Additionally, we assessed the correlation between serum Chi3L1 levels, the modified Rodnan skin score (MRSS), and pulmonary function (Figure2A).[25] Hematoxylin‐eosin (HE) staining indicated exaggerated dermal fibrosis in patients with SSc, while immunofluorescence staining revealed the upregulation of Chi3L1 in the epidermis and dermis, especially in the basal layer (Figure 2B). Here, CHI3L1 is linked to systemic sclerosis.