Pre-engraftment graft-versus-host disease after allogeneic hematopoietic cell transplantation for acute leukemia.

Objectives: Acute graft-versus-host disease (GVHD) usually occurs with neutrophil engraftment following allogeneic hematopoietic cell transplantation (HCT), but it can also occur before engraftment. We intended to analyze the effects of timing of acute GVHD on leukemia relapse and mortality.

Methods: The outcomes of pre- and postengraftment GVHD were investigated in 384 patients who underwent allogeneic HCT for acute leukemia.

Results: Acute GVHD occurred in 100 patients, pre-engraftment in 22 and postengraftment in 78. Compared with postengraftment GVHD, pre-engraftment GVHD was more severe, as assessed by overall grade, with more frequent and more severe skin involvement and higher incidences of non-infectious fever, diarrhea, hepatic dysfunction, renal insufficiency, and weight gain. Compared with patients without acute GVHD, those with postengraftment GVHD had lower cumulative incidence of relapse [CIR; hazard ratio (HR), 0.470; P=0.006] and higher cumulative incidence of non-relapse mortality (CINRM; HR, 2.568; P<0.001), while those with pre-engraftment GVHD had similar CIR (HR, 0.815; P=0.059) and higher CINRM (HR, 2.872; P=0.036). Overall survival of patients with pre-engraftment GVHD was lower than that of those without acute GVHD (HR, 1.976; P=0.017), which was similar to that of those with postengraftment GVHD (HR, 0.969; P=0.878). Separate analyses of the effects of timing of acute GVHD on post-transplant outcomes in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) showed similar trends.

Conclusion: Pre-engraftment GVHD might be a 'cytokine storm' type syndrome rather than 'real' GVHD, indicating the need for separate analyses of pre- and postengraftment GVHD in future trials.