Associations between joint status and immunological parameters in children with juvenile idiopathic arthritis

Laboratory diagnostics of juvenile idiopathic arthritis (JIA) allow us to clarify the diagnosis, determine the subtype of the disease, and assess the inflammatory and immunological activity. The aim of our study was to assess the associations between joint status and immunological parameters. Materials and methods. Our study included 80 JIA patients aged 2 to 18 years: 39 (48.8%) boys and 41 (51.2%) girls. The Control group consisted of 20 children: 5 (25.0%) boys and 15 (75.0%) girls. All children underwent physical examination, complete blood count (CBC), biochemical and immunological blood tests, and X-ray examination of the affected joints. Correlation relationships were determined using the ρ-Spearman criterion. Results. Among all classes of immunoglobulins, the most interesting observations were those regarding IgA. Thus, we obtained a significant positive correlation between IgA and arthritis of several joints: hand joints, elbow joints, shoulder joints, knee joints. A positive correlation was established between an increase in concentration of IgG and lesions of the following joints: hand joints (arthritis), shoulder joints (stiffness, arthritis), temporomandibular joints (tenderness). Also, we obtained a significant positive correlation between IgM and tenderness of elbow joints. Involvement of the joints of the upper limb in the process is more common in polyarticular forms of JIA, with an aggressive course, so, high concentrations of IgA correlate with the severity of the process. IL-6 positively correlated with lesions of the knee joints (stiffness; arthritis) and ankle joints (arthritis) Conclusions. Thus, the obtained significant positive correlations between immunological parameters and the condition of the joints allow us to assert that immunoglobulins A, M, G, and IL-6 correlate with the severity of the disease and the processes of joint damage. The research was carried out in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.