Lack of correlation between chemokine receptor and T(h)1/T(h)2 cytokine expression by individual memory T cells

Chemokine and chemokine receptor interactions may have important roles in leukocyte migration to specific immune reaction sites. Recently, it has been reported that CXC chemokine receptor (CXCR) 3 and CC chemokine receptor (CCR) 5 were preferentially expressed on T(h)1 cells, and CCR3 and CCR4 were preferentially expressed on T(h)2 cells. To investigate chemokine receptor expression by T(h) subsets in vivo, we analyzed cytokine (IL-2, IL-4 and IFN-gamma) and chemokine receptor (CXCR3, CXCR4, CCR3, CCR4 and CCR5) mRNA expression by individual peripheral CD4(+) memory T cells after short-term stimulation, employing a single-cell RT-PCR method. This ex vivo analysis shows that the frequencies of cells expressing chemokine receptor mRNA were not significantly different between T(h)1 and T(h)2 cells in normal peripheral blood. To assess a potential role of in vivo stimulation, we also analyzed unstimulated rheumatoid arthritis synovial CD4(+) memory T cells. CXCR3, CXCR4, CCR3 and CCR5 expression was detected by individual synovial T cells, but the frequencies of chemokine receptor mRNA were not clearly different between T(h)1 and non-T(h)1 cells defined by expression of IFN-gamma or lymphotoxin-alpha mRNA in all RA patients. These data suggest that chemokine receptor expression does not identify individual memory T cells producing T(h)-defining cytokines and therefore chemokine receptor expression cannot be a marker for T(h)1 or T(h)2 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.     

Identification of anti-inflammatory drugs according to their capacity to suppress type-1 and type-2 T cell profiles

BACKGROUND: Down-regulation or modulation of T cell activity by immunosuppressive drugs is an effective treatment in diseases where exaggerated T cell responses play a role. A primary effect of the anti-inflammatory drugs (AIDs) is inhibition of the synthesis of growth factors, such as IL-2, thereby down-regulating T cell proliferation. However, it is still largely unknown to what extent these AIDs are able to down-regulate specifically type-1 or type-2 T cell cytokine production, and whether they can down-modulate chemokine receptor expression, thereby preventing migration of T cells to the site of inflammation. OBJECTIVE: We investigated the suppressive effect of dermatologically used AID (cyclosporin A (CsA), lactoferrin (LF), 1 alpha, 25-dihydroxyvitamin D(3) (VD(3)), hydrocortisone (HC), di-methyl-fumarate (DMF), diclofenac (DF)) on both type-1 and type-2 T cells. Since allergic contact dermatitis is a skin disorder in which an exaggerated T cell response of both types of T cell subsets can be observed, we used this disorder as a model to study the capacity of AID to suppress type-1 or type-2 T cell responses. METHODS: Peripheral blood mononuclear cells of nickel allergic patients were cultured in the presence of allergen and increasing concentrations of AID. Proliferation was determined by measuring (3)H thymidine incorporation; chemokine receptor (CCR10, CCR4, CXCR3) expression was studied by flow cytometric analysis and IFN-gamma or IL-5 cytokine production was measured by ELISA. RESULTS: Three major patterns can be distinguished regarding the effect of AID on T cell responses. The first group, including CsA and LF, inhibited non-selectively T cell proliferation, chemokine receptor expression and cytokine production, with CsA as the most potent drug tested. A second group of AID, which included VD(3), HC and DMF, suppressed mainly type-1 T cell responses, as revealed by strong interference with IFN-gamma production and CXCR3 expression, and limited effects on either or both IL-5 and CCR4 expression. The third pattern was displayed by DF, which down-regulated IL-5 production and CCR4 expression, whereas IFN-gamma and CXCR3 were unaltered. CONCLUSIONS: Using a contact allergy model, we have demonstrated that various AIDs show distinct pharmacological profiles in that either type-1 or type-2 or both T cell responses are suppressed. These results should contribute to a more rational selection of AID in treating inflammatory skin diseases mediated by either or both of these T cell subsets.     

T lymphocytes expressing CCR3 are increased in allergic rhinitis compared with non-allergic controls and following allergen immunotherapy

BACKGROUND: In T cell-associated allergic inflammation, homing of T-helper 2 (Th2) effector cells to mucosal sites may be influenced by chemokine receptor expression. Previous studies have identified CCR3 and CCR4 as putative markers of Th2 cells and CCR5 and CXCR3 as markers of Th1 cells. The aim of this study was to assess differential chemokine receptor expression from symptomatic atopic grass pollen-sensitive subjects, compared with patients on high-dose allergen injection immunotherapy (IT) and healthy controls. METHODS: We examined chemokine receptor expression (CCR1-7 and CXCR1-4) by flow cytometry of peripheral blood CD4+ and CD8+ T cells. We also depleted peripheral blood mononuclear cell (PBMC) populations of CCR3+ CD4+ cells by magnetic bead separation and cells were stimulated with grass pollen allergen for 6 days. Cytokine production was measured by enzyme-linked immunosorbent assay. RESULTS: On freshly isolated PBMC, atopic individuals exhibited increased numbers of CCR3+ CD4+ cells compared with normal controls (P < 0.01). CCR3 expression in IT patients was reduced compared with matched atopic rhinitic controls (P < 0.05) and comparable with that observed in normal subjects. Depletion of CCR3+ CD4+ cells from allergen-stimulated PBMC cultures resulted in decreased interleukin (IL)-5 production compared with whole CD4+ populations (P < 0.05). Freshly isolated CCR3+ CD4+ cells have significantly higher intracellular IL-4 and lower IFN-gamma levels than CCR3- CD4+ cells. CD4+ T cells cultured from both peripheral cells and nasal biopsies demonstrated increased expression of CCR3 in the presence of IL-4 (P < 0.05). CONCLUSION: CCR3+ CD4+ T cells are increased in allergic rhinitis, are reduced by allergen IT, have a Th2 phenotype and contribute to allergen-specific responses. Strategies against CCR3+ T cells may be effective in human allergic diseases.     

CCR4 is an up-regulated chemokine receptor of peripheral blood memory CD4+ T cells in Crohn's disease

Several chemokine receptors are expressed selectively on the surface of T cells depending on their polarization. The aim of this study was to characterize chemokine receptor expression in peripheral blood memory T cells in Crohn's disease (CD) and ulcerative colitis (UC), and to correlate the expression with disease activity. Peripheral blood mononuclear cells (PBMCs) were obtained from 24 patients with CD, 30 patients with UC, 24 normal controls and 10 disease controls. PBMCs were stained by anti-CCR3, CCR4, CCR5, CXCR3, CD4, CD8, CD45RO and beta 7 integrin, and the expression of the chemokine receptors were determined by flow cytometry. CCR4 expression on memory T cells was significantly lower in UC than in CD or normal controls, and that of memory CD4+ T and beta 7(high) memory CD4+ T cells was significantly higher in CD than in UC or normal controls. CCR4 expression on memory CD4+ T cells exhibited significant positive correlation with disease activity in CD, and this decreased significantly after treatment. Such a decrease was not found in the disease controls. CCR5 and CXCR3 expression on memory CD8+ T cells was significantly lower in CD than in normal controls. CXCR3 expression on beta 7(high) memory CD4+ T and CXCR3 expression on memory CD8+ T cells were lower in UC than in normal controls. These findings suggest that in peripheral blood memory T cells, chemokine receptor expression is different between CD and UC. Enhancement of CCR4 and suppression of CCR5 and CXCR3 seem to be the characteristic chemokine receptor profile in peripheral blood memory T cells of CD.     

Expression of chemokine receptors on CD4+ T cells in peripheral blood from HIV-infected individuals in Uganda.

CXCR4, a coreceptor for T cell (T)-tropic HIV-1, is preferentially expressed on naive T cells, whereas CCR5, a coreceptor for macrophage (M)-tropic HIV-1, is preferentially expressed on previously activated memory T cells and the Th1 subset of CD4+ T cells. CCR4 is preferentially expressed on the Th2 subset of CD4+ T cells. A cross-sectional flow cytometry study was conducted to evaluate the expression of CXCR4, CCR5, and CCR4 on the peripheral blood CD4+ T cells from African HIV-1-infected and uninfected Ugandan adults. The plasma viral load in HIV-1-infected individuals was also examined. Upregulation of CCR4 and CCR5 expression but no decrease in CXCR4 expression on CD4+ T cells were obtained in peripheral blood from African adults with progression of the disease. Plasma HIV-1 viremia significantly and inversely correlated with the peripheral CD4+ T cell count but did not correlate with the degree of CCR4 and CCR5 expression on the peripheral CD4+ T cells in HIV-1-infected individuals. Our present data suggest an increase in percentage of activated memory CD4+ T cells in the advanced stage of HIV-1 infection among African adults. There was no evidence of a Th1 to Th2 shift in terms of chemokine receptor expression profile with advancing disease in the peripheral blood of these subjects.     

Skewing of cytotoxic activity and chemokine production,but not of chemokine receptor expression,in human type-1/-2 gamma delta T lymphocytes

Human Vgamma9/Vdelta2(+) T lymphocytes participate in the immune response against intracellular pathogens through the secretion of type-1 cytokines and chemokines and by killing of infected cells. Little is known of the effects by type-2 differentiation of gamma delta cells on these functions. Here, we report that bona fide naive cord blood-derived gamma delta lymphocytes expanded in vitro with the mycobacterial antigen isopentenyl pyrophosphate (IPP) can be differentiated as either type-1 or type-2 cells, in the presence of an appropriate cytokine milieu. Instead, peripheral gamma delta cells from PPD-negative healthy adults displayed a type-1 cytokine profile, i.e. IPP-stimulated secretion of IFN-gamma, but not of IL-4 and IL-10. Moreover, they released the macrophage inflammatory protein (MIP)-1beta, but not IL-8 nor the Th2 chemoattractants I-309 and TARC (thymus and activation-regulated chemokine). This cytokine profile was not significantly affected by in vitro culture in Th2 polarizing conditions. Only in one case out of seven were peripheral gamma delta cells fully differentiated to type-2 lymphocytes, characterized by sustained IL-4 and IL-10 production, along with secretion of substantial amounts of IL-8, I-309 and TARC. Type-2 gamma delta T lymphocytes preferentially expressed the co-stimulatory molecule CD30; conversely, no skewing in chemokine receptor expression was observed. Both polarized populations displayed high levels of CXCR3 in the absence of CCR3, CCR4 and CCR5. Finally, type-1, but not type-2, gamma delta T lymphocytes killed IPP-pulsed U937 cells and displayed elevated perforin content. Overall, our data suggest that type-2 differentiation of gamma delta T lymphocytes profoundly affects both their effector functions and their potential to recruit the appropriate leukocyte subsets to the sites of inflammation.     

Functional and phenotypic analysis of human memory CD8+ T cells expressing CXCR3

Several chemokine receptors play an important role in the migration of na?ve, memory, and effector T cells. Flow cytometric analyses showed that human CD8+ T cells with na?ve (CD27+ CD28+ CD45RA+) or memory (CD27+ CD28+/- CD45RA+) phenotypes included a population expressing a high level of CXC chemokine receptor 3 (CXCR3high) and one expressing a low level of it (CXCR3low), but those with the effector phenotype (CD27- CD28- CD45RA+/-) included a population that did not express CXCR3 (CXCR3-) and a CXCR3low population. This relation between the expression level of CXCR3 and memory/effector phenotypes also applied to Epstein-Barr virus- or human cytomegalovirus-specific CD8+ T cells. CXCR3high cells were found predominantly in CC chemokine receptor 7 (CCR7)+ CCR5- and CCR7- CCR5- subsets of CD8+ T cells with the CD27+ CD28+ CD45RA- memory phenotype, suggesting that they are memory cells with intermediate differentiation. Indeed, CXCR3high CD27+ CD28+ CD45RA- CD8+ T cells had the ability to produce interleukin-2 and interferon-gamma. These results together indicate that the expression of CXCR3 is up-regulated on intermediately differentiated memory CD8+ T cells. CXCR3high CD8+ T cells had a greater ability to migrate in response to CXCR3 ligands than CXCR3low ones. As CXCR3high memory CD8+ T cells do not express CCR5, high expression of CXCR3 on these memory CD8+ T cells might play an important role in the migration of these cells to inflammatory sites and in their differentiation.     

Increased circulating CCR3+ type 2 helper T cells in house dust mite-sensitive Chinese patients with allergic diseases

Chemokine receptor expression has been shown to be associated with the differentiation of T helper cells. The CCR3, CXCR4 and CCR5 expression on circulating T cells were studied in 30 house dust mite sensitive-patients with allergic diseases and in another 30 healthy controls. The expression was analyzed in CD4, CD8 and double negative (DN) T cells by triple fluorescence staining. In addition, intracellular cytokine staining was performed in the CCR3+ CD4+ T cells. Increased circulating portions of CCR3+ CD4+ T cells and CCR3+ DN T cells were found in these patients (p < 0.01). There was no statistically significant difference in the expression of CXCR4 and CCR5 on T cells. The follow-up data of the patients did not show a statistically significant change in the CCR3 expression. IL-4 was expressed within CCR3+ CD4+ T cells upon activation. The IL-4 secreting CCR3+ type 2 T helper cells may play a pathogenetic role in immune responses of house dust mite-sensitive Chinese patients with allergic diseases.     

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.     

Selective recruitment of CXCR3+ and CCR5+ CCR4+ T cells into synovial tissue in patients with rheumatoid arthritis

The inflamed synovial tissue (ST) of rheumatoid arthritis (RA) is characterized by the selective accumulation of interferon gamma-producing Th1-type CD4+ T cells. In this study, we investigated whether the predominance of Th1-type CD4+ cells in the ST lesion is mediated by their selective recruitment through Th1 cell-associated chemokine receptors CXCR3 and CCR5. The lymphocyte aggregates in the ST of RA contained a large number of CD4+ T cells, which mostly expressed both CXCR3 and CCR5, but not CCR4. In contrast, the frequencies of CD4+ and CD8+ T cells expressing CXCR3 and CCR5 in the blood were significantly decreased in RA patients, compared with healthy controls (HC), although there was no difference in the frequencies of CCR4-expressing CD4+ and CD8+ T cells between RA and HC. CXCR3, CCR5, and CCR4 expression in blood CD4 + T cells and CXCR3 expression in CD8+ T cells were increased after interleukin-15 (IL-15) stimulation. Therefore, the distribution of Th1-type CD4+ T cells into the ST from the blood in RA may be associated with the local expression of chemokines, both CXCR3 and CCR5 ligands, and IL-15 may play a role in enhancing these chemokine receptors on CD4+ T cell infiltrates.     

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.     

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.     

趋化因子及受体与中国HCV/HIV合并感染相关性的研究

目的：探讨趋化因子自细胞介素8（IL-8）、干扰素诱导蛋白10（IFN-inducible 10-kdaprotein，IP-10）及趋化因子受体CCR5、CXCR3，在丙肝病毒（HCV）单纯感染，艾滋病病毒（HIV）单纯感染和HCV／HIV合并感染过程中的表达及意义。方法：采用流式细胞术，检测HCV感染组（n=21）、HIV感染组（n=14）、HCV／HIV感染组（n=28）及正常对照组（n=30）人外周血CD4^＋T淋巴细胞和CD8^＋T淋巴细胞表面CCR5、CXCR3的表达。ELISA方法检测血清趋化因子IL-8、IP-10含量。结果：HCV感染组、HIV感染组和HCV／HIV合并感染组，血清IP-10水平都明显升高，而在合并感染组水平最高；血清IL-8水平在3组亦明显升高。HIV感染组及HCV／HIV合并感染组CD4^＋T细胞表面CXCR3表达显著降低（P〈0．001），CD8^＋T细胞表面CXCR3表达显著升高（P〈0．001）；HCV感染组CD4^＋及CD8^＋T细胞表面CXCR3表达轻度升高，但差异不显著。HCV感染组及HCV／HIV合并感染组CD4^＋及CD8^＋T细胞表面CCR5表达显著降低（P〈0.001）；HIV感染组CD4^＋及CD8^＋T细胞表面CCR5表达显著升高（P〈0.001）。结论：中国HCV／HIV合并感染患者中，血清IL-8和IP-10水平都明显升高；受体CXCR3在CD4^＋T细胞表面表达降低，而在CD8^＋T细胞表面表达升高；受体CCR5在CD4^＋及CD8^＋T细胞表面表达降低，提示趋化因子及受体与HCV／HIV合并感染密切相关。     

Kinetics and expression patterns of chemokine receptors in human CD4+ T lymphocytes primed by myeloid or plasmacytoid dendritic cells

We investigated the kinetics of expression of 12 chemoattractant receptors as a function of cell division following priming of human naive CD4+ T cells by different populations of dendritic cells (DC) and under conditions favoring Th1 or Th2 differentiation. Two chemokine receptors, CXCR3 and CXCR5, were rapidly up-regulated following T cell activation by either monocyte-derived DC, myeloid DC (mDC) or plasmacytoid DC (pDC). While CXCR5 expression was transient, expression of CXCR3 at advanced cell divisions was dependent on differentiation, being expressed at high levels on Th1 cells. Several other receptors (CCR2, CCR3, CCR4, CCR5, CXCR6 and CRTh2) were acquired progressively as a function of cell division and in a fashion that was influenced by polarizing cytokines. The Th2-associated chemoattractant receptors CRTh2 and CCR3 were up-regulated with slower kinetics compared to the Th1-associated receptors CXCR3 and CXCR6, consistent with a different kinetics and efficiency of polarization. Moreover, CCR4 and CXCR6 were preferentially induced in T cells activated by mDC and pDC, respectively. Finally, CXCR5 and CCR7 were also rapidly and transiently up-regulated in memory T cells following TCR stimulation. These results indicate a complex chemokine receptor regulation dependent on both T cell activation and differentiation state. In addition, they reveal the existence of DC-specific cues for the regulation of T cell migratory capacity.     

Switch in chemokine receptor expression upon TCR stimulation reveals novel homing potential for recently activated T cells.

When naive T lymphocytes are activated and differentiate into memory/effector cells, they down-regulate receptors for constitutive chemokines such as CXCR4 and CCR7 and acquire receptors for inflammatory chemokines such as CCR3, CCR5 and CXCR3, depending on the Th1/Th2 polarization. This switch in chemokine receptor usage leads to the acquisition of the capacity to migrate into inflamed tissues. Using RNase protection assays, staining with specific antibodies, and response to recombinant chemokines, we now show that following TCR stimulation, memory/effector T cells undergo a further and transient switch in receptor expression. CCR1, CCR2, CCR3, CCR5, CCR6 and CXCR3 are down-regulated within 6 h, while CCR7, CCR4, CCR8 and CXCR5 are up-regulated for 2 to 3 days. Up-regulation of CCR7 following TCR stimulation was observed also among resting peripheral blood T cells and required neither co-stimulation nor exogenous IL-2. On the other hand IL-2 down-regulated CXCR5, up-regulated CCR8 and facilitated the recovery of CCR3 and CCR5. Upon TCR stimulation, Th1 and Th2 cells produced comparable sets of chemokines, including RANTES, macrophage inflammatory protein-1beta, I-309, IL-8 and macrophage-derived chemokine, which may modulate surface chemokine receptors and contribute to cell recruitment at sites of antigenic recognition. Altogether these results show that following TCR stimulation effector/memory T cells transiently acquire responsiveness to constitutive chemokines. As a result, T cells that are activated in tissues may either recirculate to draining lymph nodes or migrate to nearby sites of organized ectopic lymphoid tissues.     

Downregulation of CXCR6 and CXCR3 in lymphocytes from birch-allergic patients

Preferential expression of chemokine receptors on Th1 or Th2 T-helper cells has mostly been studied in cell lines generated in vitro or in animal models; however, results are less well characterized in humans. We determined T-cell responses through chemokine receptor expression on lymphocytes, and cytokine secretion in plasma from birch-allergic and healthy subjects. The expression of CCR2, CCR3, CCR4, CCR5, CCR7, CXCR3, CXCR4, CXCR6, IL-12 and IL-18R receptors was studied on CD4⁺ and CD8⁺ cells from birch-allergic ( n  = 14) and healthy ( n  = 14) subjects by flow cytometry. The concentration of IL-4, IL-5, IL-10, IL-12, IFN-γ and TNF-α cytokines was measured in plasma from the same individuals using a cytometric bead array human cytokines kit. The similar expression of CCR4 in T cells from atopic and healthy individuals argues against the use of the receptor as an in vivo marker of Th2 immune responses. Reduced percentages of CD4⁺ cells expressing IL-18R, CXCR6 and CXCR3 were found in the same group of samples. TNF-α, IFN-γ, IL-10, IL-5, IL-4 and IL-12 cytokines were elevated in samples from allergic individuals. Reduced expression of Th1-associated chemokine receptors together with higher levels of Th1, Th2 and anti-inflammatory cytokines in samples from allergic patients indicate that immune responses in peripheral blood in atopic diseases are complex and cannot be simplified to the Th1/Th2 paradigm. Not only the clinical picture of atopic diseases but also the clinical state at different time points of the disease might influence the results of studies including immunological markers associated with Th1- or Th2-type immune responses.     

Characterization of chemokine receptor expression and cytokine production in circulating CD4+ T cells from patients with atopic dermatitis: up-regulation of C-C chemokine receptor 4 in atopic dermatitis

BACKGROUND: Th2 and Th1 cells have been suggested to express CCR3/CCR4 and CCR5/CXCR3, respectively. OBJECTIVE: We examined CCR3, CCR4, CCR5 and CXCR3 expression and cytokine production in peripheral blood CD4+ T cells from patients with atopic dermatitis (AD), which has been postulated to be a Th2-type cell-mediated disease, and then analysed the possible correlation between these values and the levels of several clinical parameters. METHODS: Intracellular cytokine production and chemokine receptor expression in peripheral blood CD4+ T cells from 40 AD patients and 20 sex- and age-matched healthy control subjects were studied by flow cytometry. RESULTS: The frequencies of IL-4- and IL-13-producing CD4+ T cells from patients with AD were significantly higher than those from healthy control subjects (IL-4:3.9 +/- 2.1% vs. 1.6 +/- 0.7%, P = 0.0005, IL-13:4.0 +/- 2.1% vs. 1.8 +/- 0.8%, P = 0.0023), whereas the frequencies of IL-2- and IFN-gamma-producing CD4+ T cells were significantly decreased in AD patients (IL-2:38.1 +/- 10.3% vs. 51.3 +/- 6.3%, P = 0.0003, IFN-gamma: 9.9 +/- 3.5% vs. 26.4 +/- 4.6%, P < 0.0001). The percentage of CCR4+ cells in CD4+ CD45RO+ T cells in AD patients was significantly higher than that in healthy control subjects (24.4 +/- 8.0% vs. 10.9 +/- 2.3%, P < 0.0001) and was correlated positively with the total serum IgE, serum lactic dehydrogenase (LDH) level, eosinophil number, eruption score, and IL-4 and IL-13 secretion in CD4+ T cells, and inversely with IL-2 and IFN-gamma secretion in CD4+ T cells. In contrast, CCR3 was not detected on circulating CD4+ T cells even in AD patients. On the other hand, the percentage of CCR5+ or CXCR3+ cells in CD4+ CD45RO+ T cells in AD patients was significantly decreased (CCR5:23.2 +/- 7.0% vs. 28.4 +/- 5.4%, P = 0.023, CXCR3:29.9 +/- 11.4% vs. 38.5 +/- 6.7%, P = 0.028) and was positively correlated with eruption score (P < 0.05). Multiple regression analyses showed that the percentage of CCR4 expression highly correlated with serum IgE, LDH, eosinophil number and eruption in AD patients. CONCLUSION: CCR4+ cells might be involved in the aetiopathogenesis of AD.