C3 and systemic lupus erythematosus: According to the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) criteria (7), the ANA (1:160) of the current patient and her total score was 16, including chronic cutaneous lupus (four scores), non-scar alopecia (two scores), non-deformed arthritis, or poly-arthritic pain (four scores), WBC < 4 × 109/L (two scores), and decreased C3 and C4 (four scores), indicating a diagnosis of SLE.