Development of a Predictive Response Signature to Anti-Thymocyte Globulin in Type 1 Diabetes

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PROJECT SUMMARY/ABSTRACT Type 1 diabetes (T1D) is caused by T cell-mediated destruction of pancreatic β-cells. A combination of genetic and environmental factors contributes to this complex autoimmune disease. T1D is without any durable disease- altering therapies though several clinical trials in recent-onset T1D have demonstrated transient β-cell preservation. Anti-thymocyte globulin (ATG), which at low doses can modulate T cells and other adaptive/innate immune cells, is one such immunomodulatory therapy. Compared to placebo, ATG, given in a low dose over 2 days, demonstrated more than 40% higher preservation of C-peptide and nearly 1% lower HbA1c 2 years after therapy in recent-onset T1D subjects. However, within successful T1D immunotherapy trials like low dose ATG, there are clinical “responders” (those who produce significantly more C-peptide in response to therapy) and “nonresponders.” The field of T1D lacks an ability to determine these clinical responders prior to clinical trial enrollment and drug administration, thus exposing some individuals to ineffective interventions with considerable side effect profiles. Utilizing samples from the NIH-funded TrialNet Low-dose ATG in Recent-Onset T1D clinical trial (TN19), the objective of this proposal is to develop a response signature to ATG for use in future clinical trial enrollment criteria and eventual clinical care. The objective that transcriptome, methylome and immunophenotyping differences can identify a responder signature to ATG in T1D will be tested. Specifically, Aim 1 will develop a biomarker of response using a unique in vitro model of ATG stimulation in TN19 baseline clinical trial samples. The hypothesis being that innate and adaptive-specific genes will demonstrate differential expression and methylation profiles with distinct immune phenotypes in clinical responders compared to nonresponders following in vitro ATG stimulation. This is assessing the methodology of performing in vitro pre- enrollment testing of a subject’s peripheral blood to determine their likelihood of response. Aim 2 will identify the mechanisms of clinical efficacy through innovative single cell RNA sequencing, T cell receptor (TCR) α/β pairing, TCR immunosequencing, and surface marker expression. In addition, the function of immune subpopulations known to play a key role in immune tolerance (regulatory T cells and exhausted T cells) will add to the mechanistic determination of ATG efficacy. This work may facilitate prospective personalized therapeutic planning for individual patients or precision medicine-directed clinical trial enrollment criteria. These biomarkers would improve responder rates and reduce exposure of nonresponders to side effects. My career goal of developing predictive biomarkers for T1D immunotherapy clinical trials will be advanced by this proposal. Highly valued skills set forth in the career development plan aim to promote further independence as an investigator and include training in 1) immunological assays, 2) big data analytics, 3) responsible conduct of research, and 4) clinical trial design. The collaborative rapport and mission of training the next generation of investigators across all institutes and departments of the University of Florida provide an ideal environment for career success.