Ultraviolet radiation-induced tolerance

Ultraviolet (UV) radiation is one of the most important environmental facto rs. Besides its well-known advantages and its indispensable effects on huma n life, UV light, particularly the middle wavelength range (290-320 nm [UVB ]), can harm human health by inducing skin cancer, premature skin aging, in flammation, and cell death (1-4). Over the last 25 years, it has become app arent that exposure to UVB radiation may also suppress immune reactions. Re view of the numerous studies on the immunosuppressive properties of UV radi ation led to two quite surprising observations: 1)that UV exposure can have systemic immunologic consequences 2) that UV radiation can induce antigen-specific tolerance. This paper brie fly reviews the phenomenon of UV-induced tolerance.