LGALS9 and systemic lupus erythematosus: The advancement of molecular biology technologies has facilitated more research into novel diagnostic markers of SLE, such as serum Galectine-9 and non-coding RNAs (e.g., microRNAs [miRNAs], long non-coding RNAs [lncRNAs]), which have shown some value in the diagnosis of SLE (Li et al. 2020a; Matsuoka et al. 2020).