CC chemokine receptor 4 expression on peripheral blood CD4+ T cells reflects disease activity of atopic dermatitis

Recent studies indicate that Th1 and Th2 cells differ in their chemokine receptor expression and their responsiveness to various chemokines. Therefore, selective Th2 cell recruitment in Th2-predominant inflammatory diseases such as atopic dermatitis may be under the influence of some chemokines. It is reported that CC chemokine receptor (CCR) 4 is selectively expressed on Th2 cells whereas CXC chemokine receptor (CXCR) 3 is selectively expressed on Th1 cells. In this study we examined CCR4 and CXCR3 expression on peripheral blood CD4+ and CD8+ T cells obtained from adult atopic dermatitis subjects, and compared the results with those from patients with psoriasis vulgaris and healthy controls. CCR4 was preferentially expressed on CD4+ T cells from atopic dermatitis subjects and CXCR3 was preferentially expressed on CD4+ T cells from psoriasis vulgaris subjects. This CCR4 expression was prominent especially in severe atopic dermatitis subjects. CCR4 expression on CD4+ T cells in severe atopic dermatitis subjects decreased on improvement of disease activity. CD25 was preferentially expressed on CCR4+CD4+ T cells but not on CXCR3+CD4+ T cells in atopic dermatitis subjects. Cutaneous lymphocyte-associated antigen was also preferentially expressed on CCR4+CD4+ T cells but not on CXCR3+CD4+ T cells in atopic dermatitis subjects. CD4+ T cells in atopic dermatitis skin lesions were predominantly CCR4+ cells. Taken together, this study strongly indicates that CCR4+CD4+ T cells reflect disease activity and suggests that CCR4 expression is important for T cell infiltration into atopic dermatitis lesions. Thus, CCR4 may be a possible target for therapy of atopic dermatitis in the future.     

Phenotypic Differences between Human Blood Monocyte Subpopulations in Psoriasis and Atopic Dermatitis

Peripheral blood monocytes seem to be of importance in the initiation and maintenance of cutaneous inflammatory disorders such as psoriasis and atopic dermatitis. Functional abnormalities of monocytes have been observed in both diseases. We sought to determine whether these abnormalities are reflected by an altered phenotypic expression of functionally active surface molecules. Peripheral blood monocyte subsets varying in cellular density and cell size from patients with psoriasis and atopic dermatitis were investigated using FACS analysis employing a panel of monoclonal antibodies (CD14, CD16, HLA-DR, HLA-DQ, Fc?RII, IL-2R, ICAM-1, CR3). Furthermore, the modulation of expression by interferon-γ in monocyte subsets from patients was compared to normal controls. The results show that HLA-DR and -DQ expression on monocyte subsets in psoriatic patients was significantly decreased; “large” monocytes expressed significantly less HLA-DR than “small” monocyte subpopulations. Decreased HLA-DR and -DQ expression could be upregulated by incubation of psoriatic monocytes with IFNγ. In atopic dermatitis, a different phenotype pattern of monocyte subsets was demonstrated: HLA-DR expression and HLA-DQ expression were both decreased in both “large” and “small” monocytes as compared to normal controls. However, there were no significant differences in HLA-DR and HLA-DQ expression between “large” and “small” monocyte subpopulations in atopic dermatitis. Moreover, the ICAM-1 and IL-2R expression of “large” and “small” monocyte subpopulations was significantly decreased in atopic patients from levels in normal controls and psoriatic patients. The altered expression of HLA-DR, -DQ, ICAM-1 and IL-2R could be upregulated by incubation of atopic monocytes with IFNγ. In addition, there was a significant increase in the percentage of monocytes in the differential count of patients with psoriasis or atopic dermatitis. We conclude that the differential phenotype pattern of surface molecules on monocytes in psoriasis and atopic dermatitis may reflect an abnormal monocyte maturation/differentiation state. This may explain the functional abnormalities of monocytes observed in patients with psoriasis and atopic dermatitis.     

A Th2 chemokine, TARC, produced by keratinocytes may recruit CLA+CCR4+ lymphocytes into lesional atopic dermatitis skin

Atopic dermatitis is an inflammatory skin disease in which the inflammation is characterized by the influx of lymphocytes into the dermis. It is generally believed that atopic dermatitis is a Th2-type disease, i.e., the T lymphocytes produce interleukin-4, interleukin-5, interleukin-10, and interleukin-13, although it has become evident in recent years that the cytokine profile in the skin changes during the course of the disease towards a Th1-Th2 mixed cytokine profile (interferon-gamma, tumor necrosis factor alpha, and interleukin-2). The lymphocytes that home into the skin express cutaneous lymphocyte-associated antigen, and it has recently been shown that most of the lymphocytes in this population express the chemokine receptor CCR4. CCR4 is the receptor for the CC chemokine TARC (thymus and activation regulated chemokine), and this chemokine is expressed predominantly by keratinocytes in the basal layer of the epidermis of lesional atopic dermatitis skin in mice. In humans, however, it was shown to be expressed in the endothelial cells of the dermis. We have examined the peripheral blood mononuclear cells of atopic dermatitis patients for the expression of cutaneous lymphocyte-associated antigen and CCR4 and compared them with peripheral blood mononuclear cells from normal controls. We found that the proportion of CLA+CCR4+ lymphocytes is upregulated in atopic dermatitis patients. In addition we have examined skin biopsies of lesional and non-lesional skin from atopic dermatitis patients and found that the keratinocytes, but not the endothelial cells, produce TARC in the lesional but not in the nonlesional skin. To gain insight in the stimulatory mechanisms for TARC production in keratinocytes, as previously observed in mice, we cultured HaCaT cells and found that interferon-gamma and tumor necrosis factor alpha work synergistically to induce TARC production. These observations suggest that the induction of TARC production in keratinocytes plays an important role in the late phase skin invasion by CCR4+CLA+ Th2-type lymphocytes in atopic dermatitis.     

趋化因子CCL27在常见炎陛皮肤病中的作用

临床常见的炎性皮肤病,如,银屑病、特应性皮炎和接触性皮炎等,其典型特征是T淋巴细胞浸润为主的皮肤炎症。趋化因子CCL27主要由皮肤角质形成细胞产生,其惟一受体是CCRl0。CCL27和CCRl0的相互作用,诱导皮肤记忆T细胞向局部皮肤的聚集,形成并维持了各种炎性皮损,因而已成为药物研究的新靶点。尽管目前尚无真正的临床药物可用,但体外研究和动物实验的良好效果为炎性皮肤病的治疗开启了一扇新的大门。     

Functional CD86 (B7-2/B70) is predominantly expressed on Langerhans cells in atopic dermatitis

Recently, we reported the functional expression of CD86 on cultured human Langerhans cells derived from normal epidermis. In the present study, we investigated the expression and function of co-stimulatory molecules in the pathogenesis of atopic dermatitis. In immunohistochemical analysis, CD80 and/or CD86 were detected on dendritic-shaped cells not only in the epidermis but also in the dermis in the inflammatory lesions of atopic dermatitis (n = 12). CD80 was expressed in only five cases (42%), while CD86 was expressed in all cases (100%). These molecules were not detected in normal control subjects (n = 8). In non-lesional skin of atopic dermatitis (n = 4). CD86 but not CD80 was detected in one case. CD86 was preferentially induced on dendritic-shaped cells in positive patch test sites to Dermatophagoides pteronyssinus or house dust allergen in atopic dermatitis (n = 4). The CD80- or CD86-positive cells were confirmed as Langerhans cells by double immunostaining using anti-CD1a monoclonal antibody. Neither CD86 over that CD80 was detected n keratinocytes. Similar results of the stronger expression of CD86 over that of CD80 were obtained from psoriasis vulgaris (n = 11) and from contact dermatitis (n=7), although CD86 was expressed only in 57% of the contact dermatitis cases. The percentage of Langerhans cells positive for CD86 was higher than for CD80, i.e. 48% compared with 9%, respectively, in the epidermis of lesional skin of atopic dermatitis (n=8). The expression rate of these molecules on Langerhans cells increased in the dermis. To investigate the function of co-stimulatory molecules on Langerhans cells in atopic dermatitis, we conducted an inhibition test with antibodies. Anti-CD86 monoclonal antibody almost completely nhibited T-cell proliferation stimulated with crude extract of D. pteronyssinus in the presence of epidermal cells as antigen-presenting cells, whereas anti-CD80 monoclonal antibody produced less of an inhibitory effect. These data indicate that CD86 expressed on Langerhans cells may play an important part in the pathogenesis of atopic dermatitis.for Investigative Dermatology. Washington, DC (1–5 May 1996).     

CCL28 production in HaCaT cells was mediated by different signal pathways from CCL27

Both CCL27 and CCL28 are ligands for CCR10 and attract CCR10(+) lymphocytes. We previously demonstrated that CCL27 and CCL28 were strongly expressed in sera and lesional keratinocytes of patients with atopic dermatitis and psoriasis vulgaris. However, the regulation of CCL27 and CCL28 production in keratinocytes has not been well documented. In this study, we showed that CCL27 and CCL28 expression and production by a human keratinocyte cell line, HaCaT cells, were strongly induced by inflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta. CCL27 production was downregulated by inhibitors of p38 mitogen-activated protein kinase and nuclear factor-kappa B (NF-kappaB). By contrast, CCL28 production was downregulated by inhibitors of extracellular signal-regulated kinase and NF-kappaB. Our study results suggest that CCL28 produced by keratinocytes is mediated by different signal pathways from CCL27 and that both CCL27 and CCL28 are involved in the pathogenesis of inflammatory skin diseases.     

Pathogenic implication of epidermal scratch injury in psoriasis and atopic dermatitis

Mechanical scratching, a common external stress affecting the skin, is induced by various causes, such as pruritus. Scratch injury to epidermal keratinocytes upregulates the production and release of chemokine (C-C motif) ligand 20 (CCL20) in vitro, which selectively chemoattracts interleukin (IL)-17A-producing immune cells that express chemokine (C-C motif) receptor 6 (CCR6). In IL-17A-dominant psoriasis, scratch-induced CCL20 upregulation and subsequent accumulation of IL-17A-producing immune cells and CCR6⁺ mature dendritic cells may trigger the development of psoriatic lesions, a process known as the Koebner phenomenon. In IL-4/IL-13-dominant atopic dermatitis, pruritus and subsequent scratching are the primary symptoms. Scratch-induced CCL20 production from keratinocytes may explain why IL-17A levels are also elevated in atopic dermatitis. In contrast, mechanical scratching is likely to negatively regulate IL-13 signaling by upregulating the expression of IL-13 receptor α2, which serves as a decoy receptor for IL-13 in keratinocytes. In this review, we summarize current reports on topics related to the pathogenic role of epidermal scratch injury in psoriasis and atopic dermatitis.     

Expression of monocyte chemoattractant protein-1 in the lesional skin of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease with unknown etiology characterized by excessive deposition of collagen in the skin as well as various internal organs. One of the characteristic histological features is the presence of infiltrating mononuclear cells in the dermis in its early stage. As well as T cells, macrophages are implicated to play an important role in the initial pathologic changes associated with SSc by releasing fibrogenic cytokines, including transforming growth factor-beta or platelet-derived growth factor. However, the precise mechanism for increased monocyte/macrophage recruitment in the lesional skin of SSc is still not completely elucidated. Monocyte chemoattractant protein-1 (MCP-1) is a predominant monocyte chemoattractant secreted by various cells types including mononuclear cells, fibroblasts, smooth muscle cells, endothelial cells, or keratinocytes. In this study, we examined the expression of MCP-1 protein and mRNA in the lesional skin of seven patients with SSc by immunohistochemistry and in situ hybridization. Results of immunohistochemistry showed that MCP-1 was detected on infiltrating mononuclear cells and fibroblastic cells in scleroderma skin, whereas normal skin showed only minimal MCP-1 expression. We demonstrated the expression of MCP-1 mRNA in infiltrating mononuclear cells and keratinocytes in scleroderma and contact dermatitis skin. In addition, signals were also detected in fibroblasts in the lesional skin of scleroderma, whereas fibroblasts in normal skin and contact dermatitis skin did not express MCP-1 mRNA. These findings suggest that MCP-1 plays a role in recruiting monocyte/macrophages in the lesional skin of scleroderma and that activated fibroblasts in scleroderma are involved in this process.     

Enkephalin-like immunoreactivity in human skin is found selectively in a fraction of CD68 – positive dermal cells: increase in enkephalin-positive cells in lesional psoriasis

Opioid peptides are synthesized in neurons, endocrine cells, monocytes/macrophages and B and T lymphocytes. They interact with opioid receptors located on immune cells and nociceptive nerve terminals. Because opioid peptides might be of importance in inflammatory skin diseases, for example psoriasis, sections of skin from psoriatic patients were immunohistochemically stained with antisera against methionine and leucine enkephalin, CD68 (KP1, PG-M1), calprotectin (M747), M130 (Ber-MAC3), CD1a and CD3. Enkephalin-like activity was detected selectively in dermal CD68-positive macrophages/monocytes. The activity showed no association with the activation markers M747 and Ber-MAC3. There was a statistically significant increase in enkephalin-positive cells in involved psoriatic skin compared with uninvolved and normal skin. These results were confirmed by radioimmunoassay which showed elevated levels in extracts from involved psoriatic skin compared with uninvolved skin (81%) and normal skin (204%). Furthermore, preproenkephalin mRNA of an expected size was detected in involved psoriatic skin. If the increased levels of enkephalins present in monocytes/macrophages in psoriatic skin lesions reach the threshold for biological activity, they may play a role in the regulation of the inflammatory processes seen in this skin disease. Received: 3 April 1996     

异位性皮炎的记忆性T细胞浸润及ICAM－1表达

为了解粘连分子在异位性皮炎（ＡＤ）炎症及免疫反应过程中的作用，对ＡＤ皮损部位细胞间粘连分子－１（ＩＣＡＭ－１）的表达作了研究。结果虽然正常皮肤表皮不表达ＩＣＡＭ－１，但ＡＤ皮损处角朊细胞则局灶性表达ＩＣＡＭ－１，尤其在有严重单个核细胞浸润及表皮内淋巴细胞移入的部位。免疫表型研究表明，ＡＤ真皮浸润中ＣＤ４＋／ＣＤｗ２９＋／ＣＤ４５ＲＡ－记忆性Ｔ细胞占主导，推测它们可能通过分泌某些细胞因子而诱导角朊细胞表达ＩＣＡＭ－１。ＩＣＡＭ－１与淋巴细胞表面的淋巴细胞功能相关抗原－１（ＬＦＡ－１）之间相互作用可能对淋巴细胞在皮肤内的运行起调控作用。     

Targeting the α7 nicotinic acetylcholine receptor–A novel road towards the future treatment of skin diseases

Nicotinic acetylcholine receptors (nAChRs) are members of the superfamily of neurotransmitter-gated ion channels. The natural ligand for nAChRs is the endogenous neurotransmitter acetylcholine. Among the nAChRs is the α7nAChR. It is not only expressed by neural tissues but also in the skin. A number of different resident cutaneous cell types including epidermal keratinocytes, sebocytes and dermal fibroblasts express functional α7nAChR. Moreover, cells of the immune system such as lymphocytes, macrophages and monocytes, playing an important role in skin homeostasis, also express α7nAChR. Translational research focusing on the exploitation of the α7nAChR in dermatology has revealed that this neuroendocrine receptor could be promising target for the treatment of inflammatory skin diseases. For example, α7nAChR agonists can counteract transforming growth factor-β1-mediated responses in dermal fibroblasts, key effector cells in scleroderma. In accordance with this α7nAChR, agonists are effective in both inflammation and non-inflammation-driven models of experimentally induced skin fibrosis. Moreover, α7nAChR agonists can modulate expression of proinflammatory cytokines in epidermal keratinocytes that are crucially involved in the pathogenesis of psoriasis and other inflammatory skin diseases. Finally, the capability of α7nAChR agonists to suppress ultraviolet light A/B-induced responses, for example production of proinflammatory cytokines and oxidative stress, the latter crucially involved in dermal photoageing, points to a potential of such agents in the prevention of extrinsic skin ageing. Therefore, emphasis on translational research targeting the α7nAChR in skin may lead to the development of new treatment and prevention modalities against fibrosclerotic skin diseases, psoriasis vulgaris, atopic dermatitis, acne, photodermatoses and extrinsic skin ageing.     

Thymus- and activation-regulated chemokine (TARC/CCL17) induces a Th2-dominated inflammatory reaction on intradermal injection in mice

TARC/CCL17 (thymus- and activation-regulated chemokine) is a CC chemokine, which binds to the CC chemokine receptor-4 (CCR4) known to be distinctively expressed on Th2 lymphocytes. In atopic dermatitis (AD), the skin is invaded by Th2 lymphocytes in the acute phase. TARC/CCL17 is produced by the keratinocytes in AD lesions, and CCR4 is overexpressed on CLA+ (cutaneous lymphocyte-associated antigen) lymphocytes in the skin and blood. We, therefore, hypothesized that TARC/CCL17 is pivotal in mediating a Th2-dominated inflammation in the skin. To examine this, we injected BALB/c mice with murine TARC/CCL17 in concentrations ranging from 0.1 microg/ml to 10 microg/ml and examined the skin after 48 h. This revealed that TARC/CCL17 induces lymphocytic infiltration of the skin by CD4+ lymphocytes in a dose-dependent manner with a maximum response at 1 microg/ml. Additionally, TARC/CCL17 induced interleukin-4 mRNA but not interferon-gamma mRNA expression in the skin, suggesting that the lymphocytes invading the skin are Th2 cells. Additionally, TARC/CCL17 induced its own production in the keratinocytes along with cutaneous T-cell-attracting chemokine (CTACK/CCL27) mRNA. We, therefore, conclude that TARC/CCL17 induces a Th2-dominated inflammatory reaction when injected into the skin.     

Expression of Fc receptors for IgG during acute and chronic cutaneous inflammation in atopic dermatitis

Atopic dermatitis is an allergic skin disease characterized by elevated total and antigen-specific serum IgE and IgG4 levels. In acute and chronic cutaneous inflammation, large cellular infiltrates including T cells, dendritic cells and macrophages are found, especially in the dermis. These cells play an important part in the regulation of local inflammatory reactions. Receptors binding IgG (FcgammaR) are involved in dendritic cell and macrophage function. In this study, we examined the in vivo distribution and cellular expression of the three classes of leucocyte FcgammaR in human skin during acute and chronic cutaneous inflammation in atopic dermatitis. Atopy patch test skin was used as a model for acute inflammation in atopic dermatitis, while chronic lesional skin was used to investigate FcgammaR expression in chronically inflamed skin. In atopy patch test sites no increase in the number of CD1a+ dendritic cells and a slight increase in macrophages compared with non-lesional skin was observed. Our results showed increased expression of FcgammaRI (CD64) and FcgammaRIII (CD16) in acutely inflamed skin as well as in chronically inflamed lesional skin, compared with healthy and non-lesional atopic dermatitis skin. FcgammaRI was expressed by RFD1+, RFD7+ and CD68+, but not by CD1a+ dermal dendritic cells. RFD1+ dendritic cells and CD68+ macrophages were the main FcgammaRIII-expressing cells during the acute inflammatory reaction. The significant increase in expression of FcgammaRIII (CD16) and FcgammaRI (CD64) probably results from upregulation of the receptors on resident cells. Insight into the presence of FcgammaR+ cells in human skin during inflammation is important both for our understanding of skin immune reactions and the development of new therapeutic concepts.     

Expression pattern of somatostatin receptor subtypes 1-5 in human skin: an immunohistochemical study of healthy subjects and patients with psoriasis or atopic dermatitis

In psoriasis and atopic dermatitis, the inflammatory events have neurogenic components and the neuropeptides modify the functions of immuno-active cells in the skin. Somatostatin is a neuropeptide with several neuroendocrine and immunomodulating properties and mediates its actions by five distinct subtypes of G-protein-coupled receptors (SSTR1-5). This study describes the distribution of SSTR1-5, analysed with immunohistochemistry, in psoriasis, atopic dermatitis and controls. Normal human skin and lesional skin from patients with psoriasis or atopic dermatitis showed many similarities, but also some differences, as regards SSTR expression. SSTR1-3 were strongly expressed in the epidermis of healthy skin, and in the skin of patients with psoriasis or atopic dermatitis. It is noteworthy that SSTR4 and 5 were strongly expressed in the epidermis of psoriasis patients, but weakly expressed in the epidermis of those with atopic dermatitis and normal skin. The intensity of the staining also varied considerably between the different layers of the epidermis, especially in psoriasis patients. In all cases, the dendritic cells, found mostly in the papillary and upper reticular dermis, showed a strong expression of SSTR1-4, but a weak expression of SSTR5. SSTR1-5 were strongly expressed in the sweat glands in all skin biopsies. Hair follicles and sebaceous glands expressed all five subtypes. Striated muscle fibres showed an intense positive expression of SSTR1-4, but a weak or negative expression of SSTR5. The wide distribution and expression pattern of all five SSTRs in human skin suggest that somatostatin is involved in the interactions between the nervous system and the skin.     

Interleukin‐1 from epithelial cells fosters T cell‐dependent skin inflammation

Background Chronic inflammatory skin diseases such as atopic dermatitis and psoriasis are characterized by the infiltration of lymphocytes into the epidermal compartment. Several studies point to an active role of skin epithelial cells in the pathophysiology of such diseases. Objectives In this study we addressed the regulatory function of primary human keratinocytes in the interaction with autologous T cells and monocytes. Methods We used a human coculture model with keratinocytes grown from epidermal stem cells of the outer root sheath of human hair follicles and autologous T cells. Results In our coculture system we observed a high production of interferon (IFN)‐γ, but not Th2 cytokines, in the presence of superantigen or antigen‐pulsed autologous monocytes. Critical parameters for this effect were: (i) T‐cell receptor activation, (ii) an intercellular adhesion molecule‐1/lymphocyte function‐associated antigen (LFA)‐1‐dependent interaction between keratinocytes and T cells, and (iii) secretion of interleukin (IL)‐1β. Remarkably, in the presence of activated T cells, epithelial cells seemed to be a more significant source of IL‐1β than monocytes. Application of the LFA‐1 blocker efalizumab or IL‐1 receptor antagonist anakinra enabled us to suppress completely the production of IFN‐γ by T cells in the coculture. Conclusions IL‐1 secretion and the physical contact between keratinocytes and activated, infiltrating T cells may be central for the development of chronic inflammatory skin conditions.     

趋化性细胞因子受体CCR4和CXCR3在特应性皮炎患者外周血的表达

目的为研究特应性皮炎患者外周血趋化性细胞因子受体CCR4和CXCR3在特应性皮炎的发病过程中的作用。方法采用三色流式细胞仪测定20例特应性皮炎患者和30例健康对照者外周血趋化性细胞因子受体CCR4和CXCR3的表达水平。结果特应性皮炎患者外周血CCR4+CD4+T细胞的水平明显高于对照组(P<0.01);特应性皮炎患者外周血CCR4/CXCR3比率明显高于对照组P<0.01);特应性皮炎患者外周血CXCR3+CD4+T细胞的水平与对照组差异无统计学意义。结论趋化性细胞因子受体CCR4可能促进了Th2细胞从血液进入特应性皮炎患者炎症皮损。     

Upregulation of RANTES in psoriatic keratinocytes: a possible pathogenic mechanism for psoriasis

Intraepidermal collections of neutrophils and lymphocytes are unique features of the inflammatory reaction of psoriasis. Migration of leukocytes from dermis to the epidermis suggests a role for chemotactic agent(s). In recent years, increased levels of chemokines such as IL-8 , GRO-a and MCP-1 have been reported in the keratinocytes of psoriatic tissue. IL-8 and GRO-alpha belong to a subfamily (C x C) class and MCP-1 is a beta chemokine. In this study, we investigated RANTES, which is a beta chemokine (C-C class); RANTES has been found to be associated with various cell-mediated hypersensitive disorders. We obtained eight skin biopsies from chronic psoriatic plaques, and five biopsies each from non-lesional psoriatic skin, lichen planus, eczematous dermatitis and skin from healthy controls. Snap-frozen samples were cut into 7 microm cryosections and stained with 6 mg/ml of monoclonal anti-RANTES mouse IgG (DNAX, Palo Alto, CA). Standard immunohistochemistry techniques were applied. RANTES was detected only in the keratinocytes. The number of keratinocytes in per mm2 of epidermis stained for RANTES were 116.79+/-98.42 in psoriatic tissues compared to 32.00+/-46.05 (p<0.05), 6.39+/-3.59 (p<0.01), 2.64 +/-1.15 (p<0.01) and 3.53+/-5.26 (p<0.01), respectively, in the non-lesional, lichen planus, eczematous lesions and normal skin. This is the first study to report that the keratinocytes of psoriatic tissue express high levels of RANTES compared to the controls. IL-8 and related molecules (C x C class) are predominantly chemotactic for neutrophils and MCP-1 is a strong chemotactic factor for monocytes. In contrast, RANTES is chemotactic for memory T cells and activated naive T cells. Increased amounts of RANTES as reported here provide an explanation for migration of the activated T cells to the epidermis of the psoriatic lesions. In addition, RANTES activates T cells. These results suggest that RANTES may have a significant role in the inflammatory process of psoriasis. Our findings further substantiate a regulatory role for keratinocytes in the inflammatory process of psoriasis.     

Plaque psoriasis vs. atopic dermatitis and lichen planus: a comparison for lesional T-cell subsets, epidermal proliferation and differentiation

BACKGROUND: T-cell infiltration in plaque psoriasis has recently been an important subject of investigation. Interestingly, comparative analyses of the disease-specific composition of the lesional T-cell infiltrate in plaque psoriasis and other inflammatory dermatoses have only sparsely been performed. OBJECTIVES: To compare plaque psoriasis vs. atopic dermatitis and lichen ruber planus with respect to T-cell subsets, epidermal proliferation and keratinization. PATIENTS AND METHODS: Biopsies were taken from untreated lesional skin of patients, six with psoriasis, six with atopic dermatitis and six with lichen planus. T-cell subsets (CD4+, CD8+, CD45RO+, CD45RA+, CD2+, CD25+), an epidermal proliferation (Ki-67) and a keratinization marker (K10) were stained immunohistochemically and quantified using image analysis. RESULTS: The high number of CD8+ T cells (52 +/- 13 cells mm(-1)) found in the psoriatic epidermis was not found in the epidermis of atopic dermatitis (9 +/- 4), nor in the epidermis of lichen planus (34 +/- 10). The other T-cell subsets in the epidermis and dermis showed no statistically significant differences between psoriasis and atopic dermatitis. In contrast to the limited presence of CD4+, CD8+ and CD2+ in the psoriatic dermis (110 +/- 19, 27 +/- 9, 127 +/- 41, cells mm(-1), respectively), more impressive numbers of these cells were observed in the dermis of lichen planus (300 +/- 53, 144 +/- 38, 272 +/- 48, respectively). CD45RO+ memory effector T-cell counts were significantly higher in the epidermis of lichen planus (39 +/- 10) than in psoriasis (19 +/- 5). Psoriatic epidermis proved to have major keratinocyte hyperproliferation (247 +/- 26 cells mm(-1) lamina basalis), as compared with atopic dermatitis (134 +/- 15) and lichen planus (128 +/- 20). Furthermore, a marked decreased expression of keratin 10 was observed in psoriasis (41% of epidermal area) contrary to atopic dermatitis (70%). CONCLUSIONS: Psoriatic epidermis exhibits a pronounced CD8+ epidermotropism with accompanying epidermal hyperproliferation and abnormal keratinization, which changes are only minimally expressed in atopic dermatitis and lichen planus. In plaque psoriasis, substantially fewer activated CD4+ and CD8+ T cells in the dermis and less CD45RO+ T cells in the epidermis are present in comparison with lichen ruber planus.