THE EFFECT OF AZATHIOPRINE ON SERUM LEVELS OF INTERLEUKIN-6 AND SOLUBLE INTERLEUKIN-2 RECEPTOR

Cytokine pathways are central to the perpetuation of synovial inflamma tion in rheumatoid arthritis (RA). Azathioprine (AZA) has disease modi fying activity in RA. This study addressed the effect of AZA on serum IL-6 and soluble IL-2 receptor (sIL-2R) levels in RA. Over a 24 week p eriod of therapy significant clinical improvement was observed. Howeve r, serum levels of both IL-6 and soluble IL-2R levels did not signific antly change after AZA therapy. AZA therapy did not significantly alte r the peripheral blood monocytes ability to produce IL-6 in vitro, eit her in the presence or absence of LPS. The mechanism by which AZA achi eves clinical improvement in RA patients does not appear to be through IL-6 modulation or modification of synovial lymphocyte activation as assessed by serum sIL-2R levels.