USP18 and peeling skin syndrome: To determine whether m6A modification impacts the pathogenesis and development of pSS, we detected the mRNA levels of METTL3, WTAP, RBM15, FTO, ALKBH5, YTHDF1, YTHDF2, YTHDF3, YTHDC1, YTHDC2, ISG15, and USP18 in peripheral blood from patients with pSS, patients with non-SS sicca, and healthy controls (HCs).