Identification of autoantigens in psoriatic plaques using expression cloning

To search for autoantigens in psoriatic plaques, we screened cDNA libraries of plaque epidermis with psoriatic serum samples. This approach has been highly successful in identifying tumor antigens, but has not been widely applied to autoimmune disease. We identified 11 autoantigens including three with prominent reactivity and plausible disease relevance. These are keratin 13 (K13), heterogeneous nuclear ribonucleoprotein-A1 (hnRNP-A1), and a previously uncharacterized protein, FLJ00294. Serum antibody screening for these demonstrated reactivity in 40%, 38%, and 27% of psoriasis patients, respectively. Most positive samples reacted with all three, and we found that this was due to cross-reactivity among them. Enzyme-linked immunospot assay (ELISPOT) analysis of psoriatic peripheral blood T cells confirmed that these autoantigens are also recognized by T cells. This demonstrates that this is a feasible method to identify autoantigens in an autoimmune target tissue, and suggests that these antigens warrant further study in psoriasis. Furthermore, but peripheral blood of normal controls reacted to these autoantigens with essentially the same frequencies as patients, suggesting that psoriatics may have not only an immune system which is capable of reacting to certain autoantigens, but also to a skin immunoregulatory alteration which allows this normal reactivity to develop into abnormal inflammation.     

Bacteriology of psoriatic plaques

Qualitative and quantitative studies of cutaneous bacterial flora were carried out in psoriatic patients and normal healthy controls. In psoriatics, the flora isolated from the affected skin was compared with the flora of adjacent normal skin. No significant qualitative difference was observed. The total number of bacteria isolated from the psoriatic plaque was significantly higher than on the adjacent normal skin. Flora of normal skin of psoriatics when compared with the skin of healthy controls did not reveal any qualitative difference, but a statistically significant difference was observed in the total bacterial counts. The nasal carriage rate of Staphylococcus aureus in psoriatics was higher than the control groups.     

5—羟色胺在银屑病患者皮损中的表达

目的：探讨5—羟色胺在银屑病发病机制中的作用。方法：用免疫组化SP法检测银屑病患者皮损中5—羟色胺(5—HT)的表达。结果：进行期银屑病患者皮损处棘细胞，汗腺腺细胞，皮脂腺细胞，毛囊壁细胞浆中5—HT表达呈中等以上阳性，静止期减弱。寻常型和脓疱型无明显差异，正常人皮肤为阴性。结论：5—HT可能有促进角质形成细胞过度增殖的作用，从而参与银屑病的发病。     

Multiple lentigines confined to psoriatic plaques

The development of naevus spilus-like hyperpigmentation at sites of resolving plaques of psoriasis has been reported previously.^1–4 Although the mechanism is not understood, PUVA therapy has been implicated in most cases. We report an additional case in which lentigines, confined to sites of resolving psoriasis, occurred following oral PUVA. We also describe similar clinical features in two patients who had not received PUVA, which strengthens the observation that this treatment is not a prerequisite for development of this unusual pattern of pigmentation.     

Cyclosporin A suppresses ICAM-1 expression by papillary endothelium in healing psoriatic plaques.

To analyze the mode of action of Cyclosporin A (CsA) in psoriasis, we examined the phenotypic profile of resident and passenger skin cells in seven psoriatic patients before and after 2 weeks of CsA treatment using a large panel of monoclonal antibodies in a three-step immunoperoxidase technique. For comparison, skin biopsies from psoriatic patients receiving psoralen + UVA (PUVA) therapy were examined. Although both treatment protocols were equally effective in inducing resolution of psoriatic lesions, the phenotypic changes induced by CsA differed greatly from those seen after PUVA. In CsA-treated patients there was a dramatic reduction in the ICAM-1 expression by papillary endothelial cells, but density, pattern, and phenotype of infiltrating inflammatory cells remained essentially unchanged. In contrast, PUVA therapy had no visible effect on ICAM-1 expression by papillary endothelial cells, but resulted in a significant reduction of the hemopoietic resident and infiltrating mononuclear cells within the epidermis. These results favor, but do not prove, the assumption that the CsA regimen chosen in this study exerts its anti-psoriatic effect primarily at the level of the keratinocyte, i.e., by inhibiting events leading to keratinocyte proliferation as well as by interfering with the secretion of mediators responsible for ICAM-1 expression by papillary endothelial cells.     

Localization of Peutz-Jeghers macules to psoriatic plaques

We report a case of the Peutz-Jeghers syndrome in which the characteristic pigmented macules developed within preexisting psoriatic plaques in sites extremely unusual for the syndrome. To our knowledge, ours is the first report of such a case in the English literature.     

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.     

Increased C5a anaphylatoxin in the sera of psoriatic patients and patients with inflammatory dermatoses

We measured C5a and C5a des arg (collectively called C5a) by radioimmunoassay in the sera of psoriasis and other widespread inflammatory dermatoses. Larger amounts of serum C5a were detected in patients with psoriasis and other inflammatory dermatoses than in normal healthy controls. In the psoriatic patients, the serum C5a concentrations did not correlate with extent or with activity of the skin lesions. However, when followed in 6 psoriatic patients, the C5a levels showed changes in parallel with the skin lesions. Our results suggest that complement activation with resultant release of C5a anaphylatoxin takes place in psoriasis as well as in other widespread inflammatory skin disorders.     

Control of cutaneous blood vessels in psoriatic plaques.

The aim of this study was to compare local blood flow in psoriatic plaques before and after provocations known to alter cutaneous vascular resistance, in order to determine whether plaque hyperemia is caused by a failure of normal vascular control mechanisms. Cutaneous blood flow was recorded using a laser Doppler flowmeter over plaque skin (plaque site) and clinically normal skin (nonplaque site) on the opposite arm, at least 5 cm away from the nearest plaque. It is important to note that most of the laser Doppler signal comes from the subpapillary plexus of the skin and only a small portion (2%-10%) is produced by capillary blood flow. In the psoriatic plaques the basal flux was between nine and 13 times greater than nonplaque skin. The biologic zero (a signal independent of perfusion, which also persists after complete proximal arterial occlusion) was also significantly greater at plaque sites compared with nonplaque sites. Sympathetic and local vasoconstriction in psoriatic skin was shown to be intact and responses to vasodilator tests were likewise intact, i.e., there was no failure of response to normal vascular control mechanisms, albeit some quantitative differences. Tests of vasodilatation indicated that, although basal flux is high in plaque compared with nonplaque skin, arterioles supplying plaque skin can dilate further, i.e., lesional arterioles are not normally maximally dilated but have a basal constrictor tone. Interestingly, the red cell flux at maximum dilatation in nonplaque skin is less than even the basal flux in plaque skin. This means that in plaque skin either there are more arterioles than in nonplaque skin, or there is chronic, structural widening of the existing arterioles in plaque skin.     

Methotrexate toxicity presenting as ulcerated psoriatic plaques

Methotrexate toxicity is known to cause erosions of existing psoriatic plaques, although rare. We describe two patients who developed painful ulcerated psoriatic plaques as an early presenting sign of methotrexate toxicity and review the risk factors associated with this manifestation.     

Clinical and immunohistochemical evaluation of psoriatic plaques treated with topical 5-aminolaevulinic acid photodynamic therapy

BACKGROUND/PURPOSE: The aims of this study were to investigate the clinical and immunohistochemical events of psoriatic plaques during photodynamic therapy (PDT) using topical application of 5-aminolaevulinic acid (ALA). METHODS: Twelve psoriatic patients were recruited for this study. Four of them dropped out because of pain during treatment. The effect of PDT was evaluated in the remaining eight. One plaque was selected in each patient and treated once weekly with PDT 10-30 J/cm(2) two to five times. It was evaluated by using the scale, erythema and induration (SEI) index (maximal score per patient=9). Pain during treatment was assessed by a visual analogue scale (VAS), ranging from 0 to 10. Skin biopsies were taken before treatment, after two treatments and after completion of treatment, and were evaluated by immunohistochemistry. RESULTS: Median SEI scores were significantly reduced from 7 (range 5-9) before to 1.5 (range 0-3) following treatment (P<0.0001). The median pain during PDT was 7. The number of vessels in the subpapillary dermis, identified by antibodies against Factor VIII and endoglin, increased during and/or after treatment in six of eight patients. Before treatment, the epidermal growth factor (EGF) receptor was displayed throughout the epidermis, keratin 16 suprabasally, involucrin from the stratum granulosum to the lower spinous layers and filaggrin in stratum granulosum with focal absence. There was a moderate dermal infiltrate of CD4(+) cells and a sparse one of CD8(+). Following treatment, the EGF receptor was still displayed throughout the epidermis in seven of eight specimens. Cytokeratin 16 expression decreased markedly. Involucrin was not seen as deep in the spinous layers as before PDT. Filaggrin was expressed throughout the stratum granulosum and often weakly in the upper stratum spinosum. The number of CD4(+) and CD8(+) dermal cells decreased. CONCLUSION: PDT improved psoriasis and induced dermal neovascularization. Although a good clinical response was seen in most of our patients, the high frequency of discomfort during treatment limits the usefulness of ALA-PDT for psoriasis. The mechanism of the neovascularization is unknown. It may be owing to an indirect effect of PDT on the microvasculature and immune system or recovery phenomena.     

银屑病皮损表皮内Akt的激酶活性增强

目的 探讨Akt在银屑病发病中的意义。方法 免疫组化、免疫印迹法与活性测定的方法对30例寻常型银屑病患者（进行期皮损和非皮损表皮）和20例正常人表皮中Akt的表达与磷酸化水平及Akt的活性分别进行检测,免疫染色的强度进行光密度测定, 免疫印迹和激酶活性测定结果均采用灰度扫描,统计学处理采用方差分析和t检验。结果 免疫组化显示：正常表皮、银屑病皮损和非皮损表皮内Akt蛋白的表达水平差异无统计学意义（Fakt = 0.611,P > 0.05）;正常表皮与银屑病非皮损表皮内,磷酸化Akt的表达差异无统计学意义（Tp-akt = 0.624,P > 0.05）,与二者相比,银屑病皮损表皮内磷酸化Akt的表达明显增强（Fp-akt = 19.081,P < 0.01）。免疫印迹的结果（Takt = 1.378,P > 0.05,Tp-akt = 237.75,P < 0.01）与免疫组化一致。与正常表皮相比,银屑病皮损表皮内Akt的活性增强（Tp-akt = 138.441,P < 0.01）。结论 银屑病角质形成细胞的过速增殖可能与银屑病皮损表皮内Akt的活性增强有关。     

Increased expression of CD208 (DC-LAMP) in epidermal keratinocytes of psoriatic lesions

Psoriasis is a chronic inflammatory skin disease characterized by epidermal hyperproliferation and infiltration of inflammatory leukocytes. The aim of this study was to clarify the role of innate immunity involving dendritic cells (DC) and keratinocytes in psoriasis. We immunohistochemically examined the expression of DC markers such as CD1a, CD83, CD207 (Langerin), CD208 (DC-LAMP) and CD209 (DC-SIGN) in psoriatic skin and γ-interferon (IFN-γ)/12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated keratinocytes in vitro . CD208 was strongly expressed in basal and suprabasal layer keratinocytes in addition to DC in the perivascular lesions of the psoriatic dermis. Furthermore, the enhanced expression of CD208 in the perinuclear lesions of IFN-γ-/TPA-stimulated keratinocytes was observed in vitro . Because a defect of the granular layer in psoriatic lesions has been recognized, increased expression of lysosome-related CD208 in the basal and suprabasal keratinocytes of psoriatic lesions might represent aberrant epidermal differentiation. Additionally, these CD208-positive keratinocytes possessing putative antigen-processing activity might play a key role as antigen-presenting cells in psoriatic skin.