IL-17 as a putative hallmark of intense arthralgia and age-related serum immune mediator networks during acute chikungunya fever.

Introduction: The present study aimed at evaluating the systemic profile and network connectivity of immune mediators during acute chikungunya fever (CHIKF) according to days of symptoms onset and ageing.

Methods: A total of 161 volunteers (76 CHIKF patients and 85 non-infected healthy controls) were enrolled.

Results and discussion: Data demonstrated that a massive and polyfunctional storm of serum immune mediators was observed in CHIKF. Distinct patterns of mediators were observed according to days of symptoms onset. Most chemokines and proinflammatory cytokines were increased early at D0-1, with some increased throughout the kinetics timeline, while others presented a waning profile towards D4-12. Rhythmic signatures further underscored these findings. Increased levels IL-17 appeared as a hallmark of intense arthralgia, while CCL5&IL-5 and TNF-α&IL-10 duets are age-tunning features in CHIKF. Differential connectivity of networks was observed with ageing, with a progressive increase in the overall connectivity from < 8 yo towards 51-89 yo. Of note, subsets of immune mediators (IL-17, IL-2 and IL-5) displayed hotspots of hyperconnectivity in elderly as compared to younger patients.

Conclusion: Together, the overall scenario reveals unique patterns of soluble immune mediators during acute CHIKF infection with an oscillating symphony according to days of symptoms and ageing, which brings insight to future tailor-made therapeutic interventions.