Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Evaluation of ultraviolet B exposure

Effects of increasing ultraviolet B (UVB) exposure range from an increased incidence of eye disorders (damage to the lens, cornea and retina, and possible intraocular melanoma), skin cancers, and infectious diseases. Quantitative estimates of how increased UVB plays a role in eye damage and skin cancers have already been made. For UVB effects on the immune system, and as a consequence, the contribution of such effects to the incidence of infectious diseases and tumours, such information is still lacking. The main goal of this project is to investigate the effects of UVB irradiation on the immune system, and in particular on the resistance to infectious diseases and tumours.

During this project the effect of UV exposure on the immune system in rodents and partially also in humans was investigated. Several parameters of the immune system or parameters that can influence the immune system such as urocanic acid isomerization and thymidine dimer formation were studied in animal and man. Dose dependency and kinetics of the UVB induced effects were studied using animal models. In general the natural killer cell function and the mixed lymphocyte response were inhibited by UVB exposure in animal and man. In animals the effect of the UVB induced immune alteration on the resistance against infectious diseases and tumours was studied. During photocarcinogenesis several parameters of the immune system were altered in the skin, draining lymph nodes and spleen. In addition, the UV induced immunosuppression resulted in a decreased resistance against skin associated and nonskin associated infectious diseases in rodents. The doses of UV needed for these alterations was only a suberythemal doses. The project is continuing.