CTLA4 and severe combined immunodeficiency: However, uncharacteristically for CVID, the increased infectious susceptibility and lymphoproliferation was pronounced in all patients prior to the fifth year of age, reminiscent of other recently defined monogenic combined immunodeficiencies (CID) with childhood onset, dysgammaglobulinemia, RTI, and autoimmunity, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA4) or lipopolysaccharide-responsive and beige-like anchor protein (LRBA deficiency) (14, 15).