I've heard that I can have my blood “filtered” to treat my rheumatoid arthritis. Is that possible?
Yes, there is a device that treats RA by “filtering” the blood—the so-called extracorporeal immunoadsorption protein A column. While its name sounds complex, the device's function is based on a simple theory: Antibodies have a tendency to stick to certain proteins, so this blood-filtering technique exploits that tendency. In the United States, this filtering device is sold under the name Prosorba Column.
The filtering device is a plastic cylinder that measures three by six inches, or approximately the size of a coffee mug. The cylinder contains a sand-like substance called silica that is coated with a special material called Protein A. Protein A has the unique property of being able to stick to the antibodies in the blood of patients with RA, some of which actually attack the body's own tissues (leading to RA). The patient's blood is circulated from a needle in the vein of one arm, through this filter, and then to a needle in a vein of the patient's other arm. As the blood flows through the filter, the antibodies that cause RA stick to the protein in the column and are removed from the blood. After this treatment, the patient has significantly less antibodies in his or her bloodstream.
This procedure is usually performed once a week for 12 weeks in an outpatient setting. Each treatment takes between one and two hours. Many patients experience significant relief in arthritis symptoms that can last for six to eight months.
Many patients breeze through this blood-filtering procedure with little or no discomfort. Others have experienced adverse reactions, including joint pain, fatigue, joint swelling, low blood pressure, nausea, chest pain, shortness of breath, and allergic reactions. While these reactions are not common, the doctor must watch out for them.
Treatment with the Prosorba Column is indicated for patients who have long-standing RA that is either moderate or severe. Additionally, these patients must have failed to respond to conventional drug therapy or be intolerant to those medications. By contrast, patients with the following conditions should not undergo this kind of blood-filtering therapy:
- Individuals who are receiving angiotensin-converting enzyme (ACE) inhibitor medications
- Individuals who have serious heart or lung problems
- Individuals who cannot tolerate a similar procedure called apheresis
- Individuals who have demonstrated a prior allergy or hypersensitivity to this therapy
- Individuals who have a tendency to form blood clots (hypercoagulability)
Enzyme
Any protein that regulates chemical changes in other substances.
The long-term safety and effectiveness of this therapy is unknown, but is currently being studied.