title: Selective removal of alloreactive cells from haematopoietic stem cell grafts: graft engineering for GVHD prophylaxis.
abstract: One of the main goals in allogeneic bone marrow transplantation is the abrogation of graft-versus-host disease with the preservation of antileukaemia and antiviral activity. We have established a novel system for the selective removal of alloreactive lymphocytes from donor grafts while retaining an effective allogeneic response to third-party stimulator cells. Initial feasibility studies were done with unrelated HLA-mismatched pairs and then extended into the matched setting. Mononuclear cells from HLA-matched donors were cocultured with irradiated recipient cells prestimulated with cytokines (gamma-IFN and TNF-alpha) in a modified mixed lymphocyte culture (MLC). Alloreactive donor lymphocytes were identified by expression of CD69, an early activation marker and selectively removed by paramagnetic bead sorting. The remaining 'non-alloreactive' lymphocytes were tested in proliferative assays against the original matched recipient and to a third-party donor. A mean depletion of proliferative capacity to 11.5 +/- 9.9% of the original matched recipient response was achieved while the residual third-party response was largely preserved at 77.8 +/- 20.9% which should translate into improved immune reconstitution and preservation of antiviral activity. The non-alloreactive lymphocytes could also possess functional antileukaemia activity. Moreover, the alloreactive cells are easily recoverable in this selective T cell depletion strategy for cryopreservation and ready for immediate access as therapeutic donor lymphocyte infusions in cases of frank relapse post transplant.
authors.affiliation: Department of Haematology, Royal Free Campus, Royal Free and University College Medical School, London, UK.
authors.forename: M B
authors.initials: MB
authors.lastname: Koh
authors.forename: H G
authors.initials: HG
authors.lastname: Prentice
authors.forename: M W
authors.initials: MW
authors.lastname: Lowdell
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D001698:Biomedical Engineering; D002469:Cell Separation / Q000379:methods*; D006086:Graft vs Host Disease / Q000517:prevention & control*; D018380:Hematopoietic Stem Cell Transplantation; D006650:Histocompatibility Testing; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D037181:Lectins, C-Type; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008212:Lymphocyte Depletion / Q000379:methods*; D011994:Recombinant Proteins; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014184:Transplantation, Homologous; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D007371:Interferon-gamma; D037181:Lectins, C-Type; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D000099192:CD69 Antigens