Peripheral Blood Eosinophilia Has a Favorable Prognostic Impact on Transplant Outcomes after Allogeneic Peripheral Blood Stem Cell Transplantation

Abstract

Peripheral eosinophilia after allogeneic stem cell transplant (ASCT) may reflect the activation of the Th2 cytokine pathway. A retrospective analysis was performed to evaluate the impact of early- (before day 100: EEo) or late-onset (beyond day 100: LEo) eosinophilia (≥0.5 × 10 9/L in peripheral blood) on transplant outcomes after peripheral blood SCT (PBSCT) in 237 patients. The incidence of EEo and LEo was 43% at day 100 and 62% at 2 years, respectively. Compared with patients without LEo, improved transplant outcomes were observed in patients with LEo: better overall survival (OS; 86% versus 41%, P = 5 × 10 −11), lower nonrelapse mortality (NRM; 10% versus 37%, P = 3 × 10 −6), lower relapse incidence (11% versus 31%, P = 3 × 10 −5), and higher GVHD-specific survival (GSS; 90% versus 64%, P = 1 × 10 −6) were observed. In addition, similar finding was observed when transplant outcomes were analyzed according to the occurrence of eosinophilia at the onset of cGVHD. The multivariate analyses confirmed a favorable implication of LEo on OS, NRM, and GSS. LEo was associated with: (1) less severe chronic GVHD (cGVHD), (2) higher prevalence of autoantibodies, and (3) rapid lymphocyte count recovery after ASCT. In summary, the development of eosinophila after allogeneic PBSCT seemed to be a prognostic marker for improving transplant outcome.