FOXP3 and systemic lupus erythematosus: Ex vivo expanded Foxp3+ regulatory T cells were injected intravenously into lupus mice, and the injected Foxp3+ regulatory T cells could be detected in the spleens, lymph nodes, livers, bone marrow, lungs, kidneys, and blood of the MRL/lpr mice, but mainly migrated into spleens and lymph nodes.