Interleukin-17A, or IL-17A, is a protein known as a cytokine. Cytokines are signaling proteins that play a communication role within the immune system, directing various cellular responses. IL-17A is involved in the body’s natural defense mechanisms, helping to coordinate responses against certain invaders. IL-17A antibodies are biologic medications that target and neutralize this cytokine. These specialized treatments are developed to address conditions where IL-17A activity becomes overactive, leading to unwanted inflammation.
Role of IL-17A in Immune Responses
IL-17A functions in the immune system to defend against bacterial and fungal infections. It promotes the recruitment of immune cells, such as neutrophils, to sites of infection or injury, which helps clear harmful substances and initiate healing processes. It also induces the production of other inflammatory mediators, like chemokines and antimicrobial peptides, to bolster the body’s defenses.
However, when IL-17A is excessive or unregulated, it can contribute to chronic inflammation and tissue damage. This dysregulation is a hallmark of several autoimmune and inflammatory diseases. In these conditions, the sustained presence of IL-17A can lead to ongoing inflammation, causing symptoms and progressive damage to various tissues.
How IL-17A Antibodies Work
IL-17A antibodies are monoclonal antibodies. These antibodies are engineered to bind to IL-17A molecules. When an IL-17A antibody binds to IL-17A, it neutralizes the cytokine, preventing interaction with receptors on target cells.
This binding blocks the signaling pathway IL-17A activates, which in turn reduces the inflammatory responses it initiates. By interrupting this communication, the antibodies help to dampen the excessive inflammation that characterizes certain autoimmune conditions. The targeted approach ensures that only the overactive IL-17A pathway is addressed, rather than broadly suppressing the entire immune system.
Conditions Treated by IL-17A Antibodies
IL-17A antibodies treat several chronic autoimmune and inflammatory conditions where IL-17A plays a role. Psoriasis, characterized by rapid skin cell growth and inflammation, leads to red, scaly patches. In psoriasis, elevated IL-17A contributes to keratinocyte hyperproliferation and skin inflammation; blocking it can reduce symptoms.
Psoriatic arthritis, a form of arthritis affecting some people with psoriasis, also benefits from IL-17A antibody treatment. This condition involves joint pain, stiffness, and swelling, where IL-17A drives inflammation in the joints and surrounding tissues. Similarly, ankylosing spondylitis, an inflammatory disease primarily affecting the spine, sees therapeutic benefits. IL-17A contributes to inflammation and bone formation in the spine of individuals with ankylosing spondylitis.
Medications such as secukinumab (Cosentyx) and ixekizumab (Taltz) are examples of IL-17A antibodies used to treat these conditions. These drugs neutralize the IL-17A cytokine, reducing the inflammatory cascade that contributes to the pathology of these diseases. Their targeted action alleviates symptoms and slows disease progression.
Considerations for IL-17A Antibody Treatment
IL-17A antibody treatments are administered through subcutaneous injection (under the skin). Injection frequency varies by medication and condition, often ranging from weekly to monthly. Treatment is usually long-term, continuing as long as the medication provides benefit and is well-tolerated.
Patients should be aware of potential side effects. A common side effect is an increased risk of infections, particularly candidiasis (yeast infections), as IL-17A has a role in antifungal immunity. Injection site reactions, such as redness, pain, or swelling, can also occur.
Before treatment, healthcare providers screen for latent tuberculosis due to potential reactivation. Throughout treatment, patients are monitored for signs of infection or other adverse reactions. These considerations help ensure the safe and effective use of IL-17A antibody therapies.