The Acute-phase Response Is Not Predictive for the Development of Arthritis in Seropositive Arthralgia - A Prospective Cohort Study

Objective. To evaluate whether markers of the acute-phase response in patients presenting with arthralgia and positive anticitrullinated protein antibodies (ACPA) and/or immunoglobulin M rheumatoid factor (IgM-RF) could be predictive for the development of arthritis. Methods. In total, 137 ACPA- and/or IgM-RF-positive patients were included. Patients were followed annually for the development of arthritis, defined as presence of 1 or more swollen joints at clinical examination. High-sensitivity C-reactive protein (hsCRP), procalcitonin (PCT), secretory phospholipase A2 (SPLA2), tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), IL-12p70, IL-10, and interferon-gamma (IFN-gamma) were measured in baseline serum samples. Gene expression focusing on a Results. Thirty-five patients (26%) developed arthritis within a median time of 11 months (interquartile range 3.7-18 mo). Circulating levels of cytokines, SPLA2, hsCRP, and PCT were not different between patients with progression to clinical arthritis and those without progression. However, a trend for IL-12p70, TNF-alpha, IL-10, IL-6, and SPLA2 was observed. No correlation between messenger RNA (mRNA) expression levels of inflammatory genes and progression to arthritis was found. Subgroup anal Conclusion. Although low-grade inflammation is present before onset of clinical arthritis in large cohorts and can be detected using consecutive measurements, a single measurement of acute-phase reactants seems to have limited value for prediction of development of arthritis in individual patients. (First Release Aug 1 2012; J Rheumatol 2012;39:1914-17; doi:10.3899/jrheum.120586)