Of the three sub-types of ILC, ILC2 may be involved in generating Th2 responses when activated by epithelial-derived cytokines such as thymic stromal lymphopoietin (TSLP), whereas ILC1 type cells may be stimulated by TLR7 agonists to reverse this trend towards the Th2 asthma phenotype by releasing IFNγ. Here, CCL27 is linked to asthma.