title: Emergence of a broad repertoire of GAD65-specific T-cells in type 1 diabetes patients with graft dysfunction after allogeneic islet transplantation.
abstract: Islet transplantation is one of the most promising therapies for type 1 diabetes (T1D). A major issue in islet transplantation is the loss of graft function at late phase. Several studies suggested the involvement of islet-specific T-cells in such islet graft dysfunction. In this study,  we investigated the breadth and type of glutamic acid decarboxylase 65 (GAD65)-specific T-cells in T1D patients after allogeneic islet transplantation. Peripheral blood mononuclear cells (PBMCs) were obtained from islet-transplanted T1D patients during insulin-independent period and cultured  for 7 days with pools of GAD65 overlapping peptides in the presence of IL-2. Cytokine secretion profiles of peptide-reactive T-cells were analyzed after a short-term restimulation with the same peptides by a multiplex bead-based cytokine assay and by an intracytoplasmic cytokine detection  assay. Robust GAD65-specific CD4(+) and CD8(+) T-cell responses were detected in patients who eventually developed chronic graft dysfunction. Multiple GAD65 peptides were found to induce specific T-cell responses in these patients, indicating that the repertoire of GAD65-specific  T-cells was broad. Furthermore, GAD65-specific CD4(+) T-cells were composed of heterogeneous populations, which differentially expressed cytokines including IFN-γ and type 2 cytokines, but not IL-10. In contrast, patients who showed only marginal GAD65-specific T-cell responses  maintained substantially longer graft survival and insulin independence. In conclusion, our study suggests that the emergence of islet-specific T-cells precedes the development of chronic graft dysfunction in islet-transplanted patients. Thus, our observations support the hypothesis that these  islet-specific T-cells contribute to the development of chronic islet graft dysfunction.
authors.affiliation: Baylor Institute for Immunology Research, Dallas, TX 75204, USA.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Chujo
authors.forename: Emile
authors.initials: E
authors.lastname: Foucat
authors.forename: Morihito
authors.initials: M
authors.lastname: Takita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Itoh
authors.forename: Koji
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shimoda
authors.forename: Kunimasa
authors.initials: K
authors.lastname: Yagi
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yamagishi
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Tamura
authors.forename: Liping
authors.initials: L
authors.lastname: Yu
authors.forename: Bashoo
authors.initials: B
authors.lastname: Naziruddin
authors.forename: Marlon F
authors.initials: MF
authors.lastname: Levy
authors.forename: Hideki
authors.initials: H
authors.lastname: Ueno
authors.forename: Shinichi
authors.initials: S
authors.lastname: Matsumoto
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000378:metabolism / Q000601:surgery*; D005260:Female; D005968:Glutamate Decarboxylase / Q000737:chemistry / Q000276:immunology*; D006085:Graft Survival; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D018793:Interleukin-13 / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology; D007515:Islets of Langerhans / Q000502:physiology; D016381:Islets of Langerhans Transplantation; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D008875:Middle Aged; D010455:Peptides / Q000494:pharmacology
chemical_list: D000906:Antibodies; D018793:Interleukin-13; D007376:Interleukin-2; D010455:Peptides; D016753:Interleukin-10; D007371:Interferon-gamma; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2