PASSIVE SMOKING BY HUMANS SENSITIZES CIRCULATING NEUTROPHILS

The proinflammatory effects of passive inhalation of cigarette smoke were investigated by exposing a total of 16 healthy, young nonsmokers (mean age 29 +/- 1.4 yr, 11 women and five men) to actively smoking individuals in a poorly-ventilated room. Neutrophil functions were measured before and after 3 h of exposure to cigarette smoke. Passive cigarette smoking was associated with increased leukocyte counts (mean increase 33%, p < 0.005), chemotaxis (57%, p < 0.001), and release of reactive oxidants (71%, p < 0.005) by stimulated neutrophils. These results were confirmed in a second study designed to eliminate the possible complicating effects of serial venepuncture. Plasma concentrations of the proinflammatory cytokines interleukin-1 (IL-1)alpha, IL-1-beta, IL-6, and tumor necrosis factor alpha (TNF-alpha) were not affected by passive smoking. These results indicate that inhalation of sidestream tobacco smoke promotes systemic priming of neutrophils. These potentially proinflammatory events may induce oxidant-mediated tissue damage and carcinogenesis in the lungs of passive smokers.