Multiomics analysis of immune-related adverse events in melanoma patients treated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are a standard-of-care for the treatment of advanced melanoma, but their use is limited by immune-related adverse events (irAEs). Proteomic analysis and multiplex cytokine/chemokine assay from serum at baseline and at irAEs onset in 82 patients indicated aberrant T-cell activity with differential expression of Type I and III immune signatures. This was in line with an increase in the proportions of monocytes and decrease of IL-17A producing CD4+ T-cells in the peripheral blood in single cell RNA sequencing. Multiplex immunohistochemistry on ICI-induced skin rash and inflamed colon showed increase in the proportion of CD4+ T-cells with IL-17A expression. Anti-IL17A antagonistic mAbs were administered in two patients with severe myocarditis, colitis and skin rash with resolution of the irAE. This study demonstrates the potential role of Type III CD4+ T-cells in the irAEs development and provides proof-of-principle evidence to support a clinical trial examining anti-IL17A in their management. PBMCs from 6 melanoma patients receiving combination anti-CTLA4 and anti-PD1 at baseline and at AE onset or at 2nd infusion. This submission does not contain raw data files as the fastq files contain protected patient information. Fastq files can be provided upon request.