Dose-dependent visible effect on mice Langerhans cell membrane markers.

Ultraviolet B and psoralen plus UVA treatment induce antigenic and enzymatic changes in Langerhans cells (LC). The aim of this study was to investigate the visible (VIS) effect on mice LC surface markers. As visible source, a slide projector equipped with a 150-W tungsten lamp, emitting between 400 and 740 nm (maximum at 580 nm) was used. Mice (BALB/c and C3H) were divided into groups, each irradiated with visible single fixed doses (ranging from 10 to 1000 J/cm2). The mice backs were shaved before irradiation. Skin biopsies obtained immediately after irradiation were processed for immunofluorescence and electron microscopy. Immunofluorescent studies showed: 1) a complete depletion of LC membrane markers at a dose of 700 J/cm2; 2) no effect at visible doses ranging between 0 and 75 J/cm2; 3) a dose-dependent effect with doses between 100 and 700 J/cm2. Electron microscopy revealed no cellular damage of LC at the visible doses administered.