Patients in our study did not have overt clinical or laboratory signs of ongoing CMV infection, which has been previously shown to drive loss of CD127 and features of CD8 T cell senescence in patients with CVID [17, 43], and ELISpot assessment of CMV-specific T cells performed in a subset of our patients showed evidence of immune memory in only 2/7 of those tested. Here, CD8A is linked to cytomegalovirus infection.