Previous studies reported dysregulation of the PD1/PD-L1 pathway in COPD, with increased PD-1 expression by T-cells from COPD patients compared to healthy NS45 and lower PD-L1 and/or PD-L2 expression in severe COPD AMs compared to NS46. This evidence concerns the gene PDCD1LG2 and chronic obstructive pulmonary disease.