Arthritis Treatment: How to Use Biomarkers to Treat Rheumatoid Arthritis

Wouldn't it be great to have a blood test that could predict how to treat a patient with rheumatoid arthritis?

Well, perhaps there may be soon.

Rheumatoid arthritis (RA) is the most common form of inflammatory arthritis. It is a systemic autoimmune condition that not only leads to joint destruction but to internal organ damage as well if not optimally treated.

One area of science that has gotten a lot of funding in RA is biomarker research. Biomarkers are tissue markers that have predictive value. The have been used to predict disease susceptibility, disease activity, and even potential response to treatment.

There are different categories of biomarkers. The first category is the antibody. These are proteins the body produces that are directed against abnormal proteins.

There are two examples. The first is rheumatoid factor. This is an antibody that is present in the blood of 80 per cent of people with RA. Rheumatoid factor is associated with increased amounts of disease early but is less predictive later in the course of illness. Also, rheumatoid factor can be found to be elevated in other disease conditions such as syphilis, sarcoidosis, leprosy, and bacterial endocarditis (heart infection).

Another biomarker antibody is anti-cyclic citrullinated peptide or anti-CCP. It is more specific for RA than rheumatoid factor and is also predictive of more disease severity and a worse prognosis. Patients with anti-CCP must be treated aggressively.

There are inflammatory biomarkers that are also helpful in treating patients. The old time-honored test is the erythrocyte sedimentation rate (ESR) or sed rate. The ESR correlates with disease activity but is not very specific. It can be elevated in many other disease states.

The C-reactive protein or CRP correlates with disease activity and response to treatment much more quickly than the ESR does.

There are two other lesser known inflammatory biomarkers. One is interferon. The higher the level of this substance, the more likely it is the patients will respond to biologic treatment with anti-tumor necrosis drugs.

Interleukin 1 receptor antagonist is another inflammatory marker. Again, the higher the level of this marker is, the greater the likelihood of response to anti-TNF treatment.

Biomarker levels do more than predict disease severity and possible response to treatment with certain drugs. They also correlate, in many instances, with likelihood for disability as well as x-ray progression of disease.

While some feel that blood biomarkers can predict response to different categories of drugs, these theories remain to be proven.