared with controls and the group without diabetes mellitus.