IL16 and rheumatoid arthritis: Considering the scarce knowledge related to the hyperalgesic effect evoked by IL-16 and the interest of its possible participation in rheumatoid arthritis, we designed the present set of experiments to enhance our understanding relative to the pronociceptive actions evoked by IL-16 by elucidating whether it depends on the activation of CD4 receptor in immune cells and by exploring the possible role played by cyclooxygenase–derived mediators and TRP channels.