Combination criteria based on subsets of CD4+ T-cells and B-cells were proposed by large DEFI study10, where the clinical groups (infection only, lymphoproliferation, autoimmune cytopenia and chronic enteropathy) were formed first and proportion of subset was found different among them and by Giovannetti8et al., who stressed the CD4+ Naïve T cells proportion association to clinical features (splenomegaly and overall severity). The gene discussed is CD4; the disease is infection.