Ultraviolet radiation has been shown to suppress the (skin) immune system both in animal species and in @entity1 . Whether sunscreens can prevent immunosuppression is a matter of debate. This study investigated the protective capacity of a commercial sunscreen lotion in @entity1 . Part of the right arm of healthy volunteers was exposed to erythemagenic ultraviolet B doses of 160 mJ per cm2 for four consecutive days. Before irradiation, sunscreen was applied either directly onto the skin or onto a piece of quartz fixed to the skin (to avoid penetration of the sunscreen in the epidermis where it cannot block the photoisomerization of @entity33442 in @entity33441 in the stratum corneum). The control group was irradiated without prior application of sunscreen. Four h after the last irradiation, epidermal sheets were obtained by the suction-blister method from both arms and epidermal cells were used as stimulator cells in the mixed epidermal cell lymphocyte reaction. Responses directed to epidermal cells derived from irradiated skin were expressed as percentages of responses directed to epidermal cells derived from the nonirradiated left arm. The mixed epidermal cell lymphocyte reaction responses in the control group were found to be significantly increased (205%). This enhancement of the mixed epidermal cell lymphocyte reaction responses was associated with an influx of @entity4210 +DR+ macrophages in the irradiated skin. Application of the sunscreen, either onto a piece of quartz or directly onto the skin, prevented the increase of the mixed epidermal cell lymphocyte reaction responses and the influx of @entity4210 +DR+ cells. In an earlier study, volunteers were exposed three times weekly to suberythemagenic doses of ultraviolet B over 4 wk, resulting in mixed epidermal cell lymphocyte reaction responses that were decreased to 20%. The same sunscreen was not able to prevent this suppression. These contradicting results indicate that the protective effect of sunscreens with respect to ultraviolet-induced immunomodulation is critically dependent on the choice of ultraviolet treatment.

Differential effects of sunscreens on UVB-induced immunomodulation in XXXX .

@entity1 :: ('9606', 'Species') :: ['humans'] @entity4210 :: ('948', 'Gene') :: ['CD36'] @entity33441 :: ('CHEBI:30818', 'Chemical') :: ['cis-urocanic acid'] @entity33442 :: ('CHEBI:30817', 'Chemical') :: ['trans-urocanic acid']
@entity1 :: (9606,Species) :: ['humans']
