Recent studies on large groups of patients: 131 ADA-SCID diagnosed in 1982-2017 (14) and 152 patients with SCID, including 43 ADA-SCID treated in 2006-2014 (15), showed higher OS in patients transplanted from MSD/MFD under 3.5 months of age and without active infections. This evidence concerns the gene ADA and infection.