BTG3 and systemic lupus erythematosus: Among the several classification criteria developed for SLE, the most recent are the ACR/EULAR 2019: these include positive ANA at least once as a required entry criterion, followed by additive weighted criteria grouped in seven clinical (constitutional, haematologic, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal) and three immunologic (antiphospholipid antibodies, complement fractions, SLE-specific antibodies) domains, and weighted from 2 to 10.