The classification criteria for ACR2012 dry syndrome are: 1. serum anti-SSA and/or anti-SSB antibodies (+), or positive rheumatoid factor RF with ANA ≥ 1:320; 2. OSS staining score method (ocularstainingscore) ≥ 3; 3. pathological biopsy of the lacrimal gland showing lymphocytic foci ≥ 1/4 mm2 (4 mm2 tissue with at least 50 lymphocyte aggregates). Dry syndrome can be diagnosed when 2 or more of the above three items are satisfied, and the history of cervical and head and facial radiotherapy, hepatitis C virus infection, acquired immunodeficiency disease, nodular disease, amyloidosis, graft-versus-host disease, and IgG4-related diseases are excluded.