ABSTRACT
During active inflammation C-reactive protein (CRP) synthesis rises while that of albumin and fibrinogen fall. These changes are secondary to increased IL-6 synthesis during inflammation, resulting in an increase in plasma viscosity and an elevated erythrocyte sedimentation rate (ESR). Successful treatment of rheumatoid arthritis leads to a fall in CRP and ESR so they are useful for monitoring. In SLE there is often a rise in ESR that is out of proportion when compared to the CRP. In some patients with seronegative arthritides they may both be normal, but in general a normal CRP and ESR virtually excludes active systemic inflammation.
