Research published in the April issue of Arthritis Research & Therapy says the first stage of rheumatoid arthritis differs from the early phases of other inflammatory joint diseases, and is also quite different from the disease''s later stages.

Investigators at the University of Birmingham in the United Kingdom report that, immediately after the onset of clinical symptoms, rheumatoid arthritis is characterized by a distinct profile of various immune cell-linked inflammatory proteins called cytokines in synovial fluid, the fluid surrounding the joints. The synovium is the connective tissue membrane that lines the joints and is the primary site of rheumatoid arthritis.

This finding suggests the possibility of treating rheumatoid arthritis at this early stage before it develops into a long-term condition, the study authors wrote.

In the study, the researchers examined the joints of rheumatoid arthritis patients within three months of onset of first clinical symptoms. Patients who eventually developed chronic disease had a cytokine profile different than that seen in patients in the early phases of other arthritic diseases or in patients who''d already had rheumatoid arthritis for a long time.

The cytokines present in the early stages of rheumatoid arthritis may be involved in development of the microenvironment required for chronic disease, the researchers said.

"The pathologically distinct nature of the very early phase of clinically apparent rheumatoid arthritis suggests that this phase may represent a therapeutic window" in which treatment might slow or halt the painful joint illness, study author Dr. Karim Raza said in a prepared statement.

More information

The Arthritis Foundation has more about rheumatoid arthritis.

SOURCE: BioMed Central, news release, April 7, 2005