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