A group of scientists claim testing for expression of the breast cancer resistance protein (BCRP) in the synovial tissue of rheumatoid arthritis (RA) patients can help predict which individuals are least likely to respond to disease-modifying antirheumatic drugs (DMARDs). The researchers, from Hacettepe University in Ankara, Turkey, found that while BCRP was expressed in the synovial tissues of about 40% of RA patients, it was never found in the tissues of normal controls.
In comparison with RA patients who didn’t express the protein, those who did also tended to have higher concurrent disease activity scores, despite receiving treatment for their condition, states Umut Kalyoncu, M.D., and colleagues at Hacettepe University’s department of rheumatology and department of pathology. Staining techniques indicated that the protein was being expressed at higher levels in cells actively involved in the immune response, including macrophages, endothelial cells, and fibroblasts.
Data was presented at the European League Against Rheumatism (EULAR) Annual Congress in Rome. “The results of our study show that the presence of BRCP was only detected in patients with RA and that arguably it is found more prominently in patients with high disease activity,” Dr. Kalyoncu remarks.
“What we hypothesise is that due to the location of the cells showing highest levels of BCRP, the presence of this protein may create a barrier for treatments entering the synovium of RA patients. Testing RA patients for the presence of BRCP may help us determine which patients will respond better to certain treatments.”