CCR4 ligands are up-regulated in the airways of atopic asthmatics after segmental allergen challenge.

T-helper (Th) 2 cytokines are thought to mediate most features of allergic inflammation in atopic asthma. However, it remains unclear whether chemokine pathways direct selective recruitment of Th2 cells to the airways during human allergic responses. Bronchoalveolar lavage (BAL) was performed in 15 nonsmoking mild atopic asthmatics before and 24 h after a fibreoptic segmental allergen challenge, and chemokines related to T-cell recruitment were assayed by ELISA. The Th2-related C-C chemokine (CCR)4 ligands, macrophage-derived chemokine/C-C chemokine ligand (CCL)22 and thymus and activation-regulated chemokine/CCL17, were increased in BAL after challenge. These chemokines correlated significantly with lymphocyte numbers and with interleukin (IL)-5 and IL-13 in post-challenge BAL. In contrast, two out of three putative Th1-related chemokines did not change. There were no alterations in monokine induced by interferon (IFN)-gamma/CXC chemokine ligand (CXCL)9 or macrophage inflammatory protein-1alpha/CCL3; whereas a significant increase in IFN-induced protein-10kDa/CXCL10 was observed, which did not correlate with the T-cell influx. In peripheral mononuclear cells from atopic donors, CCL22 and CCL17 were induced by IL-4 and IL-13, further supporting the relationship between CCL22/CCL17 and Th2 cytokines. Finally, CCL22 was able to trigger actin polymerisation in peripheral CD4+ T-cells expressing CCR4. Thus, C-C chemokine receptor 4 ligands are up-regulated in the airways of atopic asthmatics following allergen exposure, contribute to the T-cell influx to the airways and are closely related to the Th2-cytokine response.     

Expression of Th1 markers by lung accumulated T cells in pulmonary sarcoidosis

OBJECTIVES: The balance between Th1 and Th2 T cells, classified by virtue of their cytokine production can in an immune response influence the phenotype and progression of several clinical diseases. In this study, we examined the expression of Th1 associated chemokine and cytokine receptors CXCR3, CCR5, and interleukin (IL)-12R, IL-18R, respectively, as well as of the Th2 associated chemokine receptors CCR4 and CXCR4 on CD4+ and CD8+ T cells. SUBJECTS: Eighteen patients with untreated pulmonary sarcoidosis. MATERIALS AND METHODS: We used monoclonal antibodies and flow cytometry to analyse the expression of chemokine receptors CXCR3, CXCR4, CCR4 CCR5 and cytokine receptors IL-12R, IL-18R in combination with anti-CD4 and anti-CD8 mAbs in bronchoalveolar lavage fluid (BAL) and peripheral blood lymphocytes (PBL) from sarcoidosis patients. RESULTS: There were significantly more BAL CD4+ T cells expressing CXCR3, CCR5, IL-12R and IL-18R compared with paired PBL CD4+ T cells. In contrast, the Th2 associated chemokine receptors CXCR4 and CCR4 were expressed by a fewer percentage of BAL CD4+ compared with PBL CD4+ T cells. There was a positive correlation between the percentage of BAL lymphocytes and the number of CXCR3 and CCR5 expressing CD4+ BAL T cells. Also, the number of CD4+ IL-18R+ BAL fluid cells correlated negatively with disease duration. CONCLUSIONS: The lung accumulation of CXCR3, CCR5, IL-12R and IL-18R expressing T cells is in line with previous reports showing elevated levels in the lung of the corresponding ligands in sarcodosis. Blocking such ligands and/or receptors may develop into a future immunomodulatory therapy.     

Upregulation of CXCR1 by proliferating cells in patients with lymphoproliferative disease of granular lymphocytes

The expression and the functional activities of different chemokine receptors (CC motif: CCR1, CCR2, CCR3, CCR5, CCR6; CXC motif: CXCR1, CXCR2, CXCR3, CXCR4, CXCR5) were investigated in 12 patients with lymphoproliferative disease of granular lymphocytes (LDGL). Six patients were characterized by the proliferation of CD3+ve GL and six patients by the expansion of CD3-ve GL. The interleukin 8 (IL-8/CXCL8) receptor CXCR1 was expressed in 12/12 patients, the CXCR4 in 6/12 patients (four CD3+ve and two CD3-ve) and the CXCR3 in 3/12 patients (one CD3+ve and two CD3-ve). CXCR1 was expressed only by proliferating GL. Other CC and CXC receptors were not expressed on proliferating GL (< 2%). In functional assays, purified GL from the patients displayed significant migration in response to specific chemokines, indicating that CXCR1, CXCR3 and CXCR4 were functionally active in these patients. In addition, a significant reduction of IL-8/CXCL8-mediated cell migration was reported in the presence of anti-CXCR1 monoclonal antibody. Our results indicate that expanding cells from patients with LDGL express specific CXCR. These data may help to define functional properties of proliferating GL in patients with LDGL and contribute toward the understanding of the complex clinical features of this disease. In particular, as CXCR1 was expressed in all of the patients studied, we speculate that abnormal expression of this receptor on proliferating GL might play a role in the pathogenesis of neutropenia, which represents a common feature in LDGL patients.     

Altered expression of the receptor-ligand pair CXCR5/CXCL13 in B cells during chronic HIV-1 infection

HIV-1 infection is associated with B-cell abnormalities, such as hypergammaglobulinemia, poor immunization responses, and loss of serologic memory. To determine whether altered expression of chemokine receptors and their ligands may play a role in B-cell dysfunctions during HIV-1 infection, the expression of CXC chemokine receptor 4 (CXCR4), CXCR5, and CC chemokine receptor 7 (CCR7) and their respective ligands on CD19(+) B cells were examined in HIV-1-infected patients and controls. We report a decreased CXCR5 expression on B cells from patients (P < .05), a phenomenon associated with a low CD4 T-cell count (< 350 cells/microL). Interestingly, an increased expression of CXC chemokine ligand 13 (CXCL13), the ligand for CXCR5, was found in peripheral B cells from HIV-1-infected patients. Moreover, on B-cell activation in vitro, CXCL13 was secreted in culture. CXCL13(+) B cells were also found in the lymph nodes of HIV-1-infected patients, but not in control tissue. B-cell migration toward CXCL13, CXCL12, and CC chemokine ligand 21 (CCL21), ligands for CXCR5, CXCR4, and CCR7 was also evaluated. In patients with a low CD4 T-cell count, migration toward all ligands was increased. Our findings indicate that altered expression of the chemokine receptor-ligand pair, CXCR5/CXCL13, may participate in the establishment of B-cell dysfunctions during HIV-1 infection.     

Selective recruitment of polarized T cells expressing CCR5 and CXCR3 to the inflamed joints of children with juvenile idiopathic arthritis

OBJECTIVE: To study the expression of chemokine receptors CCR5 and CXCR3 and the Th1/Th2 cytokine balance in children with oligoarticular or polyarticular juvenile idiopathic arthritis (JIA). METHODS: Using 3-color immunofluorescence, we studied the expression of CCR5 and CXCR3 on, and T cell cytokine production by, paired samples of synovial fluid (SF) and peripheral blood (PB) T cells from 20 patients with oligoarticular- or polyarticular-onset JIA. Chemokine and cytokine phenotypes were also compared within the CD45RO+,CD3+ subsets. CCR5 genotypes were confirmed by polymerase chain reaction typing and sequencing. RESULTS: In the majority of samples, the number of T cells that were CCR5+ and CXCR3+ was higher in SF than in PB, and this difference was significant. One child was homozygous for the null A32 CCR5 allele; 4 others had lower expression of CXCR3 in SF than in blood. All samples showed strongly Th1-type cytokine production by synovial T cells compared with that by PB T cells. Both features were also markedly polarized within the synovial CD45RO+ subset compared with PB CD45RO+ T cells. CONCLUSION: The high expression of CCR5 and CXCR3 and high interferon-gamma:interleukin-4 ratios suggest a type 1 phenotype of SF T cells in JIA. The difference between CD45RO+ T cells from SF and from PB suggests that specific activation events have occurred in synovial T cells. We suggest that the highly activated, Th1-type phenotype of T cells within the chronically inflamed joints of children with JIA may reflect specific recruitment events that contribute to the polarization of these cells.     

Role of the chemokine receptors CXCR3 and CCR4 in human pulmonary fibrosis

RATIONALE: The chemokine receptors CXCR3 and CCR4 have recently been described as playing a pivotal role in the mouse model of bleomycin-induced fibrosis. OBJECTIVES: To evaluate the role of these receptors in human idiopathic pulmonary fibrosis (IPF). METHODS: We studied 57 patients: 18 with IPF, 17 with non-IPF (nIPF), 12 with sarcoidosis, and 10 healthy control subjects. MEASUREMENTS: We evaluated the expression of CXCR3 and CCR4 in blood and bronchoalveolar lavage (BAL) T lymphocytes by flow cytometry and the chemokine CXCL10, CXCL11 and CCL17 BAL concentration by singular immunoassay. MAIN RESULTS: Patients with IPF had a significantly lower CXCR3 and a higher CCR4 expression on BAL CD4 T cells compared with the other groups. Among patients with IPF, those treated with corticosteroids exhibited higher CXCR3 and lower CCR4 expression compared with untreated patients. CXCR3 expression correlated with BAL lymphocytes and CCR4 with BAL neutrophils and eosinophils. CXCL10 levels correlated with the expression of CXCR3 on BAL CD4 cells. CXCL11 was undetectable in almost all patients, whereas CCL17 was primarily detectable in patients with IPF. The percentage of BAL CCR4CD4 cells negatively correlated with DL(CO). The changes in the total lung capacity, VC, and of the alveolar-arterial PO2 gradient in patients with IPF and those with nIPF 6 to 12 mo after the first evaluation were associated with CD4CXCR3 percentage on BAL cells. CONCLUSIONS: We found an imbalance in CXCR3/CCR4 expression on BAL CD4 lymphocytes and reduced CXCL10 BAL levels in patients with IPF, suggesting a pivotal role of these molecules in IPF.     

Changes in expression of T-helper (Th) 1- and Th2-associated chemokine receptors on peripheral blood lymphocytes and plasma concentrations of their ligands, interferon-inducible protein-10 and thymus and activation-regulated chemokine, after antithyroid drug administration in hyperthyroid patients with Graves' disease

OBJECTIVE: Although Graves' disease is considered an autoantibody-mediated, T-helper 2 (Th2)-dominant disease, Th1-dominance may prevail in its initial phase. We longitudinally investigated Th1/Th2 balance in untreated hyperthyroid patients with Graves' disease after treatment of methimazole (MMI), an antithyroid drug. DESIGN: University clinic outpatients were studied prospectively. PATIENTS: Subjects included 23 untreated hyperthyroid patients with Graves' disease and 17 age-matched control subjects. METHODS: Before and after treatment, we measured Th1- and Th2-associated chemokine receptors (CXCR)3 and CCR4, on peripheral blood lymphocytes using flow cytometry, as well as plasma concentrations of their ligands, interferon-inducible protein (IP)-10 and thymus and activation-regulated chemokine (TARC). RESULTS: The percentage of CXCR3-expressing cells among CD4+T lymphocytes and plasma IP-10 was significantly higher in hyperthyroid Graves' disease patients than in controls. At 12 and 24 weeks after initiation of MMI, percentage of CXCR3-expressing CD4+T lymphocytes had decreased significantly, while the percentage of CCR4-expressing CD4+T lymphocytes had increased significantly at 24 weeks. The CXCR3/CCR4 ratio had decreased significantly at 24 weeks. Plasma concentrations of IP-10 had decreased significantly at 12 and 24 weeks. Plasma concentrations of TARC also had decreased significantly at 24 weeks. CONCLUSIONS: In hyperthyroid patients with Graves' disease in the active phase, Th1 cells rather than Th2 cells predominated among peripheral blood lymphocytes. After initiation of MMI, an ongoing transition from Th1 to Th2 dominance occurred.     

Prostaglandin E2 exacerbates collagen-induced arthritis in mice through the inflammatory interleukin-23/interleukin-17 axis

OBJECTIVE: Recently, Th17 cells, a new subset of CD4+ T cells, emerged as major players in inflammation/autoimmunity. Maintenance of the Th17 phenotype requires interleukin-23 (IL-23), whereas the Th1-promoting cytokine IL-12p70 exerts a negative effect on Th17 cell differentiation. The lipid mediator prostaglandin E(2) (PGE(2)) acts primarily as a proinflammatory agent in autoimmune conditions, through mechanisms that remain to be elucidated. The aim of this study was to investigate whether PGE(2) released in inflammatory foci activates resident dendritic cells (DCs) to express IL-23 (at the expense of IL-12) and IL-6, resulting in a shift toward Th17 cell responses. METHODS: The effect of PGE(2) on IL-23 production by DCs and subsequent induction of T cell-derived IL-17 was assessed in vitro and in vivo. The effect of the stable PGE analog misoprostol was evaluated in a murine model of rheumatoid arthritis, in conjunction with IL-23 and IL-17 expression in affected joints and draining lymph nodes. RESULTS: In vivo administration of PGE(2) induced IL-23-dependent IL-17 production. Administration of misoprostol exacerbated collagen-induced arthritis (CIA). CIA exacerbation was associated with increased levels of IL-23p19/p40 messenger RNA and reduced expression of IL-12p35, and with increased levels of the proinflammatory cytokines IL-17, IL-1beta, IL-6, and tumor necrosis factor in the affected joint. Following ex vivo restimulation, draining lymph node cells from misoprostol-treated mice secreted higher levels of IL-17 and lower levels of interferon-gamma. CONCLUSION: Our results indicate that PGE(2) enhances DC-derived IL-6 production and induces a shift in the IL-23/IL-12 balance in favor of IL-23, resulting in increased IL-17 production, presumably through the amplification of self-reactive Th17 cells.     

Circulating levels of both Th1 and Th2 chemokines are elevated in patients with sarcoidosis

BACKGROUND: In sarcoidosis, the T helper type 1 (Th1) response tends to predominate at affected disease sites; however, whether Th1/Th2 polarization occurs in the peripheral circulation is unknown. METHODS: Fifty-two patients with sarcoidosis and 21 healthy volunteers were investigated. The concentrations of interferon-inducible protein 10 (IP-10)/CXCL10 and thymus- and activation-regulated chemokine (TARC)/CCL17 in the serum, bronchoalveolar lavage fluid (BALF) and culture supernatant were measured by an enzyme-linked immunosorbent assay. The circulating CXCR3+ CD4+ T cells and CCR4+ CD4+ T cells were assessed by flow cytometry. RESULTS: The CXCR3- or CCR4-positive ratios among CD4+ T cells were both higher in sarcoidosis than in healthy volunteers. The serum levels of both IP-10 and TARC of the patients with sarcoidosis were significantly higher than those of the healthy volunteers. In patients with sarcoidosis, a larger amount of IP-10 was generated by the BALF cells, whereas IP-10 production by peripheral blood mononuclear cells did not increase in comparison to the control subjects. The TARC levels produced by peripheral blood mononuclear cells of sarcoidosis patients were significantly higher than those of the controls, while no difference existed between the 2 groups regarding TARC production by BALF cells. CONCLUSION: IP-10 is mainly produced at the lung and TARC in the peripheral circulation in sarcoidosis patients. Both IP-10 and TARC cooperatively play a role in the pathogenesis of sarcoidosis.     

Bone marrow mesenchymal stem cells express a restricted set of functionally active chemokine receptors capable of promoting migration to pancreatic islets

Bone marrow-derived mesenchymal stem cells (BM-MSCs) are stromal cells with the ability to proliferate and differentiate into many tissues. Although they represent powerful tools for several therapeutic settings, mechanisms regulating their migration to peripheral tissues are still unknown. Here, we report chemokine receptor expression on human BM-MSCs and their role in mediating migration to tissues. A minority of BM-MSCs (2% to 25%) expressed a restricted set of chemokine receptors (CXC receptor 4 [CXCR4], CX3C receptor 1 [CX3CR1], CXCR6, CC chemokine receptor 1 [CCR1], CCR7) and, accordingly, showed appreciable chemotactic migration in response to the chemokines CXC ligand 12 (CXCL12), CX3CL1, CXCL16, CC chemokine ligand 3 (CCL3), and CCL19. Using human pancreatic islets as an in vitro model of peripheral tissue, we showed that islet supernatants released factors able to attract BM-MSCs in vitro, and this attraction was principally mediated by CX3CL1 and CXCL12. Moreover, cells with features of BM-MSCs were detected within the pancreatic islets of mice injected with green fluorescent protein (GFP)-positive BM. A population of bona fide MSCs that also expressed CXCR4, CXCR6, CCR1, and CCR7 could be isolated from normal adult human pancreas. This study defines the chemokine receptor repertoire of human BM-MSCs that determines their migratory activity. Modulation of homing capacity may be instrumental for harnessing the therapeutic potential of BM-MSCs.     

Asthma severity is associated with an increase in both blood CXCR3+ and CCR4+ T cells

OBJECTIVES: A predominance of type 2 helper T cells (Th2) in the bronchoalveolar space and peripheral blood is a well-accepted feature of bronchial asthma. However, the relationship between peripheral blood Th2 cells and asthma severity has not been thoroughly investigated. METHODS: As Th1 cells predominantly express the chemokine receptor CXCR3 and Th2 cells express CCR4, we assessed the distribution of peripheral blood CXCR3+ and CCR4+ lymphocytes using flow cytometry in 186 patients with asthma and 75 normal subjects. RESULTS: The proportion of CXCR3+/CD45RO+ cells in CD4+ T cells increased as the severity of asthma increased. The percentage of CCR4+/CD45RO+ cells in CD4+ T cells were elevated in mild to severe asthma patients compared with controls. However, there was no significant difference in CCR4+/CD45RO+ cells between the mild to severe asthma patients. There was no relationship between the patient's age and the numbers of CXCR3+ or CCR4+ T cells. The percentage of CCR4+ cells in CD45RO+/CD4+ T cells correlated with the levels of total serum IgE (r = 0.630, P < 0.0001). CONCLUSIONS: The proportion of CCR4+ cells in blood memory helper T cells may be increased in patients with asthma and is associated with the level of serum IgE, but severity of asthma is also associated with the increase of blood CXCR3+ cells in memory helper T cells.     

CCR5+ and CXCR3+ T cells are increased in multiple sclerosis and their ligands MIP-1α and IP-10 are expressed in demyelinating brain lesions

Multiple sclerosis (MS) is a T cell-dependent chronic inflammatory disease of the central nervous system. The role of chemokines in MS and its different stages is uncertain. Recent data suggest a bias in expression of chemokine receptors by Th1 vs. Th2 cells; human Th1 clones express CXCR3 and CCR5 and Th2 clones express CCR3 and CCR4. Chemokine receptors expressed by Th1 cells may be important in MS, as increased interferon-gamma (IFN-gamma) precedes clinical attacks, and IFN-gamma injection induces disease exacerbations. We found CXCR3(+) T cells increased in blood of relapsing-remitting MS, and both CCR5(+) and CXCR3(+) T cells increased in progressive MS compared with controls. Furthermore, peripheral blood CCR5(+) T cells secreted high levels of IFN-gamma. In the brain, the CCR5 ligand, MIP-1alpha, was strongly associated with microglia/macrophages, and the CXCR3 ligand, IP-10, was expressed by astrocytes in MS lesions but not unaffected white matter of control or MS subjects. Areas of plaque formation were infiltrated by CCR5-expressing and, to a lesser extent, CXCR3-expressing cells; Interleukin (IL)-18 and IFN-gamma were expressed in demyelinating lesions. No leukocyte expression of CCR3, CCR4, or six other chemokines, or anti-inflammatory cytokines IL-5, IL-10, IL-13, and transforming growth factor-beta was observed. Thus, chemokine receptor expression may be used for immunologic staging of MS and potentially for other chronic autoimmune/inflammatory processes such as rheumatoid arthritis, autoimmune diabetes, or chronic transplant rejection. Furthermore, these results provide a rationale for the use of agents that block CCR5 and/or CXCR3 as a therapeutic approach in the treatment of MS.     

The role of CCR5/CXCR3 expressing CD8+ cells in liver damage and viral control during persistent hepatitis C virus infection

BACKGROUND/AIMS: CXCR3 and CCR5 play a major role in recruiting cytotoxic T cells (Tc) and secreting secondary type 1 cytokines (Tc1) in the liver. HCV could impair their expression as a survival mechanism. The role of these chemokine receptors on CD8+ cells in chronic hepatitis C is analysed. METHODS: Serum, chemokines, peripheral blood and intrahepatic lymphocytes from chronic hepatitis C patients were studied. CXCR3/CCR5 expressing CD8+ cells were quantified by flow-cytometry. Serum chemokines concentration (CXCL10/CCL3) was measured by ELISA. Basal data were correlated with liver inflammation. Longitudinal data were obtained during treatment and correlated with virologic response. RESULTS: CCR5/CXCR3 expressing CD8+ cells were enriched in the liver and correlated with inflammation. Chronic HCV patients presented the same frequency of CCR5(high)/CXCR3(high) expressing CD8+ cells in peripheral blood as in healthy controls but higher serum concentration of CXCL10/CCL3. Treatment with PEG-interferon alpha-2b plus ribavirin increased CCR5(high)/CXCR3(high) expressing CD8+ cells frequency in peripheral blood and decreased CXCL10/CCL3 serum concentration. Increase in CXCR3(high) expressing CD8+ cells after 24 weeks of treatment was correlated with SVR. CONCLUSIONS: In chronic hepatitis C, anti-viral treatment induces an increase in CD8+ cells expressing chemokine receptors associated with Tc1 response and a reduction in their ligands. Achievement of viral control is associated with an increase in CXCR3(high) expressing CD8+ cells during treatment.     

Prostaglandin E2-dependent IL-23 production in aged murine dendritic cells

CD4+ T cells of the Th17 subtype are over-represented in the aged immune system. Dendritic cells (DC) play a critical role in naïve CD4+ T cell differentiation. However, expression of cytokines by aged DC that promote differentiation or survival of Th17 cells has not been extensively investigated. Using bone marrow-derived DC from C57BL/6 mice of different ages we compared cytokine production after DC activation by Toll-like receptor agonists for TLR4 and/or TLR7/8. DC-derived TNF-α and IL-12p70 production and expression of DC co-stimulatory molecules did not vary significantly by age indicating that TLR expression, function and signal transduction were intact in aged DC. There were relatively minor age-related changes in TGF-β and IL-6 which promote Th17 differentiation, but IL-23, a Th17-suvival cytokine, increased more than 40-fold across the lifespan. DC-derived prostaglandin E2 (PGE2) also increased with age and the up-regulation of IL-23 expression by aged DC was blocked by indomethacin that prevents PGE2 production, and by antagonists of PGE2 receptors. Exogenous PGE2 added to DC cultures further enhanced IL-23 production from aged but not young DCs. These data indicate that age-related changes in DC PGE2 production are necessary, but not sufficient to induce DC IL-23 production. Such changes may play a role in the expansion of Th17 cells in the aged immune system.     

IL-8 responsiveness defines a subset of CD8 T cells poised to kill

CD8 T cells play a key role in host defense against intracellular pathogens. Efficient migration of these cells into sites of infection is therefore intimately linked to their effector function. The molecular mechanisms that control CD8 T-cell trafficking into sites of infection and inflammation are not well understood, but the chemokine/chemokine receptor system is thought to orchestrate this process. Here we systematically examined the chemokine receptor profile expressed on human CD8 T cells. Surprisingly, we found that CXC chemokine receptor 1 (CXCR1), the predominant neutrophil chemokine receptor, defined a novel interleukin-8/CXC ligand 8 (IL-8/CXCL8)-responsive CD8 T-cell subset that was enriched in perforin, granzyme B, and interferon-gamma (IFNgamma), and had high cytotoxic potential. CXCR1 expression was down-regulated by antigen stimulation both in vitro and in vivo, suggesting antigen-dependent shaping of the migratory characteristics of CD8 T cells. On virus-specific CD8 T cells from persons with a history of Epstein-Barr virus (EBV) and influenza infection, CXCR1 expression was restricted to terminally differentiated effector memory cells. In HIV-1 infection, CXCR1-expressing HIV-1-specific CD8 T cells were present only in persons who were able to control HIV-1 replication during structured treatment interruptions. Thus, CXCR1 identifies a subset of CD8 T cells poised for immediate cytotoxicity and early recruitment into sites of innate immune system activation.     

Differential effect of methotrexate on the increased CCR2 density on circulating CD4 T lymphocytes and monocytes in active chronic rheumatoid arthritis, with a down regulation only on monocytes in responders

OBJECTIVES: To evaluate the effect of orally administered methotrexate (MTX) on the density of CC chemokine receptor 2 (CCR2) and CXC chemokine receptor 3 (CXCR3) on circulating monocytes, and the coexpression of CXCR3 and CCR2 on CD4 T lymphocytes in patients with active chronic rheumatoid arthritis. METHODS: All 34 patients with rheumatoid arthritis fulfilled the 1987 American Rheumatism Association criteria and were followed for 16 weeks after starting MTX. Peripheral blood mononuclear cells were analysed for CCR2 and CXCR3 density by three-colour flow cytometry before initiation of MTX and at week 12. RESULTS: 22 (65%) patients were non-responders, 12 (35%) patients responded to MTX by American College of Rheumatology (ACR)20% criteria, and 8 (24%) of these patients responded by ACR50%. In patients with active rheumatoid arthritis before starting MTX, CCR2 density on circulating monocytes, CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was increased compared with controls. During 12 weeks of MTX treatment, the CCR2 density on monocytes decreased significantly in the ACR50% group but not in the ACR20% and non-responder groups. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was unaffected by the reduction in disease activity measured in relation to MTX treatment. The percentage of both monocytes and CD4(+) CXCR3(+) and CD4+ CXCR3(-) T lymphocytes among the peripheral circulating mononuclear cells did not change during MTX treatment. CONCLUSIONS: Active chronic rheumatoid arthritis is characterised by enhanced CCR2 density on circulating monocytes and CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes. During MTX treatment, a decrease in CCR2 density on monocytes in the ACR50% responder group was associated with decreased disease activity. The increased CCR2 density on CD4(+) CXCR3(+) and CD4(+) CXCR3(-) T lymphocytes was uninfluenced by MTX and disease activity.     

Differential expression of chemokine receptors on peripheral blood, synovial fluid, and synovial tissue monocytes/macrophages in rheumatoid arthritis

OBJECTIVE: Since it is likely that monocytes utilize chemokines to migrate to the rheumatoid arthritis (RA) joint, we investigated the expression of C-C chemokine receptors (CCR) 1-6 and C-X-C receptor 3 (CXCR3) in the peripheral blood (PB), synovial fluid (SF), and synovial tissue of patients with RA as well as in the PB of normal subjects. METHODS: We compared chemokine receptor expression on CD14+ monocytes from normal PB, RA PB, and RA SF using 2-color flow cytometry. Correlations with patient clinical data were determined. Chemokine and receptor expression were investigated in RA synovial tissue by immunohistochemistry and 2-color immunofluorescence to identify CD68+ macrophages. RESULTS: Most normal PB monocytes expressed CCR1 (87%) and CCR2 (84%), but not CCRs 3, 4, 5, or 6 or CXCR3. RA PB monocytes expressed CCR1 (56%) and CCR2 (76%), with significantly more expressing CCR3 (18%), CCR4 (38%), and CCR5 (17%) compared with normal PB monocytes. Significantly fewer SF monocytes from RA patients expressed CCR1 (17%), CCR2 (24%), and CCR4 (6%) while significantly more expressed CCR3 (35%) and CCR5 (47%) compared with RA and normal PB monocytes; CCR6 and CXCR3 were rarely detected. Clinically, the erythrocyte sedimentation rate was inversely correlated with the expression of CCR1 and CCR4 by RA PB, and CCR5 expression by RA SF was correlated with the SF white blood cell count. CCR1-, CCR2-, and CCR5-immunoreactive cells were found in RA synovial tissue and colocalized with CD68+ macrophages. RA synovial tissue RANTES (regulated upon activation, normally T cell expressed and secreted chemokine)- and monocyte chemoattractant protein 1-immunoreactive cells colocalized with CCR1 and CCR2, respectively, on serial sections. Macrophage inflammatory protein 1alpha (MIP-1alpha) was principally restricted to vascular endothelium, and MIP-1beta+ macrophages were found throughout the sections. CONCLUSION: Monocytes mainly express CCR1 and CCR2 in normal and RA PB, CCR3 and CCR5 in RA PB and RA SF, and CCR4 in RA PB. The differential expression of chemokine receptors suggests that certain receptors aid in monocyte recruitment from the circulation while others are important in monocyte retention in the joint.