Psoriasis and Arthritis

As we discussed Monday in class, there are a multitude of arthritis forms out there. One prevalent form of arthritis is Rheumatoid arthritis (RA). To review, RA is an autoimmune disease characterized by joint pain and stiffness, and can ultimately progress to the point of deformity and loss of movement in the joints. In the paper I talked about in class (“Reactive Oxygen Species and Superoxide Dismutases: Role in Joint Disease”), there was mention of one of the currently accepted treatments for RA, through the use of Tumor Necrosis Factor (TNF) blockers. However, RA is not the only autoimmune disease that sees benefit from treatment with TNF blockers.

Psoriasis is an autoimmune disease of the skin, which causes itchiness, redness, flakiness, and thickening of the skin. According to the National Center of Biotechnology Information (NCBI), about 1 of 20 people with psoriasis also come to develop a form of arthritis called psoriatic arthritis. This form of arthritis can affect any joint in the body, causing swelling, stiffness, and in severe cases, pain. These symptoms are not unlike what is seen with rheumatoid arthritis, as previously mentioned. I found it so fascinating that two seemingly unrelated diseases are so much more closely connected than one would think, and that only a small fraction of the people with psoriasis develop psoriatic arthritis.

All three of these diseases, psoriasis, psoriatic arthritis, and rheumatoid arthritis, when non-responsive to initial treatments, can be treated with a class of biologic drugs called TNF blockers, which help to relieve the symptoms of these disease by binding to TNF, and hence reducing overall inflammation. Some of these drugs on the market are Enbrel (etanercept), Humira (adalimubab), and Remicade (infliximab). From what I understand about the injection process for these drugs, they still act on a more systemic manner, rather than locally. Systemic suppression of the immune system carries risk, as we still need TNF to help our body’s defense against actual threats it encounters. Because of this, local treatment of something like arthritis would likely provide much more benefit and decreased risks for a patient.

It is interesting to see that this class of biologic agents can be used in a variety of different inflammatory disease states, and this application definitely reflects what we have discussed about TNF-alpha being central to the inflammatory process.

Rheumatoid arthritis: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001467/

Psoriasis: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001470/

Psoriatic arthritis: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001450/