Cigarette smoking influences cytokine production and antioxidant defences.

1. Smoking exerts an inflammatory stimulus on lung macrophages, and smokers generally have low intakes of antioxidant micronutrients. This study was performed to investigate the relationship between whole-blood tumour necrosis factor production, plasma interleukin-6 and acute-phase protein concentration and antioxidant vitamins in smokers and non-smokers. 2. Measurement of tumour necrosis factor was conducted in whole blood stimulated with endotoxin (lipopolysaccharide), and interleukin-6 concentrations were measured in the plasma of smokers and non-smokers. Enzyme and dietary antioxidant concentrations and acute-phase proteins were determined in the two groups. 3. Tumour necrosis factor production and plasma interleukin-6 concentrations were 38% (P = 0.01) and 16% (P = 0.07) greater, respectively, in smokers than in non-smokers. Plasma vitamin A and E concentrations were unaffected by smoking; however, a 21% lower plasma vitamin C (P = 0.04) concentration was observed in smokers, than in non-smokers despite a similar intake of this vitamin by the two groups. 4. Concentrations of the acute-phase proteins alpha 1-acid glycoprotein, caeruloplasmin and alpha 2-macroglobulin were increased in the plasma of smokers compared with non-smokers by 39%, 28% and 12% respectively (P < 0.01). Our studies indicate that smokers have a compromised antioxidant status and elevated concentrations of tumour necrosis factor and interleukin-6 as a consequence of smoking. 5. These observations may provide some insight into the biological mechanisms underlying the pathology associated with smoking.