Regarding the treatment perspectives, it is noteworthy that many IEI monogenic diseases appear to be good candidates for gene therapy, e.g., X-linked SCID and X-linked GCD, ADA-SCID and Wiskott-Aldrich Syndrome, and several clinical trials have already been accomplished (107). This evidence concerns the gene ADA and T-B+ severe combined immunodeficiency due to gamma chain deficiency.