IL-31在特应性皮炎中的表达及与瘙痒关系的机制研究

观察内、外源性特应性皮炎患儿白介素31(IL-31)表达并探讨IL-31与特应性皮炎(AD)瘙痒、皮损严重度的关系和可能的作用机制。应用相对定量实时PCR方法检测28例AD患儿和22例正常儿童外周血单个核白细胞(PBMC)IL-31 mR-NA表达水平。对AD患儿进行搔抓、失眠、皮损面积、皮损严重度评分和相关实验室检查。同时免疫组化法检测AD皮损和正常人皮肤IL-31功能受体A(IL-31RA)表达与分布。结果:AD患儿PBMC IL-31表达高于正常对照(P<0.05)。外源性AD较内源性AD PBMC表达IL-31 mRNA略有升高,但无统计学意义。AD患儿IL-31表达与疾病严重程度SCORAD评分呈正相关(r=0.495,P<0.05),同时,IL-31与瘙痒评分也呈正相关关系(r=0.584,P<0.05)。IL-31RA表达在皮肤表皮细胞胞浆内,AD皮损IL-31RA表达显著高于正常人皮肤(P<0.001),并且在触觉小体、环层小体被囊以及神经纤维束有较强表达。IL-31可能不是内、外源性AD免疫学差异的主要因素,但IL-31与AD瘙痒发生密切相关,其表达量可以反映病情严重程度。     

Different cytokine production and activation marker profiles in circulating cutaneous-lymphocyte-associated antigen+ T cells from patients with acute or chronic atopic dermatitis

BACKGROUND: Atopic dermatitis (AD) is an inflammatory skin disease whose lesions can have two stages: acute and chronic. In skin biopsies a biphasic pattern of cytokine expression has been shown, Th2 in acute lesions and Th1 in chronic AD lesions. OBJECTIVE: We investigated the expression of an activation marker and a homing receptor, as well as cytokine production, in different peripheral blood T cell subpopulations from AD patients with chronic (Group A) and acute lesions (Group B) and controls. METHODS: We evaluated 26 adult AD patients (12 Group A, 14 Group B) and 14 non-atopic controls. IgE was measured by immunoassay. CD4, CD8, cutaneous-lymphocyte-associated antigen (CLA) and human leucocyte antigen (HLA)-DR expression, and cytokine production (IL-2, IL-13, IFN-gamma, TNF-alpha, IL-10, IL-4) were analysed in mononuclear cells by flow cytometry. RESULTS: In Group B there was a significant increase in eosinophil levels and a non-significant increase in IgE. In Group A we found an increase in CLA(+)CD4(+) cells (8.19+/-1.84) compared with controls (4.83+/-0.53) (P<0.05) and CD4(+)HLA-DR(+) cells in the CLA(+) subpopulation (45.54+/-15.40) compared with controls (30.49+/-6.07) (P<0.05). In the CLA(+)CD4(+) subpopulation, there was a significant increase in IL-4, IL-13 and TNF-alpha production in Group B (12.46+/-7.7, 11.26+/-5.97, 43.92+/-15.55) compared with controls (5.34+/-3.50, 4.54+/-1.78, 19.29+/-9.97) with no differences in Group A. CONCLUSION: Greater immunological differences were detected in peripheral blood from patients with acute compared with chronic lesions, especially in the circulating T cell-subset with skin tropism that preferentially responded to cutaneous allergens. This is the first demonstration of phenotypic changes in circulating CLA(+) T cells between AD patients with acute and chronic lesions.     

Evidence for a role of Langerhans cell-derived IL-16 in atopic dermatitis

BACKGROUND: The factors controlling infiltration of inflammatory cells into atopic dermatitis (AD) lesions remain to be fully explored. Recently, epidermal cells in lesional AD were reported to contain increased messenger (m)RNA levels of IL-16, a cytokine that induces chemotactic responses in CD4(+)T cells, monocytes, and eosinophils. OBJECTIVES: We sought to determine the expression of IL-16 in epidermal cells in normal skin and skin from AD lesions and to investigate whether Langerhans cell (LC)-derived IL-16 may contribute to the initiation of atopic eczema. METHODS: The cutaneous expression of IL-16 was investigated by in situ hybridization and immunohistochemistry. Expression of IL-16 was also investigated in freshly isolated LCs and in keratinocytes by intracellular cytokine staining, quantitative real-time RT-PCR, and ELISA. RESULTS: Low levels of IL-16 mRNA, but no stored IL-16 protein, were detected in keratinocytes and LCs isolated from normal skin. Synthesis, storage, and secretion of IL-16 could be induced in LCs, but not keratinocytes, by activation with phorbol ester and ionomycin. In normal skin (n = 10) neither keratinocytes nor LCs expressed IL-16. In contrast, IL-16 was contained in approximately 40% of CD1a(+)LCs in patients with active AD (n = 16). IL-16 expression in LCs in patients with AD correlated with the number of infiltrating CD4(+)cells (r =.72, P =.0017) and was completely downregulated parallel to the clinical response of AD lesions to topical treatment with FK506. CONCLUSION: LC-derived IL-16 may participate in the recruitment and activation of inflammatory cells in AD.     

Different expression of cytokine and membrane molecules by circulating lymphocytes on acute mental stress in patients with atopic dermatitis in comparison with healthy controls.

BACKGROUND: Mental stress is believed to induce an exacerbation of atopic dermatitis (AD). Until now, however, only few psychoneuroendocrinologic mechanisms underlying the link between psychological stress and exacerbation or maintenance of AD have been described. OBJECTIVE: Our purpose was to conduct an investigation of immunologic parameters in the form of membrane molecules and cytokines with potential relevance for the cutaneous inflammation in an established psychological laboratory stress model. METHODS: Patients with AD (n = 15) and healthy controls (n = 15) were exposed to mental stress, as described in a previous report. In vitro analyses were completed 1 hour before, immediately after, and 1 hour after mental stress exposure. Lymphocyte subpopulations, the cutaneous lymphocyte-associated antigen (CLA), the membrane molecule CD69(+) (early activation antigen), and intracellular IL-4, IL-5, and IFN-gamma in blood-derived lymphocytes were analyzed by flow cytometry. IL-4 in the supernatant of concanavalin-A-stimulated PBMCs was determined by ELISA. RESULTS: An increase in heart rate and blood pressure was demonstrated during psychological stress in patients with AD and healthy volunteers. We found significantly higher stress-induced increase of CLA(+) lymphocytes, T helper cells expressing IL-5, and both CD4(+) and CD8(+) lymphocytes expressing IFN-gamma on mitogenic stimulation in patients with AD in comparison with healthy controls. In addition, we observed an earlier increase in the secretion of IL-4 in the supernatant of mitogen-stimulated lymphocytes during psychological stress in patients with AD in comparison with healthy volunteers. CONCLUSION: A higher stress-induced increase of CLA(+) cells in the circulation in patients with AD compared to healthy controls might indicate an increased ability of T lymphocytes in AD to migrate to the skin during this psychological condition. In addition, the data of this study suggest a different stress-induced cytokine profile in circulating lymphocytes in patients with AD compared to healthy controls.     

IL-31: a new link between T cells and pruritus in atopic skin inflammation

BACKGROUND: IL-31 is a novel T-cell-derived cytokine that induces severe pruritus and dermatitis in transgenic mice, and signals through a heterodimeric receptor composed of IL-31 receptor A and oncostatin M receptor. OBJECTIVE: To investigate the role of human IL-31 in pruritic and nonpruritic inflammatory skin diseases. METHODS: The expression of IL-31 was analyzed by quantitative real-time PCR in skin samples of healthy individuals and patients with chronic inflammatory skin diseases. Moreover, IL-31 expression was analyzed in nonlesional skin of atopic dermatitis patients after allergen or superantigen exposure, as well as in stimulated leukocytes. The tissue distribution of the IL-31 receptor heterodimer was investigated by DNA microarray analysis. RESULTS: IL-31 was significantly overexpressed in pruritic atopic compared with nonpruritic psoriatic skin inflammation. Highest IL-31 levels were detected in prurigo nodularis, one of the most pruritic forms of chronic skin inflammation. In vivo, staphylococcal superantigen rapidly induced IL-31 expression in atopic individuals. In vitro, staphylococcal enterotoxin B but not viruses or T(H)1 and T(H)2 cytokines induced IL-31 in leukocytes. In patients with atopic dermatitis, activated leukocytes expressed significantly higher IL-31 levels compared with control subjects. IL-31 receptor A showed most abundant expression in dorsal root ganglia representing the site where the cell bodies of cutaneous sensory neurons reside. CONCLUSION: Our findings provide a new link among staphylococcal colonization, subsequent T-cell recruitment/activation, and pruritus induction in patients with atopic dermatitis. Taken together, these findings show that IL-31 may represent a novel target for antipruritic drug development.     

Keratinocytes from patients with atopic dermatitis and psoriasis show a distinct chemokine production profile in response to T cell-derived cytokines

BACKGROUND: Atopic dermatitis (AD) and psoriasis are genetically determined inflammatory skin disorders. Keratinocytes actively participate in cutaneous inflammatory responses by elaborating various chemokines. OBJECTIVE: We investigated the capacity of IL-4, IFN-gamma, and TNF-alpha to modulate the expression of CCL and CXCL chemokines in cultured keratinocytes from patients and healthy individuals, as well as chemokine expression in situ. METHODS: Keratinocyte cultures were established from normal-looking skin of adult patients with AD or psoriasis vulgaris and from healthy subjects. Monocyte chemoattractant protein 1 (MCP-1)/CCL2, RANTES/CCL5, IL-8/CXCL8, and IFN-gamma-induced protein of 10 kd (IP-10)/CXCL10 production was evaluated at the mRNA and protein levels by using RNase protection assay and ELISA, respectively. The expression of the same chemokines was studied in chronic lesional skin by means of immunohistochemistry or in situ hybridization. RESULTS: Only IL-8 mRNA was detected in unstimulated ke-ratinocyte cultures. MCP-1 and IP-10 were potently induced by IFN-gamma, whereas IL-8 and RANTES were preferentially upregulated by TNF-alpha and, to a lesser extent, by IFN-gamma. IL-4 weakly induced IP-10, RANTES, and IL-8 but not MCP-1. Keratinocytes of patients with AD invariably responded with significantly earlier and higher RANTES expression. By contrast, keratinocytes of patients with psoriasis displayed much higher levels of both constitutive and induced IL-8 and a stronger induction of MCP-1 and IP-10. RANTES and MCP-1 mRNA(+) keratinocytes were detected in the basal layer of lesions of patients with AD and psoriasis. IP-10 and IL-8 were consistently upregulated in the epidermis of patients with psoriasis but not in lesions of patients with AD. CONCLUSIONS: Keratinocytes of patients with AD and psoriasis show an intrinsically abnormal and different chemokine production profile and may thus favor the recruitment of distinct leukocyte subsets into the skin.     

Regulation of allergic inflammation by skin-homing T cells in allergic eczema

BACKGROUND: In allergic inflammations of the skin, the pivotal role of CD45RO+ (memory/effector) T cells expressing the cutaneous lymphocyte-associated antigen (CLA) was demonstrated. In both atopic dermatitis (AD) and contact dermatitis (CD), T cells specific to skin-related allergens were confined to the CLA+ T cell population. Our research was aimed to further characterize these T cells in AD. METHODS: CD4+ and CD8+ subsets of CLA+ CD45RO+ T cells were purified from peripheral blood of AD patients and healthy control individuals. We studied, in vivo activation patterns, cytokine profiles, immunoglobulin isotype regulation and the influence of these cells on eosinophil survival and apoptosis. RESULTS: The CLA+ CD45RO+ T cells represent an in- vivo-activated memory/effector T cell subset as shown by surface expression of activation markers, spontaneous proliferation and a lower activation threshold via TCR/CD3 triggering. These cells contain and spontaneously release high amounts of preformed IL-5 and IL-13 but only very little IL-4 and IFN-gamma in their cytoplasm, as demonstrated by intracellular cytokine staining immediately after purification. Moreover, CLA+ memory/ effector T cells induce IgE production in B cells and enhance eosinophil survival by inhibiting eosinophil apoptosis in AD. In comparison, the CLA- population represents a resting memory T cell fraction, induces rather IgG4 in B cells and does not show any effect on eosinophil survival and apoptosis. CONCLUSION: Our results indicate that in-vivo-activated both CD4+ and CD8+ memory/effector T cells with skin-homing property play a specific and decisive role in the pathogenesis and exacerbation of AD. In contrast, resting memory T cells of atopic individuals retain normal, nonallergic immune functions.     

The interplay between genetic and environmental factors in the pathogenesis of atopic dermatitis

Atopic dermatitis (AD) is a chronic skin disorder characterized by pruritus and recurrent eczematous lesions that are accompanied by T-helper (Th)2-dominated inflammation. AD Etiology is not yet completely understood, but it is multifactorial. Moreover, the disease is characterized by complex interactions between genetic and environmental factors, such as skin barrier dysfunctions, allergy/immunity, and pruritus. For example, filaggrin is a key protein involved in skin barrier function. Th2 cells produce interleukin (IL)-31, which provokes pruritus, and other Th2 cytokines decrease filaggrin expression by keratinocytes. Dupilumab has recently been developed for AD treatment; its mechanism of action is to bind to IL-4 receptor α and inhibit downstream signaling induced by IL-4 and IL-13. This review summarizes the etiopathogenesis of AD and provides the rationale for selecting a novel targeted therapy.     

Milk-induced urticaria is associated with the expansion of T cells expressing cutaneous lymphocyte antigen

BACKGROUND: Two forms of IgE-mediated skin reactions, atopic dermatitis (AD) and urticaria, have been associated with milk allergy. The reason for these distinct reactions is poorly understood. T cells expressing cutaneous lymphocyte antigen (CLA), a unique skin-homing receptor, are known to play an important role in AD. In contrast, the role of lymphocytes in patients with milk-induced urticaria is unclear. OBJECTIVE: The expression of the skin-specific homing receptor CLA after in vitro milk protein-specific stimulation was investigated to determine whether T-lymphocyte homing to the skin plays a role in food-induced urticaria. METHODS: Fourteen patients with milk-induced urticaria but no evidence of AD were included in the study and compared with 6 children with milk-induced AD, 6 children with milk-induced gastrointestinal diseases, and 6 nonatopic and 6 atopic individuals without milk allergy. PBMCs were cultured in the presence or absence of caseins or tetanus toxoid. T-cell proliferation was determined, and T-cell phenotyping was performed by means of flow cytometry with anti-CD4, anti-CD8, and anti-CLA mAbs. RESULTS: After in vitro stimulation with caseins, PBMCs from patients with milk-induced urticaria and AD had a significantly greater percentage of CD4(+) T cells expressing CLA than patients with milk-induced gastrointestinal symptoms and atopic or nonatopic control subjects. After tetanus stimulation in vitro, no significant difference between the groups was observed. T cells from both patients with milk-induced urticaria and control subjects proliferated well in response to caseins and tetanus. CONCLUSION: Lymphocytes expressing CLA are selectively activated in patients with milk-induced urticaria and may play an important role in the pathogenesis of this disease. Expression of CLA is not unique to milk-induced inflammation in the skin of patients with AD and milk allergy.     

Interleukin-31: The “itchy” cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main “drivers” of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H2 cells play a central role in AD and release high levels of T_H2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.     

Expansion and proliferation of skin-homing T cells in atopic dermatitis as assessed at the single cell level

BACKGROUND: Sensitization to aeroallergens is a frequent event in patients with atopic dermatitis (AD). The role of allergen-specific T cells in the pathogenesis of AD is, however, not fully clear. A detailed immunological characterization of allergen-specific T cells able to migrate to inflamed skin might therefore be helpful in determining the relevance of allergen-specific T cells to clinical symptoms. OBJECTIVE: To establish a simple assay to simultaneously monitor the expression of skin-related homing molecules and their proliferative response to an allergen on peripheral T cells. To evaluate whether this assay is able to identify AD patients in whom exposure to an allergen induces dermatitis. METHODS: The expression of CLA, CD7 and CD4 was simultaneously measured by flow cytometry with the DNA content as a parameter of proliferation at the single cell level. House dust mite antigen (DerP) and tetanus toxoid (TT) were used as antigens. RESULTS: CD4+ CLA+ CD7-, but not CLA- T cells from patients with AD proliferated and expanded following DerP stimulation. In contrast, TT stimulation resulted in proliferation of both, CLA+ and CLA- T cells from both, atopic and healthy donors. CONCLUSIONS: Single cell analysis revealed a predominant localization of allergen-reactive T cells within the CD7- CLA+ CD4+ T cell subset in AD. Thus, this simple assay not only confirms previously published results, but also extends our knowledge on the biology of CLA and CD7 cells in AD. Ultimately, this will be helpful in classifying those patients who might benefit from allergen avoidance therapies.     

Expression of cutaneous lymphocyte-associated antigen on human CD4(+) and CD8(+) Th2 cells

The cutaneous lymphocyte-associated antigen (CLA) represents the homing receptor involved in selective migration of memory/effector T cells to the skin. Numerous reports demonstrated distinct CLA expression on Th1 cells. However, T cells isolated from skin lesions and CLA(+) T cells circulating in peripheral blood of atopic dermatitis patients expressed high IL-5 and IL-13. Accordingly, we investigated the regulation of CLA on human type 1 and type 2 T cells. CLA was induced on freshly generated Th1 and Tc1 cells only, but not on those of type 2. Anti-CD3 stimulation was sufficient to induce CLA on Th2 cells in the absence of serum in the culture medium. In serum containing medium, IL-4 inhibited CLA and related alpha-fucosyltransferase mRNA expression. IL-12 and/or staphylococcal enterotoxin B (SEB) stimulation up-regulated CLA expression on either Th2 and Tc2 cells. On stimulation with IL-12, CLA was expressed on the surface of bee venom phospholipase A(2)-specific Th1, Th2, Th0 and T regulatory 1 clones, representing non-skin-related antigen-specific T cells. In addition, CLA could be re-induced on T cells that had lost CLA expression upon resting. These results suggest that skin-selective homing is not restricted to functional and phenotypic T cell subsets.     

Evidence for increased expression of eotaxin and monocyte chemotactic protein-4 in atopic dermatitis

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with tissue eosinophilia and the activation of T lymphocytes. The novel eosinophil chemoattractants, eotaxin and monocyte chemotactic protein (MCP)-4, are up-regulated at sites of allergic inflammation, yet their contribution to the pathophysiologic mechanisms of AD remains to be determined. OBJECTIVE: We sought to investigate the expression of eotaxin and MCP-4 in acute and chronic lesions from patients with AD and to determine their relationship to the numbers of resident inflammatory cells. METHODS: With use of in situ hybridization, the expression of eotaxin and MCP-4 messenger RNA (mRNA) in skin biopsy specimens from patients with acute and chronic AD skin lesions was compared with that of uninvolved skin from these patients and skin from healthy volunteers. RESULTS: There was a constitutive expression of eotaxin and MCP-4 mRNA in skin biopsy specimens from healthy subjects. Positive signal for chemokine mRNA was observed both within the epidermis and inflammatory cells (macrophages, eosinophils, and T cells) of the subepidermis in AD skin lesions. Within the subepithelium acute and chronic skin lesions exhibited a significant increase in the numbers of eotaxin and MCP-4 mRNA-positive cells compared with uninvolved skin (P <.01), whereas the numbers of eotaxin and MCP-4 mRNA-positive cells were significantly higher in chronic AD compared with acute AD skin lesions (P <.005, P <.001, respectively). Correlations were observed between the expression of eotaxin and MCP-4 mRNA and the presence of eosinophils and macrophages, respectively, in AD lesions (r(2) = 0.84, r(2) = 0.94). CONCLUSION: There is an increased expression of eotaxin and MCP-4 in acute and chronic lesions, suggesting that these chemotactic factors play a major role in the pathophysiologic mechanisms of AD.     

Localization of interleukin-13 gene-expressing cells in tuberculin reactions and lesional skin from patients with atopic dermatitis

Interleukin (IL)-13 is a cytokine thought to play an important role in IgE-mediated allergic reactions. The aims of the present study were to localize IL-13 mRNA in positive tuberculin reactions and atopic dermatitis lesions using in situ hybridization and to study the possible influence of atopy on the cytokine gene expression in tuberculin reactions. Punch biopsy specimens were taken from tuberculin reactions in 17 nonatopic and 12 atopic (Phadiatop positive), but otherwise healthy, individuals 72h after injection of purified protein derivative, from chronic lichenified lesions and nonlesional skin in six patients with atopic dermatitis and from normal skin in 12 healthy individuals. IL-13-mRNA-producing cells were located mainly in the dermal-cell infiltrates, both in atopic dermatitis lesions and tuberculin reactions. In the atopic dermatitis lesions, IL-13-mRNA expression was found in close apposition to the epidermis. Higher numbers of IL-13-mRNA-producing cells were observed in the dermal-cell infiltrates of chronic lichenified skin lesions of patients with atopic dermatitis (13.3 cells/mm2, range 0.6-42.4 cells/mm2) than in the tuberculin reactions (1.1 cells/mm2, range 0-3.8 cells/mm2) (P<0.01) despite the larger cell infiltrates in the tuberculin reactions. No significant difference in IL-13 or interferon-gamma gene expression in the tuberculin reactions was seen between atopic and nonatopic individuals.     

Interleukin-4 induced down-regulation of skin homing receptor expression by human viral-specific CD8 T cells may contribute to atopic risk of cutaneous infection

Factors controlling the expression of cutaneous lymphocyte-associated antigen (CLA) by T cells are poorly understood, but data from murine and human CD4(+) T cell systems have suggested that cytokines play an important role. However, there are no data examining the influence of cytokines on the expression of CLA by human antigen-specific CD8(+) T cells. Peripheral blood mononuclear cells (PBMC) were isolated from 10 HLA-A*0201-positive healthy individuals. Using HLA-peptide tetrameric complexes refolded with immunodominant peptides from Epstein-Barr virus (EBV), cytomegalovirus (CMV) and influenza A virus, we investigated the temporal associations of CLA expression by viral-specific CD8(+) T cells following stimulation with antigen. Ex vivo influenza matrix-specific CD8(+) T cells expressed significantly (P < 0.05) greater levels of CLA than EBV BMLF1 and CMV pp65-specific CD8(+) T cells (mean 9.7% influenza matrix versus 1.4% BMLF1 versus 1.1% pp65) and these differences were sustained on culture. However, regardless of viral specificity, interleukin (IL)-12 and IL-4 induced significant (P < 0.05) dose-dependent up-regulation and down-regulation of CLA expression, respectively, with IL-4 showing a dominant negative effect. In many cases, IL-4 resulted in complete abrogation of detectable CLA expression by the viral-specific CD8(+) T cells. Overall these data demonstrate that CLA expression by human viral-specific CD8(+) T cells is highly dynamic and that IL-4 causes significant down-regulation. Disorders associated with a type 2 cytokine shift may reduce the efficiency of skin homing by viral-specific CD8(+) T cells. Furthermore, the ability to modify the local and systemic microenvironment may offer novel therapeutic strategies that influence tissue-specific T cell homing.     

Mechanisms of deficient interferon-γ production in atopic diseases

BACKGROUND: The mechanisms responsible for an imbalanced cytokine response in atopic diseases are still not understood. While impaired interferon-gamma (IFN-gamma) production may be the result of a pathological T-cell/antigen-presenting cell (APC) interaction, evidence was provided that the T cell itself may have an intrinsic defect to produce IFN-gamma. OBJECTIVE: To clarify whether impaired IFN-gamma production by T cells from patients with atopic dermatitis (AD) represents an intrinsic defect in producing IFN-gamma. METHODS: Effector T cells were generated from CD4+ CD45RA+-naive precursors from patients with AD and healthy control individuals by activation with anti-CD3+ anti-CD28 MoAbs. Following restimulation, IFN-gamma production was measured by ELISA and flow cytometry. RESULTS: IFN-gamma production by atopic T cells was decreased compared with healthy T cells. IL-12 present at priming or high doses of IL-2 during the culture period, even in the absence of IL-12, completely restored IFN-gamma production. Conversion of naive CD45RA+ to CD45R0+ effector cells did not differ between atopic and healthy donors' T cells. CONCLUSION: Impaired IFN-gamma production by T cells from atopic individuals is not the result of an intrinsic, genetically fixed, defect to produce sufficient amounts of IFN-gamma. The data provides evidence that correction of an impaired TH1 response in AD may be successful at the precursor T cell level.     

Skin-homing T cells in human cutaneous allergic inflammation

The cutaneous lymphocyte-associated antigen (CLA) is a carbohydrate epitope present on memory/effector T cells that infiltrate inflamed skin. E-selectin is the ligand for CLA and is induced under inflammation on endothelial cells. CLA was originally postulated as a phenotype marker for skin-associated T cells. We studied the specific in vitro response to skinassociated allergens of CLA+and CLA-CD45RO+T cells in atopic dermatitis (AD) and contact dermatitis (CD), which represent two well-characterized T cell-mediated cutaneous allergic inflammations. Whereas CLA+T cells from AD patients preferentially responded to house dust mite (HDM) and CLA+T cells from nickel CD patients showed an increased response to nickel, CLA-T cells showed very little response in both cases. In contrast, tetanus toxoid, a systemically acting antigen, induced a proliferative response in both CLA+and CLA-cells. Interestingly the response to HDM in patients with asthma±AD was preferentially found in the CLA-subset indicating the involvement of different homing receptors for mucosal tissues. Moreover, CLA+T cells showed enhanced migration through activated human umbilical vein endothelial cell monolayers compared to CLA-T cells. The CLA binding to E-selectin is initially responsible for the extravasation that also involves VLA-4/VCAM-1 and LFA-1/ ICAM-1 interactions. We have recently identified IL-8 as an endothelial cell-derived chemokine and the IL-8 receptor type B which control CLA+T cell migration. Such a CLA-mediated migration would localize memory/effector T cells that respond to antigens and reach the body through inflamed skin. Our data support the existence of a regionalization of the immune system and in particular of the skin immune system. It may allow an efficient distribution of the immune defense to different sites of the body.     

Therapeutic effects of combination using glucosamine plus tacrolimus (FK-506) on the development of atopic dermatitis-like skin lesions in NC/Nga mice

Tacrolimus (FK-506) has been found to exhibit potent inhibitory effects on spontaneously developed dermatitis. We previously showed that glucosamine prevents the development of Atopic dermatitis (AD)-like skin lesions in NC/Nga mice. The aims of our study were to investigate the synergistic therapeutic efficacy of combination of glucosamine plus FK-506 in dermatophagoides farina (Df)-induced AD-like skin lesions in NC/Nga mice and to determine the underlying therapeutic mechanisms. The Df-induced NC/Nga mice with a clinical score of 8 were used for treatment with glucosamine (500 mg/kg) alone, FK-506 (1.0 mg/kg) or in combination. The synergistic effects of combination therapy were evaluated by dermatitis scores, skin histology and immunological parameters such as IgE, Th2-mediated cytokines and chemokines, CD3(+) T cells and CLA(+) T cells. Combined therapy using glucosamine plus FK-506 improved the development of AD-like skin lesions as exemplified by a significant decrease in total skin symptom severity scores. The suppression of dermatitis by combined therapy was accompanied by a decrease in the plasma level of IgE and in the splenic level of IL-5, IL-13, TARC and eotaxin. Histological finding indicated that the dermal infiltration of inflammatory cells including mast cells and eosinophils was greatly reduced. Particularly, immunohistological evaluation reveals a reduction in CD3(+) T cells and CLA(+) cells in the combined therapy. Our findings suggest that combination therapy of glucosamine plus FK-506 was more synergistic efficacy than single-modality treatment with either alone to improve the development of established dermatitis in NC/Nga mice model. This combined immunosuppressive therapy may provide an effective therapeutic strategy for the treatment of AD.     

In vivo relevance of CD30 in atopic dermatitis

CD30 expression was evaluated by immunohistochemistry in lesional skin biopsies of eight patients with active atopic dermatitis (AD) and three patients with allergic contact (nickel-induced) dermatitis (ACD). CD30 expression was also assessed in a large panel of CD4 + and CDS + T-cell clones generated from the skin biopsies of four patients with AD. Finally, the levels of soluble CD30 (sCD30) were measured in the serum of 41 patients with AD, 19 patients with ACD, and 60 healthy controls. In all specimens of lesional AD skin, where the great majority of infiltrating cells were CD4+ T cells, remarkable numbers of cells were CD30+, whereas virtually no CD30 + cells were found in the skin of patients with ACD. In CD4+ T-cell clones generated from the lesional AD skin, most of which produced both interleukin (IL)-4 and interferon-gamma (IFN-γ) (Th0–like cells) or IL-4 and 1L-5, but not IFN-γ (Th2–like cells), CD30 expression directly correlated with the ability to produce IL-4 and IL-5, but was inversely related to IFN-γ production. High levels of sCD30 (correlated with disease activity: r = 0.618) were detected in the serum of most AD patients, whereas there was no increase of sCD30 levels in the serum of patients with ACD. These data support the view that Th0/Th2–type responses predominate in the skin of patients with AD and suggest that the presence of CD30 + T cells in tissues and/or increased levels of sCD30 in biologic fluids are indicative of Th2–dominated responses.