IL2 and autoimmune disease: IL-2 is a fundamental immunoregulatory cytokine, inducing immune tolerance at low doses.4 Previous studies have reported that patients with pSS exhibit deficiencies in Treg cell function and have reduced IL-2 levels.31,32,33 In the present study, we found that LD-IL-2 treatment led to expanded Treg population, consistent with previous clinical trials of other autoimmune diseases.5,22,23,24 Decreased pro-inflammatory cytokines, including IL-17 and IFN-α, were also observed after IL-2 treatment.