Ab0068 interleukin 40 Serum Levels Are Elevated in Patients With Early Rheumatoid Arthritis and Associate With Neutrophil Activation

Abstract

BackgroundIL-40 is a newly described cytokine associated with immune system function and malignant transformation. We have recently shown that IL-40 is up-regulated in rheumatoid arthritis (RA) and associates with disease activity, autoantibodies and NETosis1.ObjectivesAs autoantibodies and neutrophil activation are factors thought to drive the pathological processes at early phase of RA development, we aimed to investigate IL-40 in relation to neutrophils and early stages of RA (ERA).MethodsThe levels of serum IL-40 were determined in a cohort of treatment naïve patients with ERA at baseline (n=60) and three months after initiation of conventional treatment (n=60). Serum IL-40 was also determined in sex- and age- matched healthy controls (n=60). Levels of IL-40, cytokines and NETosis markers (proteinase 3, PR3 and neutrophil elastase, NE) were measured by commercially available ELISA kits. The levels of autoantibodies were analysed by routine laboratory techniques. In vitro experiments were performed on peripheral blood neutrophils from patients with ERA (n=15).ResultsLevels of IL-40 were elevated in ERA patients at baseline compared to healthy controls (p<0.0001) and normalised after three months of the treatment (p<0.0001). Baseline serum IL-40 was associated with the levels of autoantibodies RF (IgM) (p<0.01) and anti-CCP (p<0.01) and markers of NETosis PR3 and NE) (both p<0.0001). Moreover, significant decreases in the serum IL-40 following the therapy correlated with the decrease of NETosis markers PR3 (p<0.01) and NE (p<0.05). In vitro, neutrophils from patients with ERA significantly enhanced the release of IL-40 following NETosis induction (p<0.05) or after exposure to pro-inflammatory cytokines such as IL-1β, IL-8 (p<0.05), TNF (p<0.01) or to LPS (p<0.05). Lastly, recombinant IL-40 induced the secretion of IL-1β (p<0.05) and TNF (p<0.05) by ERA neutrophils.ConclusionWe demonstrated for the first time that IL-40 is upregulated in ERA and decreases after three months of conventional therapy. Moreover, we showed that neutrophils are an important source of IL-40 in RA and its release is potentiated by pro-inflammatory cytokines and NETosis. Our results suggest that IL-40 may play an important role in early stages of RA.References[1]Navrátilová A, Andrés Cerezo L, Hulejová H, Bečvář V, Tomčík M, Komarc M, et al. IL-40: A New B Cell-Associated Cytokine Up-Regulated in Rheumatoid Arthritis Decreases Following the Rituximab Therapy and Correlates With Disease Activity, Autoantibodies, and NETosis. Front Immunol. 2021 Oct 21;12:745523. doi: 10.3389/fimmu.2021.745523.AcknowledgementsSupported by AZV-NU21-05-00276, MHCR 023728, SVV 260 523 and BBMRI-CZ LM2018125Disclosure of InterestsNone declared

A Comprehensive Review on the Role of Interleukin-40 as a Biomarker for Diagnosing Inflammatory Diseases

“…Terefore, these data suggested that other immune cells that are associated with RA, such as neutrophils, T cells, and macrophages, caused the remaining 30% of IL-40 production [16]. Supporting this result, researches showed that neutrophils from arthritis patients are one of the important sources of interleukin-40 production during the early stages of the disease [17]. However, another study revealed that CD4+, CD8+ T cells, and CD68+ macrophages are additional producers of IL-40 in pSS patients, supporting the hypothesis that other immune cells may also create IL-40 [18].…”

“…To date, there have been no studies on targeting IL-40 for disease treatments or its possible side efects as a drug, and existing researches have primarily focused on identifying the presence of IL-40 in diferent infammatory disorders. In patients with early-stage rheumatoid arthritis, only a few studies have indirectly shown that the production of interleukin-40 in patients' serum decreases during 3 months of treatment with conventional drugs [17]. Terefore, in addition to demonstrating the role of this cytokine in various diseases, it may also be useful in the future to conduct studies to determine the role of using this molecule as a therapeutic target.…”