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The approval of teplizumab to delay the onset of type 1 diabetes is an important inflection point in the decades-long pursuit to treat the cause of the disease rather than its symptoms. The National Institute of Diabetes and Digestive and Kidney Diseases convened a workshop of the Diabetes Mellitus Interagency Coordinating Committee titled "Evolving Concepts in Pathophysiology, Screening, and Prevention of Type 1 Diabetes" to review this accomplishment and identify future goals. Speakers representing Type 1 Diabetes TrialNet (TrialNet) and the Immune Tolerance Network emphasized that the ability to robustly identify individuals destined to develop type 1 diabetes was essential for clinical trials. The presenter from the U.S. Food and Drug Administration described how regulatory approval relied on data from the single clinical trial of TrialNet with testing of teplizumab for delay of clinical diagnosis, along with confirmatory evidence from studies in patients after diagnosis. The workshop reviewed the etiology of type 1 diabetes as a disease involving multiple immune pathways, highlighting the current understanding of prognostic markers and proposing potential strategies to improve the therapeutic response of disease-modifying therapies based on the mechanism of action. While celebrating these achievements funded by the congressionally appropriated Special Diabetes Program, panelists from professional organizations, nonprofit advocacy/funding groups, and industry also identified significant hurdles in translating this research into clinical care. [ABSTRACT FROM AUTHOR]

ObjectiveTo investigate if recurrent autoimmunity explained hyperglycemia and C-peptide loss in three immunosuppressed simultaneous pancreas-kidney (SPK) transplant recipients.Research design and methodsWe monitored autoantibodies and autoreactive T-cells (using tetramers) and performed biopsy. The function of autoreactive T-cells was studied with in vitro and in vivo assays.ResultsAutoantibodies were present pretransplant and persisted on follow-up in one patient. They appeared years after transplantation but before the development of hyperglycemia in the remaining patients. Pancreas transplant biopsies were taken within approximately 1 year from hyperglycemia recurrence and revealed beta-cell loss and insulitis. We studied autoreactive T-cells from the time of biopsy and repeatedly demonstrated their presence on further follow-up, together with autoantibodies. Treatment with T-cell-directed therapies (thymoglobulin and daclizumab, all patients), alone or with the addition of B-cell-directed therapy (rituximab, two patients), nonspecifically depleted T-cells and was associated with C-peptide secretion for >1 year. Autoreactive T-cells with the same autoantigen specificity and conserved T-cell receptor later reappeared with further C-peptide loss over the next 2 years. Purified autoreactive CD4 T-cells from two patients were cotransplanted with HLA-mismatched human islets into immunodeficient mice. Grafts showed beta-cell loss in mice receiving autoreactive T-cells but not control T-cells.ConclusionsWe demonstrate the cardinal features of recurrent autoimmunity in three such patients, including the reappearance of CD4 T-cells capable of mediating beta-cell destruction. Markers of autoimmunity can help diagnose this underappreciated cause of graft loss. Immune monitoring during therapy showed that autoimmunity was not resolved by the immunosuppressive agents used.

There is an ongoing need to develop strategic combinations of therapeutic agents to prevent type 1 diabetes (T1D) or to preserve islet β-cell mass in new-onset disease. Although clinical trials using candidate therapeutics are commonly based on preclinical studies, concern is growing regarding the reproducibility as well as the potential clinical translation of reported results using animal models of human disorders. In response, the National Institutes of Health Immune Tolerance Network and JDRF established a multicenter consortium of academic institutions designed to assess the efficacy and intergroup reproducibility of clinically applicable immunotherapies for reversing new-onset disease in the NOD mouse model of T1D. Predicated on prior studies, this consortium conducted coordinated, prospective studies, using joint standard operating procedures, fixed criteria for study entry, and common reagents, to optimize combined anti-CD3 treatment plus interleukin-1 (IL-1) blockade to reverse new-onset disease in NOD mice. We did not find that IL-1 blockade with anti-IL-1β monoclonal antibody or IL-1trap provided additional benefit for reversing new-onset disease compared with anti-CD3 treatment alone. These results demonstrate the value of larger, multicenter preclinical studies for vetting and prioritizing therapeutics for future clinical use. [ABSTRACT FROM AUTHOR]

Type 1 diabetes results from the autoimmune destruction of insulin-producing pancreatic β-cells by cytotoxic T-lymphocytes (CTLs). In humans, few β-cell epitopes have been reported, thereby limiting the study of β-cell-specific CTLs in type 1 diabetes. To identify additional epitopes, HLA class I peptide affinity algorithms were used to identify a panel of peptides derived from the β-cell proteins islet amyloid polypeptide (IAPP), islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), insulin, insulinoma-associated antigen 2 (IA-2), and phogrin that were predicted to bind HLA-A*0201. Peripheral blood mononuclear cells from 24 HLA-A*0201 recent-onset type 1 diabetic patients and 11 nondiabetic control subjects were evaluated for γ-interferon secretion in response to peptide stimulation in enzyme-linked immunospot assays. We identified peptides IAPP9-17, IGRP215-223, IGRP152-160, islet IA-2(172-180), and IA-2(482-490) as novel HLA-A*0201-restricted T-cell epitopes in type 1 diabetic patients. Interestingly, we observed a strong inverse correlation between the binding affinity of β-cell peptides to HLA-A*0201 and CTL responses against those peptides in recent-onset type I diabetic patients. In addition, we found that self-reactive CTLs with specificity for an insulin peptide are frequently present in healthy individuals. These data suggest that many β-cell epitopes are recognized by CTLs in recent-onset type I diabetic patients. These epitopes may be important in the pathogenesis of type 1 diabetes. Diabetes 55:3068-3074, 2006 [ABSTRACT FROM AUTHOR]