2.1 Patients and healthy controls
A total of 31 pSS patients were enrolled from the Rheumatology and Immunology Department,the First Affiliated Hospital of Soochow University in the study. All patients were diagnosed according to the classification standard of primary Sjogren’s syndrome of American College of Rheumatology(ACR)/European League Against Rheumatism(EULAR) in 2016[13],and those who with malignant tumor, chronic hepatitis C(HCV), human immunodeficiency virus infection (HIV), sarcoidosis, amyloidosis, graft versus host disease (GVHD), IgG4-related diseases and other rheumatic diseases were excluded.We also recruited 29 individuals (age and gender matched) without autoimmune diseases,cancer and infectious diseases from the physical examination center as healthy controls (HCs).This research was approved by the Ethics Committee of the First Affiliated Hospital of Soochow University in 2020 (Ethical No. 2020105).And all participants signed the informed consent.