Pefloxacin and ciprofloxacin increase UVA-induced edema and immune suppression

Background: Quinolone antibiotics are popularly prescribed antibiotics beca use of their wide antibacterial spectrum and lowered bacterial resistance. Quinolone antibiotics are one of the well-known photosensitizers that induc e phototoxicity, Their role in photocarcinogenesis has been suggested in so me studies. Material and methods: Mice were treated with two quinolone antibiotics (cip rofloxacin, which is less phototoxic, and pefloxacin, which is more phototo xic) to study the effect of the antibiotics on sunburn and immune suppressi on by ultraviolet A (UVA) irradiation. The effects of a combined treatment with UVA and these quinolone antibiotics were measured on back skin swellin gs, sunburn cell formations, depletion of epidermal Langerhans cells, and l ocal and systemic suppression of contact hypersensitivity. Results: Mice treated with both UVA and quinolone showed significantly incr eased back skin swellings and decreased epidermal Langerhans cells than mic e treated with UVA only. Sunburn cells were increased significantly in mice treated with pefloxacin and 50 J/cm(2) of UVA, Combination of pefloxacin a nd UVA suppressed local contact hypersensitivity significantly, but not sys temic contact hypersensitivity. Conclusion: Phototoxic quinolones augmented the effect of UVA by increasing sunburn and apoptosis, depleting Langerhans cells and suppressing local im mune response. By affecting apoptosis and immune suppression, they may faci litate photocarcinogenesis caused by UVA.