HMOX1 and chronic obstructive pulmonary disease: Previous studies have identified informative mRNAs (CXCL16, HMOX1, SLA2, etc.) and lncRNAs (ENST00000502883.1, HIT000648516, XR_429541.1, etc.) in peripheral blood mononuclear cells (PBMCs) from COPD patients versus smokers (Sui et al., 2013; Song et al., 2015; Dang et al., 2017; Qu et al., 2018).