However, intrinsic defects of T cell subsets expressing non-functional mutated WASP or lacking WASP, including effector CD4+ T cells (Trifari et al., 2006) and CD8+ T cells (De Meester et al., 2010), Treg (Adriani et al., 2007; Humblet-Baron et al., 2007; Maillard et al., 2007; Marangoni et al., 2007) and Tfh (Zhang et al., 2016) are sought to contribute to susceptibility to infections, tumors and auto-immune manifestations described to occur at high frequency in WAS patients. The gene discussed is WAS; the disease is infection.