Serum levels of IL-8 and IL-6 in the long term pulmonary complications induced by sulfur mustard: Sardasht-Iran Cohort Study.

Sulfur mustard (SM) is a blistering chemical agent which has short and long term toxicity against many organs. The respiratory tract is one of the main targets, and is the most disabling long term complication of SM. Inflammatory mediators especially IL-8 and IL-6 play the primary role in the various chronic pulmonary diseases. Sardasht-Iran Cohort Study (SICS) was designed to evaluate immunological and molecular parameters in SM exposed people 20 years after exposure. In the present study, the association of the serum levels of IL-8, IL-6, C reactive protein (CRP) and rheumatoid factor (RF) with long term pulmonary involvement was evaluated. There were 348 exposed and 120 control participants. The clinical evaluations were done for all subjects and Spirometry was performed according to American Thoracic Society Criteria. Severity of pulmonary involvement was assessed by Global Initiative for chronic Obstructive Lung Disease (GOLD) classification. The serum levels of IL-8, IL-6 and RF were assessed by ELISA assay. CRP was assessed by photometric method. The serum levels of IL-8 and IL-6 significantly decreased in the SM exposed participants compared to the control group. There were no significant associations between the serum levels of IL-8 and pulmonary symptoms (chronic cough, sputum, hemoptysis, and dyspnea), pulmonary findings (crackles, rales, and wheezing) as well as spirometry parameters. IL-6 was associated with wheezing and CRP was associated with wheezing and rales in SM exposed group. We concluded the serum levels of these inflammatory mediators probably do not have any major role in pathogenesis and persistence of pulmonary complications and do not reflect the degree of severity of pulmonary involvement following SM exposure.