Effects of solar-simulated radiation dose fractionation on CD1a+ Langerhans cells and CD11b+ macrophages in human skin

Abstract

We found that erythema is a poor indicator of alterations in epidermal APCs and that dose fractionation is an important parameter in the immunological effects of ultraviolet radiation.

Effects of ultraviolet radiation on Langerhans cells

“…LCs which remained in the epidermis after exposure to UV radiation exhibited characteristic morphological alterations, with a tendency to be more and more evident with an increased radiation dose [6]. The changes included swelling and rounding of the cells, decrease or increase in size and initial shortening and then the loss of dendrites.…”

“…Other authors also showed a reduced number of LCs in the epidermis caused by solar simulated radiation (SSR) -UVA + UVB, 290-400 nm -both in humans after exposure to a single dose of UV-SSR (2 MED, 3 MED) [6,7] and in mice after multiple suberythematous doses of irradiation (3.7 J/cm 2 , from 10 to 60 days) [13]. According to Novakovic et al's study, the decrease in the number of LCs was the greatest 72 hours after irradiation with 2 MEDs of SSR [6]. McLoone et al observed an increase in the dendritic cells in the lymph nodes [13] with a simultaneous reduction of LCs number in murine epidermis.…”

“…It should be noted that the reduction in the number of LCs in the epidermis after SSR, UVA, UVA1 and UVB irradiation in the majority of experiments was found to be dose dependent [6,7,20].…”

“…Numerous studies showed a decrease in the number of LCs in the epidermis caused by exposure to UV radiation, including sunlight [5], solar simulated radiation (SSR) [6], UVA [7,8] and UVB [9,10]. Two mechanisms are considered responsible for this effect: mobilization and migration of LCs to the lymph nodes or induction of necrosis or apoptosis processes by UV [9][10][11][12].…”

Banning children and youth under the age of 18 years from commercial tanning facilities

“…There is considerable evidence that the photoisomerization of stratum corneum trans-urocanic acid (UCA) to the cis-form also plays an important role in immunosuppression. Exposure to erythemal UVR or repeated sub-erythemal UVR results in a loss of epidermal antigen presenting Langerhans cells (Novakovic et al, 2001). …”