IL-31 is associated with cutaneous lymphocyte antigen-positive skin homing T cells in patients with atopic dermatitis

BACKGROUND: IL-31 is a newly discovered T-cell cytokine that, when overexpressed in mice, results in pruritus and skin dermatitis resembling human atopic dermatitis (AD). OBJECTIVE: We sought to investigate the expression of IL-31 and IL-31 receptor A (IL-31RA) in skin biopsy specimens and peripheral blood cells from patients with AD and healthy individuals. METHODS: Expression of IL-31 and IL-31RA was evaluated in skin biopsy specimens from patients with AD and healthy individuals by means of immunohistochemistry and RT-PCR. IL-31 protein production by skin-homing cutaneous lymphocyte antigen (CLA)-positive T cells was also assessed. RESULTS: IL-31RA protein was expressed by keratinocytes and infiltrating macrophages in skin biopsy specimens from patients with AD. Comparisons between skin from patients with AD and healthy skin showed IL-31RA expression at higher levels on epidermal keratinocytes in AD samples. Infiltrating cells, more numerous in skin from patients with AD compared with that of healthy individuals, expressed IL31 mRNA. Histomorphometric analysis of these cells indicated they were of the lymphocytic lineage, with the majority of cells staining positive for CLA and CD3. IL31 mRNA and protein expression is largely restricted to CD45RO(+) (memory) CLA(+) T cells in peripheral blood of patients with AD and healthy volunteers. Moreover, circulating CLA(+) T cells from patients with AD, but not from patients with psoriasis, are capable of producing higher levels of IL-31 compared with CLA(+) T cells from healthy individuals. However, the average levels of IL-31 were not significantly different between patients with AD and healthy individuals. CONCLUSION: We provide evidence that IL-31 expression is associated with CLA(+) T cells and might contribute to the development of AD-induced skin inflammation and pruritus.     

Polarized in vivo expression of IL-11 and IL-17 between acute and chronic skin lesions

BACKGROUND: In atopic dermatitis (AD) there is evidence of tissue fibrosis involving a number of structural changes, including papillary dermal fibrosis and epidermal hyperplasia. These changes are suggested to be the result of chronic inflammation of the skin. Several remodeling-associated cytokines, including transforming growth factor (TGF) beta1, IL-11, and IL-17, have been shown to be increased in allergic diseases, including asthma. OBJECTIVE: We investigated TGF-beta1, IL-11, and IL-17 expression in skin biopsy specimens recovered from acute and chronic skin lesions from patients with AD, as well as from uninvolved skin of patients with AD and skin from healthy volunteers. We also examined the correlation between the expression of these cytokines and the extent of total, type I, and type III collagen deposition. METHODS: We evaluated the expression of TGF-beta1, IL-11, and IL-17 by means of immunohistochemistry. Collagen deposition was assessed by means of immunohistochemistry and van Gieson staining. RESULTS: TGF-beta1 expression was markedly enhanced in both acute and particularly chronic lesions (P <.001). Although IL-11 expression was significantly increased only in chronic lesions (P <.0001), IL-17 was preferentially associated with acute lesions (P <.005). Although collagen type III deposition was not significantly different among the groups, type I collagen deposition was significantly increased in chronic AD lesions (P <.0005). There was a significant correlation between IL-11 and type I collagen deposition, as well as the number of eosinophils in skin specimens from patients with AD (r (2) = 0.527, and r (2) = 0.622, respectively; P <.0001). CONCLUSION: These results suggest that TGF-beta1, IL-11, and IL-17 are involved in the remodeling of skin lesions in patients with AD. However, IL-11 and IL-17 are preferentially expressed at different stages of the disease. Type I collagen appeared to be the major subtype involved in this repair process.     

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。     

An obligate role for T-cell receptor alphabeta+ T cells but not T-cell receptor gammadelta+ T cells, B cells, or CD40/CD40L interactions in a mouse model of atopic dermatitis

BACKGROUND: We recently described a murine model of atopic dermatitis (AD) elicited by epicutaneous sensitization with ovalbumin (OVA). The skin lesions in these mice were characterized by a dermal infiltrate consisting of eosinophils and T cells and by increased expression of the TH2 cytokines IL-4 and IL-5. Epicutaneous sensitization induces a rise in the levels of serum total IgE and OVA-specific antibodies, further indicating that it elicits a predominantly TH2 response. OBJECTIVE: This study was undertaken to assess the roles of T cells, B cells, and CD40L-CD40 interactions in AD. METHODS: Mice with targeted gene deletions were sensitized with OVA. Histologic and immunohistochemical examinations, as well as measurements of IL-4 mRNA, were performed on OVA-sensitized skin. Total and antigen-specific serum IgE levels were determined. RESULTS: RAG2(-/-) mice, which lack both T and B cells, did not exhibit cellular infiltration, induction of dermal IL-4 mRNA, or elevation of serum IgE after OVA sensitization; all of these features were present in B-cell-deficient IgH(-/-) mice. T-cell receptor alpha(-/-) mice did not display cellular infiltration, IL-4 mRNA expression, or increased IgE levels after OVA sensitization, but these responses were elicited in T-cell receptor delta(-/-) mice after sensitization. Absence of CD40 had no effect on these responses. CONCLUSION: These results suggest that alphabeta T cells, but not gammadelta T cells, B cells, or CD40L-CD40 interactions, are critical for skin inflammation and the TH2 response in 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.     

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.     

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.     

Distinct patterns of gene expression in the skin lesions of atopic dermatitis and psoriasis: a gene microarray analysis

BACKGROUND: Atopic dermatitis (AD) and psoriasis are the two most common chronic inflammatory skin diseases. Both of these diseases have distinct clinical findings and specific inflammatory cell infiltrates. Previous reports have focused individually on one or two genes or gene products in the lesions of both skin diseases. However, they have not captured the complex gene expression that must occur to induce specific cellular infiltrates in the skin lesions of these two diseases. DNA microarray studies allow the simultaneous comparison of thousands of messenger RNAs that may identify the disease-specific pattern of tissue inflammatory responses. OBJECTIVE: To compare the complex gene expression pattern of AD versus psoriasis skin lesions. METHODS: RNA was extracted from skin biopsy specimens of 6 patients with AD and 7 patients with psoriasis and analyzed with the use of Hu-U95Av.GeneChip microarrays. To confirm GeneChip results, real-time PCR of selected genes were performed. RESULTS: In AD skin, a total of 18 genes including the CC chemokines, CCL-13/MCP-4, CCL-18/PARC, and CCL-27/CTACK showed a statistically significant, >2-fold increase of gene expression compared with psoriasis. In psoriasis skin, a total of 62 genes including CCL-4/MIP-1beta, CCL-20/MIP-3alpha, CXCL-2/GRO-beta CXCL-8/IL-8, and CXCR2/IL-8R showed a >2-fold increase of gene expression compared with AD skin. Real-time PCR confirmed several of these GeneChip results. CONCLUSIONS: These results show a very distinctive gene expression pattern in AD as compared with psoriasis that may explain several features of AD and psoriasis including the specific inflammatory cell infiltrates observed in these disorders, that is, T(H)2 cells, eosinophils, and mast cells in AD and T(H)1 cells and neutrophils in psoriasis. Such observations may contribute to a characteristic "signature" for these two skin diseases.     

Expression of fractalkine and its receptor, CX3CR1, in atopic dermatitis: possible contribution to skin inflammation

BACKGROUND: Fractalkine (FKN) induces activation and adhesion of leukocytes expressing its receptor, CX(3)CR1. FKN is released from the cell surface through proteolytic cleavage as soluble FKN (sFKN). OBJECTIVE: We sought to assess FKN and CX(3)CR1 expression in the skin, serum sFKN levels, and CX(3)CR1 expression on blood leukocytes in patients with atopic dermatitis (AD). METHODS: FKN and CX(3)CR1 expression in the skin was examined immunohistochemically. mRNA expression of FKN, thymus and activation-regulated chemokine, and macrophage-derived chemokine in the skin was assessed by means of real-time RT-PCR. Serum sFKN levels were assessed by using ELISA. Blood leukocytes were stained for CX(3)CR1 by means of flow cytometric analysis. RESULTS: FKN was strongly expressed on endothelial cells in skin lesions of patients with AD and psoriasis but not in normal skin. FKN mRNA levels in AD lesional skin increased to a similar extent to thymus and activation-regulated chemokine and macrophage-derived chemokine mRNA levels. CX(3)CR1-expressing cells in the affected skin of patients with AD or psoriasis increased compared with those in normal skin. Serum sFKN levels were increased in patients with AD but not in patients with psoriasis relative to levels in healthy control subjects. Serum sFKN levels were associated with the disease severity and decreased with the improvement of skin lesions in patients with AD. CX(3)CR1(+) cell frequencies and CX(3)CR1 expression levels were decreased in CD8(+) T cells, monocytes, and natural killer cells from patients with AD, but this was not observed in patients with psoriasis. CONCLUSIONS: These results suggest that through functions in both membrane-bound and soluble forms, FKN plays an important role in the trafficking of CX(3)CR1(+) leukocytes during the inflammation caused by AD.     

CCR4 memory CD4+ T lymphocytes are increased in peripheral blood and lesional skin from patients with atopic dermatitis

BACKGROUND: Recent studies have reported that TH1 and TH2 cells express CXCR3 and CCR4, respectively. OBJECTIVE: Our goal was to assess the association of CCR4 and CXCR3 expression with TH2 and TH1 cells and association of CCR4 and CXCR3 expression with inflammation in patients with atopic dermatitis (AD). METHODS: Intracellular cytokine production and chemokine receptor expression in blood T cells were examined by flow cytometry. Immunohistochemical expression of chemokine receptors was also investigated in chronically lesional skin. RESULTS: CCR4+ and CXCR3+ CD4+ T cells predominantly produced IL-4 and IFN-gamma, respectively. Although the frequency of CXCR3+ cells among CD4+ CD45RO+ T cells was similar for patients with AD (n = 29) and healthy control subjects (n = 19), patients with severe AD (n = 14) had a reduced frequency of CXCR3+ cells. In contrast, the frequency of CCR4+ cells and the CCR4/CXCR3 ratio were higher in patients with AD (n = 22) than healthy control subjects (n = 16) and correlated with disease severity of AD. The frequency of CCR4+ cells correlated positively with eosinophil numbers and serum IgE levels, whereas the frequency of CXCR3+ cells correlated inversely with eosinophil numbers. The frequency of CCR4+ or CXCR3+ cells was similar in patients with psoriasis (n = 6) and healthy control subjects. Immunohistochemical analysis showed that the frequency of CCR4+ cells among CD4+ T cells in chronically lesional skin of patients with AD (n = 9) was higher than that of patients with psoriasis (n = 4). CONCLUSION: Our data suggest the association of CCR4 expression with TH2 cells, the predominance of CCR4+ cells in blood from patients with AD, and an important role of CCR4 in the migration of TH2 cells from blood into AD lesional skin.     

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.     

Thymus and activation-regulated chemokine in atopic dermatitis: Serum thymus and activation-regulated chemokine level is closely related with disease activity

BACKGROUND: Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by the predominant infiltration of TH2-type cells in lesional skin. Thymus and activation-regulated chemokine (TARC/CCL17) is a chemokine that attracts CC chemokine receptor 4-positive (CCR4+) or CCR8+ cells. OBJECTIVE: The purpose of this study was to investigate the participation of TARC in AD. METHODS: We measured serum TARC levels in 40 patients with AD, 20 healthy control subjects, and 20 patients with psoriasis. We also examined disease activity by using SCORAD score; serum soluble E-selectin, soluble IL-2 receptor, IgE, and GM-CSF levels; and eosinophil numbers in peripheral blood, as well as correlations between TARC levels and these factors. The positivity of CCR4 of CD4+CD45RO+ cells in PBMCs was examined by using FACS analysis. Immunohistochemical staining of TARC and GM-CSF was performed in the lesional skin of patients with AD. RESULTS: The serum TARC levels of patients with AD were significantly higher than those of healthy control subjects and patients with psoriasis. The serum TARC levels significantly correlated with eosinophil number (r = 0.61), SCORAD score (r = 0.60), and serum soluble E-selectin levels (r = 0.58) and weakly correlated with serum soluble IL-2 receptor levels (r = 0.34) in patients with AD. The TARC levels of patients with AD decreased after the treatment in accordance with the improvement of clinical symptoms. The CCR4 positivity of CD4+CD45RO+ cells in PBMCs of patients with AD was also higher than that of healthy control subjects. Immunohistochemical staining revealed that TARC was positive in keratinocytes in the epidermis and in vascular endothelial cells, T cells, and dendritic cells in the dermis. CONCLUSION: Serum TARC levels are associated with disease activity of AD, and TARC may play an important role in the pathogenesis of AD.     

Differential in vivo cytokine mRNA expression in lesional skin of intrinsic vs. extrinsic atopic dermatitis patients using semiquantitative RT-PCR

BACKGROUND: A small subgroup of atopic dermatitis (AD) patients with normal serum IgE levels and without specific IgE sensitization has been termed 'intrinsic type of AD' (ADi) as a counterpart to the term 'extrinsic type of AD' (ADe). However, there are neither molecular markers nor clinically diagnostic tools for distinguishing between ADi and ADe. OBJECTIVE: The present studies were undertaken to clarify the pathogenesis and in vivo cytokine micromilieu of ADi patients in comparison with ADe patients. METHODS: We used semiquantitative RT-PCR to investigate the expression of various cytokines and assessed the tissue eosinophil counts in skin biopsies from both types of AD patients. RESULTS: Although there was no significant difference of cellular infiltrates in the lesional skin between ADe and ADi patients, ADe had significantly increased tissue eosinophilia than ADi. Based on our RT-PCR, the expression patterns of cytokines could be categorized into four groups. The first group includes IL-5, IL-13, and IL-1beta, whose levels of mRNA expression were higher in both types of AD patients than non-atopic (NA) subjects, while ADe patients had even higher levels than ADi patients. The second group includes interferon-gamma (IFN-gamma), IL-12, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4, and IL-10, whose levels of mRNA expression were elevated in both types of AD patients without differences between ADe and ADi patients. The third group includes tumour necrosis factor-alpha (TNF-alpha), whose mRNA expression was more decreased in both types of AD patients than NA, and the fourth group includes IL-6 and transforming growth factor-beta (TGF-beta), which did not show any differences among the three groups. CONCLUSION: These current data demonstrate that the expressions of cytokines IL-5, IL-13, and IL-1beta mRNA and the number of dermal infiltrating eosinophils are increased in ADe patients compared with ADi patients.     

CCL27 is a critical factor for the development of atopic dermatitis in the keratin-14 IL-4 transgenic mouse model

The keratin-14 IL-4 transgenic (Tg) mouse model of atopic dermatitis (AD) is characterized by skin infiltration of T cells, early up-regulation of T(h)2 cytokines and late surge of T(h)1 cytokines. In the present study, we investigated the role of CCL27, a T cell skin-homing chemokine known to be elevated in sera of human AD patients, in disease development in our animal model of AD. The results showed that the mRNA and protein levels of CCL27 in the skin and serum were significantly increased in IL-4 Tg mice. The percentage of T cells expressing CCR10 in skin draining lymph nodes of IL-4 Tg mice was increased, consistent with the findings of >80% of skin-infiltrating T cells in Tg mice expressing CCR10. Chemotaxis transmigration assay demonstrated that CCL27 promotes a greater degree of migration of T cells in diseased Tg mice. Subcutaneous injection of neutralizing anti-CCL27 to IL-4 Tg mice with early skin lesions resulted in reduced clinical progression of inflammation, accompanied with decreased T cell and mast cell infiltration in the skin, and down-regulation of inflammatory cytokines. In conclusion, CCL27 and CCR10 interaction is important for the development of skin inflammation in our AD model.     

Tear levels of interferon-γ, interleukin (IL) -2, IL-4 and IL-5 in patients with vernal keratoconjunctivitis, atopic keratoconjunctivitis and allergic conjunctivitis

BACKGROUND: A predominance of TH2 activity in chronic allergic diseases, such as vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC), has been suggested recently. However, there is no published study on tear levels of cytokines of the two different subgroups, TH1 and TH2, in patients with ocular allergy. OBJECTIVES: We measured interferon (IFN)-gamma, interleukin (IL)-2, IL-4 and IL-5 levels in tears by ELISA, to determine whether the levels of these cytokines are elevated in allergic ocular diseases when compared among patient groups and normal controls. METHODS: Tear levels of IL-2, IFNgamma, IL-4 and IL-5 were measured by ELISA using samples from patients with VKC, AKC (AKC-NP, without proliferative lesions; and AKC-P, with proliferative lesions), allergic conjunctivitis (AC) and normal subjects. The levels of these cytokines in tears and the clinical severity of AD were also compared. RESULTS: Tear IL-4 level in patients with AKC was significantly higher than those in VKC, AC and controls, and tear IL-4 levels in patients with AKC-P vs VKC differed significantly. Tear IL-5 levels in patients with diseases associated with proliferative lesions, VKC and AKC-P, were higher than those in AC and normal controls. However, tear level of IL-5 in patients with AKC-P was significantly higher than that in AKC-NP. Although the dermatological severity of AD correlated significantly with tear IL-4 level, IFNgamma, IL-2 and IL-5 levels did not correlate with dermatological severity of AD. CONCLUSION: These results indicate that the TH2-like cytokines play an important pathophysiological role in severe ocular allergic conditions such as AKC and VKC and that tear level of IL-5 may be a candidate marker to evaluate the clinical status of ocular allergy. The different patterns of tear levels of IL-4 and IL-5 among ocular allergic diseases may reflect the origin and immunological basis of these cytokines.     

Impaired TLR-2 expression and TLR-2-mediated cytokine secretion in macrophages from patients with atopic dermatitis

Background:  In many patients with atopic dermatitis (AD), the disease is complicated by their enhanced susceptibility to bacterial skin infections, especially with Staphylococcus aureus . The pattern recognition receptor toll-like receptor (TLR)-2 recognizes components of S. aureus , for example, lipoteichoic acid (LTA) and peptidoglycan (PGN) and, therefore, might be crucial in the pathogenesis and flare-ups of AD.
Objective:  To investigate TLR-2 expression and cytokine secretion in macrophages from patients with AD compared to healthy controls upon TLR-2 stimulation with PGN, LTA and Pam3Cys.
Methods:  Macrophages were cultivated from highly purified peripheral blood monocytes of AD patients and nonatopic healthy controls and stimulated with PGN, LTA and Pam3Cys in a time and dose–dependent manner. Afterwards, TLR-2 expression and cytokine secretion were measured on protein and mRNA level. TLR-1 and TLR-6 expression were investigated on the mRNA level. Immunohistochemical stainings from punch biopsies were performed to investigate TLR-2 expression in skin macrophages .
Results:  We could clearly show that macrophages from patients with AD expressed significantly less TLR-2, whereas the expression pattern of TLR-1 and TLR-6 were not altered. Macrophages had a reduced capacity to produce pro-inflammatory cytokines such as IL-6, IL-8 and IL-1β after stimulation with TLR-2 ligands.
Conclusion:  Our findings clearly show an impaired TLR-2 expression and functional differences of TLR-2-mediated effects on macrophages of AD patients compared to healthy controls which might contribute to the enhanced susceptibility to skin infections with S. aureus in AD.     

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.