Figure 1 summarizes the effects of PPARγ agonists on cytokine expression and on T regulatory cells and B cells. PPARγ is expressed by the main cell types of adaptive responses. Natural and synthetic PPARγ ligands proved to be capable of inhibiting major signaling pathways of adaptive immunity, reducing or augmenting the expression of cytokines. In fact, PPARγ ligands were shown to inhibit the production of several proinflammatory cytokines. Thus, further studies are necessary to clarify the use of PPARγ antagonists in diseases driven by the Th imbalance such as autoimmune diseases. The gene discussed is PPARG; the disease is autoimmune disease.