Background and objectives Rheumatoid arthritis (RA) is preceded by a period where the patients experience pain but no clinically apparent arthritis can be detected yet. Without treatment RA can lead to severely inflamed joints and bone damage. Early treatment has shown to be beneficial in limiting joint damage. Therefore early detection of patients at risk of developing RA is needed. Anti–citrullinated protein antibodies and Rheumatoid factor levels in the blood does not predict RA development for all patients. A betterunderstanding of the immunological processes ongoing during arthralgia could aid in early detection and prevention of joint damage. The time period between first immunisation and booster in the collagen induced arthritis (CIA) model might reflect the arthralgia stage in rheumatoid arthritis development. In this study we examined whether the CIA model could be used to investigate immunological processes during arthralgia.
Materials and methods DBA/1 mice were subjected to CIA. Blood was drawn at different time points via submandibular vein puncture during CIA development. Antibodies directed against bovine collagen type II (bCII) and mouse collagen type II (mCII) of the IgG1 and IgG2a isotype were measured by ELISA. Clustered analysis was performed to correlate CIA development with antibody levels.
Results Significantly higher antibody levels of the IgG2a isotype directed against mCII (anti-mCII-IgG2a antibodies) were found at day 12 in mice who developed CIA compared to those who did not (P = 0.037). The antibody levels directed against bCII and mCII further increased during CIA development. Anti-mCII-IgG2a antibody levels did not reflect clinical disease score reached at day 35.
Conclusions The detection of antibodies against mouse type II collagen indicates an early auto-immune process in the CIA model prior to clinical detectable disease.