Immunohistological analysis of the synovial membrane: search for predictors of the clinical course in rheumatoid arthritis

The course and outcome of rheumatoid arthritis is variable and often unpredictable. Many symptoms and characteristics of rheumatoid arthritis have been studied in an effort to better predict patients' outcomes. Histopathologic changes (disease-related cellular changes) may help to indicate worsening of disease, but have previously been thought to be difficult to study. However, good joint tissue samples were obtained from patients previously untreated for rheumatoid arthritis (RA), and results indicated that the course of the disease was reflected in levels of lymphocytes (immune system cells important in fighting infection). The presence of immune cells in synovial (joint) tissue from 57 patients with RA was studied and correlated with the disease course over three years. At the start of the study, the index of disease activity (IDA) correlated significantly with thickening of the synovial lining, infiltration by mononuclear (having one nucleus) immune cells, and the presence of T lymphocytes (T cells) containing a particular cell surface protein known as CD5. Patients were divided into two groups, one having milder disease during initial examinations, the other having more severe disease at that time. After one year, the IDA in patients with severe disease improved by 64 percent, while the other group improved by 13 percent. Synovial lining thickening correlated with medical status in the severe-disease group. After three years, synovial lining thickening correlated very significantly with medical status in patients with milder disease. Additionally in these patients, medical status correlated with levels of T cells that were positive for the CD5 protein. The report suggests that early lymphocyte infiltration may influence the course of RA, but the effects of disease-modifying drugs, usually used to treat more severe disease, on lymphocyte levels are unknown. (Consumer Summary produced by Reliance Medical Information, Inc.)