the first fifty years of stem cell transplantation in severe combined immunodeficiency (scid)

Since the first successful hematopoietic stem cell transplantation (hsct) in 1968 for severe combined immunodeficiency (scid), clinical studies have commenced. however, there is a high heterogeneity across studies. this is a review of studies evaluating the efficacy of sct in scid. there were 25 multi-center studies (mcss) and 60 single-center studies (scss). overall, mcss provided a full range of survival rates (30-88.5%), though 80% of mcss reported a survival rate of ≥60%. all mcss, except one, that reported an overall survival of <60% were performed before the year 2000. also, all mcss that reported an overall survival rate of ≥80% were conducted in american/european centers. totally, 85%, 60%, 31.67%, and 8.33% of scss reported a survival rate of ≥60%, 70%, 80%, and 90%, respectively. asian studies reported the broadest range (16.6-86.67%) of survival rate compared to american (58.3-88%) and european studies (48.39-100%). consistent with mcss, scss with survival rates of <40% were conducted across asian countries. the outcomes of sct in scid patients varies widely according to the center where the study is conducted, the sample size, the study period, age at sct, race, lung or viral infection before sct, active infection at the time of sct, the protected environment used at sct, early development of t-cell reconstitution after sct, prophylaxis against gvhd, scid phenotype and molecular diagnosis, conditioning regimen, and donor type. therefore, future investigations are needed to discover the chief determinants of such a different survival rate in scid patients who underwent sct.