VTN and systemic lupus erythematosus: Positive ANA is emphasized as an obligatory entry criterion for SLE by the EULAR/ACR-2019 SLE classification, and three immunologic biomarkers (antiphospholipid antibodies, complement proteins, SLE-specific antibodies) and seven clinical indices (constitutional, hematologic, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal) are used as additive weighted criteria for SLE [20].