CD4+CD25+ T regulatory cells (Treg) are thought to be important in the peripheral tolerance. Recent evidence suggests that human peripheral blood CD4+CD25+ T cells are heterogeneous and contain both CD4+CD25(high) T cells with potent regulatory activity and many more CD4+CD25(low/med) nonregulatory T cells. In this study, we found that virtually all peripheral blood CD4+CD25(high)Foxp3+ Treg expressed high levels of the chemokine receptor CCR4. In addition, 80% of Treg expressed cutaneous lymphocyte Ag (CLA) and 73% expressed CCR6. These molecules were functional, as CLA+ Treg showed CD62E ligand activity and demonstrable chemotactic responses to the CCR4 ligands CCL22 and CCL17 and to the CCR6 ligand CCL20. The phenotype and chemotactic response of these Treg were significantly different from those of CD4+CD25(med) nonregulatory T cells. We further demonstrated that blood CLA+ Treg inhibited CD4+CD25- T cell proliferation induced by anti-CD3. Based on homing receptor profile, CLA+ Treg should enter normal skin. We next isolated CD4+CD25(high) T cells directly from normal human skin; these cells suppressed proliferation of skin CD4+CD25- T cells. Therefore, the majority of true circulating Treg express functional skin-homing receptors, and human Treg may regulate local immune responses in normal human skin.

BACKGROUND

Juvenile idiopathic arthritis (JIA) consists of a heterogeneous group of disorders with, for the most part, an unknown immunopathogenesis. Although onset and disease course differ, the subtypes of JIA share the occurrence of chronic inflammation of the joints, with infiltrations of immunocompetent cells that secrete inflammatory mediators.

OBJECTIVE

To identify a panel of cytokines specifically related to the inflammatory process in JIA.

METHODS

Using a new technology, the multiplex immunoassay, 30 cytokines were measured in plasma of 65 patients with JIA, of which 34 were paired with synovial fluid. These data were compared with plasma of 20 healthy controls and 9 patients with type I diabetes, a chronic inflammatory disease.

RESULTS

Patients with JIA had, irrespective of their subclassification, significantly higher levels of tumour necrosis factor alpha, macrophage inhibitory factor (MIF), CCL2, CCL3, CCL11, CCL22 and CXCL9 in plasma than controls. In paired plasma and synovial fluid samples of patients with JIA, significantly higher levels of interleukin (IL)6, IL15, CCL2, CCL3, CXCL8, CXCL9 and CXCL10 were present in synovial fluid. Cluster analysis in all patients with JIA revealed a predominant pro-inflammatory cytokine cluster during active disease and a regulatory/anti-inflammatory-related cytokine cluster during remission. Whether a discrimination profile of various cytokines could help in the determination of disease classification was tested.

CONCLUSIONS

It is suggested that several cytokines (IL18, MIF, CCL2, CCL3, CCL11, CXCL9 and CXCL10) may correspond to the activation status during inflammation in JIA and could be instrumental in monitoring disease activity and outcomes of (new) immunotherapies.

De novo formation of tertiary lymphoid structures (TLS) has been described in lung cancers. Intratumoral TLS seem to be functional and are associated with a long-term survival for lung cancer patients, suggesting that they represent an activation site for tumor-specific T cells. Here, we characterized T-cell recruitment to TLS in human lung cancer to identify the adhesion molecules and chemoattractants orchestrating this migration. We found that most TLS T cells were CD62L+ and mainly of CD4+ memory phenotype, but naive T cells were highly enriched in these structures as compared with the rest of the tumor. A specific gene expression signature associated with T cell presence was identified in TLS, which included chemokines (CCL19, CCL21, CXCL13, CCL17, CCL22, and IL16), adhesion molecules (ICAM-2, ICAM-3, VCAM-1, and MAdCAM-1) and integrins (alphaL, alpha4, and alphaD). The presence of the corresponding receptors on TLS T cells was confirmed. Intratumoral PNAd+ high endothelial venules also were exclusively associated with TLS and colocalized with CD62L+ lymphocytes. Together, these data bring new insights into the T-cell recruitment to intratumoral TLS and suggest that blood T cell enter into TLS via high endothelial venules, which represent a new gateway for T cells to the tumor. Findings identify the molecules that mediate migration of tumor-specific T cells into TLS where T cell priming occurs, suggesting new strategies to enhance the efficacy of cancer immunotherapies.

Host response to viral infection involves distinct effectors of innate and adaptive immunity, whose mobilization needs to be coordinated to ensure protection. Here we show that influenza virus triggers, in human blood dendritic-cell (DC) subsets (ie, plasmacytoid and myeloid DCs), a coordinated chemokine (CK) secretion program with 3 successive waves. The first one, occurring at early time points (2 to 4 hours), includes CKs potentially attracting effector cells such as neutrophils, cytotoxic T cells, and natural killer (NK) cells (CXCL16, CXCL1, CXCL2, and CXCL3). The second one occurs within 8 to 12 hours and includes CKs attracting effector memory T cells (CXCL8, CCL3, CCL4, CCL5, CXCL9, CXCL10, and CXCL11). The third wave, which occurs after 24 to 48 hours, when DCs have reached the lymphoid organs, includes CCL19, CCL22, and CXCL13, which attract naive T and B lymphocytes. Thus, human blood DC subsets carry a common program of CK production, which allows for a coordinated attraction of the different immune effectors in response to viral infection.

BACKGROUND

Despite growing recognition of an etiologic role for inflammation in lung carcinogenesis, few prospective epidemiologic studies have comprehensively investigated the association of circulating inflammation markers with lung cancer.

METHODS

We conducted a nested case-control study (n = 526 lung cancer patients and n = 592 control subjects) within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Control subjects were matched to lung cancer case patients on age, sex, follow-up time (median = 2.9 years), randomization year, and smoking (pack-years and time since quitting). Serum levels of 77 inflammation markers were measured using a Luminex bead-based assay. Conditional logistic regression and weighted Cox models were used to estimate odds ratios (ORs) and cumulative risks, respectively.

RESULTS

Of 68 evaluable markers, 11 were statistically significantly associated with lung cancer risk (P trend across marker categories < .05), including acute-phase proteins (C-reactive protein [CRP], serum amyloid A [SAA]), proinflammatory cytokines (soluble tumor necrosis factor receptor 2 [sTNFRII]), anti-inflammatory cytokines (interleukin 1 receptor antagonist [IL-1RA]), lymphoid differentiation cytokines (interleukin 7 [IL-7]), growth factors (transforming growth factor alpha [TGF-A]), and chemokines (epithelial neutrophil-activating peptide 78 [ENA 78/CXCL5], monokine induced by gamma interferon [MIG/CXCL9], B cell-attracting chemokine 1 [BCA-1/CXCL13], thymus activation regulated chemokine [TARC/CCL17], macrophage-derived chemokine [MDC/CCL22]). Elevated marker levels were associated with increased lung cancer risk, with odds ratios comparing the highest vs the lowest group ranging from 1.47 (IL-7) to 2.27 (CRP). For IL-1RA, elevated levels were associated with decreased lung cancer risk (OR = 0.71; 95% confidence interval = 0.51 to 1.00). Associations did not differ by smoking, lung cancer histology, or latency. A cross-validated inflammation score using four independent markers (CRP, BCA-1/CXCL13, MDC/CCL22, and IL-1RA) provided good separation in 10-year lung cancer cumulative risks among former smokers (quartile [Q] 1 = 1.1% vs Q4 = 3.1%) and current smokers (Q1 = 2.3% vs Q4 = 7.9%) even after adjustment for smoking.

CONCLUSIONS

Some circulating inflammation marker levels are associated with prospective lung cancer risk.

It is now generally accepted type 2 T helper (Th2) cytokines and some chemoattractants play an essential role in the pathogenesis of the allergic inflammation. The effects of Th2 cytokines, such as interleukin (IL)-4, IL-5, IL-9, and IL-13, account for virtually all the pathophysiological manifestations of allergy and asthma. Moreover, both Th2 cells and the effector cells usually present in the areas of allergic inflammation (basophils, mast cells, and eosinophils) express chemoattractant receptors, such as CCR3, CCR4, CCR8 and CRTH2. Therefore, interactions of eotaxin(s), eotaxin/CCL11, RANTES/CCL5, and MCP-1/CCL2, MCP-2/CCL8, MCP-3/CCL7, MCP-4/CCL13 with CCR3 are responsible for the recruitment of basophils, eosinophils and mast cells, whereas interactions of CCR4 with MDC/CCL22 or TARC/CCL17, CCR8 with I-309/CCL1, and CRTH2 with prostaglandin D(2) play a critical role in the allergen-induced recruitment of Th2 cells in the target tissues of allergic inflammation. The demonstration that Th2-polarized responses against allergens represent the triggering event for the development of allergic diseases, together with the recognition that some chemoattractants are responsible for the recruitment of both Th2 cells and other effector cells of allergic inflammation, can provide the conceptual basis for the development of new therapeutic strategies in allergic conditions.

Complement component 5 (C5) has been described as either promoting or protecting against airway hyperresponsiveness (AHR) in experimental allergic asthma, suggesting pleomorphic effects of C5. Here we report that local pharmacological targeting of the C5a receptor (C5aR) prior to initial allergen sensitization in murine models of inhalation tolerance or allergic asthma resulted in either induction or marked enhancement of Th2-polarized immune responses, airway inflammation, and AHR. Importantly, C5aR-deficient mice exhibited a similar, increased allergic phenotype. Pulmonary allergen exposure in C5aR-targeted mice resulted in increased sensitization and accumulation of CD4+ CD69+ T cells associated with a marked increase in pulmonary myeloid, but not plasmacytoid, DC numbers. Pulmonary DCs from C5aR-targeted mice produced large amounts of CC chemokine ligand 17 (CCL17) and CCL22 ex vivo, suggesting a negative impact of C5aR signaling on pulmonary homing of Th2 cells. In contrast, C5aR targeting in sensitized mice led to suppressed airway inflammation and AHR but was still associated with enhanced production of Th2 effector cytokines. These data suggest a dual role for C5a in allergic asthma, i.e., protection from the development of maladaptive type 2 immune responses during allergen sensitization at the DC/T cell interface but enhancement of airway inflammation and AHR in an established inflammatory environment.

Lung CD11c(high) dendritic cells (DC) are comprised of two major phenotypically distinct populations, the CD11b(high) DC and the integrin alpha(E)beta(7)(+) DC (CD103(+) DC). To examine whether they are functionally distinguishable, global microarray studies and real-time PCR analysis were performed. Significant differences between the two major CD11c(high) DC types in chemokine mRNA expression were found. CD11b(high) DC is a major secretory cell type and highly expressed at least 16 chemokine mRNA in the homeostatic state, whereas CD103(+) DC highly expressed only 6. Intracellular chemokine staining of CD11c(high) lung cells including macrophages, and ELISA determination of sort-purified CD11c(high) cell culture supernatants, further showed that CD11b(high) DC produced the highest levels of 9 of 14 and 5 of 7 chemokines studied, respectively. Upon LPS stimulation in vitro and in vivo, CD11b(high) DC remained the highest producer of 7 of 10 of the most highly produced chemokines. Induction of airway hyperreactivity and lung inflammation increased lung CD11b(high) DC numbers markedly, and they produced comparable or higher amounts of 11 of 12 major chemokines when compared with macrophages. Although not a major producer, CD103(+) DC produced the highest amounts of the Th2-stimulating chemokines CCL17/thymus and activation-related chemokine and CCL22/monocyte-derived chemokine in both homeostasis and inflammation. Significantly, CCL22/monocyte-derived chemokine exhibited regulatory effects on CD4(+) T cell proliferation. Further functional analysis showed that both DC types induced comparable Th subset development. These studies showed that lung CD11b(high) DC is one of the most important leukocyte types in chemokine production and it is readily distinguishable from CD103(+) DC in this secretory function.

Platelets are a rich source of different chemokines and express chemokine receptors. CXCL4 is highly abundant in platelets and involved in promoting monocyte arrest from rolling and monocyte differentiation to macrophages. CXCL4 can also associate with CCL5 and amplify its effect on monocytes. The megakaryocyte CXCL7 gene product is proteolytically cleaved into the strong neutrophil chemoattractant, NAP-2, which has also been implicated in repair cell homing to vascular lesions. Platelet adhesion can induce release of CCL2 and CXCL8 from endothelial cells. Conversely, the chemokines CCL17, CCL22, and CXCL12 made by other cells amplify platelet activation. Platelet chemokines enhance recruitment of various hematopoietic cells to the vascular wall, fostering processes such as neointima formation, atherosclerosis, and thrombosis, but also vessel repair and regeneration after vascular injury.

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is an immunomodulatory agent inducing dendritic cells (DCs) to become tolerogenic. To further understand its mechanisms of action, we have examined the effects of 1,25(OH)(2)D(3) on tolerogenic properties of blood myeloid (M-DCs) and plasmacytoid (P-DCs) human DC subsets. Exposure of M-DCs to 1,25(OH)(2)D(3) up-regulated production of CCL22, a chemokine attracting regulatory T cells, whereas production of CCL17, the other CCR4 ligand, was reduced. 1,25(OH)(2)D(3) also decreased IL-12p75 production by M-DCs, as expected, and inhibited CCR7 expression. 1,25(OH)(2)D(3) treatment markedly increased CD4(+) suppressor T cell activity while decreasing the capacity of M-DCs to induce Th1 cell development. Surprisingly, 1,25(OH)(2)D(3) did not exert any discernible effect on tolerogenic properties of P-DCs, and even their high production of IFN-alpha was not modulated. In particular, the intrinsically high capacity of P-DCs to induce CD4(+) suppressor T cells was unaffected by 1,25(OH)(2)D(3). Both DC subsets expressed similar levels of the vitamin D receptor, and its ligation by 1,25(OH)(2)D(3) similarly activated the primary response gene cyp24. Interestingly, 1,25(OH)(2)D(3) inhibited NF-kappaB p65 phosphorylation and nuclear translocation in M-DCs but not P-DCs, suggesting a mechanism for the inability of 1,25(OH)(2)D(3) to modulate tolerogenic properties in P-DCs.

Experimental models have often been at the origin of immunological paradigms such as the M1/M2 dichotomy following macrophage polarization. However, this clear dichotomy in animal models is not as obvious in humans, and the separating line between M1-like and M2-like macrophages is rather represented by a continuum, where boundaries are still unclear. Indeed, human infectious diseases, are characterized by either a back and forth or often a mixed profile between the pro-inflammatory microenvironment (dominated by interleukin (IL)-1β, IL-6, IL-12, IL-23 and Tumor Necrosis Factor (TNF)-α cytokines) and tissue injury driven by classically activated macrophages (M1-like) and wound healing driven by alternatively activated macrophages (M2-like) in an anti-inflammatory environment (dominated by IL-10, Transforming growth factor (TGF)-β, chemokine ligand (CCL)1, CCL2, CCL17, CCL18, and CCL22). This review brews the complexity of the situation during infectious diseases by stressing on this continuum between M1-like and M2-like extremes. We first discuss the basic biology of macrophage polarization, function, and role in the inflammatory process and its resolution. Secondly, we discuss the relevance of the macrophage polarization continuum during infectious and neglected diseases, and the possibility to interfere with such activation states as a promising therapeutic strategy in the treatment of such diseases.

Macrophages can be polarized to exhibit either pro-inflammatory M1 or pro-angiogenic M2 phenotypes, but have high phenotypic plasticity. This pilot study investigated macrophage polarization in the macular retina and choroid of age-related macular degeneration (AMD) and non-AMD subjects, as well as in AMD choroidal neovascular membranes (CNVM). All specimens were evaluated for routine histopathology. Quantitative real-time polymerase chain reaction for representative M1 (CXCL11) and M2 (CCL22) transcripts were performed on macular choroidal trephines (MCT) of 19 AMD and nine non-AMD eye bank eyes, on the microdissected macular retinal cells from the archived slides of five geographic atrophic AMD, five exudative/neovascular AMD, and eight normal autopsied eyes, and on microdissected inflammatory cells from two surgically removed CNVM that did not respond to anti-vascular endothelial growth factor (VEGF) therapy. High M2-chemokine transcript and a low ratio of M1 to M2 chemokine transcript were found in aging non-AMD MCT. Advanced AMD maculae had a higher M1 to M2 chemokine transcript ratio compared to normal autopsied eyes. Macrophages in the two CNVM of patients unresponsive to anti-VEGF therapy were polarized toward either M1 or M2 phenotypes. The number of M2 macrophages was increased compared to M1 macrophages in normal aging eyes. A pathological shift of macrophage polarization may play a potential role in AMD pathogenesis.

Regulatory T cells (Tregs) accumulate in tumors and can contribute to the dismal immune responses observed in these tumors. We reported that the percentage of tumor infiltrating Tregs is strongly correlated with the WHO grade of the brain tumor. We now report on the clinical follow-up of this patient cohort (n=83). Subgroup analyses in patients with glioblastomas (n=29) showed a moderate, not significant, inverted association between Tregs and survival. We further show that Tregs in glioblastomas, in contrast to other tumor infiltrating effector lymphocytes, highly express the CCR4 chemokine receptor. Moreover, the CCR4 ligand CCL22 is secreted by glioblastomas and may explain the specific Treg accumulation seen in these tumors.

OBJECTIVE

The roles of alternatively activated (M2) macrophages on pro-tumour phenotypes have been well documented in many cancers except hepatocellular carcinoma (HCC). Considering their close relationship with chronic tissue injuries as well as enhanced tumour invasiveness and growth, we aimed to investigate the direct effects of M2 macrophages on HCC.

METHODS

M2 macrophages in 95 HCC clinical specimens were quantified using immunohistochemistry and quantitative PCR. The pro-tumour functions and the underlying molecular mechanisms of M2 macrophages in HCC were investigated in vivo and in an in vitro co-culture system.

RESULTS

In the clinical study, high M2-specific CD163 (hazard ratio=2.693; p=0.043) and scavenger receptor A (hazard ratio=3.563; p=0.044) levels indicated poor prognosis and correlated with increased tumour nodules and venous infiltration in HCC patients. In an orthotopic model, the liver tumour volume was increased 3.26-fold (1.27 cm3±0.36) after M2 macrophage injection compared with the control (0.39 cm3±0.05) (p=0.032). An increased rate of lung metastasis was also found in the treatment group. In vitro, co-cultivation with M2 macrophages elevated the number of HCC cells (MHCC97L) and migration events by 1.3-fold and 3.2-fold, respectively (p<0.05). Strongly induced by MHCC97L, M2 macrophage-derived CCL22 was proven to enhance tumour migration capacities and correlate with venous infiltration in HCC patients. Increased epithelial-mesenchymal transition (EMT) via Snail activation in MHCC97L was found to be promoted by M2 macrophages and CCL22.

CONCLUSIONS

M2 macrophages contribute to poor prognosis in HCC and promote tumour invasiveness through CCL22-induced EMT.

Primary T helper 2 cells are heterogeneous, expressing subsets of cytokines at varying levels. Mechanisms controlling this spectrum of phenotypes are still unclear. The ETS family transcription factor PU.1 is expressed in Th2 but not Th1 cells. Th2 cytokine production is decreased in cultures transduced with a PU.1-expressing retrovirus and increased in Th2 cells following RNAi that decreases PU.1 expression. In primary cultures, PU.1 expression is restricted to a subpopulation of Th2 cells that express CCL22 and a subset of Th2 cytokines. PU.1 regulates the Th2 phenotype by interfering with GATA-3 DNA binding without altering GATA-3 protein levels. Thus, the expression of PU.1 in subsets of Th2 cells establishes a defined cytokine profile and contributes towards establishing the spectrum of cytokine production observed in Th2 populations.

Chemokines and chemokine receptors play important roles in migration and tissue localization of various lymphocyte subsets. Here, we report the highly frequent expression of CCR4 in adult T-cell leukemia (ATL) and human T-cell leukemia virus type 1 (HTLV-1)-immortalized T cells. Flow cytometric analysis revealed that ATL and HTLV-1-immortalized T-cell lines consistently expressed CCR4. Inducible expression of HTLV-1 transcriptional activator tax in a human T-cell line Jurkat did not, however, up-regulate CCR4 mRNA. In vitro immortalization of peripheral blood T cells led to preferential outgrowth of CD4(+) T cells expressing CCR4. We further demonstrated highly frequent expression of CCR4 in fresh ATL cells by (1) reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of CCR4 expression in peripheral blood mononuclear cells (PBMCs) from patients with ATL and healthy controls; (2) flow cytometric analysis of CCR4-expressing cells in PBMCs from patients with ATL and healthy controls; (3) CCR4 staining of routine blood smears from patients with ATL; and (4) an efficient migration of fresh ATL cells to the CCR4 ligands, TARC/CCL17 and MDC/CCL22, in chemotaxis assays. Furthermore, we detected strong signals for CCR4, TARC, and MDC in ATL skin lesions by RT-PCR. Collectively, most ATL cases have apparently derived from CD4(+) T cells expressing CCR4. It is now known that circulating CCR4(+) T cells are mostly polarized to Th2 and also contain essentially all skin-seeking memory T cells. Thus, HTLV-1-infected CCR4(+) T cells may have growth advantages by deviating host immune responses to Th2. CCR4 expression may also account for frequent infiltration of ATL into tissues such as skin and lymph nodes.

Chemokines coordinate many aspects of leukocyte migration. As chemoattractants they play an important role in the innate and acquired immune response. There is good experimental evidence that N-terminal truncation by secreted or cell surface proteases is a way of modulating chemokine action. The localization of CD26/dipeptidyl peptidase IV on cell surfaces and in biological fluids, its primary specificity, and the type of naturally occurring truncated chemokines are consistent with such a function. We determined the steady-state catalytic parameters for a relevant selection of chemokines (CCL3b, CCL5, CCL11, CCL22, CXCL9, CXCL10, CXCL11, and CXCL12) previously reported to alter their chemotactic behavior due to CD26/dipeptidyl peptidase IV-catalyzed truncation. The results reveal a striking selectivity for stromal cell-derived factor-1alpha (CXCL12) and macrophage-derived chemokine (CCL22). The kinetic parameters support the hypothesis that CD26/dipeptidyl peptidase IV contributes to the degradation of certain chemokines in vivo. The data not only provide insight into the selectivity of the enzyme for specific chemokines, but they also contribute to the general understanding of CD26/dipeptidyl peptidase IV secondary substrate specificity.

The natural history of B-chronic lymphocytic leukemia (CLL) is not entirely explained by intrinsic defects of the neoplastic cell, but is also favored by microenvironmental signals. As CLL cells retain the capacity to respond to CD40 ligand (CD40L) and as CD4(+) T cells are always present in involved tissues, we asked whether malignant CLL cells might produce T cell-attracting chemokines. We studied the chemokine expression of CD19(+)/CD5(+) malignant B cells from peripheral blood (PB), lymph nodes (LN) or bone marrow (BM) of 32 patients and found a major difference. LN- and BM-, but not PB-derived cells, expressed a readily detectable reverse transcription-PCR band for CCL22 and one for CCL17 of variable intensity. CD40 ligation of PB cells induced the mRNA expression of both CCL22 and CCL17. CCL22 was also released in the culture supernatants. These supernatants induced the migration of activated CD4(+), CD40L(+) T cells expressing the CCL22 receptor, CCR4. T cell migration was abrogated by anti-CCL22 antibodies. Immunohistochemistry and cytofluorography studies revealed that a proportion of CD4(+) T cells in CLL LN and BM expressed CD40L. Our data demonstrate that malignant CLL cells chemo-attract CD4(+) T cells that in turn induce a strong chemokine production by the leukemic clone, suggesting a vicious circle, leading to the progressive accumulation of the neoplastic cells.

OBJECTIVE

This prospective study quantified cytokine and chemokine levels in seminal plasma of patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and benign prostatic hyperplasia (BPH), to evaluate inflammatory mediators as possible surrogate markers for diagnosis and treatment efficacy.

METHODS

Seminal plasma levels of eight cytokines and nine chemokines were evaluated by multiplex arrays in 83 men: 20 healthy controls and 9 men with CP/CPPS IIIA, 31 with CP/CPPS IIIB, and 23 with BPH. Prostate samples obtained by transurethral resection of the prostate from 13 patients with BPH were analysed by immunohistochemistry to detect interleukin 8 (IL-8)-producing cells and characterise inflammatory infiltrates.

RESULTS

Significantly increased levels of cytokines (IL-1alpha, IL-1beta, IL-6, IL-10, IL12p70) and chemokines (CCL1, CCL3, CCL4, CCL17, CCL22, CXCL8/IL-8) were observed in seminal plasmas from patients with CP/CPPS or BPH. However, only IL-8 was significantly elevated compared to controls (median [quartiles] 1984 [1164-2444] pg/ml), in patients with CP/CPPS IIIA (15,240 [10,630-19,501] pg/ml; p<0.0001), CP/CPPS IIIB (2983 [2033-5287] pg/ml; p=0.008), and BPH (5044 [3063-11,795] pg/ml, p<0.0001), discriminating CP/CPPS IIIA versus IIIB (accuracy=0.882+/-0.078; p=0.001). Inflammatory infiltrates were detected in prostate samples from 13 of 13 BPH patients, and IL-8-producing prostate cells in 11 of 13 samples. IL-8 concentration in seminal plasma was positively correlated with symptom score and prostate-specific antigen levels both in CP/CPPS and BPH patients.

CONCLUSIONS

IL-8 is expressed in situ by epithelial and stromal prostate cells and is functional, as shown by recruitment of cells expressing cognate receptors in BPH prostate tissue, indicating its involvement in disease pathogenesis. Among all the cytokines and chemokines analysed, IL-8 appears to be the most reliable and predictive surrogate marker to diagnose prostate inflammatory conditions, such as CP/CPPS and BPH.

Regulatory T cells (T(regs)) are found at sites of chronic inflammation where they mediate bystander and Ag-specific suppression of local immune responses. However, little is known about the molecular control of T(reg) recruitment into inflamed human tissues. We report that up to 18% of T cells in areas of inflammation in human liver disease are forkhead family transcriptional regulator box P3 (FoxP3)(+) T(regs). We isolated CD4(+)CD25(+)CD127(low)FoxP3(+) T(regs) from chronically inflamed human liver removed at transplantation; compared with blood-derived T(regs), liver-derived T(regs) express high levels of the chemokine receptors CXCR3 and CCR4. In flow-based adhesion assays using human hepatic sinusoidal endothelium, T(regs) used CXCR3 and alpha4beta1 to bind and transmigrate, whereas CCR4 played no role. The CCR4 ligands CCL17 and CCL22 were absent from healthy liver, but they were detected in chronically inflamed liver where their expression was restricted to dendritic cells (DCs) within inflammatory infiltrates. These DCs were closely associated with CD8 T cells and CCR4(+) T(regs) in the parenchyma and septal areas. Ex vivo, liver-derived T(regs) migrated to CCR4 ligands secreted by intrahepatic DCs. We propose that CXCR3 mediates the recruitment of T(regs) via hepatic sinusoidal endothelium and that CCR4 ligands secreted by DCs recruit T(regs) to sites of inflammation in patients with chronic hepatitis. Thus, different chemokine receptors play distinct roles in the recruitment and positioning of T(regs) at sites of hepatitis in chronic liver disease.

Preferential activation of regulatory T (Treg) cells limits autoimmune tissue damage during chronic immune responses but can also facilitate tumor growth. Here, we show that tissue-produced inflammatory mediators prime maturing dendritic cells (DC) for the differential ability of attracting anti-inflammatory Treg cells. Our data show that prostaglandin E(2) (PGE(2)), a factor overproduced in chronic inflammation and cancer, induces stable Treg-attracting properties in maturing DC, mediated by CCL22. The elevated production of CCL22 by PGE(2)-matured DC persists after the removal of PGE(2) and is further elevated after secondary stimulation of DC in a neutral environment. This PGE(2)-induced overproduction of CCL22 and the resulting attraction of FOXP3(+) Tregs are counteracted by IFN alpha, a mediator of acute inflammation, which also restores the ability of the PGE(2)-exposed DC to secrete the Th1-attracting chemokines: CXCL9, CXCL10, CXCL11, and CCL5. In accordance with these observations, different DCs clinically used as cancer vaccines show different Treg-recruiting abilities, with PGE(2)-matured DC, but not type 1-polarized DC, generated in the presence of type I and type II IFNs, showing high Treg-attracting activity. The current data, showing that the ability of mature DC to interact with Treg cells is predetermined at the stage of DC maturation, pave the way to preferentially target the regulatory versus proinflammatory T cells in autoimmunity and transplantation, as opposed to intracellular infections and cancer.

The existence of dendritic cell (DC) subsets is firmly established, but their trafficking properties are still largely unknown. We have indicated that myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) isolated from human blood differ widely in the capacity to migrate to chemotactic stimuli. The pattern of chemokine receptors expressed ex vivo by both subsets is similar, but P-DCs display, compared with M-DCs, higher levels of CC chemokine receptor (CCR)5, CCR7, and CXCR3. Intriguingly, most chemokine receptors of P-DCs, in particular those specific for inflammatory chemokines and classical chemotactic agonists, are not functional in circulating cells. Following maturation induced by cluster designation (CD)40 ligation, the receptors for inflammatory chemokines are downregulated and CCR7 on P-DCs becomes coupled to migration. The drastically impaired capacity of blood P-DCs to migrate in response to inflammatory chemotactic signals contrasts with the response to lymph node-homing chemokines, indicating a propensity to migrate to secondary lymphoid organs rather than to sites of inflammation. The distinct migration behavior of DC subsets is accompanied by a different profile of chemokine production. In contrast to the high production by M-DCs, the homeostatic CC chemokine ligand (CCL)17/ thymus- and activation-regulated chemokine (TARC) is not produced by PDCs in response to any stimulus tested and their production of CCL22/MDC is minimal, if any, compared with M-DCs. Thus, stimulated M-DCs, but not P-DCs, are able to produce high levels of chemokines recruiting T-helper 2 cells (Th2) and T-regulatory cells. Conversely, the proinflammatory chemokine CCL3/macrophage inflammatory protein (MIP)-1alpha is predominantly produced by P-DCs. Therefore, P-DCs appear to produce preferentially proinflammatory chemokines, but to respond selectively to homeostatic ones, whereas the reverse is true for M-DCs, highlighting not only the different migratory properties of these DC subsets, but also their capacity to recruit different cell types at inflammation sites.

Chemokines and chemokine receptors orchestrate cell migration and homing in the body. Humans have at least 44 chemokines that are further classified into four subfamilies based on the N-terminal conserved cysteine motifs: CXC, CC, C and CX3C. All the known chemokine receptors are seven transmembrane-type receptors. Humans have 18 chemotactic and 5 atypical non-chemotactic (recycling or scavenging) receptors. CC chemokine receptor 4 (CCR4) is the receptor for two CC chemokine ligands (CCLs)-CCL17 (also called thymus- and activation-regulated chemokine) and CCL22 (macrophage-derived chemokine). Among the various T-cell subsets, CCR4 is predominantly expressed by Th2 cells, cutaneous lymphocyte antigen-positive skin-homing T cells and Treg cells. Thus, CCR4 attracts much attention for its possible clinical applications in diseases involving these T-cell subsets. Furthermore, CCR4 is often highly expressed by mature T-cell neoplasms such as adult T-cell leukemia/lymphoma (ATL) and cutaneous T-cell lymphomas (CTCLs). This article is a brief overview of basic and clinical research on CCR4 and its ligands, which has eventually led to the development of a humanized defucosylated anti-CCR4 antibody 'Mogamulizumab' for treatment of relapsed/refractory ATL and CTCLs.

OBJECTIVE

The importance of chemokines and their receptors to development and maintenance of allergic asthma is reflected in the burgeoning amount of literature currently devoted to this topic. Based on a series of selected references published during the last year, this review now summarizes recent advances and discusses the likely implications of these findings.

RESULTS

Of particular interest are reports describing novel interactions between chemokines and both eosinophils and mast cells, including a role for CXCL5 (epithelial cell-derived neutrophil-activating peptide-78) and intracellular CCR3. New insights into TH2-cell dominance are presented in reports dealing with a range of chemokines, including CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL5 (RANTES), CXCL9 (Mig), and CXCL10 (IP-10). The increasing importance of structural cell participation is emphasized by reports focusing on the eotaxin family (CCL11, CCL24, and CCL26), as well as CCL17 (TARC), CCL22 (MDC), CXCL9 (Mig), and CX3CL1 (Fractalkine). A developing role for nonreceptor regulatory mechanisms is also emphasized by seminal work relating to metalloproteinases, as well as reports focusing on proteoglycans and beta-Arrestin-2. Finally, significant progress in the field of asthma heritability is featured in reports relating to both known and novel genes, including those encoding CCR5 and DPP-10.

CONCLUSIONS

The critical influence of chemokine biology on the outcome of allergic asthma continues to be highlighted in recent reports describing novel mechanisms by which eosinophils are recruited into the lung and local TH2-cell dominance is maintained. Also of considerable interest is the increasing emphasis currently being realized for structural cell participation, nonreceptor regulatory mechanisms, and the influence of susceptibility genes.