Effects of spleen status on early outcomes after hematopoietic cell transplantation

To assess the impact of spleen status on engraftment, and early morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT), we analyzed 9,683 myeloablative allograft recipients from 1990 to 2006; 472 had prior splenectomy (SP), 300 splenic irradiation (SI), 1,471 with splenomegaly (SM), and 7,440 with normal spleen (NS). Median times to neutrophil engraftment (NE) and platelet engraftment (PE) were 15 vs 18 days and 22 vs 24 days for the SP and NS groups, respectively (P<0.001). Hematopoietic recovery at day +100 was not different across all groups, however the odds ratio of days +14 and +21 NE and day +28 PE were 3.26, 2.25 and 1.28 for SP, and 0.56, 0.55, and 0.82 for SM groups compared to NS (P<0.001), respectively. Among patients with SM, use of peripheral blood grafts improved NE at day +21, and CD34+ cell dose >5.7 × 10(6)/kg improved PE at day+28. After adjusting variables by Cox regression, the incidence of GVHD and OS were not different among groups. SM is associated with delayed engraftment, whereas SP prior to HCT facilitates early engraftment without having an impact on survival.