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.     

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.     

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.     

CCR5 and CXCR4 chemokine receptor expression and beta-chemokine production during early T cell repopulation induced by highly active anti-retroviral therapy.

Expression of chemokine receptors and beta-chemokine production by peripheral blood mononuclear cells (PBMC) were determined in HIV-1-infected individuals before and after highly active anti-retroviral therapy (HAART) and their relationship to viral load, T cell phenotype and the expression of immunological activation markers was examined. We found that the expression of CCR5 is up-regulated in HIV-1-infected individuals while CXCR4 appears down-regulated on both CD4 and CD8 T cells compared with normal controls. These alterations are associated with the high levels of viral load. In addition, a relationship was observed between the degree of immune activation and chemokine receptor expression on T cells. However, after 3 months of combined anti-retroviral regimen, expression of CXCR4 significantly increased while CCR5 decreased when compared with pretherapy determinations. This was seen in strict association with a dramatic decrease of viral load and an increase of both CD45RA+/CD62L+ (naive) and CD45RA-/CD62L+ or CD45RA+/CD62L- (memory) T cells accompanied by a significant decrease of the expression of immune activation markers such as HLA-DR and CD38. At enrolment, both spontaneous and lectin-induced RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta production by PBMC were higher in HIV-1-infected individuals compared with normal controls, although differences for MIP-1beta were not statistically significant. However, RANTES and MIP-1alpha production decreased during HAART at levels closer to that determined with normal controls, while MIP-1beta production was less consistently modified. These data indicate that the expression of chemokine receptors CCR5 and CXCR4 and the production of beta-chemokines are altered in HIV-infected individuals, and suggest that their early modifications during HAART reflect both the peripheral redistribution of naive/memory T cell compartments and the decrease in levels of T cell activation. Such modifications in the expression of host determinants of viral tropism and the production of anti-viral molecules may play a role in the emergence of virus variants when a failure of HAART occurs.     

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.     

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.     

Aging is associated with increased human T cell CC chemokine receptor gene expression.

Leukocyte chemokine receptors (CR) are central to the pathogenesis of many human diseases, including human immunodeficiency virus-1 (HIV-1) infection. Elderly individuals infected with the HIV-1 virus have a shorter disease-free interval and worse clinic outcome. However, the reasons for this are unclear. We recently reported increased CC chemokine receptor (CCR) expression in CD4+ T cells in aged mice, but it is not known if similar changes occur in humans. In addition, it is unclear if the observed differences are related to aged-related expansion in the memory T cell compartment. In this report, we examined the effects of aging on CCR gene expression in human peripheral blood mononuclear cells (PBMCs), CD4+ T cells, and naive/memory T cells. Aging is found to be associated with increased CCR1-5 expression in PBMCs and CD4+ T cells. In addition, although the age-related increases in CCR expression occurred in both naive and memory T cells, the greatest changes were seen in the memory T cell subset. We propose that the observed aging-associated increase in T cell chemokine receptor expression may contribute to the worse clinical outcome of T cell chemokine receptor-dependent disease, such as HIV-1 infection, in the elderly.     

Graves' disease is associated with an altered CXCR3 and CCR5 expression in thyroid-derived compared to peripheral blood lymphocytes

The mechanisms by which T cells accumulate in the thyroid and support the autoimmune process in patients with Graves' disease (GD) are poorly understood. Chemokines and their receptors may be involved in this process. We have analysed the expression of CXCR3 and CCR5 as Th1-specific chemokine receptors, CCR3 as a marker for Th2 cells, CXCR4 (expressed on unprimed, naive T cells) and CCR2 (known to be involved in autoimmunity) on peripheral blood (PBL) and thyroid-derived lymphocytes (TL) using flow cytometry. Chemokine receptor expression on PBL of GD patients (n = 16) did not differ from that of normal controls (n = 10). In GD, CXCR3+ (67.3 +/- 4.0% versus 45.7 +/- 2.1%) and CCR5+ T cells (42.5 +/- 3.4% versus 18.8 +/- 2.1%) showed a significant enrichment in the TL compared to PBL. The positive cells were contributed mainly by the CD4+CD45R0+ subset. TL are mostly primed CD45R0+ T cells, but surprisingly, they had significantly higher levels of CXCR4+ cells among TL (96.2 +/- 1.0%) compared to PBL (66.8 +/- 4.2%). However, CXCR4 has been induced during in vitro isolation of TL. There was no correlation between chemokine receptors and the level of TSH-receptor and thyroid peroxidase autoantibodies. CCR3+ and CCR2+ cells remained unchanged in TL compared to PBL. We could confirm the results using RT PCR and immunohistology. In summary, TL showed a different chemokine receptor pattern compared to PBL from the same patient. This indicates a role for CXCR3 and CCR5 in the recruitment of T cells to the thyroid in GD.     

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.     

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.     

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。     

Enhanced replicative capacity and pathogenicity of HIV-1 isolated from individuals infected with drug-resistant virus and declining CD4+ T-cell counts

Virologic failure on continuous antiretroviral therapy (ART) is associated with variable changes in CD4 T-cell counts: peripheral CD4 T-cell counts decrease in conjunction with a resurgence of plasma virus (nonresponders) or remain stable or continue to increase despite ongoing virus replication (discordant responders). This study found that HIV-1 isolated from nonresponders had significantly greater replicative capacity in activated peripheral blood mononuclear cells (PBMCs) as well as an enhanced ability to induce apoptosis in both HIV-1-infected and HIV-1-uninfected CD4 T cells compared with virus isolated from discordant responders. Enhanced replicative capacity in PBMCs of virus isolated from nonresponders was inhibited by AMD3100, a CXCR4 antagonist. Virus quasispecies isolated from PBMCs from nonresponders used both CC chemokine receptor 5 (CCR5) and CX chemokine receptor 4 (CXCR4) for entry, in contrast to virus isolated from PBMCs from discordant responders, which predominantly used CCR5. In contrast, virus isolated from plasma from both groups predominantly used CCR5. In summary, although drug resistance may lead to impaired viral fitness, the capacity of virus quasispecies from PBMCs to use CXCR4 may have significant consequences on viral replicative capacity and potentially on clinical outcome.     

Down-regulation of CXCR4 expression on human CD8+ T cells during peripheral differentiation

Multi-color flow cytometric analysis on human CD8(+) T cell subsets revealed that CXCR4 is predominantly expressed on CD8(+) T cells with the naive CD27(+)CD28(+)CD45RA(+) phenotype, and is down-regulated during differentiation into those with an effector phenotype. The down-regulation of CXCR4 expression during peripheral differentiation was supported by the fact that the expression of CXCR4 on CD8(+) T cells was negatively correlated with that of perforin. The analysis of CCR5, CCR7, and CXCR4 co-expression further showed that CD8(+) T cells expressing a high level of CXCR4 are CCR7(+)CCR5(-) naive or central memory subsets, and those expressing a low level of CXCR4 were included in the CCR7(-)CCR5(+/-) memory/effector and effector subsets. Epstein Barr virus-specific CD8(+) T cells, which mostly express the memory phenotype, expressed CXCR4, while human cytomegalovirus-specific CD8(+) T cells, which mostly express the effector phenotype, partially expressed this receptor, showing that the expression of CXCR4 is also down-regulated during differentiation of viral antigen-specific CD8(+) T cells. The classification of human CD8(+) T cells based on the expression of these chemokine receptors should prove useful for studies that clarify the differentiation of human CD8(+) T cells.     

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.     

Multiple determinants are involved in HIV coreceptor use as demonstrated by CCR4/CCL22 interaction in peripheral blood mononuclear cells (PBMCs)

Although a number of chemokine receptors display coreceptor activities in vitro, chemokine receptor 5 (CCR5) and CXC chemokine receptor 4 (CXCR4) remain the major coreceptors used by the human immunodeficiency virus type 1 (HIV-1). In this study, we used an envelope-mediated fusion assay to demonstrate low CCR4 coreceptor activity with some primary HIV-1 and simian immunodeficiency virus-1 (mac316) isolates in vitro. The coreceptor activity was sensitive to CCR4-specific antibodies and to the CCR4-specific chemokine ligand macrophage-derived chemokine (MDC)/chemokine ligand 22 (CCL22). Treatment of peripheral blood mononuclear cells (PBMCs; which express high levels of CCR4) with CCL22 caused down-modulation of endogenous CCR4 but had no significant effect on HIV-1 entry, suggesting that CCR4 may not be used as an entry coreceptor. Despite expression of other minor coreceptors on PBMCs, CCR5 and CXCR4 are preferentially used by HIV-1 isolates, as shown by chemokine-inhibition data. To determine the factors involved in this selective use, we analyzed CCR4 coreceptor activity and compared it with CCR5 use in PBMCs. We used a quantitative fluorescence-activated cell-sorting assay to estimate the numbers of CCR4 and CCR5 antibody-binding sites (ABS) on PBMCs. Although CCR4 was found on a higher percentage of CD4(+) cells, CCR5 ABS was twofold greater than CCR4 ABS on CD4(+) cells. Confocal microscopy revealed strong cell-surface CD4/CCR5 but weak CD4/CCR4 colocalization in PBMCs. Binding studies demonstrated that soluble gp120 had greater affinity to CCR5 than CCR4. The results suggested that coreceptor density, colocalization with CD4, and affinity of the viral gp120 to the coreceptor may determine preferential coreceptor use by HIV-1.     

Impaired CD4 and CD8 T cell phenotype and reduced chemokine secretion in recent-onset type 1 diabetic children

Although the role of the T cell-mediated autoimmune reaction in type 1 diabetes (T1D) is conclusive, studies including data from human circulating CD4(+) and CD8(+) lymphocytes subsets during the disease onset and posterior development are scarce. Further, chemokines and chemokine receptors are key players in the migration of pathogenic T cells into the islets of non-obese diabetic mice developing T1D, but few studies have investigated these markers in human T1D patients. We studied the expression of T helper 1 (Th1)- and Th2-associated chemokine receptors, and the two isoforms of CD45 leucocyte antigen on CD4(+) and CD8(+) lymphocytes from T1D and healthy children, as well as the secretion of chemokines in cell supernatants in peripheral blood mononuclear cells. Our results showed increased expression of CCR7 and CD45RA and reduced CD45RO on CD8(+) cells among recent-onset T1D patients. The percentages of CD4(+) cells expressing CXC chemokine receptor 3 (CXCR3), CXCR6 and CCR5, and the secretion of interferon-gamma-induced protein-10, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta was lower among diabetics. Low expression of Th1-associated receptors and secretion of chemokines, together with an increased amount of CD8(+) cells expressing CD45RA and CCR7 in T1D patients therefore might represent suboptimal Th function in T1D, leading to impaired T cytotoxic responses or alternatively reflect a selective recruitment of Th1 cells into the pancreas.     

Adenoids provide a microenvironment for the generation of CD4(+), CD45RO(+), L-selectin(-), CXCR4(+), CCR5(+) T lymphocytes, a lymphocyte phenotype found in the middle ear effusion

Adenoidectomy in children with otitis media with effusion reduces inflammation in the middle ear by an unknown mechanism. Potentially, the adenoids of these children may serve as a site for the differentiation of lymphocytes, which after entering blood circulation eventually extravasate in the middle ear mucosa and thereby contribute to excessive inflammation. During lymphocyte extravasation various adhesion molecules and chemokines play a crucial role. To evaluate possible connections between the adenoids and middle ear inflammation, the expression of the chemokine receptors CXCR4 and CCR5 and the lymphocyte homing receptor L-selectin were analyzed in adenoidal and middle ear lymphocytes. It was found that most CD4(+) T lymphocytes in the middle ear effusion express the memory phenotype marker CD45RO and the chemokine receptors CXCR4 and CCR5, but are negative for the lymphocyte homing receptor L-selectin. This cell phenotype was rare in peripheral blood but was found much more frequently in the adenoids. The results suggest that the adenoids provide a microenvironment for the generation for CD4(+), CD45RO(+), L-selectin(-), CXCR4(+) and CCR5(+) T lymphocytes. Further, these cells may include cells that have the capacity to home to the middle ear mucosa. As the adenoidal CD4(+) memory phenotype CD45RO(+) T cells expressed the activation antigen CD69 and included cells expressing the HIV co-receptors CXCR4 and CCR5 at a high level, they may be permissive for HIV infection.