Ruth Napier, PhD: Novel Biomarker Linked to Ankylosing Spondylitis Pathogenesis

In an interview with HCPLive, Ruth Napier, PhD, assistant professor of molecular microbiology and immunology, arthritis, and rheumatic disease in the Oregon Heath & Science University School of Medicine, discusses her study “Card9/neutrophil signalling axis promotes IL-17A-mediated ankylosing spondylitis.” Results revealed a biomarker, Card9, plays a neutrophil-intrinsic role in the pathogenesis of ankylosing spondylitis (AS).

Napier was determined to research the ways in which CARD9 polymorphism enhances susceptibility to AS to better understand the challenges patients face. She theorized understanding the genetics of individual patients may help to explain the different clinical outcomes and therapeutic needs.

“I have often heard from patients, even in informal settings like dinner parties, and have read in the literature that this group of patients is highly clinically and genetically diverse,” she said. “It struck me that treating all of them similarly might not be the most effective approach.”

While the original goal was to understand why a certain genetic polymorphism related to Card9 was linked with an increased AS risk, researchers uncovered a biomarker in the process.

Findings demonstrated the expression of the gene was responsible for driving the disease. Additionally, approximately 72% of patients with AS expressed this mutation, underscoring the significance of these results. Although Card9 protects against common environmental fungi, if mutated, it can lead to the predisposition of conditions like AS.

The study initially created an animal model to explore the role of Card9, which they identified as functioning primarily in neutrophils. This led to human patient samples to confirm the findings and, when evaluated, patients' samples aligned with the mouse model results.

While the biomarker isn’t directly associated with other types of spondyloarthritis, such as psoriatic arthritis, it did have implications for inflammatory bowel disease. These results may help to stratify patients by indicating their predispositions and potential drug responses.

This transcript was edited for clarity.