IL-17A Blood Biomarker may distinguish Kawasaki Disease from other inflammatory diseases in Children

A pioneering study published in Arthritis & Rheumatology by researchers Pui Y. Lee and colleagues from Boston Children's Hospital have unveiled a potential game-changer in the realm of pediatric inflammatory disorders, particularly Kawasaki disease. This condition, marked by ambiguous clinical signs like fever and rash, often poses diagnostic challenges due to its overlap with other similar conditions. However, the study has identified a distinctive biomarker, an interleukin (IL) protein called IL-17A, which could pave the way for a blood test aiding accurate differential diagnosis.

Kawasaki disease is a form of vasculitis primarily affecting children, causing inflammation in mid-sized vessels. Diagnoses are intricate due to the shared clinical symptoms with other disorders like viral infections and multisystem inflammatory syndrome in children (MIS-C). The diagnostic process becomes even more pressing considering that untreated cases can lead to coronary artery deformities in up to 30% of patients.

The researchers harnessed the potential of the proximity extension assay (PEA), a technology capable of quantifying multiple proteins in minuscule blood samples. By analyzing blood samples from a diverse cohort of children with Kawasaki disease, MIS-C, other fever disorders, rheumatologic disorders, and healthy individuals, they pinpointed the prominence of the IL-17 cytokine family, specifically IL-17A, IL-17C, and IL-17F.

● Elevated levels of IL-17A were diagnostic for Kawasaki disease with astounding accuracy, as indicated by an area under the receiver operating characteristic curve (AUC) of 0.95.

● The elevation of all three IL-17-family cytokines (IL-17A, IL-17C, and IL-17F) was observed in over 50% of Kawasaki disease patients, especially those with coronary artery aneurysms, setting them apart from other comparator groups.

The study not only illuminates a potential blood-based diagnostic marker but also highlights the importance of prompt Kawasaki disease diagnosis. Given its potential to reduce costs, expedite treatment, and prevent complications, this discovery holds immense promise for transforming clinical practice.

While this study offers groundbreaking insights, the researchers acknowledge the need for further research and validation. Their findings are particularly based on samples from a single center, warranting broader validation across multiple sites. Additionally, longitudinal analysis is crucial to understanding the correlation between IL-17 levels and treatment responses.

Reference:

Arthritis & Rheumatology Brodeur KE, et al "Elevation of IL-17 cytokines distinguishes Kawasaki disease from other pediatric inflammatory disorders" Arthritis Rheumatol 2023; DOI: 10.1002/art.42680.