Dangerous fungus hides in hair follicles to evade immunity
A drug-resistant fungus that increasingly infects hospital patients has found a clever hiding place: the hair follicle. There it evades immune detection and persists long after treatment.
Candida auris is a fungal pathogen spreading through hospitals worldwide. It is notorious for resistance to standard antifungal drugs and primarily infects people with weakened immune systems, including older adults and intensive care patients. A new study in Science reveals a mechanism by which the fungus evades normal immune recognition.
The immune system typically recognises fungi via molecules on their cell walls. One such molecule is chitin, a sugar polymer also found in insect shells and crustaceans. The researchers found that C. auris can expose its chitin layer in a way that triggers a specific immune response: the production of interferon-gamma (IFN-γ), a signalling molecule that activates immune cells.
The hair follicle as an immune-privileged site
This immune response is normally protective. But in the hair follicle, a small cavity in the skin where hair grows, the fungus appears able to persist for extended periods. Hair follicles are naturally less well-patrolled by immune cells, an evolutionary trade-off that facilitates hair growth but creates a vulnerability to infection.
This may explain why C. auris is so difficult to eliminate in patients. Even after treatment, the fungus may remain in hair follicles and cause recurrent infections. In people with aging immune systems, where control over opportunistic infections declines, this is particularly concerning.
New targets for treatment
The discovery that chitin exposure and the IFN-γ response play a role in this process gives researchers a new handle. Targeted activation of immune responses in hair follicles, or disruption of the fungus’s persistence strategy, are possible directions. This is early-stage research based on animal and cell models; clinical applications remain distant.
From a longevity perspective, this is relevant because aging is associated with declining immune function, making opportunistic pathogens like C. auris more dangerous. Understanding their survival strategies is a step toward better protection for vulnerable older adults.
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