Heterogeneity and subtypes of CD4⁺ regulatory T cells: implications for tumor therapy

In the conventional view, CD4⁺ regulatory T cell (T_reg) represents a subset of lymphocytes that involve the perception and negative regulation of the immune response. CD4⁺T_reg plays an important role in the maintenance of immune homeostasis and immune tolerance. However, recent studies have revealed that CD4⁺T_reg do not suppress the immune response in some diseases, but promote inflammatory injury or inhibit tissue remodeling, suggesting the functional heterogeneity of CD4⁺T_reg. Their involvement in tumor pathogenesis is more complex than previously understood. This article reviews the relevant research on the heterogeneity of CD4⁺T_reg, subtype classification, and their relationship with tumor therapy.