Acute phase protein changes in antigen-induced mono-articular arthritis in rabbits and mice.

Acute phase protein levels have been measured during the induction and progression of antigen-induced mono-articular arthritis in rabbits and mice. In rabbits there was a short lived elevation in serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) immediately following intra-articular injection which returned to baseline levels 10-12 days after the injection. In BALB/c mice, serum amyloid P-component (SAP) and the third component of complement (C3) were elevated after intra-articular injection, returning towards baseline levels 6 weeks after the injection. The levels of CRP and SAP correlated with the inflammatory changes in the joints during the acute phase of the arthritic response (7 days after intra-articular injection). During the chronic phase the levels of these acute phase proteins bore no relationship to the degree of connective tissue destruction.