IKZF1 and common variable immunodeficiency: In addition to this, certain monogenic causes of the CVID phenotype, such as those affecting NFKB1, NFKB2, TNFSF12 (TWEAK), TNFRSF13B (TACI) and IKZF1 (IKAROS), have been individually reported with pronounced viral illnesses [55,56,57,58,59].