Pre-engraftment bloodstream infections in acute leukemia patients undergoing unrelated cord blood transplantation following intensified myeloablative conditioning without ATG.

Abstract

The aim of this study is to investigate the impact of pre-engraftment bloodstream infections (BSIs) on the outcomes in acute leukemia patients undergoing myeloablative cord blood transplantation (CBT). A total of 226 acute leukemia patients who received unrelated CBT were enrolled in this study, and all these patients received an intensified myeloablative conditioning without ATG. Pre-engraftment BSIs occurred in 72 patients (31.9%), and the median time of onset was 4.5days after cord blood infusion, BSIs of gram-negative bacilli, and gram-positive cocci comprised of 63.8 and 36.2%, respectively. The cumulative incidences of neutrophil and platelet engraftment, acute or chronic graft versus host disease (GVHD) were comparable among the non-BSI, gram-negative bacilli BSI, and gram-positive cocci BSI groups. The cumulative incidence of transplant-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DFS) was similar between the non-BSI and the BSI groups. For subgroups analysis, TRM was lower in gram-positive cocci BSI patients compared with that of gram-negative bacilli BSI patients (8.3 vs 39.3%) (p = 0.01) (HR = 0.39, p = 0.034), and the 5-year OS was higher in gram-positive cocci BSI cohort (79.1 vs 44.2%) (p = 0.01) (HR = 0.36, p = 0.046). Our study demonstrated that, for acute leukemia patients who received CBT after myeloablative conditioning that omitted ATG, pre-engraftment BSI had no impact on engraftment, GVHD, TRM, relapse, and long-term survival. Due to the fact that gram-negative bacilli BSI was associated with poor outcomes compared with gram-positive cocci BSI, appropriate early empirical antimicrobial management strategies and better supportive care are required to decrease the gram-negative bacilli BSI-related mortality.