Engraftment syndrome after allogeneic hematopoietic cell transplantation predicts poor outcomes.

Engraftment syndrome (ES), characterized by fever, rash, pulmonary edema, weight gain, liver and renal dysfunction, and/or encephalopathy, occurs at the time of neutrophil recovery after hematopoietic cell transplantation (HCT). In this study, we evaluated the incidence, clinical features, risk factors, and outcomes of ES in children and adults undergoing first-time allogeneic HCT. Among 927 patients, 119 (13%) developed ES at a median of 10 days (interquartile range 9 to 12) after HCT. ES patients experienced significantly higher cumulative incidence of grade 2 to 4 acute GVHD at day 100 (75% versus 34%, P < .001) and higher nonrelapse mortality at 2 years (38% versus 19%, P < .001) compared with non-ES patients, resulting in lower overall survival at 2 years (38% versus 54%, P < .001). There was no significant difference in relapse at 2 years (26% versus 31%, P = .772). Suppression of tumorigenicity 2, interleukin 2 receptor alpha, and tumor necrosis factor receptor 1 plasma biomarker levels were significantly elevated in ES patients. Our results illustrate the clinical significance and prognostic impact of ES on allogeneic HCT outcomes. Despite early recognition of the syndrome and prompt institution of corticosteroid therapy, outcomes in ES patients were uniformly poor. This study suggests the need for a prospective approach of collecting clinical features combined with correlative laboratory analyses to better characterize ES.