Several autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, type 1 diabetes mellitus and immune thyroid disease, are characterized by dominant Th1 responses, with an excess of IL-12 and TNF-α production and a deficit of IL-10 production, critical factors in the proliferation and differentiation of Th1-related autoreactive cells [51]. The gene discussed is TNF; the disease is multiple sclerosis.