Early Innate Immune Activation as a Strategy Against Pathogen-Induced Immune Delay
By Jan Cuppen & Huub Savelkoul | Wageningen University
When we think about why some infections become severe, we often focus on the pathogen’s ability to evade the immune system. But what if the real culprit is something more subtle — a deliberate delay in triggering our immune defenses?
A new review by Jan Cuppen and Huub Savelkoul proposes a compelling shift in perspective: it is not just immune evasion, but immune delay that gives pathogens like influenza, SARS-CoV-2, and uropathogenic E. coli their propagation advantage.
What is Immune Delay?
Immune delay is a temporary postponement of the host’s innate immune response, typically lasting several days. This window is enough for pathogens to replicate exponentially, establish high loads, and spread to new hosts before symptoms trigger social isolation.
Pathogens have evolutionarily optimized this delay not to maximize disease severity, but to maximize infectivity. A host that is still socially active is far more valuable to a pathogen than one bedridden with severe illness.
Neutrophils: The First Responders
At the center of this story are neutrophils — the most abundant white blood cells, replenished at 1.1 million per second. When activated early, they can contain infections before they spiral out of control through phagocytosis, ROS production, NET formation, and cytokine signaling.
When their activation is delayed — as pathogens deliberately engineer — the infection grows unchecked, eventually triggering an overwhelming immune response, including cytokine storms and severe tissue damage. This pattern was dramatically illustrated in severe COVID-19, where delayed interferon responses correlated directly with worse outcomes.
A Novel Approach: Low-Frequency Electromagnetic Fields (LF-EMF)
The authors propose that LF-EMF — non-ionizing, non-thermal fields well within WHO and EU safety guidelines — could pre-activate neutrophils and counteract immune delay. Key findings show that LF-EMF exposure:
Activates neutrophils within 30 minutes in healthy human volunteers
Enhances NET formation through the NADPH oxidase pathway
Modulates cytokine profiles without triggering excessive inflammation
Does not cause DNA damage or promote oncogenic activity
Crucially, LF-EMF primes neutrophils to respond faster when a pathogen is encountered — putting the immune system on high alert without sounding a false alarm.
Implications and Open Questions
If validated clinically, LF-EMF could enable:
Prophylactic use during flu season or pandemic outbreaks
Reduction in antibiotic use through stronger innate immunity
Prevention of cytokine storms by keeping infections small and controlled
However, most evidence remains in vitro or in animal models. Key questions around optimal exposure parameters, long-term effects, and clinical efficacy in high-risk populations still need answers.
Conclusion
As antibiotic resistance grows and new pandemic threats emerge, targeting immune delay through early neutrophil activation deserves serious scientific attention. LF-EMF represents a promising, safe, and non-invasive tool — but rigorous clinical trials are the essential next step.
📄 Read the full article here: Immune Delay, Beyond Immune Evasion, as a Driver of Pathogen Propagation Competence Through Neutrophil Dysregulation, to be Mitigated by Low-Frequency Electromagnetic Fields (LF-EMF)
Cuppen, J.J.M. & Savelkoul, H.F.J. | International Journal of Molecular Sciences | December 2025
