FCGR2A and chronic obstructive pulmonary disease: The majority of proteins in the metabolic pathways, including oxidative phosphorylation, citrate cycle, amino acids metabolism, fatty acid metabolism (Additional file 2: Table S3) and glutathione metabolism were up-regulated, while those in the FcγR-mediated phagocytosis (Fig. 4), regulation of actin cytoskeleton and lysosomal pathways were down-regulated in female COPD patients (Additional file 2: Table S3).