SLE: systemic lupus erythematosus, DNA: deoxyribonucleic acid, IV: intravenous, CNS: central nervous system, NPSLE: neuropsychiatric systemic lupus erythematosus, IL-2: interleukin-2, GI: gastrointestinal, TPE: therapeutic plasma exchange, IVIG: intravenous immunoglobulin. This evidence concerns the gene IL2 and systemic lupus erythematosus.