MiRNAs and mRNAs are differentially expressed in peripheral blood mononuclear cells (PBMCs) of patients with COPD, compared with normal controls, found the latest study. The recent research by a team of scientists from Xiangya Hospital, Central South University, Changsha, and University of Texas Southwestern Medical Center, Dallas, USA, analysed PBMCs from 12 patients with COPD and 12 normal controls for miRNA and mRNA expression levels using Affymetrix GeneChip to identify 133 upregulated and 973 downregulated genes in PBMCs of patients with COPD. The research findings also highlighted that among these, 77 upregulated mIRNAs and 43 downregulated miRNAS were differentially expressed between PBMCs from patients with COPD and normal controls. Identification of differentially expressed genes and miRNAs and their regulatory mechanisms at the whole-genome level is expected to provide a comprehensive understanding of the development of COPD as mechanisms underlying the disease remain unclear.