Serum of CHI3L1 levels were significantly higher in KD patients compared to both the fever control and healthy groups (P < 0.001), as illustrated in Fig. 1A. In comparison to the fever group, patients with iKD and cKD exhibited significantly elevated serum CHI3L1 levels (P < 0.001) (Fig. 1B). This evidence concerns the gene CHI3L1 and Fever.