Supplementary Material for: Immunological Profile of Patients with Rheumatoid Arthritis and Asthma

Objectives: The aim of this study was to investigate cytokine profiles in patients with both rheumatoid arthritis (RA) and bronchial asthma (BA). Methods: We studied 25 patients with RA, 25 with BA and 25 with both RA and BA (BARA). A respiratory questionnaire was completed by all the patients, they underwent spirometry and their production patterns of selected T helper (Th)1, Th2 and Th17 cytokines were assessed. Results: BA patients had spirometry findings similar to BARA patients, while RA patients had normal spirometry. BA patients produced significantly higher levels of interleukin (IL)-5 (p = 0.03) and IL-10 (p = 0.03) than patients with RA. Median levels of IL-17A and IL-17F, and interferon (IFN)- were higher (p = 0.001, 0.004 and 0.04) in RA patients than in BA patients. No differences were seen in the levels of cytokines produced by BA patients compared to BARA patients. IL-4 and IL-10 levels were higher (p = 0.04 and 0.03) in BARA patients than in RA patients, while levels of IL-17A and IFN- were higher (p = 0.037 and 0.009 respectively) in RA patients than in BARA patients. Ratios of Th1/Th2 and Th17/Th2 cytokines in most combinations were different between RA and BA, and between RA and BARA, but were similar in BA and BARA. Conclusions: Patients with both BA and RA have a Th2-dominant cytokine profile unlike patients with RA alone. These observations contribute to a better understanding of the immunopathogenesis of these diseases and for the management of patients using cytokine-based therapies.