There was no significant difference in mean plasma HMGB1 concentrations among the three groups (non-smokers, 1.8 ± 1.1 ng/mL; smokers without COPD, 1.9 ± 1.1 ng/mL; smokers with COPD, 1.8 ± 1.7 ng/mL; figure not shown). This evidence concerns the gene HMGB1 and chronic obstructive pulmonary disease.