Do changes in clinical improvement in rheumatoid arthritis patients treated with immunosuppressive drugs reflect the changes in acute phase proteins?

We sought to investigate whether clinical improvement after immunosuppressive treatment reflects changes in acute phase response (APR) in rheumatoid arthritis (RA). Fifty-eight patients (pts) were treated with methotrexate (MTX), nineteen with intravenous cyclophosphamide (CTX), and fifteen with cyclosporin A (CSA). C-reactive protein (CRP), alpha-1-acid glycoprotein (AGP), alpha-1 antichymotrypsin (ACT), and alpha-1 antitrypsin (AT) serum levels were measured by nephelometry or rocket immunoelectrophoresis. Clinical improvement was observed in 67% MTX pts, 53% CTX pts, and 47% CSA pts. Baseline serum levels of CRP, AGP, ACT, and AT were significantly higher as compared to healthy controls. After MTX and CTX therapy CRP level significantly decreased. The decrease in serum level of ACT and AT in CTX treated patients was also observed. All analyzed acute phase proteins remained substantially elevated after CSA therapy despite a clear reduction in disease activity. We established a correlation between changes in disease activity and all acute phase proteins (APP) in MTX and CTX pts. From our study we can conclude that clinical improvement after immunosuppressive treatment correlated with quantitative changes in all APR markers in MTX and CTX treated pts, and none in CSA pts. Although measurement of APP remains the best marker for monitoring RA pts, not always they properly reflect changes in disease activity.