The effect of pre-transplant conditioning upon the long-term outcomes of patients receiving hematopoietic stem cell transplantation (HSCT) for severe combined immunodeficiency (SCID) has not been completely determined.
To assess the outcomes of 23 mostly conditioned SCID patients and compare their outcomes to 25 nonconditioned SCID transplanted patients previously reported.
In the present study, we reviewed the medical records of these 23 consecutive mostly conditioned SCID patients transplanted between 1998 and 2007.
Eighteen patients (median age at transplant 10 [range 0.8–108] mo) received haploidentical mismatched related donor, matched unrelated donor, or mismatched unrelated donor transplants, 17 of whom received pretransplant conditioning and one was not conditioned, 13 (72%) engrafted and survive a median of 3.8 [1.8–9.8] yr, 5 of 13 (38%) require IVIG, and 6 of 6 age-eligible children attend school. Of five recipients (median age at transplant 7 [range 2–23] mo) of matched related donor transplants, all 5 engrafted and survive a median of 7.5 [range 1.5–9.5] yr, 1 requires IVIG, and 3 of 3 age-eligible children attend school. Gene mutations were known in 16 cases: IL2γR in 7 patients, IL7αR in 4 patients, RAG1 in 2 patients, ADA in 2 patients, and AK2 in 1 patient. Early outcomes and quality of life of the previous non-conditioned vs. the present conditioned cohorts were not statistically different but longer-term follow-up is necessary for confirmation.
HSCT in SCID patients results in engraftment, long-term survival, and a good quality of life for the majority of patients with or without pre-transplant conditioning.