Interleukin-6 (IL-6) exerts broad effects throughout the course of rheumatoid arthritis (RA), starting before symptoms occur and continuing through disease onset and progression.2,6,8 IL-6 is able to act directly on most cells through its unique dual signaling mechanism and activates several distinct downstream pathways.9-13 These effects go beyond the joints—adversely affecting multiple organ systems—and can impact patients’ quality of life.2,3,6,14-16
RA is more than a disease of the joints—it is associated with both articular and systemic manifestations that can significantly impact a patient’s quality of life.1-3 Manifestations of RA are driven by a network of pro-inflammatory cytokines, including IL-6.17-19
IL-6 is a multifunctional cytokine that regulates both innate and adaptive immunity. It also drives the diverse cellular processes involved in RA pathogenesis and progression.1,2,5,6,20,21 Persistently elevated levels of IL-6 have been shown to increase disease severity and promote the shift from acute to chronic inflammation.4-6
The unique dual signaling mechanism of IL-6 enables a broad range of biological activity, which can lead to chronic inflammation and diverse clinical manifestations.1,2,8,19,22,23 While cis-signaling is limited to certain cells, trans-signaling allows IL-6 to act directly on almost all other cell types.1,6,23
Utilizing dual signaling, IL-6 is able to activate 3 distinct downstream signaling pathways. Each pathway is believed to perform unique functions in RA pathogenesis.9-11
IL-6 plays a key role in the articular manifestations of RA such as morning stiffness, but it has also been shown to drive more systemic manifestations that are linked to a reduced quality of life for patients.2,3,6,14
IL-6 plays a role in multiple systemic manifestations such as pain, fatigue, poor sleep, and effects on mental health, which impact a significant proportion of patients with RA and are often ranked as top concerns by patients.2,24-26
Long-standing inflammation can cause morning stiffness and significant joint destruction1,14,23
RA is associated with neuroendocrine/neurologic manifestations such as pain, fatigue, poor sleep, and effects on mental health, which are highly correlated with one another2,24,27
RA is associated with increased risk of cardiovascular effects, including endothelial dysfunction, hypercoagulability, and atherogenesis15,16
Metabolic manifestations of RA include dyslipidemia and insulin resistance6,15
Introducing IL-6: Effects Beyond the Joints in RA
In this video, we will give a brief overview of rheumatoid arthritis, or RA, and how interleukin-6, or IL-6, is implicated in the pathogenesis and progression of RA.
The physical impact of rheumatoid arthritis is wide-reaching. It is associated with articular and systemic manifestations, characterizing it as a disease beyond just the joints.
It is driven by a network of proinflammatory cytokines, including TNF, IL-1, and IL-6. IL-6 is one of the most abundant cytokines found in the serum and synovial fluid.
IL-6 signaling plays a key role in chronic inflammation and interactions between the innate and adaptive immune systems. Its unique dual-signaling mechanism allows it to signal via both membrane-bound and soluble receptors, explaining its pleiotropic effects.
This signaling activates 3 key proinflammatory pathways: JAK/STAT, MAP-kinase, and PI3-kinase.
Elevated and dysregulated IL-6 levels ultimately contribute to a multitude of RA manifestations that patients experience, including joint damage and morning stiffness, as well as the acute-phase response, pain, fatigue, poor sleep, mood disorders, and metabolic dysregulation.
In summary, rheumatoid arthritis is more than a disease of just the joints; persistently elevated IL-6 levels can play a key role in both the articular and systemic manifestations of RA that affect a patient’s quality of life.
To find out more about IL-6, please browse additional videos in this series on RAandIL6.com. This video was brought to you by Sanofi Genzyme and Regeneron Pharmaceuticals.
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