Association of rheumatoid arthritis with a functional chemokine receptor, CCR5

The commonness in immune infiltration of rheumatoid arthritis and atherosclerosis: Screening for central targets via microarray data analysis

Background

Although increasing evidence has reported an increased risk of atherosclerosis (AS) in rheumatoid arthritis (RA), the communal molecular mechanism of this phenomenon is still far from being fully elucidated. Hence, this article aimed to explore the pathogenesis of RA complicated with AS.

Methods

Based on the strict inclusion/exclusion criteria, four gene datasets were downloaded from the Gene Expression Omnibus (GEO) database. After identifying the communal differentially expressed genes (DEGs) and hub genes, comprehensive bioinformatics analysis, including functional annotation, co-expression analysis, expression validation, drug-gene prediction, and TF-mRNA-miRNA regulatory network construction, was conducted. Moreover, the immune infiltration of RA and AS was analyzed and compared based on the CIBERSORT algorithm, and the correlation between hub genes and infiltrating immune cells was evaluated in RA and AS respectively.

Results

A total of 54 upregulated and 12 downregulated communal DEGs were screened between GSE100927 and GSE55457, and functional analysis of these genes indicated that the potential pathogenesis lies in immune terms. After the protein-protein interaction (PPI) network construction, a total of six hub genes (CCR5, CCR7, IL7R, PTPRC, CD2, and CD3D) were determined as hub genes, and the subsequent comprehensive bioinformatics analysis of the hub genes re-emphasized the importance of the immune system in RA and AS. Additionally, three overlapping infiltrating immune cells were found between RA and AS based on the CIBERSORT algorithm, including upregulated memory B cells, follicular helper T cells and γδT cells.

Conclusions

Our study uncover the communal central genes and commonness in immune infiltration between RA and AS, and the analysis of six hub genes and three immune cells profile might provide new insights into potential pathogenesis therapeutic direction of RA complicated with AS.

Beta cell and immune cell interactions in autoimmune type 1 diabetes: How they meet and talk to each other

Background

Scope of review

Major conclusions

The dysregulation of monocyte subpopulations in individuals at risk of developing rheumatoid arthritis

OBJECTIVES

Individuals carrying antibodies against citrullinated proteins (ACPA) are at high risk of developing RA. EULAR provided a clinical definition of individuals with arthralgia suspicious for progression to RA (clinically suspect arthralgia, CSA). The alteration of monocyte subpopulations in patients with established RA has been previously described. We analysed peripheral blood monocyte subpopulations in individuals with arthralgia at risk of RA.

METHODS

We included 70 at-risk individuals, defined as having arthralgia without arthritis and being either ACPA+ or meeting the clinical CSA definition, 23 patients with early RA (ERA) and 19 healthy controls (HCs). Monocytes classified as classical (CD14++CD16-), intermediate (CD14++CD16+/++) and nonclassical (CD14-/+CD16++) were analysed by flow cytometry.

RESULTS

Of the 70 at-risk individuals, 46 were ACPA+ and 45 met the CSA definition. The at-risk individuals and, especially, ERA patients had a lower percentage of classical monocytes and a higher percentage of nonclassical monocytes than the HCs. ACPA positivity had no effect on the difference in the distribution of the monocyte subsets between at-risk individuals and ERA patients, but a difference was determined in those reaching the ERA phase. However, when compared with HCs, the shift of monocyte subsets was more significant in ACPA+ than in ACPA- individuals with arthralgia. This trend was observed in individuals who did not meet the CSA definition. This finding was, however, determined by a selection bias, as these individuals were solely ACPA+.

CONCLUSION

The shift from classical to nonclassical monocyte subpopulations was observed already in individuals at risk of developing RA.

Metabolomics as an Approach to Characterise the Contrasting Roles of CCR5 in the Presence and Absence of Disease

Chemokine receptors such as C-C chemokine receptor 5 (CCR5) are activated through interaction with their ligands and are well known for their role in chemotaxis and signal transduction. While serving these roles, cellular responses are effected, hence the immune function of these molecules is established. Given the role of CCR5 in immune function and that the immune and metabolic systems are interlinked, subsequent immune-directed changes should be measurable at a metabolic level. Numerous investigations have reported on metabolic changes associated with CCR5 status in the presence of disease, so as to understand whether specific CCR5 genotypes, frequency and/or levels offer protection to the host or not. However, these metabolic changes were recorded using older conventional techniques. Depending on certain factors such as the disease model, the geography of the samples and/or the ethnic group under study, the role of CCR5 in disease differs. In addition, little is known about CCR5's role in the absence of an enhanced inflammatory state, such as when infection persists. Metabolomics is defined as the study of metabolites and informs on metabolic changes within living organisms as induced by various stimuli, such as the interaction of CCR5 with its ligand. Since metabolomics reflects the underlying biochemical activity and state of cells/tissues, this review proposes it as a tool to clarify the contrasting roles of CCR5.

The HIV co-receptor CCR5 regulates osteoclast function

C–C chemokine receptor 5 (CCR5) is a co-receptor of HIV. Epidemiological findings suggest that the functional loss of CCR5 is correlated with a lower incidence of bone-destructive diseases as well as of HIV transmission. However, it is not clear whether CCR5 is involved in regulation of the function of bone cells, in addition to that of immune cells. Here we show that blockade of CCR5 using specific antibodies impairs human osteoclast function in vitro. Ccr5-deficient (Ccr5^−/−) mice presented with dysfunctional osteoclasts and were resistant to osteoporosis induced by receptor activator of nuclear factor kappa-B ligand (RANKL), which triggers osteoporosis independently of inflammatory and immunomodulatory pathways. Furthermore, Ccr5 deficiency impairs the cellular locomotion and bone-resorption activity of osteoclasts, which is associated with the disarrangement of podosomes and adhesion complex molecules including Pyk2. Overall, the data provides evidence that CCR5 has an essential role in bone-destructive conditions through the functional regulation of osteoclasts.

CCR5 is a co-receptor for HIV, and loss of function is associated with lower incidence of HIV but also with bone-destructive diseases. Here the authors show that ablation of CCR5 impairs osteoclast function and improves resistance to osteoporosis in mouse models.

Biological and Structural Characterization of Rotamers of C-C Chemokine Receptor Type 5 (CCR5) Inhibitor GSK214096

We recently reported the discovery of preclinical CCR5 inhibitor GSK214096, 1 (J. Med. Chem. 2011, 54, 756). Detailed characterization of 1 revealed that it exists as a mixture of four separable atropisomers A-D. The two slow-interconverting pairs of rotamers A + B and C + D were separated and further characterized. HIV and CCR5-mediated chemotaxis data strongly suggest that the antiviral potency of 1 is due to rotamers A + B and not C + D. Furthermore, integrated UV, vibrational circular dichroism VCD and computational approach allowed to determine the M chirality in C + D (and P chirality in A + B). These findings imply additional avenues to be pursued toward new CCR5 antagonists.

Possible contribution of chemokine receptor CCR2 and CCR5 polymorphisms in the pathogenesis of chronic spontaneous autoreactive urticaria

BACKGROUND

Autoimmune mechanisms play a role in the pathophysiology of chronic urticaria. As the genetic background of autoimmunity is well proven, the role of genetics in chronic urticaria is hypothesised.

METHODS

153 unrelated chronic spontaneous urticaria patients with a positive result of autologous serum skin test were included into the study, as were 115 healthy volunteers as control group. In all subjects we analysed CCR2 G190A and CCR5 d32 polymorphisms.

RESULTS

We noticed higher prevalence of CCR2 A allele as well as lower frequency of CCR5 d32 in chronic urticaria group in comparison to control group, with borderline statistical significance. Additionally, we assumed haplotype Gd statistically significant negative chronic urticaria association with tendency to higher frequency of Aw haplotype in this group.

CONCLUSIONS

The results of our study imply the role of autoimmune components in chronic urticaria pathogenesis and present chronic urticaria as possibly genetically related disorder.

Chemokine receptor 5 (CCR5) delta 32 polymorphism in lupus nephritis: a large case-control study and meta-analysis

OBJECTIVES

Recent animal experiments showed that CCR5-deficient lupus mice (CCR5(-/-)) were closely associated with aggravated lupus nephritis. CCR5 Δ32 variation, a nonsynonymous mutation of CCR5, resulted in altered CCR5 function. However, the CCR5 Δ32 mutation in human lupus nephritis has been rarely reported in the literature.

METHODS

A large case-control study that included 2010 samples from a Chinese population was conducted, followed by a meta-analysis combining the current and previously published studies to explore the effect of CCR5 Δ32 on lupus nephritis susceptibility.

RESULTS

Four CCR5 Δ32 heterozygote carriers were detected in lupus nephritis patients only. We detected no CCR5 Δ32 homozygotes in our study population. In the meta-analysis, including 1,092 cases and 2,229 controls, we found great heterogeneity between studies (p < 0.001, I(2)( )= 89.6%). Furthermore, stratified and sensitivity analyses suggested that ethnicity and CCR5 Δ32 allele frequency were the main origin of heterogeneity. In the subgroups without obvious heterogeneity, we observed a positive correlation between CCR5 Δ32 and lupus nephritis risk (p < 0.05).

CONCLUSIONS

Our study confirmed that the CCR5 Δ32 mutation is a very rare variation found in the Chinese population with Han ethnicity. However, CCR5 Δ32 might play a role in lupus nephritis susceptibility. Future replications and functional studies are needed.

Selective and Dual Targeting of CCR2 and CCR5 Receptors: A Current Overview

The chemokine receptor 2 (CCR2) and chemokine receptor 5 (CCR5) are important mediators of leukocyte trafficking in inflammatory processes. The emerging evidence for a role of CCR2 and CCR5 receptors in human inflammatory diseases led to a growing interest in CCR2- and CCR5-selective antagonists. In this review, we focus on the recent development of selective CCR2/CCR5 receptor ligands and dual antagonists. Several compounds targeting CCR2, e.g., INCB8761 and MK0812, were developed as promising candidates for clinical trials, but failed to show clinical efficacy as presumed from preclinical models. The role of CCR5 receptors as the second co-receptor for the HIV-host cell fusion led to the development of various CCR5-selective ligands. Maraviroc is the first CCR5-targeting drug for the treatment of HIV-1 infections on the market. The role of CCR5 receptors in the progression of inflammatory processes fueled the use of CCR5 antagonists for the treatment of rheumatoid arthritis. Unfortunately, the use of maraviroc for the treatment of rheumatoid arthritis failed due to its inefficacy. Some of the ligands, e.g., TAK-779 and TAK-652, were also found to be dual antagonists of CCR2 and CCR5 receptors. The fact that CCR2 and CCR5 receptor antagonists contribute to the treatment of inflammatory diseases renders the development of dual antagonists as promising novel therapeutic strategy.

CCR5delta32 in systemic lupus erythematosus: implications for disease susceptibility and outcome in a Brazilian population

The aim of this study was to analyze the allelic and genotypic frequencies of the CCR5delta32 polymorphism in systemic lupus erythematosus (SLE) patients and to investigate a possible association of this allele with SLE susceptibility and clinical outcome. A total of 367 SLE patients and 435 healthy controls were genotyped for the CCR5delta32 polymorphism. We observed that, in European-derived individuals, the frequency of the CCR5delta32 allele was smaller in patients than in controls (2.7% vs. 7.5%, OR 0.34, 95% CI 0.17-0.65, p Bonf=0.002), suggesting that this allele could be considered a protective factor for the disease. Regarding clinical manifestations, we observed that CCR5delta32 female African-derived carrier patients presented a higher predisposition to class IV nephritis when compared with absent nephritis/other class group (13.8% vs. 3.8%, OR 37.1, 95% CI 2.8-1854.7, p Bonf=0.030). A multivariate analysis including all female patients and controlling for the presence or absence of anti-dsDNA antibodies, ethnicity and age at diagnosis showed an increased relative risk of 3.9 times for patients carrying the CCR5delta32 allele to develop class IV nephritis as compared with noncarriers. Our data suggest that the CCR5delta32 allele is a protective factor for the disease in European-derived patients and a susceptibility factor to class IV nephritis in African-derived female patients.

Role of CCR5Δ32 mutation in protecting patients with Schistosoma mansoni infection against hepatitis C viral infection or progression

Schistosomiasis has been incriminated in the significant increase in hepatitis C virus (HCV) infections, although the association has not been adequately explained. We hypothesized that the CCR5Δ32 mutation may be involved in the high prevalence of HCV with schistosomiasis. The aim was to explore the association between the CCR5Δ32 mutation in schistosomiasis patients and protection against HCV infection or progression. We compared 220 schistosomiasis patients (S group) and 190 patients with HCV and schistosomiasis (HCV/S group) for the presence of the CCR5Δ32 mutation. Clinical, biochemical, and radiological assessments were done. HCV infection was diagnosed with anti-HCV antibodies and a recombinant HCV antigen-based rapid immunochromatographic test, and confirmed by HCV reverse transcriptase PCR. HCV genotyping was done by reverse hybridization line probe assay. Schistosomiasis was diagnosed by FAST-ELISA and indirect hemagglutination for Schistosoma mansoni antibodies, and stool analysis for ova. Polymorphisms of the CCR5 receptor gene were assessed by PCR-based genotyping of the 32-bp deletion at the CCR5 locus in whole blood. Of HCV/S patients, 91.6 vs. 91.8 % of S patients had CCR5 WT/WT homozygosity (nonmutants). Heterozygous and homozygous CCR5Δ32 mutation patterns (CCR5Δ32/WT and CCR5Δ32/Δ32) were distributed similarly in the HCV/S and S groups (6.8 vs. 7.2 % and 0.53 vs. 0.90 %, respectively; p > 0.05, OR = 0.97). Genotype 4 was the predominant viral genotype (93 % of cases). No differences were observed in CCR5 gene patterns according to viral genotype, viral RNA count, or ALT level. However, CCR5Δ32 mutants (homozygous and heterozygous) had a lower rate of severe hepatic fibrosis vs. nonmutants (27 vs. 42 %, p = 0.101, OR = 0.51). Moreover, 53.4 % of CCR5Δ32/WT mutants showed spontaneous viral clearance vs. 26.2 % of nonmutants (p = 0.000, OR = 4.1). In conclusion, no association was detected between the CCR5Δ32 mutation and HCV disease susceptibility in schistosomiasis patients. However, patients with the CCR5Δ32 mutation and HCV infection were less prone to severe hepatic fibrosis and more likely to have spontaneous viral clearance than patients with the nonmutant genotype.

Association between the chemokine receptor 5 delta32 polymorphism and rheumatoid arthritis: a meta-analysis

OBJECTIVE

The aim of this study was to determine whether the functional chemokine receptor 5 delta32 (CCR5-Δ32) polymorphism confers susceptibility to rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA).

METHODS

Meta-analysis was conducted on associations between the CCR5-Δ32 polymorphism and RA and JIA using (1) allele contrast and (2) the recessive, (3) the dominant, and (4) the additive models.

RESULTS

Eleven population comparisons based on the data obtained from nine studies involving 13,412 subjects (RA 3,848, controls 4,095; JIA 1,599, controls 3,870) were considered. In all study subjects, meta-analysis showed a significant negative association between RA and the CCR5-Δ32 allele (OR = 0.771, 95 % CI = 0.694-0.866, p = 6.5 × 10(-7)). Stratification by ethnicity indicated a significant association between the CCR5-Δ32 allele and RA in Europeans (OR = 0.8001, 95 % CI = 0.709-0.904, p = 3.2 × 10(-5)). Meta-analysis showed associations between the CCR5-Δ32 allele and JIA in Europeans and oligoarticular type (OR = 0.797, 95 % CI = 0.690-0.921, p = 0.002; OR = 0.475, 95 % CI = 0.352-0.693, p = 9.5 × 10(-8)).

CONCLUSIONS

This meta-analysis demonstrates that the CCR5-Δ32 polymorphism may confer susceptibility to RA and JIA in Europeans, and suggests that the CCR5-Δ32 allele protects against the development of RA and JIA.

Maraviroc, a chemokine receptor-5 antagonist, fails to demonstrate efficacy in the treatment of patients with rheumatoid arthritis in a randomized, double-blind placebo-controlled trial

INTRODUCTION

The purpose of this study was to determine whether maraviroc, a human CC chemokine receptor 5 (CCR5) antagonist, is safe and effective in the treatment of active rheumatoid arthritis (RA) in patients on background methotrexate (MTX).

METHODS

This phase IIa study comprised two distinct components: an open-label safety study of the pharmacokinetics (PK) of MTX in the presence of maraviroc, and a randomized, double-blind, placebo-controlled, proof-of-concept (POC) component. In the PK component, patients were randomized 1:1 to receive maraviroc 150 or 300 mg twice daily (BID) for four weeks. In the POC component, patients were randomized 2:1 to receive maraviroc 300 mg BID or placebo for 12 weeks. Patients were not eligible for inclusion in both components.

RESULTS

Sixteen patients were treated in the safety/PK component. Maraviroc was well tolerated and there was no evidence of drug-drug interaction with MTX. One hundred ten patients were treated in the POC component. The study was terminated after the planned interim futility analysis due to lack of efficacy, at which time 59 patients (38 maraviroc; 21 placebo) had completed their week 12 visit. There was no significant difference in the number of ACR20 responders between the maraviroc (23.7%) and placebo (23.8%) groups (treatment difference -0.13%; 90% CI -20.45, 17.70; P = 0.504). The most common all-causality treatment-emergent adverse events in the maraviroc group were constipation (7.8%), nausea (5.2%), and fatigue (3.9%).

CONCLUSIONS

Maraviroc was generally well tolerated over 12 weeks; however, selective antagonism of CCR5 with maraviroc 300 mg BID failed to improve signs and symptoms in patients with active RA on background MTX.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00427934.

CCR5Δ32 variant and cardiovascular disease in patients with rheumatoid arthritis: a cohort study

Introduction

The aim of our study was to analyze the influence of the CCR5Δ32 polymorphism in the risk of cardiovascular (CV) events and subclinical atherosclerosis among patients with rheumatoid arthritis (RA).

Methods

A total of 645 patients fulfilling the American Rheumatism Association 1987 revised classification criteria for RA were studied. Patients were genotyped for the CCR5 rs333 polymorphism using predesigned TaqMan assays. Also, HLA DRB1 genotyping was performed using molecular-based methods. Carotid intima-media thickness, flow-mediated endothelium-dependent dilatation (FMD) and endothelium-independent vasodilatation, which were used as surrogate markers of subclinical atherosclerosis, were measured in a subgroup of patients with no clinical CV disease.

Results

A lower frequency of carriers of the CCR5Δ32 allele among patients with CV events (3.4% versus 11.3%, P = 0.025, odds ratio 0.28, 95% confidence interval (95% CI) 0.06 to 0.89) was observed. However, after adjusting for gender, age at time of RA diagnosis, and the presence of shared epitope, rheumatoid factor and classic CV risk factors in the Cox regression analysis, this reduction of CV events in CCR5Δ32 allele carriers was slightly outside the range of significance (P = 0.097; hazard ratio 0.37 (95% CI 0.12 to 1.19)). Carriers of the CCR5Δ32 deletion also showed higher FMD values than the remaining patients (CCR5/CCR5Δ32 patients: 7.03% ± 6.61% versus CCR5/CCR5 patients: 5.51% ± 4.66%). This difference was statistically significant when analysis of covariance was performed (P = 0.024).

Conclusions

Our results show a potential influence of the CCR5Δ32 deletion on the risk of CV disease among patients with RA. This may be due to a protective effect of this allelic variant against the development of vascular endothelial dysfunction.

Two-year safety and virologic efficacy of maraviroc in treatment-experienced patients with CCR5-tropic HIV-1 infection: 96-week combined analysis of MOTIVATE 1 and 2

BACKGROUND

Maraviroc, the first approved CCR5 antagonist, demonstrated 48-week safety and virologic efficacy in CCR5-tropic HIV-infected, treatment-experienced patients; however, critical longer-term safety and durability of responses are unknown.

METHODS

Two-year follow-up of 2 prospective, randomized, blinded studies of maraviroc once daily or twice daily, or placebo in treatment-experienced patients with R5-tropic HIV-1 receiving an optimized background regimen. Unblinding occurred after the week-48 visit of the last enrolled patient. Safety and virologic parameters were assessed through week 96.

RESULTS

One thousand forty-nine patients were randomized and received study drugs. HIV-1 RNA was <50 copies per milliliter at week 96 in 39% and 41% of patients receiving maraviroc every day or twice a day, respectively. Among patients with HIV-1 RNA <50 copies per milliliter at week 48, 81% and 87% of patients receiving maraviroc every day or twice a day, respectively, maintained this response at week 96. At week 96, median CD4+ T-cell counts increased from baseline by 89 and 113 cells per cubic millimeter with maraviroc every day and twice a day, respectively. Exposure-adjusted rates of adverse events were similar with maraviroc or placebo. No new or unexpected events were observed after week 48.

CONCLUSIONS

Maraviroc-containing antiretroviral regimens maintained durable responses in treatment-experienced patients with R5 HIV-1 through 96 weeks of treatment with a safety profile similar to placebo.

Association of the CCR5 gene with juvenile idiopathic arthritis

The CC chemokine receptor 5 (CCR5) has been shown to be important in the recruitment of T-helper cells to the synovium, where they accumulate, drive the inflammatory process and the consequent synovitis and joint destruction. A 32 base-pair insertion/deletion variant (CCR5Δ32) within the gene leads to a frame shift and a nonfunctional receptor. CCR5Δ32 has been investigated for its association with juvenile idiopathic arthritis (JIA), with conflicting results. The aim of this study was to investigate whether CCR5Δ32 is associated with JIA in an UK population. CCR5Δ32 was genotyped in JIA cases (n=1054) and healthy controls (n=3129) and genotype and allele frequencies were compared. A meta-analysis of our study combined with previously published studies was performed. CCR5Δ32 was significantly associated with protection from developing JIA, in this UK data set (P(trend)=0.006, odds ratio (OR) 0.79 95% confidence interval (95% CI): 0.66-0.94). The meta-analysis of all published case-control association studies confirmed the protective association with JIA (P=0.001 OR 0.82 95% CI: 0.73-0.93). CCR5Δ32 is a functional variant determining the number of receptors on the surface of T cells, and it is hypothesized that the level of CCR5 expression could influence the migration of proinflammatory T cells into the synovium and thus susceptibility to JIA.

Lack of Association of C-C Chemokine Receptor 5 Δ32 Deletion Status with Rheumatoid Arthritis, Systemic Lupus Erythematosus, Lupus Nephritis, and Disease Severity

Objective.

C-C chemokine receptor 5 (CCR5) plays an important role in inflammation. A 32 base-pair (Δ32) deletion in the CCR5 gene leads to a nonfunctional receptor. This deletion has been reported to have a protective effect on the development and progression of several autoimmune diseases. We investigated whether the Δ32 deletion is associated with disease susceptibility in a population of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and lupus nephritis (LN); and whether it is associated with disease severity.

Methods

DNA samples from 405 RA patients, 97 SLE patients, 113 LN patients, and 431 healthy controls were genotyped for the CCR5 Δ32 deletion. Differences in genotype frequencies were tested between patients and controls. Association of genotypes with disease severity was analyzed.

Results

Genotype frequencies of each group were in Hardy-Weinberg equilibrium. The genotype frequencies of patients did not differ significantly from controls (CCR5/Δ32, Δ32/Δ32: RA 18.3% and 1.2%, respectively; SLE 17.5% and 2.1%; LN 13.3% and 1.8%; controls 20.0% and 2.8%). However, there was a trend for lower Δ32 deletion allele frequency in LN patients compared to controls (p = 0.08). There was no significant association between the CCR5 status and disease severity in RA, SLE, or LN.

Conclusion.

Although an association with LN cannot be excluded, the CCR5 Δ32 deletion does not seem to be a disease susceptibility genotype for RA, SLE, or LN. No significant effect of the Δ32 deletion on disease severity was demonstrated.

A novel chemokine-receptor-5 (CCR5) blocker, SCH532706, has differential effects on CCR5+CD4+ and CCR5+CD8+ T cell numbers in chronic HIV infection

HIV treatment with CCR5 receptor blockers may impact CCR5(+) cell distribution. T cell subsets, plasmacytoid dendritic cells (PDC), and antigen-specific [Mycobacteria tuberculosis/avium (M.TB/MAI), cytomegalovirus (CMV), Herpes simplex (HSV), HIV-Gag] CD4(+) T cells were measured in untreated R5-tropic-HIV-infected adults receiving 10 days of SCH532706 (Phase 1), 15 days no therapy, then 10 days of cART (without SCH532706) (Phase 2). Ten males were enrolled with median cells/microl (range) of CD4(+) 310 (92-848), CCR5(+)CD4(+) 57 (17-118), CD8(+) 895 (459-1666), and CCR5(+)CD8(+) 392 (250-983), and median plasma HIV RNA of 4.6 log(10) copies/ml. At baseline, proportions of M.TB, MAI, CMV, HSV, and HIV-Gag-specific CD4(+) T cells were 0.3%, 3.0%, 6.0%, 2.0%, and 1.6%, respectively. Median log(10) HIV RNA copies/ml declines were 1.5 (Phase 1) and 1.75 (Phase 2) (p = 0.7). Median CD4(+) and CD8(+) changes, respectively, during Phases 1 (+16; +91) and 2 (+28; -71) were similar (p = 0.7 both). However, CCR5(+)CD8(+) T cell fluctuations were significantly different (p = 0.02) during Phase 1 (+147 cells) vs. Phase 2 (-35 cells). PDC increased significantly more during Phase 1 (p = 0.04). Declines in antigen-specific cells were similar except for M. avium, which declined significantly during Phase 2 (p = 0.04). Similar declines in activation and proliferation of T cell subsets were observed during both treatment phases. For equivalent HIV RNA declines, CCR5-receptor blockade differentially increased CD8(+) T cell and PDC numbers in the circulation. These results confirm that cell surface CCR5 expression on these cells constantly directs trafficking during HIV infection. The persistence and clinical meaning of these immunological changes during long-term exposure to this class of anti-HIV drugs are unknown, but may have implications for immunosurveillance of inflammation.

Genome-wide haplotype association analysis and gene prioritization identify CCL3 as a risk locus for rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease caused by a complex interaction of multiple genetic variants and environmental factors. The association between RA and genetic susceptibility loci has been observed in many different populations, and most studies have focused on univariate analyses of single nucleotide polymorphisms. We performed a genome-wide haplotype association study and prioritized RA-related genes within 100 kb in either direction of significant haplotypes (P < 0.0001), based on their similarity to known RA susceptibility genes. The results showed that the chemokine CCL3 was associated with susceptibility to RA. A haplotype that located CCL3 on chromosome 17q12 had significant correlation with RA (P = 7.56E-05), and the global similarity score of CCL3 was ranked in the top of all RA-related genes, excluding known susceptibility genes (P = 8.42E-07). Our findings provide further evidence for the potential importance of the chemokine CCL3 in RA, and will facilitate the further understanding of its role in immunological regulation and the pathogenesis of RA.

Dual targeting of CCR2 and CCR5: therapeutic potential for immunologic and cardiovascular diseases

A cardinal feature of inflammation is the tissue recruitment of leukocytes, a process that is mediated predominantly by chemokines via their receptors on migrating cells. CCR2 and CCR5, two CC chemokine receptors, are important players in the trafficking of monocytes/macrophages and in the functions of other cell types relevant to disease pathogenesis. This review provides a brief overview of the biological actions of CCR2 and CCR5 and a comprehensive summary of published data that demonstrate the involvement of both receptors in the pathogenesis of immunologic diseases (RA, CD, and transplant rejection) and cardiovascular diseases (atherosclerosis and AIH). In light of the potential for functional redundancy of chemokine receptors in mediating leukocyte trafficking and the consequent concern over insufficient efficacy offered by pharmacologically inhibiting one receptor, this review presents evidence supporting dual targeting of CCR2 and CCR5 as a more efficacious strategy than targeting either receptor alone. It also examines potential safety issues associated with such dual targeting.

[CCR5 antagonists and HIV-1 infection: Bases and consequences of this therapeutic approach]

La molécule CCR5 est un récepteur de chimiokines qui joue un rôle important en pathologie infectieuse : corécepteur des souches du VIH-1 à tropisme R5, il est également impliqué dans la défense immunitaire contre certains agents transmissibles. Les antagonistes de CCR5 constituent une nouvelle approche thérapeutique antirétrovirale. Trois inhibiteurs du CCR5 ont atteint les phases IIb et III de développement clinique : aplaviroc (GlaxoSmithKine), vicriviroc (Schering-Plough) et maraviroc (Pfizer). Le développement de l’aplaviroc a été interrompu pour toxicité hépatique. Les essais ACTG 5211 et Motivate ont démontré une amélioration de la réponse antirétrovirale par l’addition respectivement de vicriviroc (actuellement en phase III) et de maraviroc (ayant déjà obtenu l’Autorisation de Mise sur le Marché) à un traitement optimisé chez des patients en échec thérapeutique. Le rôle de cette nouvelle cible thérapeutique dans les stratégies de traitement initial, de substitution ou de sauvetage reste à préciser, de même que leur intérêt chez des patients ayant une réponse immunovirologique dissociée, en immunodépresssion sévère ou infectés par des souches à tropisme non-R5. Plusieurs points sont également à éclaircir comme la tolérance à long terme, le risque d’induire une commutation R5-X4, en particulier dans les tissus, le risque d’interférer avec les réponses immunitaires, ainsi que l’impact d’une discordance de tropisme entre le plasma et les autres compartiments de l’organisme.

CCR5 is involved in resolution of inflammation in proteoglycan-induced arthritis

OBJECTIVE

CCR5 and its ligands (CCL3, CCL4, and CCL5) may play a role in inflammatory cell recruitment into the joint. However, it was recently reported that CCR5 on T cells and neutrophils acts as a decoy receptor for CCL3 and CCL5 to assist in the resolution of inflammation. The aim of this study was to determine whether CCR5 functions as a proinflammatory or antiinflammatory mediator in arthritis, by examining the role of CCR5 in proteoglycan (PG)-induced arthritis (PGIA).

METHODS

Arthritis was induced by immunizing wild-type (WT) and CCR5-deficient (CCR5(-/-)) BALB/c mice with human PG in adjuvant. The onset and severity of PGIA were monitored over time. Met-RANTES was used to block CCR5 in vivo. Arthritis was transferred to SCID mice, using spleen cells from arthritic WT and CCR5(-/-) mice. The expression of cytokines and chemokines was measured by enzyme-linked immunosorbent assay.

RESULTS

In CCR5(-/-) mice and WT mice treated with the CCR5 inhibitor Met-RANTES, exacerbated arthritis developed late in the disease course. The increase in arthritis severity in CCR5(-/-) mice correlated with elevated serum levels of CCL5. However, exacerbated arthritis was not intrinsic to the CCR5(-/-) lymphoid cells, because the arthritis that developed in SCID mouse recipients was similar to that in WT and CCR5(-/-) mice. CCR5 expression in the SCID mouse was sufficient to clear CCL5, because serum levels of CCL5 were the same in SCID mouse recipients receiving cells from either WT or CCR5(-/-) mice.

CONCLUSION

These data demonstrate that CCR5 is a key player in controlling the resolution of inflammation in experimental arthritis.

Negative association of the chemokine receptor CCR5 d32 polymorphism with systemic inflammatory response, extra-articular symptoms and joint erosion in rheumatoid arthritis

Introduction

Chemokines and their receptors control immune cell migration during infections as well as in autoimmune responses. A 32 bp deletion in the gene of the chemokine receptor CCR5 confers protection against HIV infection, but has also been reported to decrease susceptibility to rheumatoid arthritis (RA). The influence of this deletion variant on the clinical course of this autoimmune disease was investigated.

Methods

Genotyping for CCR5d32 was performed by PCR and subsequent electrophoretic fragment length determination. For the clinical analysis, the following extra-articular manifestations of RA were documented by the rheumatologist following the patient: presence of rheumatoid nodules, major organ vasculitis, pulmonary fibrosis, serositis or a Raynaud's syndrome. All documented CRP levels were analyzed retrospectively, and the last available hand and feet radiographs were analyzed with regards to the presence or absence of erosive disease.

Results

Analysis of the CCR5 polymorphism in 503 RA patients and in 459 age-matched healthy controls revealed a significantly decreased disease susceptibility for carriers of the CCR5d32 deletion (Odds ratio 0.67, P = 0.0437). Within the RA patient cohort, CCR5d32 was significantly less frequent in patients with extra-articular manifestations compared with those with limited, articular disease (13.2% versus 22.8%, P = 0.0374). In addition, the deletion was associated with significantly lower average CRP levels over time (median 8.85 vs. median 14.1, P = 0.0041) and had a protective effect against the development of erosive disease (OR = 0.40, P = 0.0047). Intriguingly, homozygosity for the RA associated DNASE2 -1066 G allele had an additive effect on the disease susceptibility conferred by the wt allele of CCR5 (OR = 2.24, P = 0.0051 for carrier of both RA associated alleles)

Conclusions

The presence of CCR5d32 significantly influenced disease susceptibility to and clinical course of RA in a German study population. The protective effect of this deletion, which has been described to lead to a decreased receptor expression in heterozygous patients, underlines the importance of chemokines in the pathogenesis of RA.

Inhalation of carbon monoxide ameliorates collagen-induced arthritis in mice and regulates the articular expression of IL-1beta and MCP-1

Carbon monoxide (CO), long considered a toxic gas, has recently been shown to mediate anti-inflammatory effects in various animal models. The aim of this study was to investigate whether the inhalation of CO ameliorated collagen-induced arthritis (CIA) in mice. CIA was induced in female DBA/1 mice by the injection of an anti-type II collagen antibody and lipopolysaccharide. The CO treatment group was exposed to CO gas at a concentration of 200 ppm in a closed cage starting on the day of the injection with an anti-type II collagen antibody and throughout the remaining study period. The clinical arthritis scores was examined daily for swelling of the paws as a sign of arthritis. For histopathology, the sections of the hind legs were evaluated by hematoxylin-eosin staining. Moreover, we evaluated the expression of interleukin (IL)-1beta and monocyte chemoattractant protein-1 (MCP-1) mRNA in the hind paws. Both clinical arthritis scores as well as histological findings of joint inflammation were significantly reduced in mice treated with CO gas inhalation compared to untreated mice. Further, CO significantly inhibited the increased expression of IL-1beta and MCP-1 mRNA in paws at day 3 after the induction of arthritis. In conclusion, the inhalation of CO protected mice from the synovial inflammation of CIA. Based on these data, the beneficial effects of CO in murine RA model may be attributed to its anti-inflammatory properties.

Peripheral blood T4 cell surface CCR5 density as a marker of activity in rheumatoid arthritis treated with anti-CD20 monoclonal antibody

The chemokine (C-C motif) receptor CCR5 and its ligand CCL5 play key roles in the intra-articular recruitment of peripheral blood mononuclear cells (PBMC) in rheumatoid arthritis (RA). Therefore, using quantitative cytofluorometry, we followed T4 cell surface CCR5 density in 27 subjects with RA before and after treatment with the anti-CD20 monoclonal antibody rituximab. We observed low T4 cell surface CCR5 densities before treatment, which correlated positively with disease activity, as determined using a disease activity score evaluated on 28 joints (DAS 28), and negatively with CCL5 mRNA concentrations in PBMC, contrasting with a high proportion of intracellular CCR5 molecules, a pattern compatible with ligand-induced CCR5 internalization. At 3 months post-treatment, CCL5 mRNA expression in PBMC declined, whereas T4 cell surface CCR5 densities increased proportionally to the decrease in DAS 28. Thus, peripheral blood T4 cell surface CCR5 density is a good surrogate marker of RA activity and of the efficiency of anti-CD20 therapy.

The chemokine receptor CCR5 genetic polymorphism and expression in rheumatoid arthritis patients

OBJECTIVES

To identify the genetic polymorphism of the chemokine receptor CCR5 (the Delta32 allelic variant) in patients with rheumatoid arthritis (RA) and compare the findings with healthy controls. To compare the CCR5 phenotypic expression in T cells and monocytes isolated from the peripheral blood and synovial fluid in a subgroup of RA patients.

METHODS

CCR5 genes of 92 RA patients and 160 healthy controls were genotyped using specific primers flanking the region of deletion. The ethnic distribution was similar between the groups. Flow cytometric analysis was used for immunophenotyping the T cells and monocytes isolated from the peripheral blood and synovial fluid of eight RA patients. The isolated cells were triple stained with CD4 or CD8, CD25 and CCR5 monoclonal antibodies.

RESULTS

There was no difference in the CCR5Delta32 genotypic frequency between the RA patients and the control group (0.055 and 0.063, respectively, p = 0.989). No homozygote for the CCR5Delta32 allele was seen in either group. Five heterozygotes were identified in the RA patient group, whose disease was shown to be aggressive. A significant enrichment of activated CCR5+ monocytes was seen in the synovial fluid of the RA patients subjected to arthrocentesis, who were all homozygotes for the CCR5 wild-type genotype.

CONCLUSION

A protective role for the CCR5 allelic variant in RA development was not observed. Disease severity in the heterozygotes suggests that other proinflammatory mechanisms might overcome this mutation in vivo. The activated CCR5+ monocyte enrichment in the rheumatoid synovial fluid might indicate that this cell population has an important role in the pathogenesis of the disease.

Polymorphisms in CCR5 chemokine receptor gene in Japan

Mutations in the human CC chemokine receptor 5 (CCR5) gene may alter the expression or function of the protein product, thereby altering chemokine binding/signalling or human immunodeficiency virus type 1 (HIV-1) infection of the cells that normally express CCR5 protein. We performed a systematic survey of natural sequence variations in an 8.1-kb region of the entire CCR5 gene as well as CCR2V64I in 50 Japanese subjects and evaluated the effects of those variations on CCR5 promoter activity. We also analysed CCR5 promoters and CCR2V64I in 80 more Japanese and 186 Thais. There was no 32-bp deletion observed in Caucasians, but two types of non-synonymous substitutions were found in CCR5 genes of Japanese. Our results showed several novel characteristics of the CCR2-CCR5 haplotype structure that were not reported from studies on Caucasians and African-Americans. Specifically, we were able to show that the G allele at position -2852 from the CCR5 open reading frame in Japanese and Thais is the representative of the CCR5 promoter haplotype that was reported to be associated with rapid progression to acquired immune deficiency syndrome (AIDS) in HIV-1-infected individuals. Furthermore, nearly all non-synonymous polymorphisms in Japanese CCR5 occurred in haplotypes with elevated promoter activity. We thus hypothesized that there was a certain selective pressure favouring low levels of CCR5 expression during human evolution.

Targeting protein–protein interactions for HIV therapeutics

The majority of current anti-HIV drugs target the viral reverse transcriptase or protease enzymes. However, enfuvirtide and maraviroc are drugs that have been US FDA approved recently and which function by inhibiting virus cell binding and entry which normally occurs through the interaction of the viral envelope protein with its cellular coreceptor. As HIV-1 utilizes many cellular cofactors during its replication cycle, there are a number of other protein–protein interactions that can serve as targets for anti-HIV drug development. In this review article we discuss the general method used to identify anti-HIV drugs that function through targeting protein–protein interactions. We also discuss the currently known cellular cofactors that may serve as targets in future drugs screens.

CCL3L1 gene-containing segmental duplications and polymorphisms in CCR5 affect risk of systemic lupus erythaematosus

OBJECTIVES

There is an enrichment of immune response genes that are subject to copy number variations (CNVs). However, there is limited understanding of their impact on susceptibility to human diseases. CC chemokine ligand 3 like-1 (CCL3L1) is a potent ligand for the HIV coreceptor, CC chemokine receptor 5 (CCR5), and we have demonstrated previously an association between CCL3L1-gene containing segmental duplications and polymorphisms in CCR5 and HIV/AIDS susceptibility. Here, we determined the association between these genetic variations and risk of developing systemic lupus erythaematosus (SLE), differential recruitment of CD3+ and CD68+ leukocytes to the kidney, clinical severity of SLE reflected by autoantibody titres and the risk of renal complications in SLE.

METHODS

We genotyped 1084 subjects (469 cases of SLE and 615 matched controls with no autoimmune disease) from three geographically distinct cohorts for variations in CCL3L1 and CCR5.

RESULTS

Deviation from the average copy number of CCL3L1 found in European populations increased the risk of SLE and modified the SLE-influencing effects of CCR5 haplotypes. The CCR5 human haplogroup (HH)E and CCR5-Delta32-bearing HHG*2 haplotypes were associated with an increased risk of developing SLE. An individual's CCL3L1-CCR5 genotype strongly predicted the overall risk of SLE, high autoantibody titres, and lupus nephritis as well as the differential recruitment of leukocytes in subjects with lupus nephritis. The CCR5 HHE/HHG*2 genotype was associated with the maximal risk of developing SLE.

CONCLUSION

CCR5 haplotypes HHE and HHG*2 strongly influence the risk of SLE. The copy number of CCL3L1 influences risk of SLE and modifies the SLE-influencing effects associated with CCR5 genotypes. These findings implicate a key role of the CCL3L1-CCR5 axis in the pathogenesis of SLE.

Lack of association between the chemokine receptor 5 polymorphism CCR5delta32 in rheumatoid arthritis and juvenile idiopathic arthritis

BACKGROUND

The chemokine receptor CCR5 has been detected at elevated levels on synovial T cells, and a 32 bp deletion in the CCR5 gene leads to a non-functional receptor. A negative association between the CCR5Delta32 and rheumatoid arthritis (RA) has been reported, although with conflicting results. In juvenile idiopathic arthritis (JIA), an association with CCR5 was recently reported. The purpose of this study was to investigate if the CCR5Delta32 polymorphism is associated with RA or JIA in Norwegian cohorts.

METHODS

853 RA patients, 524 JIA patients and 658 controls were genotyped for the CCR5Delta32 polymorphism.

RESULTS

The CCR5Delta32 allele frequency was 11.5% in the controls vs. 10.4% in RA patients (OR = 0.90; P = 0.36) and 9.7% in JIA patients (OR = 0.85; P = 0.20). No decreased homozygosity was observed for CCR5Delta32, as previously suggested.

CONCLUSION

Our data do not support an association between the CCR5Delta32 allele and Norwegian RA or JIA patients. Combining our results with those from a recently published meta-analysis still provide evidence for a role for CCR5Delta32 in RA, albeit substantially weaker than the effect first reported.

Negative association between the chemokine receptor CCR5-Delta32 polymorphism and rheumatoid arthritis: a meta-analysis

Rheumatoid arthritis (RA) is characterized by synovial inflammation mediated by T-cells, monocytes and macrophages. The homing of these cells to the inflamed synovium is regulated by chemokine-receptors and their ligands. A 32-basepair deletion (Delta32) in the gene encoding CCR5, a chemokine-receptor, results in a non-functional receptor. A negative association between CCR5-Delta32 and RA has been described, although other studies found no associations. Furthermore, the observation that individuals homozygous for CCR5-Delta32 develop RA has raised questions about the role of CCR5-Delta32. This meta-analysis of all published case-control association studies confirms the negative association between CCR5-Delta32 and RA (Odds Ratio=0.65; 95% confidence intervals=0.55-0.77; P<0.0001), suggesting that CCR5-Delta32 is protective against the development of RA. CCR5 blockade in animal models of RA results in amelioration of arthritis, suggesting that CCR5 blockade could also modify disease in patients with RA.

Cell surface CCR5 density determines the intensity of T cell migration towards rheumatoid arthritis synoviocytes

As we have recently shown that the number of CCR5 molecules at the cell surface determines the efficiency of its function as a chemokine receptor, we tested the hypothesis that cell surface CCR5 density could influence the intensity of T lymphocyte recruitment into the rheumatoid joint. For this purpose, we established two Jurkat cell line-derived clones that differed only by their cell surface CCR5 densities. We studied their chemotaxis towards TNF-alpha-transduced rheumatoid synoviocytes supernatant. The Jurkat cell subline that expressed the higher cell surface CCR5 density migrated more intensively towards the supernatant of TNF-alpha-transduced synoviocytes than the Jurkat cell subline that expressed a lower surface CCR5 density. Moreover, this migration was blocked by an anti-CCR5 mAb. The CCR5 density on T cell surface, which is constant over time for a given individual, but varies drastically from one individual to another, might thus be a factor determining the intensity of joint inflammation in the course of RA.

The strength of the chemotactic response to a CCR5 binding chemokine is determined by the level of cell surface CCR5 density

We have shown that the intensity of expression of the C-C chemokine receptor CCR5 at the single CD4(+) cell level strongly determines the efficiency of its function as a coreceptor for human immunodeficiency virus type 1. By analogy, we examined if the number of CCR5 molecules at the cell surface might determine its chemotactic response to CCR5 ligands. To test this hypothesis, we measured by flow cytometry the migration of primary human T cells towards the CCR5-binding chemokine CCL5 in vitro. First, we observed a dose-dependent blockage of this migration exerted by an anti-CCR5 monoclonal antibody. Second, we sorted peripheral blood mononuclear cells into five subpopulations expressing various cell surface CCR5 densities, and observed a correlation between the intensity of migration towards CCL5 and the level of CCR5 expression on these subpopulations. Third, we transduced CCR5(+) peripheral blood mononuclear cells with the CCR5 gene, and observed that the CCR5 over-expression induced an over-migration towards CCL5. Finally, we observed in healthy donors a correlation between the chemotactic response of peripheral blood CD8(+) T cell to CCL5 and their level of surface CCR5 expression. T-cell surface CCR5 density, which is constant over time for a given individual, but varies drastically among individuals, might therefore be an important personal determinant of T-cell migration in many biological situations where CCR5-binding chemokines play a role, such as graft rejection, T helper 1-mediated auto-immune diseases, and infectious diseases involving CCR5. Moreover, our data highlight the therapeutic potential of CCR5 antagonists in these situations.

Assessing Theoretical Risk and Benefit suggested by Genetic Association Studies of CCR5: Experience in a Drug Development Programme for Maraviroc

The proliferation of published gene association studies of the CCR5A32 mutation is of relevance to drug development of a CCR5 antagonist for HIV, in highlighting potential safety concerns. We conducted an initial review of all non-HIV gene association studies of CCR5-Δ32, followed by detailed meta-analyses in the three disease areas most commonly reported. Our review indicated no consistent evidence of increased risk of susceptibility to hepatitis C virus infection or multiple sclerosis among individuals with CCR5-Δ32 mutation, and suggested treatment with a CCR5 inhibitor is unlikely to have related adverse effects. There was, however, evidence to suggest rheumatoid arthritis as a potential therapeutic target for a CCR5 antagonist. Clinical evidence would be required to confirm these findings.

Genetics of resistance to HIV infection: Role of co-receptors and co-receptor ligands

Susceptibility to HIV infection and AIDS progression is variable among individuals and populations, and in part genetically determined. Genetic variants of genes encoding HIV co-receptors and their chemokine ligands have been described, and some of these variants were associated with resistance to HIV infection and/or disease progression. We review here the reported data regarding the variants of the CCR5, CCR2, CX3CR1, MIP-1alpha/CCL3, MIP-1beta/CCL4, RANTES/CCL5 and SDF-1/CXCL12 genes. The Delta32 deletion mutant of CCR5, resulting in a non-functional receptor not reaching the cell surface, is unambiguously associated with strong, although incomplete, resistance to HIV infection for homozygotes, and retarded progression for heterozygotes. Specific haplotypes encompassing the CCR5 and CCR2 loci, and the copy number of the CCL3L1 gene, have also been convincingly correlated with delayed progression. For other gene variants, involving CXCL12/SDF-1 and CX3CR1, conclusive evidence for their relevance in the frame of HIV susceptibility is still lacking.

CCR5Δ32 mutation does not influence the susceptibility to HCV infection, severity of liver disease and response to therapy in patients with chronic hepatitis C

AIM: To study whether CCR5Δ32 mutation was associated with viral infection and severity of liver disease.

METHODS: Two hundred and fifty two histologically proven, chronic HCV patients (mean age: 41 ± 14 years; M/F: 164/88) were genotyped. PCR based genotyping of 32 bp deletion at the CCR5 locus was done. Four-hundred and eight matched healthy controls were studied to assess susceptibility to HCV infection. To assess correlation of immune gene polymorphism with severity of HCV related liver disease, patients with chronic HCV infection were divided into those with a fibrosis score of ≤ 2 (mild) or > 2 (severe) and histological activity index (HAI) of ≤ 5 or > 5. For correlation between CCR5Δ32 mutations and response to therapy, 129 patients who completed therapy were evaluated.

RESULTS: The majority (89.4%) of the patients were infected with genotype 3. The frequency of homozygous CCR5Δ32 mutants was comparable to HCV patients as compared to the healthy controls (0.7% vs 0%, P = 0.1). Further more, the frequency of CCR5∆32 mutation was comparable in patients with mild or severe liver disease. (P = NS). There was also no association observed with response to therapy and CCR5Δ32 mutation.

CONCLUSION: CCR5Δ32 mutation does not have a role in disease susceptibility, severity or response to therapy in patients with chronic hepatitis C infection.

Association of two functional polymorphisms in the CCR5 gene with juvenile rheumatoid arthritis

Juvenile rheumatoid arthritis (JRA) is mediated by Th1-immune responses. In children with JRA, synovial T cells express high levels of the Th1-chemokine receptor CC chemokine receptor 5 (CCR5), which has been implicated in susceptibility to rheumatoid arthritis. To test the hypothesis that genetic variation in CCR5 is associated with susceptibility to JRA, we analyzed patterns of variation in the 5'cis-regulatory region of CCR5 in 124 multiplex families from a JRA-affected sibpair registry. After sequencing the upstream region of CCR5, variants were tested for association with JRA by transmission disequilibrium testing. A single nucleotide polymorphism, C-1835T, was significantly undertransmitted to children with early-onset JRA (P<0.01). C-1835T was genotyped in 424 additional simplex and multiplex families. CCR5-1835T allele was undertransmitted in the cohort of all probands with JRA (P<0.02), as well as in those with early-onset (P<0.01) or pauciarticular JRA (P<0.05). Another variant, a 32-bp deletion in the open reading frame of CCR5 (CCR5-Delta32) was also tested in approximately 700 simplex and multiplex families. CCR5-Delta32 was also significantly undertransmitted to probands with early-onset JRA (P<0.05). Both variants are in regions under natural selection, and result in functional consequences. Our results suggest these CCR5 variants are protective against early-onset JRA.

CCR5 is essential for NK cell trafficking and host survival following Toxoplasma gondii infection

The host response to intracellular pathogens requires the coordinated action of both the innate and acquired immune systems. Chemokines play a critical role in the trafficking of immune cells and transitioning an innate immune response into an acquired response. We analyzed the host response of mice deficient in the chemokine receptor CCR5 following infection with the intracellular protozoan parasite Toxoplasma gondii. We found that CCR5 controls recruitment of natural killer (NK) cells into infected tissues. Without this influx of NK cells, tissues from CCR5-deficient (CCR5-/-) mice were less able to generate an inflammatory response, had decreased chemokine and interferon gamma production, and had higher parasite burden. As a result, CCR5-/- mice were more susceptible to infection with T. gondii but were less susceptible to the immune-mediated tissue injury seen in certain inbred strains. Adoptive transfer of CCR5+/+ NK cells into CCR5-/- mice restored their ability to survive lethal T. gondii infection and demonstrated that CCR5 is required for NK cell homing into infected liver and spleen. This study establishes CCR5 as a critical receptor guiding NK cell trafficking in host defense.

Variants of CCR5, which are permissive for HIV-1 infection, show distinct functional responses to CCL3, CCL4 and CCL5

CCR5 is one of the primary coreceptors for Env-mediated fusion between cells and human immunodeficiency virus type 1 (HIV-1). Analyses of CCR5 variants in cohorts of HIV-1 high-risk individuals led to the identification of multiple single amino-acid substitutions, which may have functional consequences. This study focused on eight naturally occurring allelic variants located between amino-acid residues 60 and 334 of CCR5. All studied allelic variants were highly expressed on the cell surface of HEK-293 cells and permissive for HIV-1 infection. Variant G301V showed 3.5-fold increase in 50% effective concentration (EC(50)) for CCL4 (MIP 1beta) in a competitive binding assay. There was also a significant reduction in CCL5 (RANTES) EC(50) for the R223Q, A335V and Y339F variants. The most unexpected functional abnormality was exhibited by the R60S variant that exhibited a loss of ligand-induced desensitization in chemotaxis assays, but showed normal CCL4 and CCL5 binding avidity. This mutation is located in the first intracellular loop, a domain that has not previously been shown to be involved in receptor desensitization. In conclusion, our results support earlier studies showing that these naturally occurring point mutations do not limit HIV-1 infection, and indicated that single amino-acid changes can have unexpected functional consequences.

Decreased IgG production but increased MIP-1β expression in collagen-induced arthritis in C–C chemokine receptor 5-deficient mice

Collagen-induced arthritis (CIA) is a widely used model of human rheumatoid arthritis (RA) characterized by chronic inflammation of the synovial joints. The pathogenesis of RA and CIA has not been completely defined, but both involve the recruitment of leukocytes and lymphocytes to the joints and Th1-type cell mediated autoimmune responses. The C-C chemokine receptor 5 (CCR5) is preferentially expressed on Th1 cells and has been strongly implicated in inflammatory process through trafficking of leukocytes and lymphocytes into the sites of inflammation. We investigated the role of the CCR5 in CIA using CCR5 knockout mice (CCR5-/-) in which we analyzed the consequences of CCR5 deficiency for the immune response and inflammation. We found that CCR5-/- mice showed a significant reduction in the incidence of CIA after collagen II (CII)-immunization as compared to wild-type (CCR5+/+) mice. The reduced incidence seen in CCR5-/- mice was associated with these animals having significantly lower IgG levels, especially IgG2a and IgG2b antibodies against CII, as well as an obviously augmented IL-10 production in splenocytes. Overproduction of MIP-1beta in CCR5-deficient mice after CII-immunization may contribute partially to the occurrence of arthritis.

CCR5-Delta32 mutation is strongly associated with primary sclerosing cholangitis

CCR5 plays a key role in the distribution of CD45RO+ T cells and contributes to generation of a T helper 1 immune response. CCR5-Delta32 is a 32-bp deletion associated with significant reduction in cell surface expression of the receptor. We investigated the role of CCR5-Delta32 on susceptibility to ulcerative colitis (UC), Crohn's disease (CD) and primary sclerosing cholangitis (PSC). Genotype and allelic association analyses were performed in 162 patients with UC, 131 with CD, 71 with PSC and 419 matched controls. There was a significant difference in CCR5 genotype (OR 2.27, P=0.003) between patients with sclerosing cholangitis and controls. Similarly, CCR5-Delta32 allele frequency was significantly higher in sclerosing cholangitis (17.6%) compared to controls (9.9%, OR 2.47, P=0.007) and inflammatory bowel disease patients without sclerosing cholangitis (11.3%, OR 1.9, P=0.027). There were no significant differences in CCR5 genotype or allele frequency between those with either UC or CD and controls. Genotypes with the CCR5-Delta32 variant were increased in patients with severe liver disease defined by portal hypertension and/or transplantation (45%) compared to those with mild liver disease (21%, OR 3.17, P=0.03). The CCR5-Delta32 mutation may influence disease susceptibility and severity in patients with PSC.

Expression of the beta chemokines CCL3, CCL4, CCL5 and their receptors in idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases characterized by chronic lymphocytic and macrophagic infiltration in muscle. Because the mechanism for recruitment of these cells probably involves chemokines, we focused on the study of the expression pattern of some beta chemokines and receptors because it may provide a basis for selective immunotherapy. The expression of CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL5 (RANTES) and their main receptors (CCR1 and CCR5) was studied by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry in a series of 16 IIM and five controls (four normal muscles and one tonsil). Except for CCL5, strong expression was observed by RT-PCR with all molecules in all IIM subtypes in comparison to control muscle. Immunohistochemistry revealed diffuse CCL4 expression in all vessels in dermatomyositis. In both polymyositis and sporadic inclusion body myositis (s-IBM) it was restricted to vessels in the vicinity of inflammatory exudates. CCL5 expression was low, restricted to a few inflammatory cells in all IIM; CCR1 expression was mainly restricted to macrophages and s-IBM endothelial cells, whereas CCR5 was localized in inflammatory cells invading non-necrotic muscle fibres. Expressions of both receptors were also recorded in few muscle fibres. In conclusion, the upregulation of beta chemokines and receptors in IIM and their differential expression by various cells may contribute to chronic inflammation and to the peculiar distribution of inflammatory exudates in these diseases.