CCL2 and chronic obstructive pulmonary disease: Clinical trials for lung diseases, such as COPD (CCR1 antagonist AZD4818, CXCR1/2 antagonists SCH527123/SB656933/GSK1325756B), asthma (CCR3 neutralizing monoclonal antibody ASM8, CCR3 antagonists GSK766994/DPC168/BMS-639623, CCR4 antagonist GSK2239633), pulmonary fibrosis (anti-CCL2 Carlumab), cystic fibrosis (CXCR2 antagonist SB656933), and bronchiectasis (CXCR2 antagonist AZD-5069), have explored interventions on the chemokine system.