Serum and sputum levels of IL-17, IL-21, TNFα and mRNA expression of IL-17 in sulfur mustard lung tissue with long term pulmonary complications (28 years after sulfur mustard exposure)

Abstract

BackgroundIranian veterans who had exposed to Sulfur Mustard (SM) suffer from long term complications such as Chronic Obstructive Pulmonary Disease (COPD) and bronchiolitis obliterate (BO). Th17 cells product IL-17A, IL-17F, IL-21, and IL-22. They have important roles in chronic inflammatory diseases. Also, TNFα has a major part in pathobiological processes of COPD. In this study, we evaluate the serum and sputum levels of IL-17, IL-21, TNF-α, and mRNA expression of IL-17 in the lung tissue of the patients 28 years after SM exposure. Material and methodThe cytokine levels of IL-17, IL-21 and TNFα were measured by ELISA method in serum and sputum of 455 SM-exposed and 123 unexposed people participated in Sardasht-Iran Cohort Study (SICS) of chemical victims. The mRNA expression of IL-17 was evaluated with qRT-PCR in lung biopsies (SM-exposed =52, control =33). Analyses of all data were accomplished with the SPSS software with P value ≤05. ResultThe results show the sputum level of IL-17 in the exposed group decreased significantly compared to control group (P = 0.007) and Veterans and Martyrs Affair Foundation (VMAF) assessment was significantly lower in abnormal/exposed than normal/exposed group (P = 0.042). There were no significant differences between control and exposed groups in serum level of IL-17; also serum and sputum levels of IL-21, TNF-α, and IL-17 mRNA expression. ConclusionConclusively, The IL-17 level decreased in the exposed group. This decline could cause by mutation on transcription factors like Signal transducer and activator of transcription 3 gene (STAT3) or CCL20 as a chemokine.