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Aims/hypothesis The incidence of type 1 diabetes is increasing more rapidly than can be explained by genetic drift. Viruses may play an important role in the disease, as they seem to activate the 2′-5′-linked oligoadenylate (2′-5′A) pathway of the innate antiviral immune system. Our aim was to investigate this possibility. Methods Innate antiviral immune pathways were searched for type 1 diabetes-associated polymorphisms using genome-wide association study data. SNPs within ±250kb flanking regions of the transcription start site of 64 genes were examined. These pathways were also investigated for type 1 diabetes-associated RNA expression profiles using laser-dissected islets from two to five tissue sections per donor from the Diabetes Virus Detection (DiViD) study and the network of Pancreatic Organ Donors (nPOD). Results We found 27 novel SNPs in genes nominally associated with type 1 diabetes. Three of those SNPs were located upstream of the 2′-5′A pathway, namely SNP rs4767000 (p = 1.03 × 10−9, OR 1.123), rs1034687 (p = 2.16 × 10−7, OR 0.869) and rs739744 (p = 1.03 × 10−9, OR 1.123). We also identified a large group of dysregulated islet genes in relation to type 1 diabetes, of which two were novel. The most aberrant genes were a group of IFN-stimulated genes. Of those, the following distinct pathways were targeted by the dysregulation (compared with the non-diabetic control group): OAS1 increased by 111% (p < 1.00 × 10−4, 95% CI −0.43, −0.15); MX1 increased by 142% (p < 1.00 × 10−4, 95% CI −0.52, −0.22); and ISG15 increased by 197% (p = 2.00 × 10−4, 95% CI −0.68, −0.18). Conclusions/interpretation We identified a genetic predisposition in the 2′-5′A pathway that potentially contributes to dysregulation of the innate antiviral immune system in type 1 diabetes. This study describes a potential role for the 2′-5′A pathway and other components of the innate antiviral immune system in beta cell autoimmunity. Graphical abstract

immune signatures of immunotherapy-specific of cell subsets utilising mass cytometry with 38 markers. Results and discussions PD-L1 blockade induced the expansion of highly specific tumor-infiltrating CD4 and CD8 T cells, displaying both activating (ICOS) and inhibitory (PD-1, LAG-3) molecules. Expansion of these therapy-induced T cell subsets was observed three days after treatment and significantly expanded in time leading to tumour delay. By targeting the activating and inhibiting molecules on the T cells by agonistic and blocking antibodies, respectively, we were able to further restore the T cell dysfunction and thereby improving the therapeutic benefit of single immunotherapy. Conclusion Thus, high-dimensional profiling is a powerful means for rational designing combinatorial T-cell based immunotherapies. PO-363ABSTRACT WITHDRAWN Introduction Several preclinical studies have shown that exercise can reduce the tumour growth across a range of tumour models. We recently demonstrated that this exercise-dependent suppression of tumour growth was due to an epinephrinedependent mobilisation and IL-6-driven activation of cytotoxic cells. In line with this, exercise markedly increased intratumoral immune cell infiltration, thus promoting an immunestimulatory intratumoral environment. Based on these original findings, we hypothesised that exercise may enhance the effect of immune checkpoint blockade treatment given the exercisedependent increased intratumoral immune cell infiltration. Material and methods We used C57Black/C mice randomised to cages with or without running wheels (EX). After 4 weeks of running (with a running distance ranging from 1.8 km to 5.4 km per mice per day), the mice were inoculated with B16 melanoma cancer cells. In addition, a subset of mice was treated with aPD-L1 antibodies (100 mg per mouse three times per week starting on day 4 after tumour cell injection). Results and discussions First, we observed that voluntary wheel running increased intratumoral expression of the immune checkpoint molecules, PD-L1, B7.1 and B7.2. In parallel, voluntary wheel running increased intratumoral infiltration of cytotoxic NK and T cells, and thus intratumoral expression of the receptors, PD-1 and CD28. Next, we tested the combination therapy of exercise and aPD-L1 antibody treatment. In this setup, wheel running had an overall suppressive effect (p=0.01, 2-way ANOVA). Post hoc analysis showed that aPD-L1 +EX reduced tumour growth by 82.6%, while EX alone reduced tumour growth by 72% with no significant difference between the two interventions. qPCR analysis of these tumours revealed that combination therapy further increased the expression of immune cell markers and immune check point molecules. PO-364 EFFECT OF EXERCISE AND IMMUNOTHERAPY ON TUMOUR IMMUNOGENICITY AND GROWTH

BackgroundThe Multiplex Ligation-dependent Probe Amplification (MLPA) is widely used for analysis of copy number variations (CNVs) in single or multiple loci. MLPA is a versatile methodology and important tool in cancer research; it provides precise information on increased or decreased copy number at specific loci as opposed to loss of heterozygosity (LOH) studies based upon microsatellite analysis. Pre-designed MLPA kits and software are commercially available to analyze multiple exons, genes, and genomic regions. However, an increasing demand for new gene specific assays makes it necessary to self-design new MLPA probes for which the available software may not be applicable. During evaluation of new self-designed reference probes, we encountered a number of problems, especially when applying the MLPA methodology to tumor samples.FindingsDNA samples from 48 unaffected individuals and 145 breast cancer patients were used to evaluate 11 self-designed MLPA probes and determine the cut-off values for CNV, before applying the MLPA probes to normalize the target probes in a cohort of affected individuals. To test the calculation strategy, three probes were designed to cover regions in Regulator of G-protein Signaling 8 (RGS8), which we previously have identified as being affected by allelic imbalance by LOH analysis across RGS8 in the cohort comprising 145 breast tumors. Agreement between the LOH results and the results obtained by each of the three MLPA probes in RGS8 was found for 64%, 73%, and 91%, of the analyzed samples, respectively.ConclusionHere, we present a straightforward method, based upon the normalization pattern in both unaffected and affected individuals, to evaluate self-designed reference probes and to calculate CNV for the MLPA assay with specific focus on the difficulties when analyzing tumor DNA.