Correlation matrix and heatmap with unsupervised clustering comparing the relationship of IL-18 axis biomarkers and other cytokines during CRS and carHLH. Multiparameter Spearman correlation matrix, comparing the average biomarkers levels per patient from their inflammatory course (A). Heatmap with unsupervised clustering analysis demonstrates the patients with carHLH cluster separately from those with CRS only but form 2 distinct clusters (B). Biomarker levels represent averages from inflammatory course beginning at CRS onset and ending at the timepoint before the response to anti-inflammatory therapy, as defined based on the downtrending levels of total IL-18, IL-18BP, and free IL-18. Analysis was performed in R using the FactoMineR, factoextra, and pheatmap packages. Matrix in panel A was created in R using corrplot package, and significant associations are denoted by ∗P < .05; ∗∗P < .01; ∗∗∗P < .001.