Nickel-responding T cells are CD4+ CLA+ CD45RO+ and express chemokine receptors CXCR3, CCR4 and CCR10

BACKGROUND: Whereas T lymphocytes are widely accepted as effector cells determining the pathogenesis of allergic contact dermatitis, contradictory results have been found regarding the roles of different T-cell subsets. The use of various experimental models, involving long-term cultured T-cell lines or clones, may explain these contradictory results. OBJECTIVE: To investigate the involvement of distinct T-cell subsets in patients with nickel contact allergy. METHODS: Different T-cell subsets were directly isolated from peripheral blood mononuclear cells (PBMCs) of nickel-allergic patients, and their proliferative capacity, type-1 or type-2 cytokine secretion [measured by interferon (IFN)-gamma or interleukin (IL)-5 release] and phenotypical marker expression were analysed after stimulation with nickel. RESULTS: Only CD4+ CLA+ CD45RO+ and not CD8+ T cells proliferate and produce both type-1 (IFN-gamma) and type-2 (IL-5) cytokines in response to nickel. Moreover, cells expressing the marker CLA in combination with CD4, CD45RO or CD69 are increased after nickel-specific stimulation. Interestingly, in addition, CD45RA+ CLA+ cells showed an increased frequency after allergen-specific stimulation. Analysis of nickel-reactive T cells for expression of distinct chemokine receptors showed that both proliferative capacity and cytokine production are restricted to subsets expressing CXCR3, CCR4 but not CCR6. Fluorescence-activated cell sorting analysis of chemokine receptors expressed on nickel-stimulated T cells confirmed these results; a subset of T cells expressing CLA and CXCR3, CCR4 and, most importantly, CCR10 increased in response to allergen, while these CLA+ nickel-reactive T cells were all negative for CCR6. CONCLUSIONS: These findings demonstrate that freshly isolated nickel-reactive T cells can be characterized as CD4+ CLA+ memory T cells which express the chemokine receptors CXCR3, CCR4 and CCR10, but not CCR6.     

Homing receptor and chemokine receptor on intraepidermal T cells in psoriasis vulgaris

Intraepidermal T lymphocytes found in psoriatic skin lesions are involved in the development and maintenance of lesional pathology. It has become clear that differential expression of homing and chemokine receptors determines the specific migration of T cells to distinct tissues and microenvironments, including psoriasis lesions. The aim of the present study was to clarify expression of homing (CLA, VLA-4, and LFA-1) and chemokine (CCR4, CCR6, CCR7, and CXCR3) receptors on intraepidermal T cells in psoriatic lesions using flow cytometry. The vast majority of intraepidermal T cells in psoriatic lesions expressed CLA and LFA-1, whereas 58% of CD4+ and 85% of CD8+ T cells expressed VLA-4. The majority of CD4+ T cells and about half of the CD8+ T cells expressed CCR4 and CCR6, whereas less than one-third of CD4+ and CD8+ T cells expressed CXCR3 or CCR7. In patients with psoriasis the percentages of T cells expressing CLA, CCR4, and CCR6 were much higher in the epidermis of psoriatic plaques than in the peripheral blood. Thus, CLA, CCR4, and CCR6 may play a more important role in the migration of T cells to psoriatic epidermis.     

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.     

特应性皮炎患者外周血皮肤归巢的CD8+ T细胞研究

【摘要】 目的 探讨特应性皮炎（AD）患者外周血CD8+ T细胞皮肤归巢及杀伤功能相关蛋白的表达。 方法 15例AD患者和14例健康人,用流式细胞仪,检测外周血CD8+ T细胞、表达皮肤淋巴细胞相关抗原的CD8+ T细胞（CLA+CD8+ T细胞）的比例。 结果 CD8+ T细胞比例在AD组和对照组之间差异无统计学意义（P > 0.05）;CD8+ T细胞穿孔素、颗粒酶B和FasL的表达在两组间差异亦无统计学意义（均P > 0.05）。CLA+CD8+ T细胞比例在AD组（3.80% ± 1.46%）高于健康对照组（2.18% ± 0.85%）（t = 3.636,P < 0.01）,AD组CLA+CD8+ T细胞比例与SCORAD（SCORing of Atopic Dermatitis）评分呈正相关（r = 0.565,P < 0.05）;CCR4在CD8+ T细胞表达在AD组（13.86% ± 4.42%）高于健康对照组（9.50% ± 2.14%）（t = 3.738,P < 0.01）,而CCR10和CXCR6的表达在两组间差异均无统计学意义（P > 0.05）。CLA+CD8+ T细胞穿孔素的表达在AD组（74.27% ± 15.94%）高于健康对照组（57.20% ± 14.64%）（t = 2.998,P < 0.01）,颗粒酶B的表达在AD组（70.90% ± 13.85%）也高于健康对照组（56.41% ± 11.00%）（t = 3.104,P < 0.01）,而FasL的表达在两组间差异无统计学意义（P > 0.05）。CLA+CD8+ T细胞CCR4、CCR10和CXCR6的表达在AD组与对照组间差异无统计学意义（均P > 0.05）。 结论 AD患者外周血CLA+CD8+ T细胞数量增加,杀伤功能相关蛋白穿孔素、颗粒酶B的表达增强,可能参与了AD的发病。     

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。     

Circulating clonal CLA(+) and CD4(+) T cells in Sezary syndrome express the skin-homing chemokine receptors CCR4 and CCR10 as well as the lymph node-homing chemokine receptor CCR7

BACKGROUND: Adhesion molecules and chemokine receptors are involved in tissue-specific homing of T cells to the skin and play an important role in the pathophysiology of cutaneous lymphoma. It has recently been reported that the chemokine CCL27 expressed by keratinocytes attracts lymphocytes bearing the chemokine receptor CCR10. OBJECTIVES: To investigate the expression of CCR4, CCR7 and CCR10 on skin-homing CLA(+) and CD4(+) T cells in the peripheral blood of patients with Sezary syndrome (SS), a rare leukaemic variant of cutaneous T-cell lymphoma. METHODS: Lymphocytes from five patients with SS, six patients with mycosis fungoides and four healthy volunteers were isolated and analysed using flow cytometry. Additionally, the T-cell receptor (TCR)-Vbeta CDR3 regions were cloned and sequenced in two patients. RESULTS: We found that CCR4 is expressed on almost all CLA(+) and CD4(+) memory T cells. Using monoclonal antibodies specific for single TCR-Vbeta chains we identified malignant T cells in four patients with SS. Importantly, we found that most but not all malignant Sezary cells expressed the skin-homing chemokine receptor CCR10. Additionally, we found that a significant proportion of these cells also expressed the lymph node-homing chemokine receptor CCR7. CONCLUSIONS: Our results support the concept that chemokine receptors play an important role in the pathophysiology of SS and suggest that the malignant clone may represent an expansion of skin-homing cutaneous 'central' memory T cells in the peripheral blood of these patients.     

Expression of chemokines and chemokine receptors in cutaneous CD30+ lymphoproliferative disorders

BACKGROUND: Little is known about the mechanisms involved in skin-specific homing in CD30+ cutaneous lymphoproliferative disorders (CLPD). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. OBJECTIVES: To investigate tissue samples from patients with CD30+ CLPD for the expression of the chemokine receptors CXCR3, CCR4 and CCR3 and their ligands MIG, TARC and RANTES. METHODS: Tissue samples from patients with primary cutaneous anaplastic large cell lymphoma (PCALCL, n=12) and lymphomatoid papulosis (LyP, n=13) were studied by immunohistochemistry on paraffin-embedded sections. Immunohistochemical analysis was also performed for CD20 (for B cells), CD45RO and CD3 (for T cells), CD30 and ALK-1. A portion of each skin specimen was stored at -80 degrees C and later examined using monoclonal antibodies against CD2, CD3, CD4, CD5, CD8, CD15, CD19, CD20 and CD30. RESULTS: CD30+ atypical lymphoid cells were frequently seen in PCALCL, and to a variable degree in LyP. In both disorders there were scattered CD3+ and CD45RO+ atypical lymphoid cells, but CD2, CD5, CD15, CD19, CD20 and ALK-1 showed negative reactivity. In addition, CD4+, but not CD8+, atypical lymphoid cells were occasionally seen in both disorders. CCR3 was expressed by atypical lymphoid cells in 10 of 12 (83%) cases of PCALCL, but in only five of 13 (38%) cases of LyP. CXCR3 was expressed in 11 of 13 (85%) cases of LyP, but in only one of 12 (8%) cases of PCALCL. CCR4 was expressed in 11 of 12 (92%) cases of PCALCL, but in only two of 13 (15%) cases of LyP. RANTES was strongly expressed by lymphoma cells in PCALCL (11 of 12: 92%), but was weak or sporadic in LyP (seven of 13: 54%). TARC showed weak or sporadic reactivity in both LyP and PCALCL, and MIG did not show a distinctive expression pattern in either disorder. CONCLUSIONS: We speculate that CCR3 is associated with the autocrine function in PCALCL, as evidenced by CCR3 coexpression with its ligand RANTES. We also found that LyP cells expressed CXCR3, which might support their migration towards the CXCR3 ligand MIG, which is expressed in stromal cells of the skin.     

镍接触性皮炎皮损趋化因子及其受体的研究

目的 探讨趋化因子及其受体在镍接触性皮炎发病中的作用.方法 留取镍接触性皮炎患者直接接触部位皮损和部分患者非直接接触部位皮损进行趋化因子受体CXCR3和CCR4免疫组化染色,同时采用RT-PCR分析HaCaT细胞经硫酸镍刺激后γ干扰素诱导蛋白-10(IP-10)、干扰素诱导T细胞趋化因子α(I-TAC)、胸腺活化调节的趋化因子(TARC)和巨噬细胞来源趋化因子(MDC)在mRNA水平的表达情况.结果 镍接触性皮炎患者皮损中浸润细胞以CD45Ro⁺CD4⁺T细胞为主,CD8⁺细胞比例小于25%;直接接触与非直接接触部位皮损浸润细胞中50%以上CXCR3染色阳性,CCR4阳性细胞少于20%.HaCaT细胞经硫酸镍刺激后主要表达趋化因子IP-10和I-TAC,48～72 h最明显.结论 镍所致系统性接触性皮炎患者非直接与直接接触部位皮损在T细胞免疫反应的效应阶段炎症反应类型基本相同.     

Expression pattern of chemokine receptors and chemokine release in inflammatory erythroderma and Sézary syndrome

BACKGROUND: Erythroderma can be caused by inflammatory dermatoses or cutaneous T-cell lymphoma. Even if chemokines and their receptors are involved in the skin-selective lymphocyte recruitment, their role in inflammatory erythroderma is yet unclear. OBJECTIVE: To evaluate the chemokine release (TARC, MDC, IP-10) and to define the expression pattern of Th1- (CCR5, CXCR3) and Th2-related (CCR4) chemokine receptors in inflammatory erythroderma and Sézary syndrome (SS). MATERIALS AND METHODS: Flow cytometry has been carried out on both circulating and skin-infiltrating T lymphocytes; serum chemokine levels have been evaluated using ELISA techniques. RESULTS: CCR4, CCR5 and CXCR3 were expressed on about 40% of peripheral blood lymphocytes and on the majority of skin-infiltrating lymphocytes in the inflammatory erythroderma patients, whereas the leukemic CD4+CD26- subpopulation in SS was characterized by a high CCR4 expression without a concurrent increase in CCR5 or CXCR3. TARC, MDC and IP-10 serum levels were significantly increased in both erythrodermic and SS patients. CONCLUSIONS: Our results confirm that SS is a Th2 disorder with a selective expression of CCR4, whereas inflammatory erythroderma shares an overexpression of both Th1- and Th2-related chemokine receptors, suggesting an activation of different pathways driving reactive lymphocytes to the skin.     

外周血流式细胞仪分析在淋巴瘤性红皮病诊断中的作用研究

【摘要】 目的 探讨外周血流式细胞仪检测在红皮病诊断中的应用价值。方法 收集2017年9月至2020年12月在中国医学科学院皮肤病医院就诊的29例红皮病患者,包括6例红皮病型蕈样肉芽肿（EMF）、5例Sézary综合征（SS）及18例不同病因的炎症性红皮病（IE）,4例健康志愿者为健康对照。采用流式细胞仪检测外周血淋巴细胞亚群、免疫表型及克隆性,比较其在炎症性红皮病与淋巴瘤相关红皮病的差异。采用单因素方差分析及LSD-t检验进行组间比较。结果 4组受试者的T细胞、B细胞、NK细胞及CD4-CD8-细胞比例差异均有统计学意义（均P < 0.001）,SS患者T细胞比例（93.8% ± 3.4%）高于EMF（42.7% ± 6.4%）及IE（46.0% ± 6.8%,t = 12.8、14.4, P < 0.001）,IE患者CD4-CD8-细胞比例（0.37% ± 0.40%）低于EMF（2.93% ± 0.84%）及SS（2.38% ± 0.74%,t = 9.2、6.7, P < 0.05）。健康对照及IE患者均未检测到克隆性T细胞受体可变区β链（TCR-vβ）表达;3例 EMF及所有SS患者检测到表达克隆性TCR-vβ的细胞亚群,且TCR-vβ克隆性细胞均为CD4+CD7-CD26-表型。4组受试者CD4+ T淋巴细胞表面表达趋化因子受体CCR4、CXCR3、CCR5与皮肤淋巴细胞抗原（CLA）及程序性死亡受体1（PD-1）的细胞比例差异均有统计学意义（均P < 0.001）,IE患者表达CCR4、CLA、PD-1细胞比例低于SS及EMF患者（均P < 0.001）,表达CXCR3、CCR5细胞比例高于SS患者及EMF患者 （均P < 0.001）。 结论 流式细胞仪检测外周血淋巴细胞亚群、免疫表型及克隆性,可为红皮病患者的病因诊断提供佐证,有助于淋巴瘤相关红皮病与炎症性红皮病的鉴别诊断。     

High level of thymus and activation-regulated chemokine in blister fluid and sera of patients with bullous pemphigoid

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by eosinophilia and high serum IgE levels. The accumulated evidence suggests that various cytokines are involved in the lesional skin of patients with BP. Recently, thymus and activation-regulated chemokine (TARC/CCL17), a CC chemokine, was identified as a selective chemoattractant for CC chemokine receptor 4 (CCR4)-expressing cells. OBJECTIVE: In this study, we examined the involvement of TARC in patients with BP. METHODS: We determined the fluid and serum TARC levels in patients with BP by enzyme-linked immunosorbent assay and compared the serum TARC levels with the eosinophil numbers in peripheral blood. We also compared the serum TARC levels in five patients with BP before and after they were treated. Moreover, we examined TARC, CCR4 and CXC chemokine receptor 3 (CXCR3) expression in the lesional skin of patients with BP by immunohistochemical procedures. Furthermore, we measured CCR4 positivity in CD4+ CD45RO+ cells of peripheral blood mononuclear cells (PBMCs) in patients with BP and healthy control subjects. RESULTS: The fluid TARC levels in patients with BP were significantly higher than those in blisters from burn patients or suction blisters of healthy control subjects. The serum TARC levels in patients with BP were also significantly higher than those in pemphigus vulgaris (PV) patients and healthy control subjects, and decreased after the treatment. The serum TARC levels in patients with BP significantly correlated with the eosinophil numbers in peripheral blood (r = 0.72, P < 0.002). Immunohistochemistry showed a strong reactivity of TARC in the epidermal keratinocytes (KCs) of BP. Moreover, both CCR4 and CXCR3 were expressed on the dermal infiltrating CD4+ T cells mainly beneath the bullae of patients with BP. Fluorescence-activated cell sorting analysis showed a higher percentage of CCR4 positivity in CD4+ CD45RO+ cells of PBMCs in patients with BP than that in healthy control subjects, while there was no significant difference of CXCR3 positivity in CD4+ CD45RO+ cells of PBMCs between patients with BP and healthy control subjects. CONCLUSIONS: These findings strongly suggest that TARC may be one of the important chemokines that are involved in the pathogenesis of BP.     

Resolving lesions in human cutaneous leishmaniasis predominantly harbour chemokine receptor CXCR3‐positive T helper 1/T cytotoxic type 1 cells

Background Cutaneous leishmaniasis (CL) is an epidemic disease affecting millions of individuals worldwide. Treatment options have several side‐effects and a vaccine does not exist at present. Objectives To translate information about protection against CL from mice to man, we studied the local immune response in CL skin biopsies and correlated these findings with clinical information. Methods The frequency of inflammatory cells was determined in skin biopsies of 20 patients diagnosed with CL using immunohistochemistry. In addition, the nature of the resulting adaptive immune response was assessed by (double) immunostaining against CD4 and chemokine receptors CXCR3 (T helper 1, Th1)/CCR4 (Th2). Results All lesions contained CD4+ and CD8+ T cells, B cells and CD68+ macrophages. CD1a+ epidermal Langerhans cells were absent above the centre of the lesions, but normally distributed in the surrounding tissue. Mast cell and CD56+ natural killer cell numbers were not affected. Interestingly, CCR4+ Th2 cells were not detected in any of the 20 samples. In contrast, the number of infiltrating CXCR3+ cells was high and the majority of these were CD4+ or CD8+ indicating that they represent interferon‐γ‐producing Th1/T cytotoxic type 1 (Tc1) cells. Finally, these findings did not correlate with clinical information about the country where the infection was acquired, or age or sex of the patients. However, lesions that had already persisted for more than 6 months contained fewer CXCR3+ CD4 and CD8 T cells than those that had persisted for less than 6 months. Conclusions Our data on the inflammatory infiltrate of human CL lesions underline the relevance of findings obtained in experimental models. Both Th1 and Tc1 cells appear to be critical for healing in CL in mouse and man.     

雷公藤多苷含药血清对变应性接触性皮炎小鼠淋巴细胞表面CXCR3、CCR3表达的影响

目的观察雷公藤多苷含药血清对变应性接触性皮炎小鼠(ACD)体外培养淋巴细胞趋化因子受体CX-CR3、CCR3表达的影响,进一步探讨雷公藤治疗接触性皮炎的机理。方法用血清药理学方法,流式细胞术检测了雷公藤多苷含药血清对体外培养48h后的ACD小鼠淋巴细胞趋化因子受体CXCR3、CCR3表达的影响。结果雷公藤多苷含药血清高、中、低三个浓度组体外培养的ACD小鼠淋巴细胞CXCR3的表达明显低于对照组,差异均有统计学意义(P<0.05);雷公藤多苷含药血清三个浓度组之间比较,CXCR3表达差异均无统计学意义(P>0.05);雷公藤多苷含药血清三个浓度组之间及与对照组比较,体外培养的ACD小鼠淋巴细胞CCR3的表达差异均无统计学意义(P>0.05)。结论雷公藤多苷含药血清可以明显抑制体外培养的ACD小鼠淋巴细胞CXCR3的表达,但与浓度高低无明显关系。雷公藤多苷含药血清对体外培养的ACD小鼠淋巴细胞CCR3的表达影响不明显。抑制CXCR3的表达可能是雷公藤治疗ACD的机理之一。     

Mycosis fungoides and S&eacute;zary syndrome: Role of chemokines and chemokine receptors

Mycosis fungoides is the most common form of cutaneous T-cell lymphoma (CTCL), and is characterized by a clonal expansion of malignant CD4⁺ T lymphocytes with skin-homing properties. Clinically and pathologically, mycosis fungoides can be categorized into patch, plaque and tumor stages. The clinical course of mycosis fungoides is usually chronic and indolent, but a proportion of patients may develop progressive disease with peripheral blood, lymph node and visceral organ involvement. Sézary syndrome is an aggressive leukemic form of CTCL characterized by a clonal population of malignant T cells in the peripheral blood. Various forms of skin-directed and systemic treatments are available for mycosis fungoides and Sézary syndrome. However, current treatments are generally not curative, and can only control the disease. Currently, the etiology and pathogenesis of mycosis fungoides and Sézary syndrome are not well defined. Proposed mechanisms include chronic antigenic stimulation by infectious agents, expression of specific adhesion molecules, altered cytokine production, mutations of oncogenes and tumor suppressor genes, and avoidance of apoptosis. In recent years, a number of chemokine receptors and their corresponding chemokine ligands have been found to contribute to the migration and survival of lymphoma cells in mycosis fungoides and Sézary syndrome, including CC chemokine receptor 4 (CCR4), CCR10, C-X-C chemokine receptor type 4 (CXCR4), CCR7, CCR3 and CXCR3. Since chemokines and chemokine receptors have been found to play important roles in the pathophysiology of mycosis fungoides and Sézary syndrome, they may be potentially useful targets for the development of new treatments for these diseases in the future.     

Chemokine receptor expression on neoplastic and reactive T cells in the skin at different stages of mycosis fungoides

We analyzed the expression of 13 chemokine receptors in mycosis fungoides, in order to assess the contribution of chemotaxis to the pathogenesis of the disease. Material from skin biopsies of six patients with early disease and six patients at the tumor stage of mycosis fungoides was analyzed by immunohistochemistry and partly also by flow cytometry. The receptors CCR1, CCR2, CCR3, CCR5, CCR6, CXCR1, CXCR2, CXCR5, and CX3CR1 were rarely and inconsistently detected in lesional skin and thus their participation in mycosis fungoides could largely be ruled out. In contrast, CCR4, CXCR3, and CXCR4 were substantially expressed on both mycosis fungoides cells and the surrounding reactive T cells in the early patch and plaque stages of the disease, indicating an involvement of these chemokine receptors in the disease process. In the tumor stage of mycosis fungoides, we interestingly observed a loss of a relevant chemokine receptor in four out of six patients. In three patients CXCR3 and in one patient CCR4 was absent on tumor mycosis fungoides cells, whereas the reactive T cells showed normal levels of expression. Within these samples, tumor mycosis fungoides cells exhibited high levels of CCR7, a chemokine receptor central for the entry of T cells to lymphatic tissue. Taken together, our data suggest that the loss of one or more of the chemokine receptors involved in the homing of the mycosis fungoides cells to the skin may trigger the latent potential of these cells to metastasize into regional lymphatic tissue.     

A novel method for the isolation of skin resident T cells from normal and diseased human skin

T cells resident in normal skin likely conduct immunosurveillance and are implicated in the development of inflammatory disorders such as psoriasis. This population of cells is difficult to study because existing techniques allow isolation of only few cells. We report here a novel method of isolating T cells from both normal and diseased human skin. Explants of skin cultured on three-dimensional matrices led to the outgrowth of dermal fibroblasts that elaborated T cell chemoattractant factors. These factors led to the migration of skin resident T cells out of skin explants where they could be collected and studied. Skin resident T cells isolated from explant cultures were CD45RO(+) memory T cells and expressed high levels of cutaneous lymphocyte antigen (CLA) and chemokine receptor (CCR)4. Inclusion of IL-2 and IL-15 in explant cultures produced up to a 10-fold expansion of skin-resident T cells, while maintaining the CLA(+)CCR4(+) skin-homing phenotype as well as a diverse T cell repertoire. This method also allowed efficient isolation of malignant T cells from the skin lesions of cutaneous T cell lymphoma and the isolation of tumor-infiltrating lymphocytes from primary squamous cell carcinomas and melanoma metastases.     

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.     

Absence of CD26 expression on skin-homing CLA+ CD4+ T lymphocytes in peripheral blood is a highly sensitive marker for early diagnosis and therapeutic monitoring of patients with Sézary syndrome

Patients with Sézary syndrome (SS) show clonal expansion in the peripheral blood of skin-homing CD4+ T-helper cells expressing cutaneous lymphocyte antigen (CLA). However, an increase of CLA+ CD4+ T cells can also be observed in various inflammatory dermatoses. To facilitate early diagnosis and therapeutic monitoring of SS using flow cytometry, we evaluated the expression of CD7 and CD26 on the CLA+ CD4+ lymphocyte subset. Peripheral lymphocytes from 7 patients with SS, 16 patients with mycosis fungoides (MF) and 11 healthy controls were analysed by flow cytometry for the expression of CD4, CD7, CD26, CLA and CCR4. In addition, a longitudinal study was performed over 16 months in two patients with SS. Absence of CD7 and CD26 on CLA+ CD4+ T cells was highly specific for SS. Importantly, the absence of CD26 on CLA+ CD4+ T cells was very sensitive for SS, at 100% in our patient cohort. The number of CD26- CLA+ CD4+ T cells closely correlated with therapeutic interventions in the longitudinal analysis of two patients over more than 1 year. We conclude that the absence of CD26 expression on skin-homing CLA+ CD4+ T-helper cells is a very sensitive and highly specific parameter for early diagnosis and therapeutic monitoring of patients with SS.     

Vascular endothelium express CS-1 fibronectin in allergic contact dermatitis

BACKGROUND: Allergic contact dermatitis (ACD) is a common human dermatosis in which not all the mechanisms involved in its pathogenesis have been elucidated. OBJECTIVE: To study the expression of CS-1 fibronectin, TARC and Th1-associated chemokine receptors in biopsies from allergic patch test reactions. MATERIAL AND METHODS: Thirteen patients already diagnosed with ACD were challenged on the back with the antigen responsible of the disease and macroscopic responses and biopsies taken after 48 h. Skin biopsies from negative control challenge sites, AD and ICD were also taken. Samples were fixed, embedded in paraffin wax and processed in order to perform histological and immunohistochemical studies. RESULTS: All subjects with ACD showed a positive clinical response and a perivascular mononuclear cell infiltration at 48 h, which was not seen in the negative controls. The majority of skin-infiltrating cells were CD4+ and CD8+ and up to 54% or 40% of them expressed CXCR3 or CCR5, respectively. We also showed expression of CS-1 fibronectin in inflamed endothelial cells not only in ACD but also in AC and ICD. In contrast TARC was only expressed in ACD and AC. CONCLUSION: We showed for the first time that CS-1 fibronectin is expressed in dermal vessels from allergic patch tests positive reactions, as well as irritant and atopic skin lesions.