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Purpose: Liver metastasis develops in >50% of patients with colorectal cancer (CRC), and is a leading cause of CRC-related mortality. We aimed to identify which inhibitory immune checkpoint pathways can be targeted to enhance functionality of intra-tumoral T-cells in mismatch repair-proficient liver metastases of colorectal cancer (LM-CRC). Methodology: Intra-tumoral expression of multiple inhibitory molecules was compared among mismatch repair-proficient LM-CRC, peritoneal metastases of colorectal cancer (PM-CRC) and primary CRC. Expression of inhibitory molecules was also analyzed on leukocytes isolated from paired resected metastatic liver tumors, tumor-free liver tissues, and blood of patients with mismatch repair-proficient LM-CRC. The effects of blocking inhibitory pathways on tumor-infiltrating T-cell responses were studied in ex vivo functional assays. Results: Mismatch repair-proficient LM-CRC showed higher expression of inhibitory receptors on intra-tumoral T-cells and contained higher proportions of CD8+ T-cells, dendritic cells and monocytes than mismatch repair-proficient primary CRC and/or PM-CRC. Inhibitory receptors LAG3, PD-1, TIM3 and CTLA4 were higher expressed on CD8+ T-cells, CD4+ T-helper and/or regulatory T-cells in LM-CRC tumors compared with tumor-free liver and blood. Antibody blockade of LAG3 or PD-L1 increased proliferation and effector cytokine production of intra-tumoral T-cells isolated from LM-CRC in response to both polyclonal and autologous tumor-specific stimulations. Higher LAG3 expression on intra-tumoral CD8+ T-cells associated with longer progression-free survival of LM-CRC patients. Conclusion: Mismatch repair-proficient LM-CRC may be more sensitive to immune checkpoint inhibitors than mismatch repair-proficient primary CRC. Blocking LAG3 enhances tumor-infiltrating T-cell responses of mismatch repair-proficient LM-CRC, and therefore may be a new promising immunotherapeutic target for LM-CRC.

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ObjectiveHLA‐DRB1*15:01 has been recently associated with interstitial lung disease (LD), eosinophilia, and drug reactions in systemic juvenile idiopathic arthritis (sJIA). Additionally, genetic variants in IL1RN have been linked to poor response to anakinra. We sought to reproduce these findings in a prospective cohort study of new‐onset sJIA patients treated with anakinra as first‐line therapy.MethodsHLA and IL1RN risk alleles were identified via whole genome sequencing. Treatment responses and complications were compared between carriers versus non‐carriers.ResultsSeventeen of 65 patients (26%) carried HLA‐DRB1*15:01, comparable to the general population, and there was enrichment for HLA‐DRB1*11:01, a known risk locus for sJIA. The rates of clinical inactive disease (CID) at 6 months, 1 and 2 years were generally high, irrespective of HLA‐DRB1 or IL1RN variants, but significantly lower in carriers of an HLA‐DRB1*11:01 allele. One patient, an HLA‐DRB1*15:01 carrier, developed sJIA‐LD. Of the three patients with severe drug reactions to biologics, one carried HLA‐DRB1*15:01. The prevalence of eosinophilia did not significantly differ between HLA‐DRB1*15:01 carriers and non‐carriers at disease‐onset (6.2% vs 14.9%, p=0.67) nor after the start of anakinra (35.3% versus 37.5% in the first 2 years of disease).ConclusionWe observed high rates of CID using anakinra as first‐line treatment irrespective of HLA‐DRB1 or IL1RN variants. Only one of the 17 HLA‐DRB1*15:01 carriers developed sJIA‐LD, and of the 3 patients with drug reactions to biologics, only one carried HLA‐DRB1*15:01. Although thorough monitoring for the development of drug hypersensitivity and refractory disease courses in sJIA, including sJIA‐LD remains important, our data support the early start of biological therapy in new‐onset sJIA patients irrespective of HLA‐DRB1 background or IL1RN variants.image