New attack on pain

The research relates to a family of molecules firstly discovered in Melbourne that applied to blood cell development. One of these, granulocyte macrophage colony-stimulating factor or GM-CSF, acts as a messenger between cells acting at a site of inflammation.

Professor John Hamilton has posed the question: could blocking GM-CSF action lead to a new treatment for inflammatory diseases? In experimental models of rheumatoid arthritis, Professor Hamilton and Dr Andrew Cook had previously shown that blocking GM-CSF function with an antibody suppressed the disease leading to clinical trials which are already showing patient benefit.

They have now shown, in a paper that has just appeared in the world's top ranking arthritis journal, Annals of the Rheumatic Diseases, that GM-CSF depletion also suppresses pain in such models; they have also noted similar efficacy in an osteoarthritis experimental model.

"Without a doubt, quality of life and to be free from pain are important issues for people suffering with arthritis-related conditions" said Professor Hamilton.

Rheumatoid arthritis is a debilitating condition with the peak incidence being in people in their 30s and 40s. It is more common in women than in men.

"With our ageing population, the more common condition of osteoarthritis impacts more on our community and medical resources. A new therapy that can block such painful conditions would have massive benefits for health providers and governments in the future" said Dr Cook.

Rheumatoid Arthritis and Joint Inflammation

Joint inflammation is a hallmark of rheumatoid arthritis. That includes:

Stiffness. The joint is harder to use and might have a limited range of motion. "Morning stiffness" is one of the hallmark symptoms of rheumatoid arthritis. While many people with other forms of arthritis have stiff joints in the morning, it takes people with rheumatoid arthritis more than an hour (sometimes several hours) before their joints feel loose.

Swelling. Fluid enters into the joint and it becomes puffy; this also contributes to stiffness.

Pain. Inflammation inside a joint makes it sensitive and tender. Prolonged inflammation causes damage that also contributes to pain.

Redness and warmth. The joints may be somewhat warmer and more pink or red than neighboring skin.

Which joints does RA affect? The hands are almost always affected, although literally any joint can be affected with rheumatoid arthritis symptoms: knees, wrists, neck, shoulders, elbows, even the jaw. Joints are usually affected in a symmetrical pattern - the same joints on both sides of the body.