JAK3 and severe combined immunodeficiency: In addition, the bone marrow reconstitution in human patients with severe combined immunodeficiency (SCID) due to mutation of the gene encoding the common γ chain cytokine receptor subunit IL-2Rγ or the tyrosine kinase JAK3 did not restore presence of ILCs in various peripheral tissues (Vely et al., 2016), supporting the notion that tissue-resident ILCs are established at early ontogenic stages.