Fibrinogen and inflammatory cytokines in spontaneous sputum of sulfur-mustard-exposed civilians — Sardasht-Iran Cohort Study

Sulfur mustard (SM) causes late complications in respiratory system of exposed individuals. In this preliminary study, the levels of IL-1α and β, TNF, IL-1Ra, IL-6 and fibrinogen in the spontaneous sputum of SM-exposed individuals were examined 20years after exposure and the correlation with pulmonary function was tested. The participants were categorized into two major subgroups (hospitalized and non-hospitalized) based on the severity of the clinical complications immediately after exposure. Every participant was visited by a physician; the respiratory functions were checked using spirometry and were categorized as normal, mild, moderate or severe pulmonary complications. The levels of cytokines in the sputum and serum samples were measured using ELISA method. The mean values of TNF, IL-1α and IL-1β were 524.15, 115.15, 1951.33pg/ml respectively, and the mean levels of IL-1Ra and IL-6 were 6410.52 and 124.44pg/ml respectively; fibrinogen was 71.59ng/ml and index of IL-Ra/IL-1β was 7.78. There was more TNF-α and IL-1β and less IL-1Ra and fibrinogen in the sputum of the hospitalized subgroup. The level of TNF-α and IL-1β also increased in moderate and severe pulmonary status comparing with the group with mild disorders, while fibrinogen was lower or decreased significantly in problematic patients. IL-1β and TNF showed positive correlation (r=0.5, and r=0.59, respectively); fibrinogen and IL1Ra/IL-1β have negative correlation with lung function according to the GOLD classification (r=−0.4, and r=−0.61, respectively). It is concluded that sputum cytokines and fibrinogen, reflect the degree of the severity of airway inflammation and the cytokine levels in the sputum might be completely different from the serum fluctuations. ► Sulfur mustard causes delayed complications in the respiratory system observable after more than 20year. ► There are significant amounts of cytokines in spontaneous sputum of SM-exposed individuals. ► The level of TNF-α and IL-1β increased in moderate and severe pulmonary status, while fibrinogen decreased significantly. ► TNF has a negative correlation with FEV1, while that of IL-1Ra is positive. ► IL-1β has positive and fibrinogen has negative correlation with spirometry GOLD.