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.     

Assessment of chemokine receptor expression by human Th1 and Th2 cells in vitro and in vivo.

The preferential association of some chemokine receptors with human Th1 or Th2 cells has recently been reported. In this study, the expression of CCR3, CCR5, CXCR3, and CXCR4 were analyzed by flow cytometry in three distinct in vitro models of Th1/Th2 polarization, activated naive and memory T cells, and T-cell clones, in which the intracellular synthesis of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) and the surface expression of CD30 and LAG-3 were also assessed. Moreover, by using immunohistochemistry the in vivo expression of CCR3, CCR5, CXCR3, and CXCR4 was examined in the gut of patients suffering from Crohn's disease, a Th1-dominated disorder, and in the skin of patients suffering from systemic sclerosis, a Th2-dominated disorder. CCR5 and LAG-3 exhibited the same pathway of Th1 association, whereas CXCR3 did not discriminate between Th1- and Th2-dominated responses. On the other hand, CCR3 was found only occasionally in a small proportion of allergen-specific memory T cells with Th2/ThO profile of cytokine production in vitro. However, it was neither seen in Th2-polarized activated naive T cells nor in established Th2 clones and could be detected in vivo only on non-T cells. Finally, whereas CXCR4 expression was not limited to Th2 cells in vivo, it was markedly up-regulated by IL-4 and down-regulated by IFN-gamma in vitro. Thus, the results of this study confirm the existence of flexible programs of chemokine receptor expression during the development of Th1 and Th2 cells. However, caution is advised in interpreting these receptors as surrogate markers of a given type of effector response.     

Integration and independent acquisition of specialized skin- versus gut-homing and Th1 versus Th2 cytokine synthesis phenotypes in human CD4+ T cells

CD4+)T helper cells are heterogeneous in terms of tissue-specific homing and cytokine synthesis phenotypes. The mechanisms for the acquisition of tissue-specific homing phenotypes and their relationship with the attainment of polarized cytokine synthesis profiles of T cells are critically important but poorly understood. Here, we analyze the coordinate acquisition of Th1 versus Th2 cytokine (IFN-gamma vs. IL-4) and skin- versus gut-homing (CLA vs. integrin beta7) phenotypes in human CD4+ T cells. We show that the acquisition of skin- versus gut-homing T cell phenotypes is independent of Th1 versus Th2 cell fate determination and that it occurs in relation to cell cycle progression following instructive mechanisms and distinct kinetics. Expression of chemokine receptors CXCR3 and CCR4 correlates with the acquisition of Th1 versus Th2 rather than skin- versus gut-homing phenotypes. These findings, together with the skewed overlap observed in vivo between CLA vs. integrin beta7 and IL-4 vs. IFN-gamma expression, suggest a novel interpretation to the complex patterns of chemokine receptor expression on memory T cells.     

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.     

The CC-chemokine receptor 5 (CCR5) is a marker of, but not essential for the development of human Th1 cells

The CC-chemokine receptor 5 (CCR5) has recently been described as a surface marker of human T cells producing type 1 (Th1) cytokines. Here we confirm that CCR5 is expressed on human Th1 but not on Th2 T-cell clones. Using intracellular cytokine staining, we show that alloantigen specific CD4+ T-cell lines derived from a CCR5-deficient individual (delta32 allele homozygote) contain high numbers of both interferon gamma (IFN-gamma) and interleukin (IL)-2 producing cells, low numbers of IL-10 producing cells and no IL4 or IL-5 producing cells when stimulated with phorbol ester and ionomycin in vitro. These results were similar to those obtained from alloantigen specific CD4+ T-cell lines derived from CCR5 expressing individuals. An enzyme-linked immunoabsorbent assay (ELISA) confirmed that the Th1 cytokine-positive cells from the CCR5-deficient individual were able to produce equal amounts of cytokines when compared to T-cell lines from CCR5-expressing individuals, These results demonstrate that CCR5-negative T cells display the same capacity of Th1 T-cell differentiation as T cells derived from CCR5-expressing individuals. Thus, CCR5 expression is not essential for differentiation of human Th1 T cells.     

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.     

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.     

Abnormal expression of intracellular cytokines and chemokine receptors in peripheral blood T lymphocytes from patients with systemic sclerosis

In patients with systemic sclerosis (SSc), there are conflicting findings regarding which is predominant between type 1 and type 2 immune responses. To determine the balance between type 1 and type 2 T lymphocytes in peripheral blood from SSc patients, we investigated the expression of intracellular cytokines, such as interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, and IL-13, and chemokine receptors such as CXCR3 and CCR4 by flow cytometry. The frequency of IFN-gamma-producing cells among CD8+ cells was significantly increased in patients with diffuse cutaneous SSc (n = 11, P < 0.0001) and limited cutaneous SSc (lSSc; n= 16, P < 0.0001) compared with normal controls (n = 17) while there was no significant difference in the frequency of IL-4- or IL-13-producing cells. In contrast, the frequency of IFN-gamma- or IL-4-producing cells among CD4+ cells was similar between the three groups. Similar results were obtained when absolute numbers were assessed. The frequency of IFN-gamma-producing cells among CD8+ cells inversely correlated with percentage DLco in SSc patients (r = - 0.650, P < 0.005). CXCR3+ CD8+ cells selectively produced IFN-gamma, and the frequency of CXCR3+ CD45RO+ cells among CD8+ cells was higher in lSSc patients (n = 14, P < 0.01) than in normal controls (n = 22). In contrast, there was no significant difference in the frequencies of CXCR3- or CCR4-expressing CD45RO+ cells among CD4+ cells. These results demonstrate the predominance of type 1 cytokine-producing cells (Tc1 cells) in peripheral blood CD8+ T cells from SSc patients, but no definite Th1/Th2 imbalance in CD4+ T cells. Tc1 cells may be associated with pulmonary vascular damage in SSc.     

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.     

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.     

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.     

Switch in Chemokine Receptor Phenotype on Memory T Cells without a Change in the Cytokine Phenotype

Th1 and Th2 cells as defined by their cytokine profile are associated with the expression of the chemokine receptors CCR5 and CCR3, respectively. In committed human memory Th1 cells the cytokine profile is irreversibly expressed. However, it is not known if the chemokine receptor phenotypes of Th1 and Th2 cells are permanently associated to the cytokine profile or if it can be changed. To analyze the possibility of inducing a switch in chemokine receptor phenotype on memory Th cells we used differentiated memory Th cells isolated from synovial tissue (ST) samples of patients with rheumatoid arthritis (RA). Freshly isolated T cells, T-cell lines and T-cell clones from these tissues were manipulated with Th1 (interleukin (IL)-12 + anti IL-4) or Th2 (IL-4 + anti IL-12) inducing conditions. The surface expression of CCR5 and CCR3 was analyzed by flowcytometry and interferon (IFN)-gamma and IL-4 production by ELISA. A Th1-inducing cytokine environment increased the expression of CCR5 in Th1 cells and induced the expression of CCR5 in Th2 cells as compared to culture condition with only IL-2. Induction of CCR5 expression on Th2 clones was associated with secretion of some IFN-gamma. Moreover, the Th2-associated chemokine receptor CCR3 could be expressed on both Th1-dominant cell lines, and clones of Th1 and Th0 type after culture conditions with IL-4. This expression of CCR3 was associated with a reduced IFN-gamma production, but no IL-4 production could be induced. The IL-4-treated Th1 clones had a reduced migratory capacity against chemokines produced by ST cells compared to nonmanipulated T-cell clones. In contrast, the same IL-12-treated Th1 clones showed an increased migratory potential. Induction of the Th2-associated marker CCR3 on memory Th1 cells demonstrates that a change in chemokine receptor phenotype related to the Th2 type can be induced on terminally differentiated Th1 cells, without a change in the cytokine profile.     

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.     

Th2 dominance in nasal mucosa in patients with Wegener's granulomatosis

Wegener's granulomatosis initially affects upper respiratory tract organs including the nasal mucosa in more than 90% of patients. The inflammation is typically granulomatous with associated vasculitis. T lymphocytes are usually a prominent component of the leucocyte infiltrate. Previous studies using peripheral blood T cells have implicated IFN-gamma rich Th1-type responses. This study addressed the cytokine milieu in nasal mucosa from 10 patients with active Wegener's granulomatosis using immunohistochemistry. Increased levels of CD3+ T cells and eosinophils were present compared with normal and disease controls. There was increased expression of IL-4, down-regulation of IL-2 and no detectable IFN-gamma. There was increased expression of the chemokine receptor CCR3 by infiltrating cells, consistent with an IL-4 dominant, Th2-biased response. In contrast, renal biopsy tissue from 10 patients with active Wegener's granulomatosis showed expression of IL-2 and IL-4. The Th2-type environment within nasal mucosa, often the initial site of disease activity in Wegener's, is consistent with a local allergic response in these patients.     

CRTH2 is the most reliable marker for the detection of circulating human type 2 Th and type 2 T cytotoxic cells in health and disease

Cells expressing the chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) and the chemokine C receptor (CCR)4 were consistently detected in the circulation of healthy subjects, whereas numbers of cells expressing CCR3 were much lower. While all CCR4+ cells were T cells, a small proportion of CRTH2+, and about a half of the few CCR3+ cells were basophils. Only CRTH2+ T cells contained Th2 or Tc2 cells, but neither Th0 or Tc0, nor Th1 or Tc1 cells, although not all of them produced Th2-type cytokines. By contrast, CCR4+ T cells contained both Th2 or Tc2 and Th0 or Tc0 cells and even Th1 or Tc1 cells, whereas the few CCR3+ T cells were not clearly classifiable for their cytokine profile. CRTH2+ T lymphocytes were virtually devoid of chemokine CX receptor (CXCR)3+ and CCR5+ cells, but enriched in CCR3+ and CCR4+ cells. By contrast, CCR3+ or CCR4+ T cells did not show a similar clear-cut dichotomy in the expression of CCR5/CXCR3 or CCR3/ CCR4. Subjects with atopic dermatitis or HIV infection with low levels of circulating CD4+ T cells revealed a significant increase of CRTH2+ cells within both the CD4+ and the CD8+ T cell subset. These data support the concept that at present CRTH2 is the more reliable marker for detection of both human Th2 and Tc2 cells in health and disease.     

Expression of L-selectin (CD62L) discriminates Th1- and Th2-like cytokine-producing memory CD4+ T cells.

Human memory (CD45RO+) CD4+ T cells can be distinguished into two subpopulations on the basis of expression of the lymph node homing receptor, L-selectin (CD62L). In a prior study we showed that human L-selectin-positive memory T-helper (Th) cells promote the maturation of IgG- and IgA-producing cells by naive B cells. To further elucidate the contribution of memory CD4+ T cells to B-cell differentiation, human memory CD4+ T cells with or without L-selectin expression were evaluated for production of cytokines that participate in regulation of immunoglobulin production. It was found that L-selectin-positive human memory CD4+ T cells produce mainly interleukin (IL)-4 and IL-5, whereas L-selectin-negative CD4+ T cells produce mainly interferon-gamma (IFN-gamma). This profile of cytokine expression coincides with the profile that distinguishes Th1 and Th2 subsets. In contrast to the murine system, IL-10 production was similarly contributed by human L-selectin-positive and -negative memory CD4+ T-cell subpopulations. These results suggest that the human L-selectin-negative and -positive subpopulations of human memory CD4+ T cells contain Th1-like and Th2-like cytokine-producing cells, respectively.     

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.     

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.