title: Absence of a CD34- hematopoietic precursor population in recipients of CD34+ stem cell transplantation.
abstract: The purified CD34(+) cell fraction has been used for hematopoietic stem cell transplantation since they were demonstrated to have long-term reconstituting ability. Therefore, the potential effects of CD34(-) stem cells on the clinical course have been a major concern in recipients of CD34(+)-selected transplantation. To address this concern, we used an in vitro assay to determine whether transplant recipients have CD34(-)precursor population. Lin(-)CD34(-) cells were isolated from bone marrow cells in 11 transplant recipients including four CD34-selected transplantations, six standard bone marrow transplantations, and one T cell-depleted marrow transplantation. The frequency of the Lin(-)CD34(-) population in four CD34-enriched transplantation recipients was not different from those of normal donors or recipients of other modes of transplantation: 0.96 +/- 1.01% (mean +/- s.d., n = 4), 0.45 +/- 0.16% (n = 6), and 0.66 +/- 0.59% (n = 7), respectively. However, the Lin(-)CD34(-)population obtained from the recipients of CD34-enriched transplantation acquired neither CD34 expression nor colony-forming activity after 7 days of culture, whereas the cells from all the normal individuals and standard BMT recipients were able to differentiate into CD34(+) cells accompanied by the emergence of colony-forming activity.We conclude that recipients of CD34-enriched transplantation appear to have defects in their CD34(-) precursor population. The clinical significance of these defects will be determined in a life-long follow-up of these patients.
authors.affiliation: Research Center for Cell Transplantation, Tokai University, School of Medicine, Kanagawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Muguruma
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Yabe
authors.forename: M
authors.initials: M
authors.lastname: Yabe
authors.forename: K
authors.initials: K
authors.lastname: Hattori
authors.forename: Y
authors.initials: Y
authors.lastname: Yasuda
authors.forename: T
authors.initials: T
authors.lastname: Hotta
mesh_terms: D000293:Adolescent; D000328:Adult; D018952:Antigens, CD34 / Q000032:analysis*; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology*; D018929:Cell Culture Techniques; D002455:Cell Division; D002648:Child; D002675:Child, Preschool; D003114:Colony-Forming Units Assay; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D008212:Lymphocyte Depletion; D014019:Tissue Donors
chemical_list: D018952:Antigens, CD34