RNA, DNA, and cell surface characteristics of lesional and nonlesional psoriatic skin

We have measured the RNA and DNA content and examined cell surface characteristics of human epidermal cells derived from normal skin, and lesional and nonlesional areas of psoriatic skin prior to and following treatment on a modified Goeckerman protocol. Our results show that cells from active psoriatic lesions contain greater numbers of basal keratinocytes when compared with either nonlesional skin from the same patients or skin from healthy volunteers and individuals with other inflammatory skin lesions. Follow-up measurements 2-3 weeks after the initiation of therapy showed that the numbers of basal keratinocytes in resolving psoriatic lesions had decreased and approached normal levels. Multiparameter RNA/DNA flow cytometric analysis on parallel samples from the same psoriasis patients revealed an increased growth fraction and proportion of cycling cells in both the nonlesional and lesional skin compared with controls. Furthermore, the cellular RNA content was elevated in lesional psoriatic skin when compared with either nonlesional or normal skin. Flow cytometric examination of nonlesional and lesional epidermal cells obtained 2-3 weeks after the commencement of therapy revealed that the growth fraction and mean RNA content of the keratinocytes from resolving psoriatic plaques decreased in response to therapy. In contrast, the proportion of keratinocytes within the S + G2 + M phases of the cell cycle remained elevated. These data indicate that "uninvolved" psoriatic skin exhibits characteristics more closely resembling lesional psoriatic skin than normal skin. The results further suggest that quantitation of cellular RNA content and basal cell number might be sensitive indicators of early treatment response in psoriasis.     

寻常型银屑病皮损肥大细胞密度及IL-8表达的研究

目的：探讨肥大细胞和IL-8在寻常型银屑病中的作用。方法：采用免疫组化技术(SABC法)观察寻常型银屑病皮损处MC分布和IL-8在表皮中的表达情况。结果：寻常型银屑病皮损处MC密度明显高于皮肤血管炎组和健康对照组；寻常型银屑病皮损处KC中IL-8的表达明显高于两对照组。结论：结果提示MC和IL-8参与寻常型银屑病的致病过程，并且两者之间存在相关性。     

Mast cell density in psoriatic skin. The effect of PUVA and corticosteroid therapy

Summary Numbers and volume fractions of mast cells in nonlesional and chronic lesional skin of psoriatic patients were compared with those of normal control skin. Mast cell densities were similar in psoriatic nonlesional and normal control skin. The superficial dermis of lesional psoriatic skin contained more mast cells than either normal or nonlesional psoriatic skin. Neither PUVA nor corticosteroid treatment for 3–4 weeks significantly reduced mast cell numbers or volume fractions in lesional skin, although both treatments clinically and histologically markedly improved the lesions. The results indicate that the initiation of the healing process in psoriatic plaques is not correlated with the mast cell density. The remaining high mast cell density may be normalized later, or after a longer therapy.     

Increased expression of adhesion receptors in both lesional and non-lesional psoriatic skin

Adhesion receptors and their ligands play a vital role in the immune system. We studied the expression of different adhesion receptors, using single- and double-staining immunohistochemical techniques, in both lesional and non-lesional skin specimens from seven psoriasis patients and in skin biopsy specimens from eight normal healthy controls. Our results showed an overall increased expression of several adhesion receptors in both lesional and non-lesional psoriatic skin. We consistently found an increased expression in particular of ICAM-1 and E-selectin on endothelial cells, and ICAM-1 on T cells and Langerhans cells. In contrast, a weak expression of VCAM-1 was found on endothelial cells and mononuclear cells in lesional psoriatic skin specimens alone. Interestingly, LFA-1 was also expressed on Langerhans cells, with a greater frequency in skin from lesional than from non-lesional sites, but was never expressed in skin from normal healthy individuals. Furthermore, significantly increased numbers of Langerhans cells and T cells with a positive reactivity for MAb HECA-452 were found in both lesional and non-lesional psoriatic skin. We hypothesize that the enhanced expression of adhesion receptors on migrating immunocompetent cells and endothelial cells of psoriatic skin in general facilitates the increased influx of activated T lymphocytes and other immunocomponent cells into the skin, and thus underscores the generalized character of the disease.     

Merkel cell polyomavirus DNA detection in lesional and nonlesional skin from patients with Merkel cell carcinoma or other skin diseases

Summary Background A novel polyomavirus, the Merkel cell polyomavirus (MCPyV), has recently been identified in Merkel cell carcinoma (MCC). Objectives To investigate the specificity of this association through the detection, quantification and analysis of MCPyV DNA in lesional and nonlesional skin biopsies from patients with MCC or with other cutaneous diseases, as well as in normal skin from clinically healthy individuals. Methods DNA was extracted from lesional and nonlesional skin samples of patients with MCC or with other cutaneous diseases and from normal‐appearing skin of clinically healthy subjects. MCPyV DNA was detected by polymerase chain reaction (PCR) and quantified by real‐time PCR. Additionally, the T antigen coding region was sequenced in eight samples from seven patients. Results MCPyV DNA was detected in 14 of 18 (78%) patients with MCC, five of 18 (28%) patients with other skin diseases (P = 0·007) and one of six (17%) clinically healthy subjects. In patients with MCC, viral DNA was detected in nine of 11 (82%) tumours and in 10 of 14 (71%) nontumoral skin samples (P = 0·66). MCPyV DNA levels were higher in MCC tumours than in nontumoral skin from patients with MCC, and than in lesional or nonlesional skin from patients with other cutaneous disorders. Signature mutations in the T antigen gene were not identified in the two MCC tumour specimens analysed. Conclusions High prevalence and higher levels of MCPyV DNA in MCC supports a role for MCPyV in tumorigenesis. However, the high prevalence of MCPyV in the nontumoral skin and in subjects without MCC suggests that MCPyV is a ubiquitous virus.     

Increased lysophosphatidylcholine content in lesional psoriatic skin

Various cell stimuli occur via activation of phospholipase A₂, which hydrolyses polyunsaturated fatty acids from the sn-2 position of membrane phospholipids, resulting in the formation of polyunsaturated fatty acids and lysophospholipids. The level of lysophospholipids is determined by the balance between phospholipase A₂ activity and the rate of catabolism of the lysophospholipids. One of the lysophospholipid classes, lysophosphatidylcholine, has been shown to stimulate certain leucocyte activities which are of importance for the induction and maintenance of inflammation. In addition, it has been demonstrated that phospholipase A₂ activity is increased in psoriatic skin. In the present study, we analysed the levels of lysophosphatidylcholine, by thin layer chromatography, in lesional psoriatic skin, uninvolved psoriatic skin and normal skin. The lysophosphatidylcholine content, expressed as μmol lysophosphatidylcholine/μmol phosphatidylcholine, was 1.55, 0.21 and 0.12% in lesional psoriatic skin, uninvolved psoriatic skin and normal skin, respectively. The level of lysophosphatidylcholine was significantly elevated in lesional compared with uninvolved psoriatic skin (P= 0.004) and normal skin (P= 0.002). The increased lysophosphatidylcholine levels in psoriatic skin indicate that the phospholipase A₂ activation is not accompanied by a corresponding increase in the activity of enzymes catabolizing lysoPC. If present in biologically active concentrations, lysophosphatidylcholine may contribute to the induction and maintenance of the inflammatory and immunological processes occurring in lesional psoriatic skin.     

Transition from symptomless to lesional psoriatic skin

Numerous investigations have been carried out to describe the cellular biological changes in lesional and symptomless psoriatic ski. Although these studies have increased our knowledge of the pathogenesis of psoriasis, our insight into the relevance of the individual changes in the whole pathogenic process is still limited. Studies on the transition between symptomless and lesional skin are of importance in assessing the pathogenic relevance of the individual aspects. In this paper, the literature is reviewed with respect to the transitional changes; in particular, studies on changes at the margin of the psoriatic lesion and the response of the symptomless skin to standardized injury are reviewed. From the available studies it may be concluded that changes in the stroma (i.e. increased expression of tenascin and increased endothelial alkaline phosphatase activity) are early pathogenic features. The appearance of a predominantly lymphocytic infiltrate, in particular the extravasation of CD4+ T lymphocytes, and the suprabasal expression of keratin 16 are intermediary stages. Relatively late in the pathogenesis are increased recruitment of cycling epidermal nuclei, parakeratosis, decreased expression of filaggrin and premature expression of involucrin. In order to discover the pathogenic relevance of molecules which might have an impact on the development of psoriasis, sequential studies during transition from symptomless to lesional skin are worthwhile.     

脓疱性银屑病患者外周血IL-8水平及其在皮损中的表达

许多学者发现,IL-8与银屑病发病有密切关系,脓疱性银屑病皮损中有比寻常性银屑病皮损中更多的中性粒细胞浸润和IL-8持续升高.2004年7月至2006年2月,我们采用双抗体夹心法及免疫组化技术检测脓疱性银屑病、寻常性银屑病及正常人对照组外周血IL-8水平及皮损处IL-8的表达情况.     

银屑病皮损中IL—1受体拮抗物的蛋白和mRNA表达

采用抗人ＩＬ－１ｒａ单抗和地高辛标记的ＲＮＡ探针,在银屑病破损和正常人皮肤切片上进行ＡＰＡＡＰ染色和原位杂交,检测并比较ＩＬ－Ｉｒａ的蛋白表达和ｍＲＮＡ转录水平。结果发现,正常人皮肤中ＩＬ－１ｒａ蛋白染色阴性,ＩＬ－１ｒａｍＲＮＡｗ信号微弱;相比之下,银屑病皮损中ＩＬ－１ｒａ蛋白和ｍＲＮＡ的表达均异常增高,统计学比较相差显著。上述结果显示：ＩＬ－１ｒａ在银屑病皮损中增强表达,提示银屑病病理过程中Ｉ