Risk factors for secondary poor graft function after bone marrow transplantation in children with acquired aplastic anemia

In patients with acquired AA, PGF is a major cause of cytopenia after hematopoietic stem cell transplantation. An increased incidence of PGF, especially sPGF, has been noted after the introduction of the FLU/CY regimen in children with acquired AA. To clarify the risk factors for sPGF, the clinical data of 49 patients (median age, 11 years; range, 1‐19 years) with AA who received allogeneic BMT at Nagoya University Hospital from 1997 to 2016 were analyzed. Out of the 49 patients, 7 developed sPGF, and the 5‐year CI was 0.15 (95% CI, 0.04‐0.25). Five received the FLU/CY regimen, and the 5‐year CI of sPGF was significantly higher in patients who received the regimen (0.36; 95% CI, 0.12‐0.62) than in those who were conditioned with the non‐FLU/CY regimen (0.06; 95% CI, 0.01‐0.17; P = .01). The multivariate analysis confirmed that the FLU/CY regimen (hazard ratio, 6.12; 95% CI, 1.16‐32.4; P = .03) was a significant risk factor for sPGF. sPGF improved spontaneously without stem cell boost infusions in 5 patients, ranging from 460 to 3539 days after BMT. The 10‐year CI of the spontaneous trilineage recovery was 0.83 (95% CI, 0.00‐0.97), and all 7 patients are alive. The FLU/CY regimen was identified as a risk factor for the sPGF development in patients with AA. The establishment of the optimal conditioning regimens for children with AA is warranted.