Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Interleukin-35 (IL-35) is a newly described heterodimeric cytokine that belongs to the IL-12 family and consists of p35 (IL-12a) and EBI3 (IL-27b) subunits. IL-35 exerts immunomodulatory activities in several human autoimmune inflammatory diseases. Our objective was to assess IL-35 expression in muscle tissue and serum levels of IL-35 in myositis patients compared to healthy controls and characterise its potential association with myositis disease activity.
Methods: The expression of IL-35 was studied by primary rabbit anti-human EBI3 polyclonal antibody and mouse anti-human p35 monoclonal antibody in a series of 19 muscle biopsy samples of idiopathic inflammatory myopathies (9 dermatomyositis/DM, 10 polymyositis/PM) and 10 cases of non-inflammatory myopathies and 10 control muscles biopsies. Serum levels of IL-35 were determined in 28 DM, 26 PM and 17 cancer associated myositis patients as well as in 40 healthy controls. Disease activity was evaluated by the score of the Myositis Disease Activity Assessment Tool (MYOACT), including both extramuscular, muscular and the physician’s score of overall disease activity.
Results: Both IL-35 subunits were found in immune cells of the inflammatory infiltrates in idiopathic inflammatory myopathies, but not in muscle cells. No immunoreactivity was observed in muscle tissue of healthy controls and in non-inflammatory myopathies. IL-35 serum levels were increased in all myositis patients compared to healthy controls (p< 0.001). There were no differences in IL-35 serum levels among myositis subgroups. In patients with PM, but not DM, serum IL-35 levels correlated with MYOACT score (r=0.548, p=0.023), lactate dehydrogenase (r=0.621, p=0.024), CRP (r=0.632, p=0.009) and physician’s score (r=0.514, p=0.042).
IL-35 subunits are overexpressed in inflamed muscle tissue and elevated circulating IL-35 levels are associated with several disease activity parameters in polymyositis patients. These data suggest potential role of IL-35 in the pathogenesis of inflammatory myopathies.
Acknowledgement: Supported by MHCR support for conceptual development of a research organization (023728) and BTCure (115142-2).
To cite this abstract in AMA style:Mann HF, Hulejova H, Zámecník J, Hacek J, Filková M, Kryštufková O, Vencovsky J, Senolt L. Interleukin-35 in Idiopathic Inflammatory Myopathies [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/interleukin-35-in-idiopathic-inflammatory-myopathies/. Accessed January 31, 2023.
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