FPR1 and chronic obstructive pulmonary disease: In line with our findings that FPR1 expression on neutrophil was increased in COPD patients with a high MMRC dyspnea scale and reversed to normal after 1-year treatment, previous studies reported that cigarette smoking increased FPR1 numbers on blood neutrophils in emphysema patients, and that its expression was not correlated with the severity of airflow limitation [24, 25].