Immune recovery after in vivo T-cell depletion myeloablative conditioning hematopoietic stem cell transplantation in severe beta-thalassemia children

Background The clinical outcome of hematopoietic stem cell transplantation (HSCT) in those with severe beta-thalassemia (beta-TM) is closely related to post-transplantation immune reconstitution (IR). However, the data on the IR in these settings are scarce. Methods A prospective analysis of the clinical outcome and IR in 47 children with severe beta-TM who underwent in vivo T-cell depletion myeloablative conditioning and matched sibling donor HSCT was performed. Immune reconstitution, including immune cell subset counts, as well as the generation of new T and B cells assays after HSCT, was measured. Results In the first year after HSCT, bacterial infections and cytomegalovirus (CMV) reactivation were observed in 70.2% and 36.2% of the patients, respectively. In the same period, poor CD4(+) T-cell recovery was observed. The B cells recovered within 6 months. Natural killer (NK) cells recovered as early as 1 month, but their function was defective. Cord blood and bone marrow (CB + BM) group had slower T-cell recovery, and higher B cells and NK cells in comparison with peripheral blood and bone marrow (PB + BM) group. Conclusions The high incidence of infection within 1 year after in vivo T-cell depletion myeloablative conditioning HSCT in severe beta-TM was consistent with poor IR.