Perforin and granzyme B may contribute to skin inflammation in atopic dermatitis and psoriasis

BACKGROUND: Infiltration of the skin by pathogenic T cells is regarded as a key factor in the development of inflammatory skin diseases such as atopic dermatitis (AD) and psoriasis. OBJECTIVES: To investigate whether T cells containing cytotoxic proteins may contribute to the generation of skin inflammation in these skin diseases. METHODS: Skin biopsy specimens were obtained from non-lesional and lesional skin of patients with chronic AD (n = 8) and psoriasis (n = 6), and from non-atopic controls with normal skin (n = 6). Expression of perforin and granzyme B was investigated by immunohistochemistry. RESULTS: A significant enhancement of perforin and granzyme B expression was observed in lesional AD skin as compared with normal skin, non-lesional AD skin and psoriasis. Expression of these cytotoxic proteins was also increased in psoriasis as compared with normal skin and non-lesional psoriatic skin. Immunoreactivity for perforin and granzyme B was mainly found in the cytoplasm of lymphocytic cells located in the perivascular infiltrate. In AD increased numbers of positive cells were also observed focally at sites of spongiosis in the epidermis. Double immunostaining revealed that both CD4+ and CD8+ T cells are capable of expressing perforin and granzyme B. CONCLUSIONS: Our data suggest that cytotoxic CD4+ and CD8+ T cells containing perforin and granzyme B may play an integral part in eliciting cutaneous inflammation in AD.     

Epidermal DR+T6- dendritic cells in inflammatory skin diseases

T lymphocyte and dendritic cell subpopulations were counted in three biopsies each of endogenous eczema and pityriasis rosea and two of lichen planus and compared with previous findings in psoriatic lesions. In common with psoriasis, proportionately more CD4 T cells than CD8 T cells were DR+ in both epidermis and dermis of all lesions. In addition, total numbers of epidermal dendritic cells were significantly increased in endogenous eczema and pityriasis rosea, and variably in lichen planus lesions. Interestingly, a DR+T6- subpopulation of dendritic cells was present in varying proportions in all three skin lesion types. Electron microscopy of DR+T6- dendritic cells from psoriatic lesions, using an immunogold staining technique, showed the cells to be of the Langerhans' cell lineage. DR+T6- dendritic cells are a subpopulation of Langerhans' cells which are not specific to psoriasis, but present in the lesions of other benign, inflammatory skin conditions in which CD4 T cells are preferentially activated.     

The development of manifest psoriatic lesions is linked with the invasion of CD8+ T cells and CD11c+ macrophages into the epidermis

Koebner response was studied in 35 psoriatic patients. Two punch biopsies per patient were taken from non-lesional psoriatic skin before, and 6 h, 2 days, 7 days, 14 days and 21 days after, tape stripping. Alterations in the numbers of CD1+ Langerhans cells, CD4+ and CD8+ T cells and CD11c+ macrophages were mapped morphometrically. Results were compared with lesional and non-lesional psoriatic skin, and control skin. Nine of 35 patients were Koebner-positive. No statistically significant differences were noted between non-lesional psoriatic and control skin. CD4+ T cells increased in number 2 days after trauma in both the epidermis and the dermis, whereas epidermal CD8+ T cells and CD11c+ macrophages increased only in the Koebner-positive lesional skin after 7 days. The changes in lesions induced by tapestripping resembled those seen in lesional psoriatic skin (mature plaques). The number of CD1+ cells increased in mature psoriatic lesions only. It seems possible that trauma per se stimulates the accumulation of CD4+ T cells at the site of injury, but the development of manifest psoriatic lesions correlates with invasion of CD8+ T cells and CD11c+ macrophages into the epidermis.     

银屑病患者皮损中转化生长因子-β1及受体基因表达的研究

目的 研究银屑病患者皮损及非皮损处转化生长因子-β1(TGF-β1)、转化生长因子β受体(TGF-βRⅡ)及CD105的基因(mRNA)表达,并初步探讨其临床意义。方法 采用异硫氰酸胍法抽提皮肤组织中的RNA;采用逆转录聚合酶链反应(RT-PCR)检测皮肤组织中mRNA的表达。结果 银屑病患者皮损组织TGF-β1及TGF-βRⅡmRNA的表达均低于非皮损组织及正常人(P<0.05);非皮损组织及正常人皮肤组织中mRNA的表达量差异无显著性(P>0.05)。而银屑病皮损组织CD105的mRNA表达量高于非皮损组及正常人(P<0.05);非皮损组织和正常人皮肤组织比较P>0.05。结论 银屑病皮损中TGF-β1及TGF-βRⅡ表达降低和CD105的表达上调可能与银屑病的表皮过度增殖及真皮炎症细胞浸润有关。     

Expression of nerve growth factor receptors in cutaneous inflammation

Evidence indicates that the neurotrophin nerve growth factor (NGF) is a mediator of cutaneous inflammatory responses. Cellular responses to NGF are facilitated by two receptors called trk A and p75 neurotrophin receptor (p75^NTR). In the current study we have investigated the expression of these receptors in lesional and non-lesional skin from patients with plaque psoriasis and in normal skin exposed to three times the minimal erythema dose of ultraviolet (UV) B radiation. Trk A immunostaining was confined to the basal keratinocytes in normal skin. There was a significant reduction in trk A immunostaining in both non-lesional and lesional psoriatic skin compared with control skin. In UVB-irradiated normal skin, there was a significant reduction in trk A immunostaining at 4 h after irradiation, which was still evident at 48 h. In normal skin, p75^NTR immunopositive fine nerve fibres were present throughout the dermis and occasionally seen in the epidermis. Thick nerve fibres were evident in the deep dermis and in the middle region of the dermis. p75^NTR immunopositive basal keratinocytes were occasionally seen. There was a statistically significant loss of p75^NTR immunopositive fine nerve fibres in the epidermis of lesional psoriatic skin and a statistically significant loss of p75^NTR immunopositive fine nerve fibres in the dermis in both non-lesional and lesional psoriatic skin. p75^NTR immunopositive thick nerve fibres were reduced in lesional psoriatic skin compared with normal skin. UVB irradiation of normal skin led to a statistically significant decrease in the p75^NTR immunopositive fine nerve fibres in the epidermis at 48 h after irradiation. There was no significant reduction in the dermal p75^NTR immunoreactivity. These results demonstrated that expression of both NGF receptors is decreased following an acute inflammatory stimulus and also in association with a chronic inflammatory dermatosis.     

Immunofluorescence localization of nuclear retinoid receptors in psoriasis versus normal human skin

Psoriasis responds favourably to treatment with retinoids but the cellular pathways mediating these effects are poorly understood. Retinoids regulate keratinocyte proliferation and maturation via binding to nuclear retinoic acid receptors (mainly RARalpha and RARgamma) which form heterodimers with the 9-cis-RA receptor, RXRalpha. We have previously shown that mRNA expression of RARalpha and RXRalpha is down-regulated in psoriatic lesions as compared with non-lesional human skin. In the present study, we investigated the protein expression of RARalpha, RARgamma and RXRalpha in normal and psoriatic skin using indirect immunofluorescence analysis. Epidermal keratinocytes of normal and non-lesional psoriatic skin displayed similar nuclear localization of all three receptors; RARalpha was detected with decreasing intensity from basal to suprabasal layers, RARgamma showed the opposite trend, whereas RXRalpha was evenly expressed throughout the epidermis. In lesional psoriatic skin, however, all three receptor proteins showed a much higher staining intensity in the lower half of the epidermis; in particular, RARalpha immunoreactivity was low or even absent in the upper layers of epidermis. The results support the idea that psoriasis is associated with abnormal retinoid signalling in lesional epidermis.     

Intraepidermal lymphocytes in psoriatic lesions are activated GMP-17(TIA-1)+CD8+CD3+ CTLs as determined by phenotypic analysis

The onset and persistence of psoriatic lesions are linked to the presence of an inflammatory infiltrate of CD3+ lymphocytes that includes CD4+ and CD8+ subsets. Since a primary susceptibility factor for psoriasis is the Class I HLA-Cw6 molecule, we set out to learn more about the features of the epidermal CD8+ lymphocytes. The markers tested were GMP-17, a cytotoxic granule protein found in activated cytotoxic lymphocytes (CTLs), and the alpha chain of the IL-2 receptor (CD25), a plasma membrane molecule found on activated T cells. Lymphocytes in lesional skin expressed the GMP-17 protein, whereas lymphocytes in non-lesional skin, resolving lesional skin and normal skin had little or no GMP-17. By flow cytometry analysis, lesional epidermal GMP-17+ cells were CD8+CD3+, with a subpopulation expressing the activation marker CD25+. Due to the abundance of activated GMP-17+CD8+CD3+ lymphocytes (the phenotype of activated cytotoxic cells) in psoriatic lesions compared to non-lesional and normal skin, we hypothesize that they are contributing directly to the psoriatic phenotype.     

Epidermal Langerhans cells, HIV-1 infection and psoriasis

Summary Langerhans cells (LCs) subserve an important antigen-presenting function in the skin immune system. They bear CD4 receptors, which make them potential targets for infection with the human immunodeficiency virus (HIV-1).
The observation of reduced numbers of LCs in the skin of patients with the acquired immunodeficiency syndrome (AIDS), and the association of severe psoriasis with HIV-1 infection, raise interesting questions regarding the role of LCs in the skin of HIV-1-positive psoriatic patients.
In this study, LCs were quantified in the lesional and non-lesional skin of seven HIV-1-positive psoriatic patients, and the results were compared with age-, sex- and site-matched HIV-1-negative psoriatic patients. The number of LCs was determined by staining skin sections with S-100 polyclonal antibody, using the three-step avidin—biotin immunoperoxidase method. The S-100-positive cells above the basal layer were quantified in two ways: cells/mm² of epidermal area, and cells/mm of length of basement membrane.
HIV-1-positive psoriatic patients showed a reduction in the number of epidermal LCs compared with HIV-1-negative psoriatic patients using both methods of quantification, in both lesional and non- lesional skin (P <0·05, Mann-Whitney test). In addition, a reduction in the number of LCs in lesional compared with non-lesional skin was observed in both HIV-1-positive and -negative patients when LCs were quantified per mm² of epidermal area (P<0·05, Wilcoxon test). This reduction was also observed when LCs were quantified per mm length of basement membrane, but the reduction was not statistically significant in the control group of HIV-1-negative psoriatic patients. Our findings of a reduced number of LCs in the epidermis of HIV-1 -positive psoriatic patients may be associated with the clinical deterioration of psoriasis in these patients.     

CD69+T细胞在银屑病皮损中的表达及其临床意义

目的 探讨银屑病患者皮肤CD69+T细胞的表达及其与疾病活动性的关系.方法 免疫组化检测31例银屑病患者皮损和非皮损中CD69+T细胞在皮肤中的表达,与6例健康人进行对照.结果 CD69+T细胞主要分布于皮肤真皮.31例银屑病患者皮损和非皮损的真皮中,CD69+T细胞分别为(35.16±12.67)％和(8.70±3.29)％,皮损明显高于非皮损(t=12.5,P＜0.01).6例健康人对照皮肤中CD69+T细胞(8.71±2.55)％,明显低于银屑病皮损(t=5.03,P＜ 0.01),与非皮损相比,差异无统计学意义(t=0.05,P＞ 0.05).20例急性期与1 1例稳定期银屑病患者皮损中CD69+T细胞分别为(40.89±10.31)％和(24.46±9.49)％,急性期明显高于稳定期(t=0.36,P＜ 0.01).结论 银屑病患者皮损中CD69+T细胞表达增高,与疾病的活动性有关.     

Expression of the T-cell activation antigens CD27 and CD28 in normal and psoriatic skin

Activated T lymphocytes are thought to be involved in the pathogenesis of psoriasis. From studies with peripheral blood T lymphocytes it is known that T cells show a decrease in membrane expression of CD27 molecules during continuous antigenic stimulation. The T-cell activation molecule CD28 is thought to be involved in the transduction of an antigen-non-specific costimulatory signal. Therefore, in order to elucidate further the pathogenesis of psoriasis we studied the expression of CD27 and CD28, together with CD4, CD8 and CD45RA in this benign inflammatory dermatological disease. We used immunohistochemical techniques to determine absolute numbers of T lymphocytes and expression of these T-cell activation and T-subset-specific molecules in normal (n= 7), uninvolved perilesional (n= 7) and lesional psoriatic (n= 7) skin. We found that not only lesional but also clinically uninvolved perilesional skin showed an increased number of T cells. Further, immunohistochemical studies showed that CD27 is expressed by a minority of normal skin T cells, while in lesional psoriatic skin, expression was even lower, and almost absent in perilesional skin sections. In contrast to normal skin, both perilesional and lesional psoriatic skin contained no CD28 positive T cells. In lesional psoriatic skin, however, T cells showed predominantly the CD4 phenotype, while in perilesional skin CDS positive T cells were dominant. Two conclusions were reached: first, the absolute number of T cells, their CD27, CD28 and CD45RA expression, and the influx of CD8 positive T cells, indicate that perilesional psoriatic skin is different from normal and lesional psoriatic skin; and secondly, the data on CD27 and CD28 suggest that not only lesional but also perilesional psoriatic skin is subject to continuous antigenic stimulation, thus leading to decreased CD27 and CD28 expression on skin T cells.     

Expression of integrin subunits and CD44 isoforms in psoriatic skin and effects of topical calcitriol application

Increasing evidence suggests involvement of integrins and CD44 isoforms in the pathogenesis of psoriasis, contributing to uncontrolled keratinocyte proliferation, neovascularization, and invasion of inflammatory cells. We have analyzed immunohistochemically in situ expression of integrins (CD29, CDw49b, CDw49c, CDw49e, CDw49f) and CD44 isoforms (CD44 standard, CD44 var/v6, CD44 v10) on frozen sections of normal and psoriatic skin (nonlesional skin, lesional skin before and along with topical calcitriol treatment). We did not observe visual changes of immunoreactivity in normal as compared to nonlesional psoriatic skin, while the staining pattern of CDw49c, CDw49f, and CD29 was severely altered in untreated lesional psoriatic skin. Most markedly, CDw49c, CDw49f, and CD29 were focally upregulated in suprapapillar epidermal compartments of lesional psoriatic skin, a staining pattern that is in accordance with the phenomenon that was described by Pinkus as 'squirting papilla'. Additionally, an increased proportion of inflammatory and endothelial cells revealed immunoreactivity for CD44(std.) in untreated lesional psoriatic as compared to nonlesional psoriatic or normal skin. After 8 weeks of topical calcitriol treatment (15 μg/g ointment), the staining pattern for CDw49c, CDw49f and CD29 was markedly changed in epidermis of lesional psoriatic skin, reverting to the staining pattern characteristic for the nonlesional psoriatic or normal human skin, although epidermal expression of CDw49f was still upregulated and CDw49e-, CDw49f-, CD29-, and CD44(std.)- immunoreactive inflammatory and endothelial cells were still to be found in the dermal compartment.     

Reticulate hyperpigmentation distributed in a zosteriform fashion: a new clinical type of hyperpigmentation

Sequential skin biopsies from six patients with severe psoriasis were studied during treatment with cyclosporin. Four of the patients cleared completely and the remaining two showed a marked improvement. A subset of dendritic cells, HLA-DR+ but lacking the T6 antigen characteristically expressed by Langerhans cells (DR+ 6-), was observed in lesional epidermis. They disappeared during treatment, before clinical improvement was apparent and at a rate which correlated with clearance of psoriasis. These cells were not found in normal or uninvolved psoriatic epidermis and their number in lesional skin appeared to be related to the clinical severity of the disease. Total numbers of CD4 and CD8, and HLA-DR+ CD8 T cells were substantially reduced in both epidermis and dermis prior to clinical improvement. In contrast, there was generally no decrease in the number of HLA-DR+ CD4 T cells in the epidermis during resolution, whereas these cells were reduced by an average of 68% in the dermis. The beneficial effects of cyclosporin in psoriasis further support the hypothesis that T cells play a central role in the pathogenesis of psoriasis. The cellular changes observed in the skin during cyclosporin treatment may help to elucidate the effects of this drug on immunoregulatory mechanisms in man.     

银屑病患者表皮及真皮中Bcl-X、Bcl-2、Bax表达的免疫组化研究

目的 探讨银屑病患者细胞增殖与凋亡的调节。方法 用免疫组化ＳＰ法检测银屑病皮损及非皮损中Ｂｃｌ－Ｘ、Ｂｃｌ－２、Ｂａｘ的表达情况。结果 银屑病皮损中,Ｂｃｌ－Ｘ在表皮各层、真皮炎症细胞及血管内皮的表达均较正常明显增高;Ｂａｘ在颗粒层与棘层的表达轻度增高。上述异常在非皮损中已经部分存在,且隍未完全恢复正常。而Ｂｃｌ－２表达与正常相似,局限于基底层黑素细胞,角质形成细胞未是性。结论 银屑病中角质形成细     

CD103+T细胞在银屑病皮损中的表达

目的：明确银屑病患者皮肤CD103+T细胞的表达及其与银屑病严重程度的关系。方法：免疫组化检测29例银屑病患者皮损和非皮损皮肤及6名健康对照皮肤中表皮及真皮CD103+T细胞的表达。计算银屑病患者PASI值。结果：CD103+T细胞主要在真皮表达。银屑病患者皮损和非皮损真皮中每个高倍视野CD103+T细胞百分率分别为（26.06%±11.72）%和（12.82±4.5）%（P<0.05）;健康人对照皮肤真皮内CD103+T细胞百分率为（7.47±1.3）%,明显低于银屑病非皮损区（P<0.05）。银屑病患者皮损中,CD103+T的表达与PASI值正相关（P<0.05）。 结论：真皮中CD103+T细胞可能与银屑病的发病及严重程度有关。     

K16 expression in uninvolved psoriatic skin: a possible marker of pre-clinical psoriasis

BACKGROUND: K16, a type I keratin, is upregulated in hyperproliferative states including psoriasis. It has been used as a marker of psoriasis and its expression is upregulated in relapsing psoriasis and downregulating in resolving. We evaluated non-lesional psoriatic skin for K16 expression. METHODS: Sixty-seven non-lesional and lesional skin samples from patients with psoriasis and normal skin from 19 non-psoriatic patients were studied by immunohistochemistry on frozen sections with K16. RESULTS: Seventeen of 19 normal skin samples showed staining of basal cells in the deeper part of the rete ridges. Sixty-two non-lesional psoriatic skin samples showed intense basal staining of K16. Of the remaining five non-lesional samples, diffuse intense suprabasal staining in one, pan-epidermal staining in two, and no staining was seen in two samples. Suprabasal (37), diffuse (14), sandwich (12), and basal (3) pattern staining were seen in psoriatic skin. One psoriatic skin sample did not show any expression. CONCLUSION: Our results demonstrate that K16 expression is also observed in non-lesional psoriatic skin and may serve as a marker of preclinical psoriasis.     

The development of manifest psoriatic lesions is linked with the appearance of ICAM-1 positivity on keratinocytes

The development of psoriatic lesions was studied in 36 psoriatic patients using the Koebner reaction induced by tape stripping. Two biopsies per patient were taken from non-lesional psoriatic skin before, and 6 h, 2 days, 7 days, 14 days and 21 days after tape stripping. Alterations in HLA-DR, ICAM-1, Ki-67 and FXIIIa positivities in both the dermis and the epidermis were estimated using immunohistochemical methods. A double staining for CD4⁺ and CD8⁺ T cells was also carried out to show their possible Ki-67 positivity. Results were compared with those from lesional (mature plaque) and non-lesional psoriatic skin, and control skin. Of the 36 patients, 9 were Koebner-positive. The most important finding in Koebner-positive psoriatic skin was the appearance of ICAM-1 positivity on epidermal keratinocytes simultaneously with the clinically observed lesion on day 7. The number of FXIIIa⁺ dendrocytes in the dermis was quite constant, and increased in mature psoriatic lesions only. The number of active HLA-DR⁺ immunocompetent cells increased in developing psoriatic lesions, being highest in mature lesions, but no Ki-67 positivity was detected in epidermal or dermal T cells in the psoriatic specimens. Based on these results, it is concluded that T cells divide and are activated extracutaneously in psoriasis, and also that ICAM-1/LFA-1 interactions are important in the recruitment of inflammatory cells and in controlling the effector cell functions.     

Alterations of glucosylceramide-beta-glucosidase levels in the skin of patients with psoriasis vulgaris

Hydrolysis of glucosylceramides by the enzyme glucosylceramide-beta-glucosidase (GlcCer'ase) results in ceramide, a critical component of the intercellular lamellae that mediates the epidermal permeability barrier. A disturbance of ceramide formation is supposed to influence the transepidermal water loss in common skin diseases like atopic eczema or psoriasis. The aim of this study was to investigate whether GlcCer'ase levels were altered in the skin of subjects with psoriasis vulgaris. Skin punch biopsies were taken from lesional and non-lesional psoriatic skin and GlcCer'ase was evaluated both at the RNA and at the protein level. Normal skin from surgical patients provided the baseline GlcCer'ase expression in healthy subjects. Our results show that GlcCer'ase mRNA expression was decreased in psoriatic non-lesional skin compared to normal controls in all cases. Interestingly, in lesional psoriatic skin the level of GlcCer'ase was increased compared to non-lesional skin in all cases. For the immunohistochemical analysis, we used a newly synthesized monoclonal antibody anti-human GBC (GlcCer'ase-GST fusion protein). The results confirmed that GlcCer'ase, mainly present in the upper epidermis, was decreased in psoriatic skin compared to normal control and was increased in lesional compared to non-lesional psoriatic skin. Our findings support the concept that alteration in water permeability barrier in lesional psoriatic skin can serve as a trigger for the upregulation of the expression of enzymes like GlcCer'ase with consequent stimulation of ceramide generation.     

早幼粒细胞白血病基因及其蛋白在银屑病表皮中的表达

目的探讨早幼粒细胞白血病(PML)基因及其蛋白在银屑病发病中的作用机制。方法用原位杂交和免疫组化方法检测正常组织、进行期银屑病皮损及非皮损区PMLmRNA和蛋白表达。结果在正常人皮肤组织中,PMLmRNA和蛋白不表达(阴性);在非皮损区,PMLmRNA和蛋白在基底层和基底上层细胞核内低表达(52%,36%);在银屑病皮损周边PMLmRNA和蛋白在基底层和基底上层细胞核内呈灶状表达(72%,64%);在银屑病皮损中心表皮中,PMLmRNA和蛋白高表达(96%,88%)。结论PML基因和其蛋白在银屑病表皮中的过表达提示,PML基因可能与银屑病表皮细胞的过度增殖相关。     

Interleukin-8 immunoreactivity in the skin of healthy subjects and patients with palmoplantar pustulosis and psoriasis.

Previous studies have shown that neutrophil-activating peptide 1/interleukin-8 (IL-8) is present in psoriatic scales and to a lesser extent in normal human epidermis. A panel of monoclonal antibodies and polyclonal antisera raised against IL-8 was used to localize IL-8 with immunoperoxidase techniques in non-lesional and lesional skin of patients with psoriasis and palmo-plantar pustulosis (PPP), and in corresponding sites from healthy subjects. Intracellular IL-8 immunoreactivity was found in all epidermal cell layers in biopsies of healthy subjects and in non-lesional and lesional skin in both PPP and psoriasis. The most intense immunolabeling was regularly found in the basal cell layer. Intercellular epidermal IL-8 immunolabeling was regularly detected in lesional biopsies in PPP and psoriasis, but not in healthy subjects or non-lesional skin in PPP and psoriasis. No intercellular immunolabeling was detected after successful treatment of lesional skin. The majority of cells along the eccrine sweat glands, dermal mononuclear cell infiltrates, and endothelial cells were IL-8 immunoreactive in all biopsies studied. The present study suggests that IL-8, its precursor form, or, alternatively, a degradation product is present in normal human epidermis.