FPR2 and asthma: It was also found that in severe asthma the expression of ALX/FPR2, the receptor binding resolvin D1 and LXA4, is reduced on peripheral blood Eos and neutrophils and increased on BAL macrophages and neutrophils and peripheral blood natural killer (NK) cells (Planaguma et al., 2008; Barnig et al., 2013; Ricklefs et al., 2017).