Influence of ultraviolet B exposure on immune responses following hepatitis B vaccination in human volunteers

Exposure to ultraviolet radiation can modulate immune responses in animal a nd humans. Remarkably, the ultraviolet-induced immunosuppression is not res tricted to the exposed skin but is also found at other body sites, i.e., sy stemic immunosuppression. Effects of ultraviolet radiation on infections ca nnot be determined by experimentation on humans, but the effects of ultravi olet on vaccination may serve as a model. Moreover, it is important in its own right to assess whether ultraviolet radiation affects vaccination respo nses. In this study the effect of ultraviolet B exposure on the development of immune responses after hepatitis B vaccination in human volunteers was investigated. To this end, 191 human volunteers were vaccinated against hep atitis B with the Engerix-B (R) vaccine. Ninety-seven of them were prior to the first vaccination exposed to ultraviolet B on 5 consecutive days with one personal minimal erythema dose per day. At several time-points before a nd after the ultraviolet B exposure regimen and the vaccination, blood samp les were taken. Parameters for specific as well as nonspecific cellular and humoral immunity were analyzed. It was demonstrated that ultraviolet B exp osure prior to hepatitis B vaccination did not alter the cellular (lymphocy te stimulation test) nor the humoral (antibody titers) immune response agai nst hepatitis B surface antigen significantly. In contrast, contact hyperse nsitivity to diphenylcyclopropenone was significantly suppressed after ultr aviolet B exposure, as was natural killer cell activity. These latter resul ts confirm earlier findings and demonstrate immunosuppressive effectiveness of the ultraviolet regimen. In summary, although natural killer cell activ ity and contact hypersensitivity responses were suppressed, the ultraviolet B radiation protocol did not alter the humoral nor the cellular immune res ponses against hepatitis B surface antigen after vaccination.