CXCL9 and chronic obstructive pulmonary disease: Overall, CXCL9/10/11 produced by macrophages and bronchial epithelial cells act on CXCR3+ cells to recruit inflammatory cells into the lungs, such as T lymphocytes, but CXCL11 seems to be also involved in lymphocyte clearance, emphasizing the possible dual role of chemokines in COPD.