Klinisk institutt 2

Midtveisevalureing - Maria Karoline Jonsson


Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that may lead to joint damage and loss of function. In a modern treatment regimen, patients are monitored closely to achieve a predefined low level of disease activity or remission. Traditional prognostic markers are not sufficient to identify patients with poor prognosis who will profit most from early aggressive treatment. We wished to investigate whether presence and/or levels of plasma calprotectin and serum anti-citrullinated protein antibody (ACPA) reactivities and activity of serum peptidyl arginine deiminase (PAD) enzyme were associated with disease activity and/or are predictive of treatment response and development of radiographic damage in patients with treatment naïve early RA. 

The study is based on 230 treatment-naïve patients with early RA classified according to the 2010 ACR/ EULAR classification criteria [1]. The patients were followed for 2 years in the Norwegian multicenter clinical ARCTIC trial [2]. A broad range of data was collected, including clinical evaluations, ultrasonographic examinations, radiographs and magnetic resonance imaging, in addition to biobank samples. Levels of plasma calprotectin were analyzed by ELISA. Antibodies to ACPA reactivities were analyzed by a multiplex chip-based assay. PAD activity in serum was analyzed using high performance liquid chromatography (HPLC) fluorometric method.

Results/conclusion for calprotectin analyses
Plasma calprotectin was significantly correlated with clinical disease activity index (CDAI), erythrocyte sedimentation rate (ESR) and ultrasonography power Doppler before treatment onset. After 12 months of treatment, calprotectin was statistically significantly correlated with power Doppler, while ESR and C-reactive protein (CRP) were not. Calprotectin, ESR and CRP baseline levels were not predictive of treatment response, but high levels of baseline calprotectin were associated with radiographic progression in multivariate models.

Preliminary data for ACPA reactivities
Positivity for ACPA reactivities was seen mainly in the anti-CCP+ and RF+ patients, but also occurred more frequently in RF- and anti-CCP- patients than in controls.

Preliminary data for PAD activity
Sera from approximately one third of the RA patients had a significant stimulatory effect on PAD4 activity compared with healthy controls.


1.            Aletaha, D., et al., 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum, 2010. 62(9): p. 2569-81.

2.            Haavardsholm, E.A., et al., Ultrasound in management of rheumatoid arthritis: ARCTIC randomised controlled strategy trial. Bmj, 2016. 354: p. i4205.