The prevalence rates of systemic lupus erythematosus (SLE) may vary within 17-48/100,000 population worldwide. Although population-based epidemiological studies are still missing, the cutaneous variants of lupus erythematosus (LE) are 2-3 times more frequent than SLE itself. The most common age of onset is 20-40 y. Overall, cutaneous LE is regarded as a variant with less severe course and better prognosis. However, CDLE and SCLE last for many years and may lead, like SLE, to severe disability for work and limited life quality; also, a small proportion of patients with cutaneous LE develops SLE during the course of their disease. This implies considerable amount of medical management and costs for the community. Early recognition of cutaneous LE patients at risk to develop SLE and preventive measures against disease triggering factors are important tasks for physicians attending with cutaneous LE patients. It seems that signs of nephropathy, elevated ANA-titers and arthralgias may serve as prognostic predictors for transition into SLE. Characteristic features of cutaneous LE are photosensitivity and female predominance. UV light is a major environmental triggering factor in cutaneous LE. Skin lesions may be induced or preexistent lesions may exacerbate due to UV light in up to 80-90% of all patients. Therefore, socioeconomic counseling of the young patients, for example choice of occupation and sun protection, are essentials in compliant patients. Also, since females are 3-6 times more frequently affected than males, the possibility of hormonal influences including pregnancy and estrogen-containing drugs should be discussed. Risk considerations for females wishing to become pregnant are required, and avoidance of estrogen-containing contraceptives should be recommended.
We investigated the antioxidative effect of L-ascorbic acid on lipid peroxidation and on secretion and mRNA expression of IL-1alpha and IL-6 after UVA irradiation (20 J/cm2) in cultured human keratinocytes. Lipid peroxidation was measured by (i) high performance liquid chromatography with UV detection of malondialdehyde (MDA) at 256 nm and (ii) spectrometric measurement of thiobarbituric acid-reactive substances (TBARS). To evaluate UV-induced cytotoxicity, we assessed cell membrane damage by measuring lactate dehydrogenase (LDH) release. UVA-induced lipid peroxidation in cultured human keratinocytes was inhibited by ascorbic acid in a concentration-dependent manner: MDA protein equivalent was reduced by 47% (10(-6)), compared to keratinocytes not exposed to L-ascorbic acid (p < 0.05), and the TBARS showed a concentration-dependent decrease of 49% (10(-6) M) in L-ascorbic acid-supplemented cultures compared to controls (p < 0.05). LDH release was decreased by 45% in L-ascorbic acid-supplemented keratinocyte cultures, indicating protection against cell death (p < 0.05). L-Ascorbic acid was able to downregulate IL-1alpha mRNA expression in both UVA-irradiated and nonirradiated cells; however, IL-6 mRNA expression remained unaffected. The secretion of these cytokines was reduced nearly to normal in the presence of L-ascorbic acid. These findings indicate a major cell-protective effect of L-ascorbic acid on UVA-induced lipid peroxidation and the secretion of pro-inflammatory cytokines by UVA-irradiated human keratinocytes.
An immunohistochemical analysis of skin biopsies was performed in 18 patients with cutaneous lupus erythematosus (LE), using the alkaline phosphatase and monoclonal anti-alkaline phosphatase method (APAAP). The study group was subdivided on the basis of clinical criteria into 10 patients with chronic discoid LE (CDLE) and eight patients with subacute cutaneous LE (SCLE). Using a panel of monoclonal antibodies the following results were obtained: (i) ICAM-1 was expressed on epidermal keratinocytes, dermal inflammatory cells, and endothelial cells in most biopsies, whereas LFA-1 was confined to the dermis. Attachments between keratinocytes or endothelial cells and activated T lymphocytes via ICAM-1/LFA-1 may be a possible mechanism of target/effector recognition in cutaneous LE. (ii) HLA-DR was expressed on epidermal keratinocytes and cells of the dermal infiltrate, but not on endothelial cells. HLA-DR+ cells probably function as antigen-presenting cells, leading to major histocompatibility complex-restricted cellular cytotoxicity in cutaneous LE. (iii) Interleukin 2 receptor expression on dermal inflammatory cells was weak, indicating non-specific activation of T lymphocytes. (iv) The dermal inflammatory cells were T lymphocytes, mainly of the helper/inducer subtype. B lymphocytes were rarely found in the dermis. In general, no significant immunohistochemical differences were found between CDLE and SCLE, suggesting that these variants represent clinical subtypes rather than different pathogenetic entities.
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