title: Implication of early lymphocyte recovery after allogeneic hematopoietic stem cell transplantation in children with leukemia.
abstract: OBJECTIVE
  The repopulating lymphocytes after allogeneic hematopoietic stem cell transplantation have an important role not only on the prevention of serious infections in the early transplantation period, but also on the killing of residual leukemic cells by graft-versus-leukemia effect. The aim of this study was to analyze the impact of lymphocyte recovery after allogeneic stem cell transplantation in children with hematologic malignancies.
  
  
  METHODS
  We evaluated 69 children transplanted for acute lymphoblastic leukemia (ALL) (n=34), acute myeloid leukemia (AML) (n=26), chronic leukemia (n=7) and juvenile myelomonocytic leukemia (n=2) between 1996 and 2008 at the Chonnam National University Hospital, Korea. The patients were grouped based on absolute lymphocyte counts (ALC) <500/μL or ≥ 500/μL at D+21 and D+30 after transplant.
  
  
  RESULTS
  Patients with a High ALC at D+21 and D+30 had a faster neutrophil and platelet engraftment. The High at D+30 group had a better 5 year overall survival (71% vs. 53%, p=0.043) and event-free survival (72% vs. 53%, p=0.065) than the Low at D+30 group. The incidence of grade II-IV acute and chronic graft-versus-host disease (GVHD), and relapse rate did not differ by the ALC counts. However, the Low at D+30 group had a significantly increased risk for transplant-related mortality (p=0.019). The univariate analysis showed that the factors associated with decreased survival were a Low ALC at D+30, patients with high risk ALL, and grade II-IV aGVHD in patients with ALL and AML.
  
  
  CONCLUSIONS
  Early posttransplant serial lymphocyte measurement would be a simple but useful method for predicting transplant outcomes.
authors.affiliation: Department of Pediatrics, Environmental Health Center for Childhood Leukemia and Cancer, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Hwasun, Korea.
authors.forename: Dong Kyun
authors.initials: DK
authors.lastname: Han
authors.forename: Hee Jo
authors.initials: HJ
authors.lastname: Baek
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Tai Ju
authors.initials: TJ
authors.lastname: Hwang
authors.forename: Hoon
authors.initials: H
authors.lastname: Kook
mesh_terms: D000293:Adolescent; D001792:Blood Platelets / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D020544:Graft vs Leukemia Effect; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007223:Infant; D007694:Killer Cells, Natural / Q000166:cytology; D007938:Leukemia / Q000628:therapy*; D018655:Lymphocyte Count; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D009504:Neutrophils / Q000166:cytology; D011379:Prognosis; D012008:Recurrence; D012074:Remission Induction; D056910:Republic of Korea; D012189:Retrospective Studies; D013234:Stem Cells / Q000166:cytology; D019172:Transplantation Conditioning; D014184:Transplantation, Homologous; D016896:Treatment Outcome