RESUMO
AIM OF THE WORK: To identify the role of serum IL-13, and its receptor subunit expressions as a serologic marker of rheumatoid arthritis (RA)-associated ILD (RA-ILD). PATIENTS AND METHODS: Fifty RA patients with ILD and 50 RA patients without ILD were examined, in addition to 50 controls. Disease Activity Score in 28 joints (DAS-28), the Health Assessment Questionnaire (HAQ), and medication history were evaluated. ESR, CRP, RF, Anti-CCP, Serum Krebs von den Lungen-6 (KL-6), surfactant protein D (SP-D) levels, Interleukin 13 and its receptors (IL-13 Rα1 and L-13 Rα2), and mRNA relative expression levels in peripheral blood mononuclear cells (PBMCs) were measured. High-resolution computed tomography (HRCT) scores were used with all RA patients with interstitial lung disease. RESULTS: Mean age, percent of male affection, duration of the disease, DAS28 and MHAQ were significantly higher in the RA-ILD group than in the RA-no ILD group. ESR, CRP, RF, anti-CCP, serum KL-6, SP-D, IL-13 levels, IL-13 Rα1and IL-13 Rα2 mRNA expressions were significantly increased in RA patients compared to controls; in addition, their levels were significantly higher in the RA-ILD group than in the RA-no ILD group. Serum IL-13 levels and IL-13 Rα1and IL-13 Rα2 were positively correlated with RF, Anti-CCP, KL-6, SP-D, and the HRCT score (P < .001). CONCLUSIONS: Serum IL-13 and its receptor subunit expressions are useful biomarkers which can be used in detecting severity of the interstitial lung disease in RA patients.
