CXCL5 and chronic obstructive pulmonary disease: Other proteins significantly elevated in COPD include 6 of the 10 chemokines in the panel, T-cell/antigen-presenting cell co-stimulatory molecules (CD40, CD40L), neutrophil-associated proteins (EN-RAGE, myeloperoxidase, ENA-78), and thrombosis-related proteins (thrombopoietin, PAI-1).