FABP4 and chronic obstructive pulmonary disease: Airway FABP4 levels were lower in COPD patients than in controls, reaching statistical significant differences in BALF [219.2 (96.0–319.6) vs. 273.4 (203.1–426.7) (pg/ml)/protein, p = 0.03], but not in sputum [12.2 (0.7–27.5) vs. 14.5 (0.5–45.6) ng/ml, p = 0.4] (Fig. 1A, C).