Infections after allogeneic hematopoietic stem cell transplantation with a nonmyeloablative conditioning regimen

Hematopoietic stem cell transplantation with a non-myeloablative conditioning (NMSCT) could theoretically be associated with a reduced risk of infection because it causes less mucosal damage or severe neutropenia compared to standard myeloablative allogeneic transplantation. Previous studies have sometimes indicated a reduced incidence of infection after NMSCT but other reports have not. We analyzed the incidence and risk factors (Cox model) of infection in 62 patients (16 F and 46 M, aged 54±11 yrs) undergoing NMSCT with a conditioning regimen of low-dose TBI±fludarabine and immunosuppression with CsA+MMF (Seattle protocol). We compared them to 119 recipients (72 peripheral blood (PBSCT) and 47 bone marrow (BMT) transplants) of a conventional HCT. The proportion of NMSCT patients with repeated infections (at least 1, 2, 3 or 4 infections) was significantly lower than in the 2 other groups, but the difference was confined to the first 30 days post-transplant (34% vs 89% and 74%, p