Hematopoietic stem cell transplantation for CD3δ deficiency.

[omenn syndrome]

CD 3 δ deficiency is a fatal form of severe combined immunodeficiency that can be cured by hematopoietic stem cell transplantation (HSCT ). The presence of a thymus loaded with T -cell progenitors in patients with CD 3 δ deficiency may require special considerations in choosing the regimen of conditioning and the type of HSCT .To study the outcome of CD 3 δ deficiency by using various modalities of stem cell transplantation .We analyzed data on 13 patients with CD 3 δ deficiency who underwent HSCT in 7 centers . HSCT was performed by using different sources of donor stem cells as well as various conditioning regimens .One patient received stem cells from a matched related donor and survived after a second transplant , needing substantial conditioning in order to engraft . Only 2 of 7 other patients who received a mismatched related donor transplant survived ; 2 of them had no conditioning , whereas the others received various combinations of conditioning regimens . Engraftment of T cells in the survivors appears incomplete . Three other patients who received stem cells from a matched unrelated donor survived and enjoyed full immune reconstitution . Two patients received unrelated cord blood without conditioning . One of them has had a partial but stable engraftment , whereas the other engrafted well but is only 12 months after HSCT . We also report here for the first time that patients with CD 3 δ deficiency can present with typical features of Omenn syndrome .HSCT is a successful treatment for patients with CD 3 δ deficiency . The small number of patients in this report prevents definitive statements on the importance of survival factors , but several are suggested : (1 ) HLA-matched donor transplants are associated with superior reconstitution and survival than are mismatched donor transplants ; (2 ) substantial conditioning appears necessary ; and (3 ) early diagnosis and absence of opportunistic infections may affect outcome .