title: Evidence for the presence of multilineage chimerism and progenitors of donor dendritic cells in the peripheral blood of bone marrow-augmented organ transplant recipients.
abstract: We have postulated that the donor leukocyte microchimerism plays a seminal role in the acceptance of allografts by inducing and perpetuating variable degree of donor-specific nonreactivity in long-surviving organ recipients. Limited information is available, however, concerning the phenotype and function of these chimeric cells in humans. The unequivocal presence of donor dendritic cells (DCs), a prominent lineage in the microchimerism observed in rodents and clinical organ recipients, was difficult to demonstrate in bone marrow (BM)-augmented organ transplant recipients. This enigma was resolved by the recent description of a method for propagating circulating human DCs from their progenitors by culture in a medium enriched with granulocyte-macrophage colony-stimulating factor and interleukin 4, a condition known to inhibit outgrowth of monocytes, thus providing a selective growth advantage to committed progenitors of the myeloid lineage. Cells from BM-augmented organ recipients and normal control subjects harvested from 12- to 14-day cultures exhibited dendritic morphology and potent allostimulatory capacity. Using appropriate primers, the presence of donor DNA was verified by polymerase chain reaction within the lineage(null)/class II(bright) sorted DC. Phenotypic analysis of cultured DCs from BM-augmented patients, unlike that of controls, exhibited a marked down-regulation of B7-1 (CD80) while retaining normal levels of expression of B7-2 (CD86) cell surface molecules. The presence of donor DNA was also confirmed by polymerase chain reaction in individually sorted lineage+ (T, B, and NK) cells and macrophages, suggesting that the chimerism in BM-augmented patients is multilineage. The presence of progenitors of donor DCs in the peripheral blood of BM-augmented patients further substantiates the already convincing evidence of stem cell engraftment.
authors.affiliation: Thomas E. Starzl Transplantation Institute and the Department of Surgery, University of Pittsburgh Medical Center, Pennsylvania 15261, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Rugeles
authors.forename: A
authors.initials: A
authors.lastname: Aitouche
authors.forename: A
authors.initials: A
authors.lastname: Zeevi
authors.forename: J J
authors.initials: JJ
authors.lastname: Fung
authors.forename: S C
authors.initials: SC
authors.lastname: Watkins
authors.forename: T E
authors.initials: TE
authors.lastname: Starzl
authors.forename: A S
authors.initials: AS
authors.lastname: Rao
mesh_terms: D016026:Bone Marrow Transplantation / Q000473:pathology*; D002469:Cell Separation; D002478:Cells, Cultured / Q000737:chemistry; D003470:Culture Media / Q000737:chemistry; D004247:DNA / Q000032:analysis; D003713:Dendritic Cells / Q000166:cytology* / Q000637:transplantation* / Q000648:ultrastructure; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D007963:Leukocytes, Mononuclear; D008213:Lymphocyte Activation; D008854:Microscopy, Electron; D016377:Organ Transplantation / Q000473:pathology*; D010641:Phenotype; D011994:Recombinant Proteins / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology*; D013601:T-Lymphocytes / Q000276:immunology; D018183:Transplantation Chimera; D019172:Transplantation Conditioning
chemical_list: D003470:Culture Media; D011994:Recombinant Proteins; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA