title: Eosinophilia, regardless of degree, is related to better outcomes after allogeneic hematopoietic stem cell transplantation.
abstract: OBJECTIVE
  Several recent studies report that, after allogeneic hematopoietic cell transplantation (allo-HCT), eosinophilia is a favorable factor for transplant outcomes. However, whether the degree of eosinophilia influences transplant outcomes is yet to be established.
  
  
  METHODS
  We studied 144 patients with hematological malignancy who received allo-HCT at our institution. The stem cell sources were bone marrow in 84 patients, peripheral blood stem cells in 32 patients, and cord blood in 28 patients. One hundred and twelve patients underwent myeloablative conditioning and 49 patients had high-risk disease. We performed semi-landmark analysis to examine the influence of eosinophilia.
  
  
  RESULTS
  Eosinophilia developed at a median of 47 days after transplantation in 63 patients (44%). The patients with eosinophilia showed significantly better overall survival (OS) and a lower relapse rate at three years, compared to those without eosinophilia (66% vs 55%, p=0.04 and 30% vs 50%, p=0.002). On analysis following division into groups with mild (500-1,500×10(6)/L) and hyper- (>1,500×10(6)/L) eosinophilia, three-year OS and relapse rates were 68% and 65% (p=0.92), and 31% and 28% (p=0.90), respectively. On multivariate analysis, eosinophilia was significantly associated with lower relapse rates [HR: 0.5 (95% CI: 0.3-0.9), p=0.01] and the same trend was preserved in the analysis of the mild and hyper-eosinophilic groups.
  
  
  CONCLUSIONS
  The results suggest that eosinophilia after allo-HCT was associated with better OS and a lower relapse rate, regardless of the levels. The mechanism of this effect is still unclear, and requires study of the pathophysiological process to clarify the relationship between the higher levels of eosinophilia after allo-HCT and organ infiltration.
authors.affiliation: Hematology, Graduate School of Medicine, Osaka City University, Japan. nakane@med.osaka-cu.ac.jp
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nakane
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Nakamae
authors.forename: Asao
authors.initials: A
authors.lastname: Hirose
authors.forename: Mika
authors.initials: M
authors.lastname: Nakamae
authors.forename: Hideo
authors.initials: H
authors.lastname: Koh
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Mitsutaka
authors.initials: M
authors.lastname: Nishimoto
authors.forename: Yukari
authors.initials: Y
authors.lastname: Umemoto
authors.forename: Takuro
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Masato
authors.initials: M
authors.lastname: Bingo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshida
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Ichihara
authors.forename: Mizuki
authors.initials: M
authors.lastname: Aimoto
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Terada
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nakao
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ohsawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004802:Eosinophilia / Q000097:blood* / Q000401:mortality* / Q000473:pathology; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000401:mortality* / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D019172:Transplantation Conditioning / Q000401:mortality / Q000639:trends; D014184:Transplantation, Homologous / Q000401:mortality / Q000639:trends; D016896:Treatment Outcome; D055815:Young Adult