Photoimmunology

Abstract

Photoimmunology is the study of the effects of non-ionizing electromagnetic radiation (principally ultraviolet light) on the immune system. Ultraviolet (UV) light represents the spectrum of electromagnetic radiation between the wavelengths of 100 and 400 nm. Through its actions on the immune system, UV radiation promotes the development of skin cancers, modulates the development of allergic contact dermatitis, and triggers several specific photosensitivity disorders collectively known as the immunologically-mediated photodermatoses. These disorders include polymorphic light eruption, actinic prurigo, solar urticaria, hydro vacciniforme, and chronic actinic dermatitis. In addition to discussing the molecular underpinnings of UV-induced carcinogenesis and the effects of UV radiation on contact hypersensitivy responses, this chapter reviews the clinical features, epidemiology, pathophysiology and treatment of the immunologically-mediated photodermatoses. Additionally, this chapter highlights the key immunologic mechanisms by which UV radiation is used therapeutically to treat dermatologic diseases, especially T-cell mediated skin disorders.