Combinatorial detection of autoreactive CD8+ T cells with HLA-A2 multimers: a multi-centre study by the Immunology of Diabetes Society T Cell Workshop

Aims/hypothesis: Validated biomarkers are needed to monitor the effects of immune intervention in individuals with type 1 diabetes. Despite their importance, few options exist for monitoring antigen-specific T cells. Previous reports described a combinatorial approach that enables the simultaneous detection and quantification of multiple islet-specific CD8+ T cell populations. Here, we set out to evaluate the performance of a combinatorial HLA-A2 multimer assay in a multi-centre setting. Methods: The combinatorial HLA-A2 multimer assay was applied in five participating centres using centralised reagents and blinded replicate samples. In preliminary experiments, samples from healthy donors were analysed using recall antigen multimers. In subsequent experiments, samples from healthy donors and individuals with type 1 diabetes were analysed using beta cell antigen and recall antigen multimers. Results: The combinatorial assay was successfully implemented in each participating centre, with CVs between replicate samples that indicated good reproducibility for viral epitopes (mean %CV = 33.8). For beta cell epitopes, the assay was very effective in a single-centre setting (mean %CV = 18.4), but showed sixfold greater variability across multi-centre replicates (mean %CV = 119). In general, beta cell antigen-specific CD8+ T cells were detected more commonly in individuals with type 1 diabetes than in healthy donors. Furthermore, CD8+ T cells recognising HLA-A2-restricted insulin and glutamate decarboxylase epitopes were found to occur at higher frequencies in individuals with type 1 diabetes than in healthy donors. Conclusions/interpretation Our results suggest that, although combinatorial multimer assays are challenging, they can be implemented in multiple laboratories, providing relevant T cell frequency measurements. Assay reproducibility was notably higher in the single-centre setting, suggesting that biomarker analysis of clinical trial samples would be most successful when assays are performed in a single laboratory. Technical improvements, including further standardisation of cytometry platforms, will likely be necessary to reduce assay variability in the multi-centre setting

Functional monovalency amplifies the pathogenicity of anti-MuSK IgG4 in myasthenia gravis

Human immunoglobulin (Ig) G4 usually displays antiinflammatory activity, and observations of IgG4 autoantibodies causing severe autoimmune disorders are therefore poorly understood. In blood, IgG4 naturally engages in a stochastic process termed "Fab-arm exchange" in which unrelated IgG4s exchange half-molecules continuously. The resulting IgG4 antibodies are composed of two different binding sites, thereby acquiring monovalent binding and inability to cross-link for each antigen recognized. Here, we demonstrate that this process amplifies autoantibody pathogenicity in a classic IgG4-mediated autoimmune disease: muscle-specific kinase (MuSK) myasthenia gravis. In mice, monovalent anti-MuSK IgG4s caused rapid and severemyasthenicmuscleweakness, whereas the same antibodies in their parental bivalent form were less potent or did not induce a phenotype. Mechanistically this could be explained by opposing effects onMuSK signaling. Isotype switching to IgG4 in an autoimmune response thereby may be a critical step in the development of disease. Our study establishes functional monovalency as a pathogenic mechanism in IgG4-mediated autoimmune disease and potentially other disorders.Neurological Motor Disorder

Zwecke der genossenschaftlichen Pflichtpruefung

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel A 218501 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

CD8 T cell autoreactivity to preproinsulin epitopes with very low human leucocyte antigen class I binding affinity

Transplantation and autoimmunit

Regulatory T cells in human geohelminth infection suppress immune responses to BCG and Plasmodium falciparum.

Item does not contain fulltextChronic helminth infections induce T-cell hyporesponsiveness, which may affect immune responses to other pathogens or to vaccines. This study investigates the influence of Treg activity on proliferation and cytokine responses to BCG and Plasmodium falciparum-parasitized RBC in Indonesian schoolchildren. Geohelminth-infected children's in vitro T-cell proliferation to either BCG or pRBC was reduced compared to that of uninfected children. Although the frequency of CD4(+)CD25(hi)FOXP3(+) T cells was similar regardless of infection status, the suppressive activity differed between geohelminth-infected and geohelminth-uninfected groups: Ag-specific proliferative responses increased upon CD4(+)CD25(hi) T-cell depletion in geohelminth-infected subjects only. In addition, IFN-gamma production in response to both BCG and parasitized RBC was increased after removal of CD4(+)CD25(hi) T cells. These data demonstrate that geohelminth-associated Treg influence immune responses to bystander Ag of mycobacteria and plasmodia. Geohelminth-induced immune modulation may have important consequences for co-endemic infections and vaccine trials.1 februari 201

Efgartigimod improves muscle weakness in a mouse model for muscle-specific kinase myasthenia gravis

Functional Genomics of Muscle, Nerve and Brain Disorder

Bundling HIV and TB Care at a District-Level Center in Sierra Leone: A high-yield method for diagnosing co-infection with TB and antiretroviral treatment failure among people living with HIV

Background: Protocols for HIV care are widely accepted by all international organizations and are proven to reduce mortality and complications from living with HIV. Unfortunately, executing best practice recommendations in Sierra Leone is difficult due to shortages in staff, training, and medications. Methods: From June 2016 to August 2016, we implemented both an HIV guideline-based clinical evaluation protocol and a patient-centered workflow for TB screening and CD4 testing in the HIV clinic at Koidu Government Hospital (KGH) in rural Sierra Leone. The primary outcome of interest was how often this service center resulted in a clinically significant change in the patients’ HIV regimen. Reasons for changing regimen included diagnosis of co-infection with tuberculosis (TB), diagnosis of clinical or presumed immunologic treatment failure of antiretroviral (ART) medications and, need for adherence to weight-based dosing in pediatric patients. Findings: A total of 188 patients with HIV were seen in the clinic; 49 (26%) of these patients had a clinically significant change in their HIV regimen. The most common reason for regimen change was TB co-infection diagnosis in 38 (20%) patients. The other reasons for HIV regimen changes included: eight children whose ART was adjusted to meet appropriate levels for weight-based guidelines, five patients diagnosed with presumed immunologic treatment failure (some also co-infected with tuberculosis), and two patients with a serious side effect to ART. Interpretation: A comprehensive, patient-centric HIV clinic can result in high rates of case detection for tuberculosis and recognition of immunological ART failure. Keywords: HIV, Immunological failure, Co-infection, Quality, Tuberculosis, Afric