The big picture: Interleukin-6 (IL-6) is a cytokine, or small signaling protein, produced primarily by immune cells in response to infection, tissue injury, or chronic stress. IL-6 is integral to initiating inflammation, which helps the body defend against harmful agents, and is also involved in the regulation of metabolic, regenerative, and neural processes. Elevated levels of IL-6 are often seen in acute infections, autoimmune diseases, and chronic inflammatory conditions, making it an important marker for assessing both acute and chronic inflammation.

Role in health: IL-6 helps coordinate the body’s inflammatory response and immune defense. During an infection or injury, IL-6 signals immune cells to gather at the affected area and promotes the production of acute-phase proteins, essential for healing and recovery. IL-6 also plays a role in metabolism, influencing fat breakdown and insulin sensitivity. In normal amounts, it supports immune balance and tissue repair, but chronic elevation can lead to tissue damage and increase the risk of diseases like cardiovascular disease, type 2 diabetes, and autoimmune disorders.

High IL-6 levels: Chronic elevation of IL-6 is associated with conditions like rheumatoid arthritis, lupus, inflammatory bowel disease, and cardiovascular disease. Symptoms associated with high IL-6 often include fatigue, pain, and swelling, especially in autoimmune diseases. Persistently high IL-6 can contribute to insulin resistance, increased risk of heart disease, and even cancer, as ongoing inflammation damages tissues and promotes abnormal cell growth.

Low or balanced IL-6 levels: Normal IL-6 levels indicate a balanced immune response and a reduced risk of chronic inflammation-related conditions. Low IL-6 levels in the absence of infection or disease reflect a state of immune health, but overly low levels can reduce the body’s ability to respond to infections or injury.

Managing abnormal IL-6 levels: Addressing elevated IL-6 levels often involves lifestyle changes, such as adopting an anti-inflammatory diet, managing stress, and increasing physical activity. Medications like anti-inflammatory drugs or biologics may also be used in severe inflammatory diseases. Routine monitoring of IL-6 can help guide interventions and prevent further complications from chronic inflammation.