Barbosa-Cobos RE, et al. - Researchers sought to determine if serum substance P (SP) levels can serve as a simple biomarker for rheumatoid arthritis (RA) disease activity. They also examined its correlation with other markers of disease activity, and with selected clinical parameters. Findings indicated the usefulness of SP for therapeutic decisions for RA patients as higher levels of it were detected in those with high disease activity and, additionally, it enabled the detection of subtle disease activity even in patients in apparent remission.