Psychiatric morbidity associated with some cytokines (IL-1beta, IL-12, IL-18 and TNF-alpha) among rheumatoid arthritis patients.

Abstract

Psychiatric morbidity is common in rheumatoid arthritis (RA) patients and may affect disease activity and immunological markers. We studied the relationship of the psychiatric morbidity and immunological factors; the serum levels of Interleukin-1beta (IL-1beta), Tumor Necrosis Factor Alpha (TNF-alpha), Interleukin-18 (IL-18) and its inducer interleukin-12 (IL-12), and their impact on RA disease activity. Forty-two RA patients and 20 apparently healthy individuals as a control group were included in this study. Psychiatric morbidity was identified according to the International Classification of Disease, tenth version criteria (ICD-10). The Hospital Anxiety and Depression Scale (HADS) and the mental health Short Form 36 (SF-36) were applied for further analysis. Serum IL-1beta, IL-12, IL-18 and the TNF-a were measured using Enzyme-Amplified Sensitivity Immunoassays (EASIA) and were correlated with psychiatric morbidity and disease activity as measured by Health Assessment Questionnaire and Overall Status. Psychiatric morbidity was found in 40.48% of the studied patients, the most common psychiatric disorders among RA patients were depressive disorders and anxiety disorders. The SF-36 score was closely correlated to the anxiety and depression score (P < 0.001). RA patients showed high levels of IL-1beta, IL-12, IL-18 and TNF-alpha than the control group. There was a significant correlation between psychiatric morbidity, serum levels of IL-1beta, IL-12, IL-18, TNF-alpha and disease activity measurements. We have to view rheumatoid arthritis as a psycho-immumological disorder rather than an autoimmune disease. Furthermore, the studied cytokines may be a novel target for therapeutic intervention of rheumatoid arthritis and its psychiatric morbidity.