Serum albumin and paraoxonase activity in Iranian veterans 20 years after sulfur mustard exposure.

Sulfur mustard, a chemical warfare agent, has short- and long-term effects on various organs including respiratory system. Its late toxic effects on biological macromolecules among exposed veterans have not been well studied. We performed a study to determine paraoxonase-1 (PON1) activity and phenotype distribution as well as its correlation with albumin level in 289 male veterans with severe pulmonary complications who had exposure to sulfur mustard 20 years ago and in 66 age and ethnic matched healthy male subjects as controls. Serum albumin levels were lower in the veterans compared to controls (P < 0.001). Mean basal PON1 activity was 91.61 ± 44.80 U/mL in the veteran group versus 110.27 ± 50.23 U/mL in controls (P = 0.005). Arylesterase activity was not significantly different between the two groups. Paraoxonase to arylesterase activity ratio was significantly lower in the veterans as compared to controls (P = 0.005), mainly indicative of decreased PON1 activity rather the enzyme level. Significant reduction was found in serum albumin and PON1 activity with disease severity. Moreover, decreased high active BB (high activity) phenotype and increased intermediate active AB (moderate activity) phenotype were found in the veterans. This condition may lead to long-term accumulation of reactive oxygen metabolites resulting in a pro-oxidation milieu, which in turn can lead to increased peroxide levels and decreased antioxidant PON1 activity. In conclusion, lower serum PON1 activity and albumin might contribute to morbidity and occurrence of other complications such as atherosclerosis and rapid aging in the veterans suffering from late toxic effects of sulfur mustard.