Moreover, we explored the relationship among bacterial burden, inflammtory response such as neurotophil count and cytokine levels of IL-1β, IL-6 and IL-8 in BALF, and the forced expiratory volume in one second (FEV1) % predicted, forced vital capacity (FVC) % predicted, and FEV1/FVC lung function values in COPD patients. Here, IL1B is linked to chronic obstructive pulmonary disease.