Emergence of a broad repertoire of GAD65-specific T-cells in type 1 diabetes patients with graft dysfunction after allogeneic islet transplantation.

Islet transplantation is one of the most promising therapies for type 1 diabetes (T1D). A major issue in islet transplantation is the loss of graft function at late phase. Several studies suggested the involvement of islet-specific T-cells in such islet graft dysfunction. In this study, we investigated the breadth and type of glutamic acid decarboxylase 65 (GAD65)-specific T-cells in T1D patients after allogeneic islet transplantation. Peripheral blood mononuclear cells (PBMCs) were obtained from islet-transplanted T1D patients during insulin-independent period and cultured for 7 days with pools of GAD65 overlapping peptides in the presence of IL-2. Cytokine secretion profiles of peptide-reactive T-cells were analyzed after a short-term restimulation with the same peptides by a multiplex bead-based cytokine assay and by an intracytoplasmic cytokine detection assay. Robust GAD65-specific CD4(+) and CD8(+) T-cell responses were detected in patients who eventually developed chronic graft dysfunction. Multiple GAD65 peptides were found to induce specific T-cell responses in these patients, indicating that the repertoire of GAD65-specific T-cells was broad. Furthermore, GAD65-specific CD4(+) T-cells were composed of heterogeneous populations, which differentially expressed cytokines including IFN-γ and type 2 cytokines, but not IL-10. In contrast, patients who showed only marginal GAD65-specific T-cell responses maintained substantially longer graft survival and insulin independence. In conclusion, our study suggests that the emergence of islet-specific T-cells precedes the development of chronic graft dysfunction in islet-transplanted patients. Thus, our observations support the hypothesis that these islet-specific T-cells contribute to the development of chronic islet graft dysfunction

J Clin Immunol

We report a longitudinal analysis of the immune response associated with a fatal case of COVID-19 in Europe. This patient exhibited a rapid evolution towards multiorgan failure. SARS-CoV-2 was detected in multiple nasopharyngeal, blood, and pleural samples, despite antiviral and immunomodulator treatment. Clinical evolution in the blood was marked by an increase (2–3-fold) in differentiated effector T cells expressing exhaustion (PD-1) and senescence (CD57) markers, an expansion of antibody-secreting cells, a 15-fold increase in γδ T cell and proliferating NK-cell populations, and the total disappearance of monocytes, suggesting lung trafficking. In the serum, waves of a pro-inflammatory cytokine storm, Th1 and Th2 activation, and markers of T cell exhaustion, apoptosis, cell cytotoxicity, and endothelial activation were observed until the fatal outcome. This case underscores the need for well-designed studies to investigate complementary approaches to control viral replication, the source of the hyperinflammatory status, and immunomodulation to target the pathophysiological response. The investigation was conducted as part of an overall French clinical cohort assessing patients with COVID-19 and registered in clinicaltrials.gov under the following number: NCT04262921

Adult-onset type 1 diabetes patients display decreased IGRP-specific Tr1 cells in blood.

The breakdown of immune tolerance against islet antigens causes type 1 diabetes (T1D). The antigens associated with adult-onset T1D (AT1D) remain largely undefined. It is possible that AT1D patients display a unique type of CD4(+) T cells specific for a certain islet antigen. Here we analyzed the cytokine production profiles of CD4(+) helper T (Th) cells that are specific for three islet antigens; GAD65, preproinsulin, and IGRP in patients with AT1D, juvenile-onset T1D (JT1D), and age-, gender- and human leukocyte antigen (HLA)-matched control adults. While IGRP-specific Th cells in AT1D patients were dominantly Th1 cells, IGRP-specific Th cells in control adults and JT1D patients were dominantly Th2 and T regulatory type 1 (Tr1) cells. Notably, the frequency of IGRP-specific Tr1 cells was significantly lower in AT1D patients than in control adults and JT1D patients. In conclusion, our study suggests that IGRP-specific Th cells play a unique pathogenic role in AT1D. Clin Immunol 2015 Dec; 161(2):270-7

Combined Plasma Elevation of CRP, Intestinal-Type Fatty Acid-Binding Protein (I-FABP), and sCD14 Identify Older Patients at High Risk for Health Care-Associated Infections

International audienceBackground: We hypothesized that low-grade inflammation was driven by microbial translocation and associated with an increased risk of health care-associated infections (HAIs).Methods: We included 121 patients aged 75 years or over in this prospective cohort study. High-sensitivity C-reactive protein (hs-CRP), I-FABP, and sCD14-as markers for low-grade inflammation, intestinal epithelial barrier integrity, and monocyte activation, respectively-were measured at admission.Results: HAIs occurred during hospitalization in 62 (51%) patients. Elevated hs-CRP (≥6.02 mg/L, ie, the median) was associated with a significantly higher HAI risk when I-FABP was in the highest quartile (odds ratio [OR], 4; 95% confidence interval [95% CI], 1.39-11.49; p = .010). In patients with hs-CRP elevation and highest-quartile I-FABP, sCD14 elevation (≥0.65 µg/mL, ie, the median) was associated with an 11-fold higher HAI risk (OR, 10.8; 95% CI, 2.28-51.1; p = .003). Multivariate analyses adjusted for invasive procedures and comorbidities did not change the associations linking the three markers to the HAI risk.Conclusion: Increased levels of hs-CRP, I-FABP, and sCD14 may reflect loss of intestinal epithelial barrier integrity with microbial translocation leading to monocyte activation and low-grade inflammation. In our cohort, these markers identified patients at high risk for HAIs

Numbers of peptides and peptide clusters.

<p>PPI, preproinsulin; GAD65, glutamic acid decarboxylase 65; ZnT8, zinc transporter 8; C, peptide cluster.</p

Cytokine secretion profiling of specific CD4⁺ T cells by the Cytokine-driven assay.

<p>(<b>A</b>) Cytokine secretion by ZnT8 p65-specific T cells in HS#4. Results from the Direct assay. (<b>B</b>) ZnT8 p65-specific CD4⁺ T cell proliferation in HS#4. (<b>C–D</b>) The Cytokine-driven assay. CFSE-labeled PBMCs from HS#4 were cultured with single peptides from ZnT8 C#11 for 7 days in the presence of IL-2 (day 2–7). (<b>C</b>) Cytokine secretion during 24 h re-stimulation with peptides. (<b>D</b>) ICS assay after 6 h re-stimulation in the presence of brefeldin A. Gated to CFSE-diluted CD4⁺ T cell populations. (<b>E-F</b>) Cytokine secretion profiling of islet-antigen-specific CD4⁺ T cells in healthy adults by the Cytokine-driven assay. (<b>E</b>) Cytokine secretion during 24 h re-stimulation with peptides. (<b>F</b>) ICS assay after 6 h re-stimulation in the presence of brefeldin A.</p

Combined Plasma Elevation of CRP, Intestinal-Type Fatty Acid-Binding Protein (I-FABP), and sCD14 Identify Older Patients at High Risk for Health Care-Associated Infections

International audienceBackground: We hypothesized that low-grade inflammation was driven by microbial translocation and associated with an increased risk of health care-associated infections (HAIs).Methods: We included 121 patients aged 75 years or over in this prospective cohort study. High-sensitivity C-reactive protein (hs-CRP), I-FABP, and sCD14-as markers for low-grade inflammation, intestinal epithelial barrier integrity, and monocyte activation, respectively-were measured at admission.Results: HAIs occurred during hospitalization in 62 (51%) patients. Elevated hs-CRP (≥6.02 mg/L, ie, the median) was associated with a significantly higher HAI risk when I-FABP was in the highest quartile (odds ratio [OR], 4; 95% confidence interval [95% CI], 1.39-11.49; p = .010). In patients with hs-CRP elevation and highest-quartile I-FABP, sCD14 elevation (≥0.65 µg/mL, ie, the median) was associated with an 11-fold higher HAI risk (OR, 10.8; 95% CI, 2.28-51.1; p = .003). Multivariate analyses adjusted for invasive procedures and comorbidities did not change the associations linking the three markers to the HAI risk.Conclusion: Increased levels of hs-CRP, I-FABP, and sCD14 may reflect loss of intestinal epithelial barrier integrity with microbial translocation leading to monocyte activation and low-grade inflammation. In our cohort, these markers identified patients at high risk for HAIs

Clinical characteristics of T1D patients and HLA-matched controls.

<p>T1D, Type 1 diabetes patients; Ctrl, HLA-matched controls; n., number;</p><p>M, male; F, female; NA, not applicable.</p

Summary of cytokine secretion profiles in the Cytokine-driven assay.

<p>HS, healthy subject; p, peptide.</p

Distinct cytokine expression patterns of ZnT8 specific CD4⁺ T cells between T1D patients and healthy adults.

<p>PBMCs from 15 T1D patients and 15 age/gender/HLA-matched controls were cultured with ZnT8 single peptides for 7 days in the presence of IL-2 (day 2–7). ICS assay was performed after 6 h re-stimulation with the same peptides. Gated to CD4⁺ T cells. (<b>A</b>) Representative results of cytokine expressions by CD4⁺ T cells specific for ZnT8 single peptides in T1D patients and controls. (<b>B, C</b>) Cytokine expression patterns of ZnT8-specific CD4⁺ T cells. 24 from 60 control PBMC cultures (15 subjects×4 peptides) and 22 from 60 T1D PBMC cultures, which contained CD4⁺ T cells expressing any of three cytokines at a frequency of >0.5%, were used for the analysis. Statistical significance between control group and T1D group was tested by Student’s <i>t</i>-test. (<b>D</b>) Composition of ZnT8-specific CD4⁺ T cells with distinct cytokine-expression pattern in T1D patients and controls.</p