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Biologic treatment of T1D typically results in transient stabilization of C-peptide levels (a surrogate for endogenous insulin secretion) in some patients, followed by progression at the same rate as in untreated control groups. Here, we used integrated systems biology and flow cytometry approaches with clinical trial blood samples to elucidate pathways associated with C-peptide stabilization in T1D subjects treated with the anti-CD3 monoclonal antibody teplizumab. We identified a population of CD8 T cells that accumulated in subjects with the best response to treatment (responders) and showed that these cells phenotypically resembled exhausted T cells by expressing high levels of the transcription factor EOMES, effector molecules, and multiple inhibitory receptors (IRs), including TIGIT and KLRG1. These cells expanded after treatment, with levels peaking after 3–6 months. To functionally characterize these exhausted-like T cells, we isolated memory CD8 TIGIT+KLRG1+ T cells from responders and showed that they exhibited expanded TCR clonotypes, indicative of prior in vivo expansion; recognized a broad-based spectrum expressed of environmental and auto-antigens; and were hypo-proliferative during polyclonal stimulation, increasing expression of IR genes and decreasing cell cycle genes. Triggering these cells with a recombinant ligand for TIGIT during polyclonal stimulation further downregulated their activation, demonstrating their exhausted phenotype was not terminal. These findings identify and functionally characterize a partially exhausted cell type associated with response to teplizumab therapy and suggest that pathways regulating T cell exhaustion may play a role in successful immune interventions for T1D.

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 ∼1 year from hyperglycemia recurrence and revealed β-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 β-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 β-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.

We examined the association of individual HLA genes with rheumatoid arthritis (RA), using oligonucleotide probes that identified both DRCassociated and non-DR4-associated genes. Two distinct HLA-DRP alleles (Dw4 and Dw14) were found in DR4+ RA patients compared with controls (Dw4 50% versus 17%; Dw14 35 % versus 5 % ; total DR4 73 % versus 30 % ) , indicating that these 2 alleles are independent susceptibility genes. Remarkably, the majority of the DR4-RA patients also demonstrated a linear DNA sequence, apparently "shuffled" between different susceptibility alleles, identified with an oligonucleotide probe to a key portion of the Dw14 gene.The etiology of rheumatoid arthritis (RA) is multifactorial, involving both genetic and nongenetic