ISG15 and systemic lupus erythematosus: Notably, consistent with this regulatory axis, upregulated mRNA levels of PBLD, IFNA, IFNB, and ISGs (ISG15, CXCL10, CCL5, IFIT1, IFIT2, STING, and TFEB), alongside downregulated MARCH2 expression, were markedly observed in the clinical blood samples of patients with SLE compared with healthy controls.