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 and platelet engraftment 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 of days +14 and +21 neutrophil and day +28 platelet engraftment were 3.26, 2.25, and 1.28 for splenectomy, and 0.56, 0.55, and 0.82 for splenomegaly groups compared to normal spleen (p<0.001), respectively. Among patients with splenomegaly, use of peripheral blood grafts improved neutrophil engraftment at day +21, and CD34+ cell dose >5.7x10(6)/kg improved platelet engraftment at day+28. After adjusting variables by Cox regression, the incidence of graft-versus-host disease (GVHD) and overall survival were not different among groups. Splenomegaly is associated with delayed engraftment while splenectomy prior to HCT facilitates early engraftment without impact on survival.