IL2RA and major depressive disorder: However, (i) thymic-derived Tregs that constitutively express CD25 are the main target of ld-IL-2 and are not prone to such instability; (ii) when present, the inflammation associated with MDD is a mild systemic inflammation rather than a focal high inflammation like in some autoimmune diseases, and (iii) the activation of the STAT5 pathway by IL-2R signaling actually contributes to stabilize FOXP3 expression and likewise the Treg-suppressive phenotype.