Tracking the immune changes in children with cancer and multisystem inflammatory syndrome

How cancer affects the immune system of children, which is different to adults, is unclear and has not been described systematically. Immune-modulating therapies are proving promising novel therapeutic options in adult cancers but their use in paediatric cancers remains limited. A better understanding of the immune system is needed in order to target the right pathways and optimise immunotherapeutic approaches. Furthermore, the new virus (SARS-CoV2) has led to the development of a novel disease occurring only in children, called multisystem inflammatory syndrome in children (MIS-C). This disease shares many similarities with different inflammatory paediatric conditions (such as Kawasaki Disease (KD) but also many differences. Identifying the immunological changes occurring in MIS-C patients and how these relate to other paediatric inflammatory conditions is important both to understand the pathogenesis of this new disease and inform rational treatment selection. Through this study, novel NK pathways have been identified in paediatric cancer patients that can potentially be targeted as well as potential new biomarkers. In MIS-C patients a hyper-inflammation state, with activation of both innate and adaptive immunity, was identified. Treatment with intravenous immunoglobulin (IVIG, standard care) administration led to multiple anti-inflammatory changes including the expansion of CD163+ monocytes and production of arginase

Defects in NK cell immunity of pediatric cancer patients revealed by deep immune profiling

Systemic immunity plays an important role in cancer immune surveillance and response to therapy, but little is known about the immune status of children with solid cancers. We performed a high-dimensional single-cell analysis of systemic immunity in 50 treatment-naïve pediatric cancer patients, comparing them to age-matched healthy children. Children with cancer had a lower frequency of peripheral NK cells, which was not due to tumour sequestration, had lower surface levels of activating receptors and increased levels of the inhibitory NKG2A receptor. Furthermore, the NK cells of pediatric cancer patients were less mature and less cytotoxic when tested in vitro. Culture of these NK cells with interleukin-2 restored their cytotoxicity. Collectively, our data show that NK cells in pediatric cancer patients are impaired through multiple mechanisms and identifies rational strategies to restore their functionality

Transcriptional profiling of human Vδ1 T cells reveals a pathogen-driven adaptive differentiation program

γδ T cells are generally considered innate-like lymphocytes, however, an “adaptive-like” γδ compartment has now emerged. To understand transcriptional regulation of adaptive γδ T cell immunobiology, we combined single-cell transcriptomics, T cell receptor (TCR)-clonotype assignment, ATAC-seq, and immunophenotyping. We show that adult Vδ1+ T cells segregate into TCF7+LEF1+Granzyme Bneg (Tnaive) or T-bet+Eomes+BLIMP-1+Granzyme B+ (Teffector) transcriptional subtypes, with clonotypically expanded TCRs detected exclusively in Teffector cells. Transcriptional reprogramming mirrors changes within CD8+ αβ T cells following antigen-specific maturation and involves chromatin remodeling, enhancing cytokine production and cytotoxicity. Consistent with this, in vitro TCR engagement induces comparable BLIMP-1, Eomes, and T-bet expression in naive Vδ1+ and CD8+ T cells. Finally, both human cytomegalovirus and Plasmodium falciparum infection in vivo drive adaptive Vδ1 T cell differentiation from Tnaive to Teffector transcriptional status, alongside clonotypic expansion. Contrastingly, semi-invariant Vγ9+Vδ2+ T cells exhibit a distinct “innate-effector” transcriptional program established by early childhood. In summary, adaptive-like γδ subsets undergo a pathogen-driven differentiation process analogous to conventional CD8+ T cells

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vβ21.3+ activation in multi-inflammatory syndrome in children

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vβ21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vβ21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vβ21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells

Transcriptional profiling of human Vδ1 T cells reveals a pathogen-driven adaptive differentiation program

γδ T cells are generally considered innate-like lymphocytes, however, an “adaptive-like” γδ compartment has now emerged. To understand transcriptional regulation of adaptive γδ T cell immunobiology, we combined single-cell transcriptomics, T cell receptor (TCR)-clonotype assignment, ATAC-seq, and immunophenotyping. We show that adult Vδ1+ T cells segregate into TCF7+LEF1+Granzyme Bneg (Tnaive) or T-bet+Eomes+BLIMP-1+Granzyme B+ (Teffector) transcriptional subtypes, with clonotypically expanded TCRs detected exclusively in Teffector cells. Transcriptional reprogramming mirrors changes within CD8+ αβ T cells following antigen-specific maturation and involves chromatin remodeling, enhancing cytokine production and cytotoxicity. Consistent with this, in vitro TCR engagement induces comparable BLIMP-1, Eomes, and T-bet expression in naive Vδ1+ and CD8+ T cells. Finally, both human cytomegalovirus and Plasmodium falciparum infection in vivo drive adaptive Vδ1 T cell differentiation from Tnaive to Teffector transcriptional status, alongside clonotypic expansion. Contrastingly, semi-invariant Vγ9+Vδ2+ T cells exhibit a distinct “innate-effector” transcriptional program established by early childhood. In summary, adaptive-like γδ subsets undergo a pathogen-driven differentiation process analogous to conventional CD8+ T cells

The immune landscape of SARS-CoV-2-associated Multisystem Inflammatory Syndrome in Children (MIS-C) from acute disease to recovery.

Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening disease occurring several weeks after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Deep immune profiling showed acute MIS-C patients had highly activated neutrophils, classical monocytes and memory CD8+ T-cells; increased frequencies of B-cell plasmablasts and double-negative B-cells. Post treatment samples from the same patients, taken during symptom resolution, identified recovery-associated immune features including increased monocyte CD163 levels, emergence of a new population of immature neutrophils and, in some patients, transiently increased plasma arginase. Plasma profiling identified multiple features shared by MIS-C, Kawasaki Disease and COVID-19 and that therapeutic inhibition of IL6 may be preferable to IL1 or TNF-α . We identified several potential mechanisms of action for IVIG, the most commonly used drug to treat MIS-C. Finally, we showed systemic complement activation with high plasma C5b-9 levels is common in MIS-C suggesting complement inhibitors could be used to treat the disease

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vβ21.3+ activation in multi-inflammatory syndrome in children.

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vβ21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vβ21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vβ21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.Action Medical Research Addenbrookes Charitable Trust Gates Foundation NIHR BR

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vβ21.3+ activation in multi-inflammatory syndrome in children.

Funder: Action Medical Research (AMR); doi: https://doi.org/10.13039/501100000317Funder: CUH | Addenbrooke’s Charitable Trust, Cambridge University Hospitals (Addenbrooke’s Charitable Trust, Cambridge University Hospitals NHS Foundation Trust); doi: https://doi.org/10.13039/501100002927Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vβ21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vβ21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vβ21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.Action Medical Research Addenbrookes Charitable Trust Gates Foundation NIHR BR

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vβ21.3+ activation in multi-inflammatory syndrome in children

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vβ21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vβ21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vβ21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells