Increased Genes Expression Levels of Cytokines Related to Th17/Treg Cells in Peripheral Blood Mononuclear Cell Correlate with Clinical Severity in COPD and Mustard Gas-exposed Patients

The long lasting inflammation and immune dysregulation is one of the main mechanisms involved in lung complication of veterans exposed to sulfur mustard (SM) gas. Th17/Treg cells have an important role in immunopathogenesis of chronic obstructive pulmonary disease (COPD) and mustard lung disease. In this study, expression of cytokines genes levels related to Th17/Treg cells was determined in peripheral blood mononuclear (PBMC) of mustard lung patients and was compared with COPD patients and healthy controls (HC). Real time-polymerase chain reaction was used to assay genes expression levels of Th17 related cytokines (IL-17, IL-6 and TGF-β) and Treg related cytokines (IL-10, TGF-β). IL-17 gene expression level considerably was higher in SM patients (9.98±0.65, p 0.001), and COPD (4.75±0.71, p 0.001), compare to HC group. Also, gene expression level of IL-6 in the SM group (3.31±0.93, p 0.001) and COPD group (2.93±0.21, p 0.001) were significantly higher than the HC group. The IL-10 gene expression level showed a high increase in SM patients (4.12±0.91, p 0.01), and COPD (2.1±0.45, p 0.01). Finally, the TGF-β gene expression level was increased in SM patients (4.91±0.69, p 0.001) as well as in COPD group (5.41±0.78, p 0.001). In SM patients, IL-17 (R=-0.721, p 0.05), IL-6 (R=-0.621, p 0.05) and TGF-β (R=-0.658, p 0.05) had significant negative association with FEV1 (%). Inversely, Il-10 showed positive correlation (R=0.673) with FEV1 (%). Th17/Treg cells related cytokines genes were highly expressed and imbalanced in peripheral blood mononuclear cells of SM and COPD patients which correlated with pulmonary dysfunction.