Chronic cigarette smoke exposure leads to pulmonary tertiary lymphoid tissue (TLT) formation that persists following smoking cessation. BALB/c mice were exposed to room air (open bars) or cigarette smoke (solid bars) for (A) 8 weeks ± 20 days of smoking cessation or for (B) 24 weeks ± 60 and 120 days of smoking cessation. Lung sections were stained with hematoxylin and eosin (H&E). (C) Pulmonary TLT were quantified using Image J software. Data represent means ± SEM; n = 5 per group. *p < 0.05.