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

Background: Iranian 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 method: The 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.

Result: The 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.

Conclusion: Conclusively, 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.

Keywords: Interleukin-17; Interleukin-21; Lung tissue; Pulmonary complications; Sulfur mustard; TNFα.