Systemic lupus erythematosus (SLE) is considered the prototype of autoimmune diseases, the most complex autoimmune pathology and it is characterized by a wide range of immune processes, important antibodies production as well as an impressive spectrum of clinical manifestations. The great variety of lupus signs and symptoms caused difficulties in establishing well-defined classification criteria, as well as sustaining the clinical diagnosis.
In 2019, a joint initiative of European League Against Rheumatism (EULAR) and American College of Rheumatology (ACR) released a new set of classification criteria for SLE, worldwide SLE experts were involved, this being the largest SLE classification effort up to date.