Evaluation of exposure to secondhand smoke and serum level of interleukin 18 in non-smokers

•Smoking is one significant global health care problems.•That not only affects the users but also endangers the health of people inhaling the smoke.•The serum level of IL-18, an important regulator of inherent and acquired immune response.•The exposure to secondhand smoke has no significant effect on serum level of IL-18.