Thus, while successful targeting of TNF-α has led to effective treatments for peripheral autoimmune diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease [24, 27, 40], targeting TNF-α in MS patients via administration of a recombinant TNF receptor p55 immunoglobulin fusion protein (lenercept) increased frequency, duration, and severity of MS exacerbations [21], revealing critical roles for this molecule in recovery. Here, TNF is linked to rheumatoid arthritis.