Cigarette smoke exposure elicits pulmonary but not systemic anti-nuclear antibodies production. BALB/c mice were exposed to room air (open bars) or cigarette smoke (solid bars) for 4 days, 8 weeks ± 20 days of smoking cessation or for 24 weeks ± 60 and 120 days of smoking cessation. ANA levels were measured by ELISA in the (A) bronchoalveolar lavage fluid (BALF) and antibody isotypes dissected in mice exposed for (B) 8 weeks and (C) 24 weeks. (D) ANA levels were also measured in the serum of mice exposed for 8 weeks ± 20 days of smoking cessation or for 24 weeks ± 60 and 120 days of smoking cessation. (E) ANA levels were measured in the sputum of different GOLD stage subjects (see Tables 1 and 2 for complete description) and expressed as fold increase of GOLD 0/1 subjects. (A and D) Data represent means ± SEM; n = 5-10 mice per group. *p < 0.05. (B and C) Data represent the values obtained from pooled samples from each group. Fold changes were calculated by using the average O.D. value of the corresponding room air-exposed group as baseline expression (fold increase of 1).