TREG cells generally refer to regulatory T cells, a subpopulation of T cells that control autoimmune reactivity in the body. Regulatory T cells are immune cells with significant immunosuppressive effects. Regulatory T cells are closely related to the occurrence of autoimmune diseases. If the regulatory T cells in the body are absent or function abnormally, autoimmune diseases such as systemic lupus erythematosus, autoimmune thyroiditis and rheumatoid arthritis may result. In-depth study of regulatory T cells can help to understand the pathogenesis of autoimmune diseases, which is important for the prognosis and further treatment of these diseases. For more information, please consult a hematologist.