How Cosentyx (secukinumab) affects the immune system
Cosentyx is an immune-targeted biologic that suppresses part of the immune response rather than shutting down the entire immune system. It blocks interleukin-17A (IL-17A), a signaling molecule involved in inflammation, including the inflammatory pathways behind conditions like psoriasis, psoriatic arthritis, and ankylosing spondylitis [1].
Because IL-17A is part of normal host defenses, Cosentyx can increase the risk of certain infections, showing that it does meaningfully affect immune function [1].
Does it make you more likely to get infections?
Yes. By inhibiting IL-17A, Cosentyx can increase susceptibility to infections—particularly those linked to mucosal immunity (for example, fungal infections such as candida) [1]. Clinically, this is the main practical “immune suppression” concern patients and clinicians monitor for while on therapy [1].
If a person develops fever, worsening symptoms, or signs of infection while taking Cosentyx, they should contact their clinician promptly [1].
Is it “global” immunosuppression like chemotherapy?
No. Cosentyx is considered more targeted than broad immunosuppressants because it blocks a specific inflammatory pathway (IL-17A) rather than broadly impairing multiple immune cell types and functions [1].
That targeted action is also why its risk profile differs from drugs that cause more generalized immune suppression.
What immune pathways does it block (and what doesn’t it block)?
Cosentyx specifically inhibits IL-17A. It does not work as a blanket inhibitor of all immune signaling pathways [1]. The immune effect you see clinically comes from reducing IL-17A-driven inflammation and the downstream effects on inflammatory responses [1].
What conditions is Cosentyx used for, and how does that relate to immune effects?
Cosentyx is prescribed for immune-mediated inflammatory diseases such as plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis [1]. In these conditions, the immune system is overactive in particular pathways. By blocking IL-17A, Cosentyx reduces that overactivity, which can also change infection risk in people with functioning IL-17-dependent defenses [1].
When should patients be extra cautious?
Patients should discuss infection history and current infection symptoms with their clinician before or during treatment, since Cosentyx can increase infection risk due to its immune pathway inhibition [1]. Clinicians also monitor for fungal infections, consistent with IL-17A’s role in antifungal defenses [1].
Sources
[1] https://www.cosentyx.com/how-it-works