Accumulation of CCR4-expressing CD4+ T cells and high concentration of its ligands (TARC and MDC) in bronchoalveolar lavage fluid of patients with eosinophilic pneumonia

BACKGROUND: Th2 cells are thought to be involved in eosinophilic inflammation of the lung. CC chemokine receptor 4 (CCR4) has been identified as a specific receptor for both thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC), and is preferentially expressed on Th2 cells. OBJECTIVE: Our aim was to evaluate the role of Th2 cells in the lung of patients with eosinophilic pneumonia (EP). METHODS: The concentrations of TARC, MDC, and interleukin (IL)-5 were measured in bronchoalveolar lavage fluid (BALF) by ELISA. Proportion of CCR4-expressing CD4+ T cells (CCR4+ CD4+ T cells) was determined by flow cytometry. RESULTS: TARC and MDC concentrations in BALF were higher in patients with EP than in normal subjects. The proportion of CCR4-expressing cells among CD4+ T cells was higher in BALF than in peripheral blood of patients with EP. There was a significant correlation between the number of CCR4+ CD4+ T cells and the levels of TARC, MDC, and IL-5 in BALF of patients with EP. CONCLUSIONS: Our data suggest that Th2 cells, which express CCR4 and its ligands (TARC and MDC), contribute to the pathogenesis of EP in the lung.     

Potential role of the chemokine receptors CXCR3, CCR4, and the integrin alphaEbeta7 in the pathogenesis of psoriasis vulgaris

Various adhesion molecules have been implicated in T lymphocyte binding to dermal vascular endothelium in psoriasis vulgaris, but the chemotactic signals that promote subsequent homing into the adjacent dermis and overlying epidermis are poorly defined. We studied chemokine receptor (CCR1-CCR5, CXCR1-CXCR3), chemokine (interferon-gamma inducible protein 10 [IP-10]), monokine induced by interferon-gamma (MIG), thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), and adhesion molecule (cutaneous lymphocyte antigen [CLA], E-selectin, lymphocyte function-associated antigen-1 [LFA-1], intercellular adhesion molecule-1 [ICAM-1], very late antigen 4 [VLA-4], vascular cell adhesion molecule-1 [VCAM-1], alphaEbeta7, and E-cadherin) expression in psoriasis by immunohistology, flow cytometry, and molecular techniques. CXCR3 and CCR4 were expressed by dermal CD3+ lymphocytes, and their chemokine ligands, IP-10, MIG, TARC, and MDC, were up-regulated in psoriatic lesions. Keratinocytes stimulated with tumor necrosis factor-alpha and interferon-gamma up-regulated expression of IP-10, MIG, and MDC mRNA, whereas dermal endothelial cells, similarly stimulated, up-regulated expression of IP-10, MDC, and TARC mRNA, suggesting that these cell types were sources of the chemokines detected in biopsies. There was enhanced expression of E-selectin, CLA, LFA-1, ICAM-1, VLA-4, VCAM-1, and alphaEbeta7 in psoriatic lesions versus nonlesional skin. Finally, intra-epidermal CLA+ and alphaEbeta7+ T lymphocytes selectively expressed the chemokine receptor CXCR3. Collectively, these data suggest that CXCR3 and CCR4 may be involved in T lymphocyte trafficking to the psoriatic dermis and that CXCR3 is selectively involved in subsequent T cell homing to the overlying epidermis.     

CC chemokine receptor 4 ligand production by bronchoalveolar lavage fluid cells in cigarette-smoke-associated acute eosinophilic pneumonia

We examined the production of macrophage-derived chemokine (MDC/CCL22) and thymus- and activation-regulated chemokine (TARC/CCL17) by bronchoalveolar lavage fluid (BALF) cells in cigarette-smoke-associated acute eosinophilic pneumonia (CS-AEP). The CC Chemokine Receptor 4 (CCR4) ligand levels in BALF from patients with CS-AEP were considerably higher than those in healthy volunteers and correlated well with Th2 cytokine levels. Interleukin-4 enhanced CCR4 ligand production. MDC expression was observed in CD68-positive cells from patients with CS-AEP and in healthy control smokers. In contrast, TARC expression in CD68- or CD1a-positive cells was detected only in CS-AEP. An in vivo cigarette smoke challenge test induced increases in CCR4 ligands in the BALF and in the cultured supernatant of BALF adherent cells. These results suggest that alveolar macrophages and dendritic cells contribute to the pathogenesis of CS-AEP by generating CCR4 ligands, probably in response to cigarette smoke.     

Selective recruitment of CCR4-bearing Th2 cells toward antigen-presenting cells by the CC chemokines thymus and activation-regulated chemokine and macrophage-derived chemokine

Helper T cells are classified into Th1 and Th2 subsets based on their profiles of cytokine production. Th1 cells are involved in cell-mediated immunity, whereas Th2 cells induce humoral responses. Selective recruitment of these two subsets depends on specific adhesion molecules and specific chemoattractants. Here, we demonstrate that the T cell-directed CC chemokine thymus and activation-regulated chemokine (TARC) was abundantly produced by monocytes treated with granulocyte macrophage colony stimulating factor (GM-CSF) or IL-3, especially in the presence of IL-4 and by dendritic cells derived from monocytes cultured with GM-CSF + IL-4. The receptor for TARC and another macrophage/dendritic cell-derived CC chemokine macrophage-derived chemokine (MDC) is CCR4, a G protein-coupled receptor. CCR4 was found to be expressed on approximately 20% of adult peripheral blood effector/memory CD4+ T cells. T cells attracted by TARC and MDC generated cell lines predominantly producing Th2-type cytokines, IL-4 and IL-5. Fractionated CCR4+ cells but not CCR4- cells also selectively gave rise to Th2-type cell lines. When naive CD4+ T cells from adult peripheral blood were polarized in vitro, Th2-type cells selectively expressed CCR4 and vigorously migrated toward TARC and MDC. Taken together, CCR4 is selectively expressed on Th2-type T cells and antigen-presenting cells may recruit Th2 cells expressing CCR4 by producing TARC and MDC in Th2-dominant conditions.     

Type 1 chemokine receptor expression in Chagas' disease correlates with morbidity in cardiac patients

Chemokines and chemokine receptors (CKRs) control the migration of leukocytes during the inflammatory process and are important immunological markers of type 1 (CCR5 and CXCR3) and type 2 (CCR3 and CCR4) responses. The coexpression of CKRs (CCR2, CCR3, CCR5, CXCR3, and CXCR4) and intracellular cytokines (interleukin-10 [IL-10], IL-4, tumor necrosis factor alpha [TNF-alpha], and gamma interferon [IFN-gamma]) on T CD4+ and CD8+ peripheral cells from individuals with indeterminate (IND) or cardiac (CARD) clinical forms of Chagas' disease after in vitro stimulation with Trypanosoma cruzi antigens, were evaluated in this study. The percentage of T CD4+ and CD8+ cells coexpressing CCR5 and IFN-gamma, CXCR3 and IFN-gamma, and CXCR3 and TNF-alpha were higher in CARD than in IND individuals; on the other hand, the percentage of T CD4+ or CD8+ cells coexpressing CCR3 and IL-10 or coexpressing CCR3 and IL-4 were lower in CARD individuals than in IND individuals. In addition, a significant positive correlation between the expression of CCR5 or CXCR3 and IFN-gamma was observed in CARD individuals contrasting with a significant positive correlation between the expression of CCR3 and IL-4 and of CCR3 and IL-10 in IND patients. These results reinforce the hypothesis that a T. cruzi-exacerbated specific type 1 immune response developed by CARD chagasic patients is associated with the development of heart pathology.     

Pulmonary T(H)2 response in Pseudomonas aeruginosa-infected patients with cystic fibrosis

BACKGROUND: Pseudomonas aeruginosa infection determines the course of cystic fibrosis (CF) lung disease. Studies in human peripheral blood indicate that P aeruginosa infection is associated with a predominant T(H)2 immune response, whereas T(H)1 responses are accompanied by a better pulmonary outcome. OBJECTIVE: Analyses of peripheral blood may not correspond directly with the local pulmonary immune response. Therefore, we asked whether the T(H)1/T(H)2 response is altered in bronchoalveolar lavage fluid from P aeruginosa-infected patients with CF. METHODS: Bronchoalveolar lavage fluid was obtained from 12 patients with CF chronically infected with P aeruginosa, 11 noninfected patients with CF, and 8 healthy controls. Pulmonary CXCR3(+) (T(H)1) and CCR4(+) (T(H)2) expressing CD4(+) and CD8(+) lymphocytes were quantified by flow cytometry. Levels of T(H)1-associated (IL-2, IFN-gamma, IFN-gamma inducible T cell-alpha chemoattractant, Monokine induced by IFN-gamma, IFN-gamma inducible protein of 10 kd) and T(H)2-associated (IL-4, IL-5, IL-10, thymus and activation-regulated chemokine [TARC], macrophage-derived chemokine) cytokines and chemokines and a panel of proinflammatory molecules were quantified at the protein level. Chemokines mRNA levels were assessed by real time RT-PCR. RESULTS: P aeruginosa-infected patients with CF had significantly higher levels of pulmonary CCR4(+)CD4(+) (T(H)2) cells, IL-4, IL-13, and TARC and lower levels of IFN-gamma compared with noninfected patients with CF and healthy controls. Bronchoalveolar lavage fluid levels of IL-4, IL-13, and TARC correlated inversely with FEV(1) in P aeruginosa-infected patients with CF. CONCLUSION: These results reveal the prevalence of a pulmonary T(H)2 immune response in P aeruginosa-infected patients with CF. The modulation of the pulmonary T(H)2 response in P aeruginosa infection may be an option for the treatment of P aeruginosa lung disease in patients with CF.     

Accumulation of CXCR3-expressing eosinophils and increased concentration of its ligands (IP10 and Mig) in bronchoalveolar lavage fluid of patients with chronic eosinophilic pneumonia

BACKGROUND: Since human peripheral eosinophils have been shown to migrate to the CXC chemokine receptor 3 (CXCR3) ligands IFN-gamma-inducible protein 10 (IP10) and monokine induced by IFN-gamma (Mig), this confirms that CXCR3 is functionally expressed on these cells. IP10 expression has been shown to be increased in the airways of asthmatics. Eosinophil accumulations are found in bronchoalveolar lavage fluid (BALF) from patients with chronic eosinophilic pneumonia (CEP). To examine the contribution of IP10 and Mig in the pathogenesis of CEP, we measured the concentration of IP10 and Mig, and evaluated the expression of CXCR3 on eosinophils in BALF taken from patients with CEP. METHODS: The concentrations of IP10 and Mig in BALF were measured by ELISA. The proportion of CXCR3-expressing CD4+ T cells and CD16-negative eosinophils was determined by flow cytometry. RESULTS: The BALF concentrations of IP10 and Mig were higher in patients with CEP, as well as in patients with sarcoidosis, when compared to healthy controls. The absolute number of CXCR3+ CD4+ T cells was significantly higher in the BALF of patients with sarcoidosis, but not in the patients with CEP, when compared to healthy volunteers. There were higher percentages of CXCR3-expressing eosinophils in the BALF than in the peripheral blood of patients with CEP. CONCLUSIONS: Our findings suggest that IP10 and Mig contribute to the accumulation of CXCR3-expressing eosinophils in the lungs of patients with CEP, and modulate the eosinophilic inflammation of the lung.     

Increased levels of a TH2-type CC chemokine thymus and activation-regulated chemokine (TARC) in serum and induced sputum of asthmatics

BACKGROUND: Cytokines liberated by TH2 cells play crucial roles in the pathogenesis of bronchial asthma. Recent studies have demonstrated that CC chemokine receptor (CCR)4 is preferentially expressed by TH2 cells. These facts suggest possible involvement of two CCR4-specific ligands i.e., thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC), in the pathogenesis of bronchial asthma via recruitment of TH2 cells to inflammatory sites. We investigated the levels of TARC and MDC in the serum and induced sputum of asthmatics. METHODS: The levels of TARC in the serum (46 asthmatics and 26 healthy subjects) and induced sputum (30 asthmatics and 6 healthy subjects) were measured using a highly sensitive ELISA system. The levels of eotaxin and MDC were also measured by ELISA. RESULTS: TARC, but not MDC, was significantly increased in asthmatic sera (P<0.001). Although MDC was undetectable in the sputum of most cases by our assay system, sputum TARC was significantly increased (P=0.027). CONCLUSIONS: The elevated TARC levels in asthmatics might be involved in the pathophysiology of asthma.     

趋化因子受体CCR5、CCR7、CXCR3和CXCR6在丙肝患者肝内及外周血CD4+ T淋巴细胞上的表达及其意义

目的比较趋化因子受体CCR5、CCR7、CXCR3和CXCR6在丙肝患者肝内和外周血CD4^＋T淋巴细胞表面表达水平及其意义,同时进一步了解其与肝脏组织学炎症反应的关系.方法采用荧光标记抗趋化因子受体的单克隆抗体对肝内及外周血中CD4^＋T淋巴细胞表面的趋化因子受体进行染色后,采用9色11参数流式细胞仪LSRⅡ进行检测分析.结果（1）肝内CCR5^＋、CXCR3^＋或/和CXCR6^＋的CD4^＋T淋巴细胞频数高于外周血（P＜0.001）,而CCR7^＋CD4^＋T淋巴细胞频数低于外周血（P＜0.001）;（2）肝内CCR5^＋或CXCR6^＋的活性（CD38^＋）CD4^＋T淋巴细胞频数高于外周血（P＜0.05）;（3）肝内表达2种或2种以上趋化因子受体CCR5、CXCR3和CXCR6的CD4^＋T淋巴细胞频数明显高于外周血（P＜0.001）,而不表达或仅表达一种上述趋化因子受体CD4^＋T淋巴细胞频数明显低于外周血（P＜0.001）;（3）CCR5和CXCR6在肝内CD4^＋T淋巴细胞表面的表达有中等度相关;（4）肝内组织学炎症明显组表达趋化因子受体CCR5、CXCR3或CXCR6的CD4^＋T淋巴细胞频数高于炎症轻微组.结论趋化因子受体CCR5、CXCR3和CXCR6可能介导CD4^＋T淋巴细胞向肝内迁徙定植,并参与肝脏炎症的病理免疫学反应过程.     

Release of both CCR4-active and CXCR3-active chemokines during human allergic pulmonary late-phase reactions

BACKGROUND: Segmental antigen bronchoprovocation has long been used as a model to study allergic pulmonary inflammatory responses. Among the characteristics of the resulting cellular infiltrate is the preferential recruitment of TH2 lymphocytes. The mechanisms responsible for their selective recruitment remain unknown, but T(H)(2) cells preferentially express the chemokine receptors CCR4 and CCR8. OBJECTIVES: We tested the hypothesis that the chemokines thymus- and activation-regulated chemokine (TARC) (CCL17) and macrophage-derived chemokine (MDC) (CCL22), whose receptor is CCR4, and I-309 (CCL1), whose receptor is CCR8, would be released at sites of segmental allergen challenge. METHODS: Segmental allergen challenge with saline or allergen was performed in 10 adult allergic subjects with asthma, who were off medications. Bronchoalveolar lavage (BAL) was performed at both the saline- and allergen-challenged sites 20 hours after challenge. BAL fluids were analyzed for total cell counts and differentials, and supernatants were assayed by ELISA for levels of TARC, MDC, and I-309. As a control, the BAL fluids were also analyzed for levels of interferon-inducible protein 10 (IP-10) (CXCL10), an IFN-gamma-induced chemokine active on CXCR3, a chemokine receptor that is preferentially expressed on TH1 lymphocytes. RESULTS: Allergen challenge led to an approximately 6-fold increase in total leukocytes, including lymphocytes, compared with those seen at saline-challenged sites. At antigen-challenged sites, eosinophils predominated. Chemokine levels at control, saline-challenged sites were either below the detectable limit or low, with the predominant chemokine detected being IP-10. At antigen-challenged sites, levels of MDC, TARC, and IP-10 were all significantly increased compared with saline sites, each with a median of 486 to 1130 pg/mL detected. On the basis of a comparison with serum values, BAL chemokine levels at most antigen-challenged sites could not be accounted for by transudation from plasma. In contrast, levels of I-309 were extremely low or undetectable in all BAL and serum samples tested. Finally, BAL levels of MDC significantly correlated with those for TARC, but no significant correlations were found between levels of chemokine and any cell type. CONCLUSIONS: These data suggest that among the chemokines measured in this study, IP-10 is the predominant chemokine detected 20 hours after saline challenge, likely representing baseline production of a chemokine that favors TH1 cell recruitment. At antigen-challenged sites, levels of both CCR4 and CXCR3 active chemokines, but not CCR8 active chemokines, are markedly increased and are produced at levels that are likely to have biologic significance. Given the preferential accumulation of TH2 cells at these antigen-challenged sites, the increased production of CCR4-active chemokines might contribute to this response.     

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.     

Abnormal expression of chemokine receptors in Behçet's disease: relationship to intracellular Th1/Th2 cytokines and to clinical manifestations

Dynamic interplay between cytokines and chemokines directs trafficking of peripheral blood mononuclear cells to tissues in autoimmune and/or viral diseases. The aim of the current study was to define the expression on CD3+ T cells of six chemokine receptors associated with inflammatory sites and the expression of intracellular cytokines, such as interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), in Behcet's disease (BD). Flow cytometry was used to detect chemokine receptor and intracytoplasmic cytokines' expression. We observed that CD3+ T cells in the peripheral blood express a restricted array of inflammatory chemokine receptors, specifically, CCR5, CCR6 and CXCR3, but little CCR1-3. The highest expression of CXCR3 on CD3+ T cells is associated with the presence of central nervous system (CNS) manifestations or pulmonary involvement. CXCR3 is the principal inflammatory chemokine receptor involved in BD. CCR5 chemokine receptor is increased in BD regardless of clinical manifestations. The frequency of IFN-gamma-producing cells expressing CXCR3+ CD3+ cells is significantly increased in patients with BD compared with normal controls. IL-4-producing cells are decreased in BD. These results demonstrate the predominance of type 1 cytokine producing cells in CXCR3+ CD3+ T cells during BD. We hypothesize that CXCR3 is the principal inflammatory chemokine receptor involved in BD, particularly during CNS and pulmonary manifestations.     

Clonal Th2 cells associated with chronic hypereosinophilia: TARC-induced CCR4 down-regulation in vivo

We analyzed the expression of chemokine receptors on clonal Th2-type CD4(+)CD3(- )lymphocytes isolated from blood of two patients with chronic hypereosinophilia. First, we observed that these Th2 cells express membrane CCR5 and CXCR4 but neither CCR3 nor CCR4 when analyzed immediately after purification. However, CCR4 appeared following culture in human serum-free medium, suggesting that it was down-regulated in vivo. Indeed, patient's serum, but not control human serum, strongly down-regulated CCR4 expression on cultured Th2 cells. As high levels of TARC, a CCR4 ligand, were detected in the serum of four hypereosinophilic patients with CD3(-)CD4(+) clonal Th2 cells, we evaluated the effect of TARC neutralization in this system. Addition of a neutralizing anti-TARC mAb inhibited CCR4 down-regulation by patient's serum, indicating that circulating TARC contributed to CCR4 down-regulation on Th2 cells in vivo. Clonal Th2 cells did not secrete high levels of TARC themselves but induced a sustained production of TARC by monocyte-derived dendritic cells, a phenomenon that was inhibited by addition of blocking mAb against IL-4 receptor. We conclude that high circulating levels of TARC in serum of patients with chronic hypereosinophilia, most likely derived from antigen-presenting cells stimulated by Th2-type cytokines, induce down-regulation of CCR4 on Th2 cells in vivo.     

Differential expression of the chemokine receptors by the Th1- and Th2-type effector populations within circulating CD4+ T cells

The in vitro studies have proposed that human Th1 cells favor expression of CXCR3 or CCR5, whereas Th2 cells favor CCR3 and CCR4. In this study, the in vivo relevance of expression of these chemokine receptors on Th cells was investigated in patients with atopic dermatitis (AD) as the Th2-dominated disorder and nonatopic normal individuals. Flow-cytometric analysis using monoclonal antibodies against CXCR3, CCR5, CCR3, and CCR4 disclosed that a substantial proportion of memory (CD45RO+) CD4+ T cells in the blood of AD and normal patients expressed CXCR3, CCR5, or CCR4, but expression of CCR3 on these cells was negligible. Stimulation studies combined with intracellular cytokine staining revealed that the cells capable of producing Th2 cytokines, such as interleukin-4 (IL-4), IL-5, and IL-13, were restricted to the CCR4-expressing population within memory CD4+ T cells. Concerning Th1 cytokine production, interferon-gamma (IFN-gamma)-producing cells resided exclusively in CXCR3-expressing memory CD4+ T cells, although IFN-gamma production was found in both memory CD4+ T cells with and without CCR5 expression. We observed that CCR4-expressing memory CD4+ T cells in the blood were more increased in AD patients as compared with normal patients, whereas CXCR3-expressing memory CD4+ T cells were present in a lower frequency in AD than seen in normal patients. These results suggest that CXCR3 and CCR4, but not CCR5 or CCR3, appear to serve as the useful markers for identification of circulating Th1 and Th2 effector populations.     

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.     

Systemic chemokine and chemokine receptor responses are divergent in allergic versus non-allergic humans

T(h)1- and T(h)2-polarized human T cell clones display distinct patterns of chemokine receptor expression and selective chemokine responsiveness in vitro. We hypothesized that natural exposure to environmental grass pollen would induce differential systemic chemokine and chemokine receptor expression patterns in individuals with allergic rhinitis compared to healthy controls with type 2- and type 1-dominated responses to allergen respectively. To this end, we compared chemokine receptor expression on peripheral blood T cells directly ex vivo and plasma chemokine levels between these two groups of study participants prior to and during the grass pollen season. T(h)1-associated CXC chemokine receptor (CXCR) 3 was strongly expressed on >50% CD4(+)/CD45RO(+) cells of all subjects. When examined longitudinally, CXCR3 expression increased over the grass pollen season (P < 0.0001), solely in non-allergic subjects. In contrast, for both allergic and non-allergic subjects, CC chemokine receptor (CCR) 5 (T(h)1-associated) and CCR3 (T(h)2-associated) were weakly expressed on <10% of CD4(+)/CD45RO(+) cells both prior to and during the grass pollen season. Type 1 chemokines CXC chemokine ligand (CXCL) 9 and CXCL10 (monokine induced by IFN-gamma and IFN-gamma-inducible protein of 10 kDa: CXCR3 ligands), and type 2 chemokines CC chemokine ligand (CCL) 11 (eotaxin: CCR3 ligand), CCL17 (thymus and activation-regulated chemokine: CCR4 ligand) and CCL22 (monocyte-derived chemokine: CCR4 ligand) were readily detectable in the plasma of most participants. Systemic CXCL9 levels decreased from pre- to grass pollen season in allergics (P < 0.05), whereas CCL17 decreased in non-allergics (P < 0.05) over the same period. Taken together, these longitudinal data suggest a systemic shift to more intensely type 1-dominated responses in non-allergic individuals and, conversely, to more type 2-dominated responses in allergic individuals upon natural re-exposure to grass pollen.     

Serum macrophage-derived chemokine (MDC) levels are closely related with the disease activity of atopic dermatitis

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by the predominant infiltration of T cells, eosinophils and macrophages in lesional skin. Recently, macrophage-derived chemokine (MDC)/CCL22, a CC chemokine, was identified as a selective chemoattractant for CC chemokine receptor 4 (CCR4)-expressing cells, in addition to thymus and activation-regulated chemokine (TARC). We have previously reported that serum TARC levels correlate with the severity of AD. In this report, we investigated the participation of MDC in AD. First, we measured serum MDC levels in 45 patients with AD, 25 patients with psoriasis vulgaris and 25 healthy controls. Serum MDC levels in AD patients were significantly higher than those in healthy controls and psoriasis patients. Furthermore, the increases in serum MDC levels in AD patients were greater in the severely affected group than in the moderate or mild groups. We compared serum MDC levels in 11 AD patients, before and after treatment, and observed a significant decrease after treatment. Moreover, the serum MDC levels significantly correlated with the Scoring AD (SCORAD) index, serum soluble (s) E-selectin levels, serum soluble interleukin-2 receptor (sIL-2R) levels, serum TARC levels and eosinophil numbers in peripheral blood. Our study strongly suggests that serum MDC levels have a notable correlation with disease activity and that MDC, as well as the CC chemokine TARC, may be involved in the pathogenesis of AD.