Evaluation of serum calprotectin (MRP-8/MRP-14) levels in patients with juvenile idiopathic arthritis

Abstract

Aim: To compare the levels of serum calprotectin (sCal) in patients with juvenile idiopathic arthritis (JIA) depending on the type of therapy to assess the disease activity comprehensively for further treatment correction.

Material and methods: We determined the sCal levels in 74 JIA patients who had normal C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels. High-sensitivity C-reactive protein was evaluated in 16 patients. All children were divided into 2 groups depending on the type of therapy. Group I consisted of 33 children on methotrexate (MTX) therapy, 11 of which were in the state of clinical pharmacologic remission. Group II included 41 children treated with biological Disease-Modifying Antirheumatic Drugs (bDMARDs), 14 of which achieved the state of clinical pharmacologic remission. A results analysis was carried out according to the Mann-Whitney U test. A Spearman rank correlation was performed to define the type of correlation between the indicators.

Results: sCal level was 5.5 times higher in patients with JIA (3,300 μg/L), compared with healthy children (600 μg/L) (p = 0.015). The highest sCal level observed was among the patients in Group I, who received MTX exclusively both in the active phase of the disease (U = 71.5, p = 0.000006) and in the state of clinical pharmacologic remission (U = 11, p = 0.00034). There was a moderate positive correlation of sCal level and disease activity indices, such as the 27-joint Juvenile Arthritis Disease Activity Score (JADAS27) (Spearman’s rho = 0.58, p = 0.0001) and high-sensitivity CRP (Spearman’s rho = 0.56, p = 0.024).

Conclusions: sCal levels should be used to monitor the subclinical inflammatory activity in patients with JIA. The use of bDMARDs in JIA treatment is effective.