Inclusion Criteria:  meet the 2016 American College of Rheumatology (ACR) / European League Against Rheumatism Classification Criteria for Sjogren's Syndrome (EULAR SS) ESSDAI score ≥6 IgG >16 g/L Positive anti-SS-A/Ro antibody at screening  Exclusion Criteria:  Pregnancy or breast feeding Secondary Sjogren's syndrome severe renal or haematological failure, a history of cancer, hepatitis B or C, human immunodeficiency virus, severe diabetes or any other chronic disease or evidence of infection  Prior administration of any of the following:  Rituximab in the past 12 months prior to randomization; Cyclophosphamide, mycophenolate mofetil, methotrexate, leflunomide and iguratimod in the past 12 weeks prior to randomization; Azathioprine, cyclosporin, tacrolimus, sirolimus, sulfasalazine in the past 4 weeks prior to randomization; live vaccine in the past 12 weeks prior to randomization Corticosteroids: > 10 mg/day oral prednisone (or equivalent); Any change or initiation of new dose within 4 weeks prior to randomization; Intramuscular, subcutaneous, intravenous, or intra-articular corticosteroids within 4 weeks prior to randomization.