title: Implication of maternal-cell contamination in the clinical banking of umbilical cord blood.
abstract: BACKGROUND
  The increasing utilization of human UC blood (UCB) in transplantation has drawn attention to the need for rationalization of selection, collection, processing, testing, banking and release of UCB. However, the issue of maternal blood contamination has not been well addressed. There are concerns that maternal T cells might elicit GvHD post-UCB transplant.
  
  
  METHODS
  Maternal T cells in 58 male UCB allografts were enumerated using fluorescent in situ hybridization and flow cytometry. Obstetric factors, preceding labor, multi-parity and gestational age, were also analyzed.
  
  
  RESULTS
  Levels of maternal cells of 0.75-5.25% were found in 15.5% (9/58) UCB. There was no association of maternal-cell contamination with preceding labor [25% (2/8) with previous delivery versus 35.4% (17/48) first born, P = 0.702], nor any correlation with multi-parity [37.5% (3/8) para > or = 3 versus 16.7% (8/48) para < 3, P = 0.181]. Gestation age of newborns also exhibited no association with maternal-cell contamination (39.47 weeks in newborn UCB with maternal cells, versus 39.58 weeks without: P = 0.674). The extrapolated maternal T cells/kg in nine UCB transplants were 1.05 x 10(5) +/- 1.12 x 10(5) (3.40 x 10(4) - 3.18 x 10(5)).
  
  
  CONCLUSIONS
  In relation to the arbitrary threshold of 1 x 10(5) T cells/kg in HLA-mismatched transplants utilizing T-cell depleted BM, 22.2% (2/9) of UCB transplants having maternal-cell contamination might be at risk of GvHD. Data support the need for testing for maternal blood in UCB, and evaluating the clinical relevance of GvHD in patients post-UCB transplant. The establishment of guidelines and standards for release of such UCB collections would be advisable in evidence-based UCB transplantation.
authors.affiliation: Division of Hematology and Bone Marrow Transplantation, Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
authors.forename: K S
authors.initials: KS
authors.lastname: Tsang
authors.forename: A P Y
authors.initials: AP
authors.lastname: Wong
authors.forename: M S
authors.initials: MS
authors.lastname: Cheung
authors.forename: S H
authors.initials: SH
authors.lastname: Tang
authors.forename: Y
authors.initials: Y
authors.lastname: Leung
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.forename: T T
authors.initials: TT
authors.lastname: Lau
authors.forename: M H L
authors.initials: MH
authors.lastname: Ng
authors.forename: P M P
authors.initials: PM
authors.lastname: Yuen
mesh_terms: D001771:Blood Banks; D017252:CD3 Complex / Q000378:metabolism; D003114:Colony-Forming Units Assay; D005260:Female; D005312:Fetal Blood / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology; D014184:Transplantation, Homologous
chemical_list: D017252:CD3 Complex