Ultraviolet A1 radiation (UVA1)

UVA1 radiation (wavelength 340-400 nm) is the longest ultraviolet wavelength and represents up to 80% of total solar UV rays, particularly in winter in temperate zones. Rather than a molecular target, UVA1 is a physical therapeutic agent that penetrates deeply into the dermis, affecting fibroblasts, dendritic cells, and immune-competent cells. UVA1 exerts its biological effects primarily through generation of reactive oxygen species and oxidative stress, leading to DNA damage, protein modifications, and lipid peroxidation. While UVA1 phototherapy has been successfully used to treat inflammatory and autoimmune skin diseases such as atopic dermatitis and cutaneous T-cell lymphoma through T-cell apoptosis induction, excessive natural exposure to UVA1 contributes to photoaging, photoimmunosuppression, and skin carcinogenesis. The dual nature of UVA1 as both a therapeutic tool and a harmful environmental exposure underscores the need for appropriate photoprotection strategies that specifically include UVA1 wavelengths.

Other names

Long UVAUVA1 rayslongwave UVA

Not applicable as a mechanism of action for drugs targeting UVA1 radiation, as UVA1 is not a molecular target. The biological effects of UVA1 exposure include: T-cell apoptosis induction; Collagenase (matrix metalloproteinase-1) expression; Calcineurin suppression; Depletion of Langerhans cells and mast cells.