title: CD4+CD25bright+ regulatory T cells can mediate donor nonreactivity in long-term immunosuppressed kidney allograft patients.
abstract: CD4+ CD25bright+ FoxP3+ T cells are potent regulators of T-cell reactivity, but their possible involvement in donor-specific nonresponsiveness after clinical kidney transplantation remains to be elucidated. We assessed the proliferative donor-reactivity in 33 kidney allograft recipients who were maintained on a combination of proliferation inhibitors (mycophenolate mofetil (MMF) or Azathioprine (Aza)) and prednisone, long (> 5 years) after transplantation. Of the 33 patients, 8 still exhibited donor-reactivity, whereas 25 were classified as donor nonreactive patients. Within these 25 donor nonreactive patients, we assessed the involvement of CD4+ CD25bright+ regulatory T cells both by depleting them from the responder population as well as by reconstituting them to the CD25(-/dim) effector population. The absence of proliferation in these 25 patients, was abolished in 7 (28%) recipients upon depletion of the CD4+ CD25bright+ T cells. Reconstitution of these cells suppressed the donor-reactivity in a dose-dependent manner. Adding-back CD4+ CD25bright+ T cells inhibited the anti-third party response in all recipients, indicating that functional CD4+ CD25bright+ T cells circulate despite more then 5 years of immunosuppressive treatment. Altogether, we conclude that in long-term immunosuppressed kidney allograft patients functional regulatory CD4+ CD25bright+ T cells circulate but that these cells mediate donor non reactivity only in a subset of patients.
authors.affiliation: Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands. j.velthuis@erasmusmc.nl
authors.forename: J H L
authors.initials: JH
authors.lastname: Velthuis
authors.forename: W M
authors.initials: WM
authors.lastname: Mol
authors.forename: W
authors.initials: W
authors.lastname: Weimar
authors.forename: C C
authors.initials: CC
authors.lastname: Baan
mesh_terms: D015703:Antigens, CD / Q000097:blood; D001379:Azathioprine / Q000627:therapeutic use; D015704:CD4 Antigens / Q000097:blood; D004359:Drug Therapy, Combination; D005434:Flow Cytometry; D006085:Graft Survival; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D053645:Interleukin-2 Receptor alpha Subunit / Q000097:blood*; D007518:Isoantibodies / Q000097:blood*; D016030:Kidney Transplantation / Q000276:immunology*; D019520:Living Donors; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008212:Lymphocyte Depletion; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D011241:Prednisone / Q000627:therapeutic use; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014184:Transplantation, Homologous / Q000276:immunology
chemical_list: D015703:Antigens, CD; D015704:CD4 Antigens; D007166:Immunosuppressive Agents; D053645:Interleukin-2 Receptor alpha Subunit; D007518:Isoantibodies; D009173:Mycophenolic Acid; D001379:Azathioprine; D011241:Prednisone