Risk assessment for the harmful effects of UVB radiation on the immunological resistance to infectious diseases.

Risk assessment comprises four steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. According this scheme, we have analysed the effects of UVB radiation on basal immune functions in rats and man, and the immunological resistance to infectious diseases in rats. Non-threshold mathematical methods were used in order to estimate the risk for the human population after increased exposure to UVB radiation. These data demonstrate that UVB radiation, at doses relevant to outdoors exposure, may affect the immunological resistance to infectious diseases in human individuals. This study may also provide a basis for a strategy to assess the risk of adverse effects of exposure to immunotoxic agents.