PIK3AP1 and COVID-19: ILC1s, ILC2s and ILCps in COVID-19 patients also downregulated the gene PIK3AP1 (adj.p= 1.4e-14, 3.5e-16 and 2.7e-06, respectively) (Figures 2A, 3A–C), which encodes a signaling adapter protein linking the phosphoinositide 3-kinase (PI3K) signaling pathway to various coreceptors.