In this study, we detected the expression of IL21‐AS1 in CD4+ T cells of SLE patients and lupus‐like mice model, cloned the full sequence of IL21‐AS1 and mouse Il21‐AS1 (mIl21‐AS1) and identified the intracellular localization of IL21‐AS1/mIl21‐AS1. The gene discussed is IL21; the disease is systemic lupus erythematosus.