Islet-autoreactive CD4+ T cells are linked with response to alefacept in type 1 diabetes

Immunosuppressive agents in diabetes treatment: Hope or despair?

Exploration of immunosuppressive agents for the treatment of diabetes is a burgeoning field that has captured the attention of the medical community. The innovative approach of using these agents to combat diabetes is driven by their diverse capabilities to regulate the immune system, which is pivotal for disease pathogenesis. The primary objective is to enhance the management of blood glucose levels, which is a critical factor in the daily life of diabetic patients. This comprehensive review delves into the therapeutic horizons opened by immunosuppressive agents, particularly their potential impact on type 1 and type 2 diabetes mellitus, and their utility in the transplantation process. The complex etiology of diabetes, which involves a delicate interplay of genetic, environmental, and immunological factors, presents a multifaceted target landscape for these therapies. The agents discussed in the review, including CD3 inhibitors, cytotoxic T-lymphocyte-associated protein 4-immunoglobulin G, Janus kinase inhibitors, anti-thymocyte globulin, tumor necrosis factor-α inhibitors, CD20 inhibitors, alefacept, and alemtuzumab, each bring a unique mechanism to the table, offering a tailored approach to immune modulation. As research progresses, emphasis is being placed on evaluating the long-term efficacy and safety of these agents to pave the way for more personalized and effective diabetes management strategies.

Identification of BHLHE40-Expressing CD4+ T Cells Producing GM-CSF in Rheumatoid Arthritis

BACKGROUND

Granulocyte-macrophage colony-stimulating factor (GM-CSF: CSF2) plays a crucial role in the pathogenesis of autoimmune diseases. The basic helix-loop-helix family member e40 (BHLHE40) gene is important for GM-CSF production in CD4+ T cells. However, the relationship between the expression of these genes and rheumatoid arthritis (RA) remains unclear, particularly in interleukin-1 (IL-1)-enriched inflammatory sites. Therefore, we investigated the expression of BHLHE40 and CSF2 in CD4+ T cells in RA.

METHODS

We analyzed gene expression using previously deposited and publicly available databases containing peripheral blood (PB) and synovial fluid (SF) from patients with RA and healthy controls (HC). Comprehensive datasets, including single-cell RNA-sequencing (scRNA-seq), RNA-seq, and microarray data, were used for this analysis.

RESULTS

BHLHE40 expression in PB CD4+ T cells from HC was higher in central memory, effector memory, Th17, and Th1/17 cells than in naive CD4+ T cells. Furthermore, BHLHE40 and CSF2 expression in the CD45RA-CCR7+ /-CD4+ T cell subset was significantly higher in the SF of patients with RA than in those with PB. scRNA-seq revealed that BHLHE40-expressing cells showed higher CSF2 expression than those that did not. Additionally, scRNA-seq showed higher BHLHE40 expression in PB CD4+ T cells from RA patients than in those from HC.

CONCLUSION

We analyzed the gene expressions of BHLHE40, which is crucial for GM-CSF production, IL1R1, which regulates BHLHE40 induction, and CSF2, its resulting product, in CD4+ T cells. Their expression levels were compared across RA SF, PB, and HC. Notably, increased expression of these genes was identified in SF.

The role of memory T cells in type 1 diabetes: Phenotypes, mechanisms, and therapeutic implications

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the loss of insulin-producing cells in the pancreatic islets. Patients with T1D have autoreactive CD4+ and CD8+ T cells that show specific features, indicating previous exposure to self-antigens. Despite that memory T cells are vital components of the adaptive immune system, providing enduring protection against pathogens; individuals with T1D have a higher proportion of memory T cells compared to healthy individuals with naїve phenotypes. Targeting memory T cells in newly diagnosed T1D patients has shown promising results, providing evidence for the significant role of memory T cells in this disease. There are various types of memory T cells, each with unique characteristics and functions. Recent advancements in understanding the complexity and heterogeneity of T cell subpopulations have shown that T1D cannot be fully understood through simple categorization. This review aims to discuss various types of memory T cells in the immunopathogenesis of T1D, focusing on their phenotypes and frequencies, as well as epigenetic and metabolic alterations. Additionally, it will address novel immunotherapeutic approaches targeting memory T cell subsets in T1D.

Immunotherapies for prevention and treatment of type 1 diabetes

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing β-cells of the pancreatic islets necessitating lifelong insulin therapy. Despite significant advancements in diabetes technology with increasingly sophisticated methods of insulin delivery and glucose monitoring, people with T1D remain at risk of severe complications like hypoglycemia and diabetic ketoacidosis. There has long been an interest in altering the immune response in T1D to prevent or cure T1D across its various stages with limited efficacy. This review highlights immunomodulatory approaches over the years including the anti-CD3 monoclonal antibody teplizumab which is now approved to delay onset of T1DM and other interventions under current investigation.

Early expansion of TIGIT+PD1+ effector memory CD4 T cells via agonistic effect of alefacept in new-onset type 1 diabetes

The CD2-depleting drug alefacept (LFA3-Ig) preserved beta cell function in new-onset type 1 diabetes (T1D) patients. The most promising biomarkers of response were late expansion of exhausted CD8 T cells and rare baseline inflammatory islet-reactive CD4 T cells, neither of which can be used to measure responses to drug in the weeks after treatment. Thus, we investigated whether early changes in T cell immunophenotypes could serve as biomarkers of drug activity. We characterized T cell responses by flow cytometry and identified an exhausted-like population of CD2low CD4 effector memory T cells coexpressing TIGIT and PD1 that expanded by 11 wk after the start of treatment. This population was not entirely spared from alefacept-mediated depletion in vivo or in vitro but recovered through homeostatic proliferation of CD2low cells in vivo. Proliferation of TIGIT+PD1+ effector memory CD4 T cells increased with treatment, with a concomitant reduction of proinflammatory cytokine production. The persistent increase of TIGIT+PD1+ effector memory CD4 T cells was specific to alefacept treatment; 2 other T cell depleting therapies, teplizumab and anti-thymocyte globulin, induced only a transient increase in this CD4 population. Our data suggest that the expanding TIGIT+PD1+ effector memory CD4 T cell population represents a promising biomarker of early treatment effects of alefacept. The nondepleting effects on proliferation and cytokine production also suggest agonistic activity by this CD2 targeted therapy.

The Type 1 Diabetes T Cell Receptor and B Cell Receptor Repository in the AIRR Data Commons: a practical guide for access, use and contributions through the Type 1 Diabetes AIRR Consortium

Human molecular genetics has brought incredible insights into the variants that confer risk for the development of tissue-specific autoimmune diseases, including type 1 diabetes. The hallmark cell-mediated immune destruction that is characteristic of type 1 diabetes is closely linked with risk conferred by the HLA class II gene locus, in combination with a broad array of additional candidate genes influencing islet-resident beta cells within the pancreas, as well as function, phenotype and trafficking of immune cells to tissues. In addition to the well-studied germline SNP variants, there are critical contributions conferred by T cell receptor (TCR) and B cell receptor (BCR) genes that undergo somatic recombination to yield the Adaptive Immune Receptor Repertoire (AIRR) responsible for autoimmunity in type 1 diabetes. We therefore created the T1D TCR/BCR Repository (The Type 1 Diabetes T Cell Receptor and B Cell Receptor Repository) to study these highly variable and dynamic gene rearrangements. In addition to processed TCR and BCR sequences, the T1D TCR/BCR Repository includes detailed metadata (e.g. participant demographics, disease-associated parameters and tissue type). We introduce the Type 1 Diabetes AIRR Consortium goals and outline methods to use and deposit data to this comprehensive repository. Our ultimate goal is to facilitate research community access to rich, carefully annotated immune AIRR datasets to enable new scientific inquiry and insight into the natural history and pathogenesis of type 1 diabetes.

Decoding the Significance of Alpha Cell Function in the Pathophysiology of Type 1 Diabetes

Alpha cells in the pancreas, traditionally known for their role in secreting glucagon to regulate blood glucose levels, are gaining recognition for their involvement in the pathophysiology of type 1 diabetes (T1D). In T1D, autoimmune destruction of beta cells results in insulin deficiency, which in turn may dysregulate alpha cell function, leading to elevated glucagon levels and impaired glucose homeostasis. This dysfunction is characterized by inappropriate glucagon secretion, augmenting the risk of life-threatening hypoglycemia. Moreover, insulin deficiency and autoimmunity alter alpha cell physiological responses, further exacerbating T1D pathophysiology. Recent studies suggest that alpha cells undergo transdifferentiation and interact with beta cells through mechanisms involving gamma-aminobutyric acid (GABA) signaling. Despite these advances, the exact pathways and interactions remain poorly understood and are often debated. Understanding the precise role of alpha cells in T1D is crucial, as it opens up avenues for developing new therapeutic strategies for T1D. Potential strategies include targeting alpha cells to normalize glucagon secretion, utilizing glucagon receptor antagonists, enhancing GABA signaling, and employing glucagon-like peptide-1 (GLP-1) receptor agonists. These approaches aim to improve glycemic control and reduce the risk of hypoglycemic events in individuals with T1D. This review provides an overview of alpha cell function in T1D, highlighting the emerging focus on alpha cell dysfunction in the context of historically well-developed beta cell research.

Ustekinumab for type 1 diabetes in adolescents: a multicenter, double-blind, randomized phase 2 trial

Immunotherapy targeting the autoimmune process in type 1 diabetes (T1D) can delay the loss of β-cells but needs to have minimal adverse effects to be an adjunct to insulin in the management of T1D. Ustekinumab binds to the shared p40 subunit of interleukin (IL)-12 and IL-23, targeting development of T helper 1 cells and T helper 17 cells (TH1 and TH17 cells) implicated in the pathogenesis of T1D. We conducted a double-blind, randomized controlled trial of ustekinumab in 72 adolescents aged 12-18 years with recent-onset T1D. Treatment was well tolerated with no increase in adverse events. At 12 months, β-cell function, measured by stimulated C-peptide, was 49% higher in the intervention group (P = 0.02), meeting the prespecified primary outcome. Preservation of C-peptide correlated with the reduction of T helper cells co-secreting IL-17A and interferon-γ (TH17.1 cells, P = 0.04) and, in particular, with the reduction in a subset of TH17.1 cells co-expressing IL-2 and granulocyte-macrophage colony-stimulating factor (IL-2+ GM-CSF+ TH17.1 cells, P = 0.04). A significant fall in β-cell-targeted (proinsulin-specific) IL-17A-secreting T cells was also seen (P = 0.0003). Although exploratory, our data suggest a role for an activated subset of TH17.1 cells in T1D that can be targeted with minimal adverse effects to reduce C-peptide loss, which requires confirmation in a larger study. (International Standard Randomised Controlled Trial Number Registry: ISRCTN 14274380).

RNA aggregates harness the danger response for potent cancer immunotherapy

Cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Here, we create "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) to substantially enhance the payload packaging and immunogenicity of tumor mRNA antigens. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for Toll-like receptor engagement in immune cells, systemically administered RNA-LPAs activate RIG-I in stromal cells, eliciting massive cytokine/chemokine response and dendritic cell/lymphocyte trafficking that provokes cancer immunogenicity and mediates rejection of both early- and late-stage murine tumor models. In client-owned canines with terminal gliomas, RNA-LPAs improved survivorship and reprogrammed the TME, which became "hot" within days of a single infusion. In a first-in-human trial, RNA-LPAs elicited rapid cytokine/chemokine release, immune activation/trafficking, tissue-confirmed pseudoprogression, and glioma-specific immune responses in glioblastoma patients. These data support RNA-LPAs as a new technology that simultaneously reprograms the TME while eliciting rapid and enduring cancer immunotherapy.

Transplantation: platform to study recurrence of disease

Beyond the direct benefit that a transplanted organ provides to an individual recipient, the study of the transplant process has the potential to create a better understanding of the pathogenesis, etiology, progression and possible therapy for recurrence of disease after transplantation while at the same time providing insight into the original disease. Specific examples of this include: 1) recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation, 2) recurrent autoimmunity after pancreas transplantation, and 3) recurrence of disease after orthotopic liver transplantation (OLT) for cirrhosis related to progressive steatosis secondary to jejuno-ileal bypass (JIB) surgery. Our team has been studying these phenomena and their immunologic underpinnings, and we suggest that expanding the concept to other pathologic processes and/or transplanted organs that harbor the risk for recurrent disease may provide novel insight into the pathogenesis of a host of other disease processes that lead to organ failure.