Regulatory T cells (Tregs) maintain immune homeostasis by inhibiting excessive immune responses. Dysregulation of Tregs, characterized by reduced cell numbers or impaired suppressive function, is implicated in the pathogenesis of autoimmune diseases. Low-dose interleukin-2 (IL-2) therapy expands Tregs and enhances their suppressive capacity while minimizing the activation of T cells and natural killer (NK) cells.