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Patients with type 1 diabetes (T1D) may develop severe outcomes during COVID-19 disease, but their ability to generate an immune response against the SARS-CoV-2 messenger RNA (mRNA) vaccines remains to be established. Here we evaluated the safety, immunogenicity and glycometabolic effects of the SARS-CoV-2 mRNA vaccines in patients with T1D. A total of 375 patients, 326 with T1D and 49 non-diabetics, who received two doses of the SARS-CoV-2 mRNA vaccines (mRNA-1273, BNT162b2) between March and April 2021 at the ASST FBF-Sacco Milan, Italy, were included in this monocentric observational study (NCT04905823). Local and systemic adverse events were reported in both groups after SARS-CoV-2 mRNA vaccination without statistical differences between them. While both T1D patients and non-diabetic subjects exhibited a parallel increase in anti-SARS-CoV-2S titers after vaccination, the vast majority of T1D patients (70% and 78% respectively) did not show any increase in the SARS-CoV-2-specific cytotoxic response as compared to the robust increased observed in all non-diabetic subjects. A reduced secretion of the T cell-related cytokines IL-2 and TNF-alpha in vaccinated patients with T1D was also observed. No glycometabolic alterations were evident in patients with T1D using continuous glucose monitoring during follow-up. Administration of the SARS-CoV-2 mRNA vaccine is associated with an impaired cellular SARS-CoV-2-specific cytotoxic immune response in T1D patients. [ABSTRACT FROM AUTHOR]

Extracellular ATP (eATP) activates T cells by engaging the P2X7R receptor. We identified two loss-of-function P2X7R mutations that are protective against type 1 diabetes (T1D) and thus hypothesized that eATP/P2X7R signaling may represent an early step in T1D onset. Specifically, we observed that in patients with newly diagnosed T1D, P2X7R is upregulated on CD8+ effector T cells in comparison with healthy control subjects. eATP is released at high levels by human/murine islets in vitro in high-glucose/inflammatory conditions, thus upregulating P2X7R on CD8+ T cells in vitro. P2X7R blockade with oxidized ATP reduces the CD8+ T cell-mediated autoimmune response in vitro and delays diabetes onset in NOD mice. Autoreactive CD8+ T-cell activation is highly dependent upon eATP/P2X7R-mediated priming, while a novel sP2X7R recombinant protein abrogates changes in metabolism and the autoimmune response associated with CD8+ T cells. eATP/P2X7R signaling facilitates the onset of autoimmune T1D by fueling autoreactive CD8+ cells and therefore represents a novel targeted therapeutic for the disorder. [ABSTRACT FROM AUTHOR]

The authors respond to a comment on their a study on the safety and immunogenicity of the severe acute respiratory syndrome coronavirus 2 mRNA vaccine in patients with type 1 diabetes. Topics discussed include the alteration in T-cell immune response in patients with type 1 diabetes following vaccination, and the exclusion of asymptomatic coronavirus disease 2019 in their study population.

Impaired regulatory B cell (Breg) responses are associated with several autoimmune diseases in humans; however, the role of Bregs in type 1 diabetes (T1D) remains unclear. We hypothesized that naturally occurring, interleukin-10 (IL-10)-producing Bregs maintain tolerance to islet autoantigens, and that hyperglycemic nonobese diabetic (NOD) mice and T1D patients lack these potent negative regulators. IgVH transcriptome analysis revealed that islet-infiltrating B cells in long-term normoglycemic (Lnglc) NOD, which are naturally protected from diabetes, are more antigen-experienced and possess more diverse B-cell receptor repertoires compared to those of hyperglycemic (Hglc) mice. Importantly, increased levels of Breg-promoting CD40+ B cells and IL-10-producing B cells were found within islets of Lnglc compared to Hglc NOD. Likewise, healthy individuals showed increased frequencies of both CD40+ and IL-10+ B cells compared to T1D patients. Rituximab-mediated B-cell depletion followed by adoptive transfer of B cells from Hglc mice induced hyperglycemia in Lnglc human CD20 transgenic NOD mouse models. Importantly, both murine and human IL-10+ B cells significantly abrogated T-cell-mediated responses to self- or islet-specific peptides ex vivo. Together, our data suggest that antigen-matured Bregs may maintain tolerance to islet autoantigens by selectively suppressing autoreactive T-cell responses, and that Hglc mice and individuals with T1D lack this population of Bregs. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) is one of the major autoimmune diseases affecting children and young adults worldwide. To date, the different immunotherapies tested have achieved insulin independence in <5% of treated individuals. Recently, a novel hematopoietic stem cell (HSC)-based strategy has been tested in individuals with new-onset T1D. The aim of this study was to determine the effects of autologous nonmyeloablative HSC transplantation in 65 individuals with new-onset T1D who were enrolled in two Chinese centers and one Polish center, pooled, and followed up for 48 months. A total of 59% of individuals with T1D achieved insulin independence within the first 6 months after receiving conditioning immunosuppression therapy (with antithymocyte globulin and cyclophosphamide) and a single infusion of autologous HSCs, and 32% remained insulin independent at the last time point of their follow-up. All treated subjects showed a decrease in HbA1c levels and an increase in C-peptide levels compared with pretreat-ment. Despite a complete immune system recovery (i.e., leukocyte count) after treatment, 52% of treated individuals experienced adverse effects. Our study suggests the following: 1) that remission of T1D is possible by combining HSC transplantation and immunosuppression; 2) that autologous nonmyeloablative HSC transplantation represents an effective treatment for selected individuals with T1D; and 3) that safer HSC-based therapeutic options are required. [ABSTRACT FROM AUTHOR]

Extracellular ATP (eATP) activates T cells by engaging the P2X7R receptor. We identified two loss-of-function P2X7R mutations that are protective against type 1 diabetes (T1D) and thus hypothesized that eATP/P2X7R signaling may represent an early step in T1D onset. Specifically, we observed that in patients with newly diagnosed T1D, P2X7R is upregulated on CD8 + effector T cells in comparison with healthy control subjects. eATP is released at high levels by human/murine islets in vitro in high-glucose/inflammatory conditions, thus upregulating P2X7R on CD8 + T cells in vitro. P2X7R blockade with oxidized ATP reduces the CD8 + T cell-mediated autoimmune response in vitro and delays diabetes onset in NOD mice. Autoreactive CD8 + T-cell activation is highly dependent upon eATP/P2X7R-mediated priming, while a novel sP2X7R recombinant protein abrogates changes in metabolism and the autoimmune response associated with CD8 + T cells. eATP/P2X7R signaling facilitates the onset of autoimmune T1D by fueling autoreactive CD8 + cells and therefore represents a novel targeted therapeutic for the disorder., (© 2018 by the American Diabetes Association.)