Abstract. Keratinocytes play an important role in the inflammatory response of the skin. UVB stimulates keratinocytes to secrete several cytokines. To our knowledge, there are no reports that have examined which layer or cell type is responsible for producing these cytokines. Thus, in this study we performed immunohistochemical experiments to determine the potential cells or layers that express interleukin (IL)-1 and IL-6. The results show that the expression of IL-1α and IL-6 was induced 3 and 6 h after irradiation, respectively. Furthermore, IL-1α was maximally expressed earlier than IL-6, suggesting that IL-1α exists in the cytokine cascade of the UVB response upstream of IL-6. In addition, IL-1α expression began in the upper layers of the epidermis, whereas all layers expressed IL-6. This study provides further insight into the roles of cytokines in UVB-induced skin inflammation.

The pulsed ruby laser has a selective thermolytic effect. Recently, it has been available for the treatment of superficial pigmented disorders. We studied 5 cases of epidermal nevus treated with the pulsed ruby laser. In comparison with the usual methods including electrocautery, cryotherapy and skin abrasion, ruby laser therapy is an excellent tool due to technological ease and rapid improvement. Depigmentation after treatment in 2 cases was the only side effect of this therapy. Bose cases had a dark pigmentation of the skin. Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.

Metallothionein (MT) has many functions that are modulated by several factors, including ultraviolet (UV) radiation and cytokines. We thought that these diverse functions of MT might reflect the specific regulatory mechanisms of its expression. To understand some of the molecular mechanisms underlying MT expression, we examined the effects of several cytokines and UVB on the promoter activity of the MT gene. First, we introduced the MT promoter construct into the HaCaT keratinocytes and treated them with various concentrations of interleukin-1α (IL-1α) and IL-6. The addition of IL-1α and IL-6 led to an increase in the promoter activity of the MT gene. UVB is known to induce MT expression in epidermal keratinocytes, and IL-6 is a possible mediator of MT induction by UV radiation. Therefore, we investigated whether UVB could induce MT promoter activity. Our results showed, interestingly, that UVB radiation has no or little effect on the promoter activity. This suggested a complex molecular regulation of the MT gene.