Diagnostic criteria: The diagnosis should have more than one typical symptom or sign of rheumatic disease, accompanied by more than one high titer autoantibody positive, with a disease duration of more than two years, and excluding any other CTD. Laboratory tests: 1. Leukopenia, thrombocytopenia or anemia can be seen in blood tests. 2. Serological examination is most commonly positive for ANA, with a positive rate of 55% to 100% and an average of 58%. The fluorescence karyotype is most common with spot type, while homogeneous type and perinuclear type are less common, and the titer is similar to that of SLE. 3. A small number of patients may have positive rheumatoid factor anti-RNP antibodies, anti-SSA or SSB antibodies. 4. Urinary routine may show proteinuria and hematuria, etc.