7 of 57 (12%) cases were identified with isolated T cell lymphopenia (selective deficiency of CD4+ T cells (n = 6) or CD8+ T cells (n = 1) and were eventually grouped under the category “Combined Immunodeficiency (CID) generally less profound than Severe combined Immunodeficiency” according to the IUIS classification (9). This evidence concerns the gene CD8A and combined immunodeficiency.