Effect of 1064-nm Q-switched Nd:YAG laser on invasiveness and innate immune response in keratinocytes infected with Candida albicans

Candida albicans is an opportunistic pathogen commensal in the oral cavity, vagina, and healthy skin. Common therapeutic options for fungal infections are topical or systemic antifungal drugs. Recently, in cutaneous pathologies, lasers and light-based treatments have emerged showing few contraindications and minimal side effects. The Q-switched (Nd-YAG) laser at a wavelength of 1064 nm has been shown to be useful in dermatology, dentistry, and some other medical specialties. It is used to treat onychomycoses, warts, and wounds and in some other treatments. We analyzed the effect of Q-switched (Nd-YAG) laser 1064 nm on human keratinocytes infected with C. albicans. In particular, we evaluated the effect of laser on invasiveness of C. albicans and on inflammatory and protective response of HaCaT cells infected. The results obtained did not show inhibitory, fungicidal, or fungistatic effects of laser on yeast; in addition, laser did not affect HaCaT vitality. HaCaT cells infected with C. albicans and irradiated with laser showed a reduction of invasiveness of TNF-alpha and IL8 gene expression and an increase of immunomodulatory cytokines such as TGF beta. Furthermore, laser induces a significant over-expression of HSP70B (heat shock protein) and of HBD-2 (Human beta defensin-2) in HaCaT infected with C. albicans, compared to the untreated control. The use of Q-switched Nd:YAG laser in skin mycosis caused by C. albicans reduces yeast invasiveness in keratinocytes, downregulates inflammatory activities, and facilitates cytoprotection and antimicrobial defense. Our results offer a promising therapeutic strategy in the management of skin candidiasis, also in combination with conventional therapies.