CCL27 and cystic fibrosis: Since the reduction of ILC2s in the blood of CF, IBD and RA patients was accompanied by a parallel decrease of total circulating ILCs (Figure 1C), it is unlikely that the observed effect can fully be explained by transdifferentiation of pb ILC2s into other ILC subsets, as described for ILC2s in nasal polyps of CF patients or COPD-affected lungs (30, 53).