ABSTRACT
Inflammatory immune disorders such as inflammatory bowel disease and multiple sclerosis are major health problems. Currently, the intestinal whipworm Trichuris suis is being explored in clinical trials to reduce inflammation in these diseases; however, the mechanisms by which the parasite affects the host immune system are not known. Here we determined the effects of T. suis soluble products (SPs) on Toll-like receptor-4 (TLR4)-stimulated human dendritic cells (DCs) using Illumina bead chip gene arrays. Pathway analysis of lipopolysaccharide-stimulated DCs with or without T. suis treatment showed that co-stimulation with T. suis SPs resulted in a downregulation of both the myeloid differentiation primary response gene 88-dependent and the TIR-domain-containing adaptor-inducing interferon-ß-dependent signalling pathways triggered by TLR4. These data were verified using quantitative real-time PCR of several key genes within these pathways and/or defining their protein levels. In addition, T. suis SPs induce Rab7b, a negative regulator of TLR4 signalling that interferes with its trafficking, which coincided with a reduced surface expression of TLR4. These data indicate that the mechanism by which T. suis SPs reduce inflammatory responses is through suppression of both TLR4 signalling and surface expression on DCs.
Subject(s)
Dendritic Cells/parasitology , Toll-Like Receptor 4/metabolism , Trichuris/immunology , rab GTP-Binding Proteins/metabolism , Animals , Dendritic Cells/drug effects , Dendritic Cells/immunology , Dendritic Cells/metabolism , Down-Regulation , Humans , Inflammation/immunology , Inflammation/parasitology , Inflammation/therapy , Lipopolysaccharides/pharmacology , Real-Time Polymerase Chain Reaction , Signal Transduction , Transcriptome , rab7 GTP-Binding ProteinsABSTRACT
Recent clinical trials in patients with inflammatory diseases like multiple sclerosis (MS) or inflammatory bowel disease (IBD) have shown the beneficial effects of probiotic helminth administration, although the underlying mechanism of action remains largely unknown. Potential cellular targets may include innate immune cells that propagate inflammation in these diseases, like pro-inflammatory macrophages. We here investigated the effects of the helminth Trichuris suis soluble products (SPs) on the phenotype and function of human inflammatory (granulocyte-macrophage colony-stimulating factor (GM-CSF)-differentiated) macrophages. Interestingly, we here show that T. suis SPs potently skew inflammatory macrophages into a more anti-inflammatory state in a Toll-like receptor 4 (TLR4)-dependent manner, and less effects are seen when stimulating macrophages with TLR2 or -3 ligands. Gene microarray analysis of GM-CSF-differentiated macrophages further revealed that many TLR4-induced inflammatory mediators, including interleukin (IL)-12B, CCL1 and CXCL9, are downregulated by T. suis SPs. In particular, we observed a strong reduction in the expression and function of P2RX7, a purinergic receptor involved in macrophage inflammation, leading to reduced IL-1ß secretion. In conclusion, we show that T. suis SPs suppress a broad range of inflammatory pathways in GM-CSF-differentiated macrophages in a TLR4-dependent manner, thereby providing enhanced mechanistic insight into the therapeutic potential of this helminth for patients with inflammatory diseases.
Subject(s)
Helminth Proteins/pharmacology , Macrophages/drug effects , Toll-Like Receptor 4/metabolism , Trichuris/immunology , Animals , Cells, Cultured , Chemokine CCL1/genetics , Chemokine CCL1/metabolism , Chemokine CXCL9/genetics , Chemokine CXCL9/metabolism , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Helminth Proteins/immunology , Humans , Immunity, Innate , Inflammation/immunology , Inflammation/metabolism , Interleukin-12 Subunit p40/genetics , Interleukin-12 Subunit p40/metabolism , Macrophages/immunology , Receptors, Purinergic P2X7/genetics , Receptors, Purinergic P2X7/metabolism , Trichuris/chemistryABSTRACT
In this review we compare expression studies on monocyte subsets as an example to show the integrated possibilities of molecular databases and bioinformatic analysis tools. Monocytes have been recognized as cells with great plasticity and differentiation potential that play a pivotal role in revascularization processes, i.e. angiogenesis and arteriogenesis. To gain more insight in the relevant developmental programs, we compared the full-genome mRNA expression profiles of several distinct human monocyte subpopulations previously identified based on surface marker expression. These included classical and non-classical, M1 and M2 macrophages, circulating angiogenic cells (CAC), and non-monocyte-derived endothelial colony-forming cells (ECFC). Their transcriptional profiles revealed distinct and overlapping gene expression signatures and pathways reminiscent of utilization of transcription factors driving polarization into the different monocytic phenotypes. Hierarchical cluster analysis revealed that CAC are most related to M2 macrophages and unstimulated macrophages, and to a lesser extent to classical monocytes, and are quite distinct from M1 macrophages and ECFC. Analysis of the promoter region of CAC-expressed genes suggests that in particular the ETS family of transcription factors is important in CAC development. These analyses show the power of combining multiple datasets with existing databases on biological knowledge, to interpret full genome expression data.
Subject(s)
Computational Biology/methods , Monocytes/metabolism , Neovascularization, Physiologic/physiology , Cell Differentiation , Cluster Analysis , Data Interpretation, Statistical , Databases, Factual , Gene Expression Profiling , Gene Expression Regulation/physiology , Genome, Human , Humans , Macrophages/metabolismABSTRACT
Interferon-ß (IFNß) therapy is effective in approximately half of the patients with relapsing-remitting multiple sclerosis (RRMS). Clinical non-responders were characterized by an increased expression of IFN response genes before the start of therapy, and a lack of a pharmacologically induced increase in IFN response gene activity. Because Interferon Regulatory Factor 5 (IRF5) is a master regulator of IFN-activity, we carried out a candidate gene study of IRF5 gene variants in relation to the pharmacological and clinical response upon IFNß treatment. We found that patients with the IRF5 rs2004640-TT and rs47281420-AA genotype exerted a poor pharmacological response to IFNß compared with patients carrying the respective G-alleles (P=0.0006 and P=0.0023, respectively). Moreover, patients with the rs2004640-TT genotype developed more magnetic resonance imaging (MRI)-based T2 lesions during IFNß treatment (P=0.003). Accordingly, an association between MRI-based non-responder status and rs2004640-TT genotype was observed (P=0.010). For the rs4728142-AA genotype a trend of an association with more T2 lesions during IFNß treatment and MRI-based non-responder status was observed (P=0.103 and P=0.154, respectively). The clinical relevance of the rs2004640-TT genotype was validated in an independent cohort wherein a shorter time to first relapse was found (P=0.037). These findings suggest a role for IRF5 gene variation in the pharmacological and clinical outcome of IFNß therapy that might have relevance as biomarker to predict the response to IFNß in multiple sclerosis.
Subject(s)
Interferon Regulatory Factors/genetics , Interferon-beta/therapeutic use , Multiple Sclerosis, Relapsing-Remitting/drug therapy , Adult , Biomarkers , Cohort Studies , Female , Gene Expression , Genetic Variation , Genotype , Humans , Interferon-beta/pharmacology , Magnetic Resonance Imaging , Male , Multiple Sclerosis, Relapsing-Remitting/genetics , Polymorphism, Single Nucleotide , Treatment OutcomeABSTRACT
To provide insight into the pharmacological changes in the peripheral blood (PB) molecular profile induced by tumor necrosis factor (TNF)-blockade in patients with rheumatoid arthritis (RA), blood was obtained in PAXgene tubes from 33 RA patients before and 1 month after TNF-blocking therapy (infliximab). From 15 randomly chosen patients pre- and post-treatment gene expression profiles were determined. The remaining 18 RA patients served as validation cohort. A group-based paired analysis of the gene expression profiles from the post- vs pre-treatment samples revealed a signature of genes significantly regulated by TNF-blockade. Downregulated genes reflected several biological pathways such as inflammation, angiogenesis, B- and T-cell activation. Further analysis revealed that the pharmacological response signature was significantly regulated in all treated patients, irrespective of clinical response, which is indicative for the presence of an active TNF pathway in all RA patients. The data imply that all patients carried features of TNF bioactivity irrespective of clinical response. These results favor a model for the parallel presence of TNF-dependent and TNF-independent pathways in the individual RA patient. Clinical response status to TNF-blockade may be dependent on the relative contribution of TNF-independent effector pathways.
Subject(s)
Antibodies, Monoclonal/pharmacology , Antirheumatic Agents/pharmacology , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/genetics , Gene Expression Regulation , Adult , Aged , Arthritis, Rheumatoid/blood , Arthritis, Rheumatoid/pathology , Blood Cells/metabolism , Case-Control Studies , Female , Gene Expression Profiling , Humans , Infliximab , Male , Middle Aged , Pharmacogenetics , Signal Transduction/genetics , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The objective of this study was to identify molecular profiles that may distinguish clinical subtypes in systemic sclerosis (SSc). Large-scale gene expression profiling was performed on peripheral blood (PB) from 12 SSc patients and 6 healthy individuals. Significance analysis of microarrays, two-way hierarchical cluster analysis and PANTHER (Protein ANalysis THrough Evolutionary Relationships) ontology classification were used to analyze the data. Quantitative PCR was applied for validation in a cohort of 43 SSc patients. The results show that the expression of genes involved in immune defense, cell cycle and signal transduction was significantly elevated in PB of SSc patients (n=12) compared with healthy individuals (n=6). SSc patients could be stratified into subgroups based on differential expression of genes induced by type I interferon (IFN) and genes involved in antimicrobial (AM) activity. Differential expression of type I IFN or AM signature genes was validated and extended in an independent cohort of 31 patients by quantitative PCR. Low expression of IFN response genes was associated with the presence of anti-centromere antibodies, whereas increased expression was associated with the appearance of digital ulcers. In conclusion, patients with SSc can be classified on the basis of differential expression of immune defense genes. Differences in the activity of the type I IFN response program stratify patients into two clinically relevant subgroups.
Subject(s)
Antibodies, Antinuclear/immunology , Centromere/immunology , Interferon Type I/genetics , Scleroderma, Systemic/genetics , Skin Ulcer/genetics , Adult , Aged , Aged, 80 and over , Cohort Studies , Down-Regulation/genetics , Down-Regulation/immunology , Female , Fingers , Gene Expression Profiling , Humans , Interferon Type I/immunology , Male , Middle Aged , Scleroderma, Systemic/classification , Scleroderma, Systemic/immunology , Skin Ulcer/immunology , Up-Regulation/genetics , Up-Regulation/immunologyABSTRACT
OBJECTIVE: The response of rheumatoid arthritis (RA) patients to treatment with neutralising antibodies to tumour necrosis factor alpha (TNFalpha) is highly variable. The underlying mechanism for therapy responsiveness is currently unknown. We therefore evaluated the relationship between baseline molecular profiles of synovial tissues from RA patients and the clinical response to treatment with infliximab. METHODS: Synovial biopsies were obtained by arthroscopy from 18 RA patients with active disease (28 joint count Disease Activity Score (DAS28) > or = 3.2) before initiation of treatment with infliximab. All patients were on stable methotrexate treatment. Clinical response at 16 weeks was defined as a reduction in DAS28 of > or = 1.2, non-response as reduction in DAS28 < 1.2. Large-scale gene expression profiling using microarrays was performed on synovial tissue samples. To identify biological processes in synovial biopsies that could discriminate between responders and non-responders, we performed pathway analysis on the expression profiles. RESULTS: A total of 12 patients responded to therapy, while 6 patients failed to fulfil the response criteria. We identified several biological processes, related to inflammation, which were up-regulated in patients who responded to therapy, compared to those who did not show clinical improvement. CONCLUSION: These results indicate that patients with a high level of tissue inflammation are more likely to benefit from anti-TNFalpha treatment.
Subject(s)
Antibodies, Monoclonal/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Synovitis/drug therapy , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adult , Aged , Aged, 80 and over , Arthritis, Rheumatoid/genetics , Arthritis, Rheumatoid/pathology , Binding Sites , Biopsy , Drug Therapy, Combination , Female , Follow-Up Studies , Gene Expression Profiling/methods , Humans , Infliximab , Male , Methotrexate/therapeutic use , Middle Aged , Prognosis , Severity of Illness Index , Synovial Membrane/metabolism , Synovial Membrane/pathology , Synovitis/genetics , Synovitis/pathology , Transcription Factors/metabolism , Treatment OutcomeABSTRACT
Rheumatoid arthritis (RA) is a heterogeneous disease with unknown etiology. Here we aimed to distinguish RA subtypes based on peripheral blood (PB) gene expression profiles in comparison with a pathogen-response transcriptional program. PB was obtained from 35 RA patients and 15 healthy individuals. For expression profiling we used DNA microarrays. A combined cluster analysis of RA and control samples together with samples from a viral infection model revealed that the gene expression profile of a subgroup of RA patients (RA(A)) was reminiscent to that of poxvirus-infected macaques. Statistical analysis, followed by Gene Ontology analysis of the RA(A) patients confirmed that these patients form a distinct group, with activation of several host defense mechanisms that resemble a common host-pathogen response. Analysis of the promoter region of genes that were overexpressed in the RA(A) patients, revealed an enrichment of transcription factor binding sites for NF kappaB and interferon-activated transcription factors. Moreover, this subgroup of RA patients expressed significantly increased titers of anti-cyclic citrullinated peptide antibodies. We conclude that activation of a host-pathogen response defines a subgroup of RA patients characterized by increased autoreactivity against citrullinated proteins.
Subject(s)
Arthritis, Rheumatoid/classification , Arthritis, Rheumatoid/genetics , Gene Expression Profiling , Leukocytes, Mononuclear/metabolism , Transcription Factors/metabolism , Animals , Arthritis, Rheumatoid/blood , Case-Control Studies , Cluster Analysis , Female , Gene Expression Regulation , Genes, Viral , Host-Parasite Interactions , Humans , Leukocytes, Mononuclear/cytology , Macaca/virology , Male , Middle Aged , Oligonucleotide Array Sequence Analysis , Promoter Regions, Genetic , Smallpox , Transcription Factors/geneticsABSTRACT
BACKGROUND: Rheumatoid arthritis (RA) is a heterogeneous disease with unknown cause. AIM: To identify peripheral blood (PB) gene expression profiles that may distinguish RA subtypes. METHODS: Large-scale expression profiling by cDNA microarrays was performed on PB from 35 patients and 15 healthy individuals. Differential gene expression was analysed by significance analysis of microarrays (SAM), followed by gene ontology analysis of the significant genes. Gene set enrichment analysis was applied to identify pathways relevant to disease. RESULTS: A substantially raised expression of a spectrum of genes involved in immune defence was found in the PB of patients with RA compared with healthy individuals. SAM analysis revealed a highly significant elevated expression of interferon (IFN) type I regulated genes in patients with RA compared with healthy individuals, which was confirmed by gene ontology and pathway analysis, suggesting that this pathway was activated systemically in RA. A quantitative analysis revealed that increased expression of IFN-response genes was characteristic of approximately half of the patients (IFN(high) patients). Application of pathway analysis revealed that the IFN(high) group was largely different from the controls, with evidence for upregulated pathways involved in coagulation and complement cascades, and fatty acid metabolism, while the IFN(low) group was similar to the controls. CONCLUSION: The IFN type I signature defines a subgroup of patients with RA, with a distinct biomolecular phenotype, characterised by increased activity of the innate defence system, coagulation and complement cascades, and fatty acid metabolism.
Subject(s)
Arthritis, Rheumatoid/genetics , Gene Expression Profiling , Interferon Type I/genetics , Oligonucleotide Array Sequence Analysis , Up-Regulation , Adult , Arthritis, Rheumatoid/immunology , Blood Coagulation/genetics , Complement Activation/genetics , Female , Humans , Male , Middle AgedABSTRACT
Given the heterogeneous nature of multiple sclerosis (MS), we applied DNA microarray technology to determine whether variability is reflected in peripheral blood (PB) cells. In this study, we studied whole-blood gene expression profiles of 29 patients with relapsing-remitting MS (RRMS) and 25 age- and sex-matched healthy controls. We used microarrays with a complexity of 43K cDNAs. The data were analyzed using sophisticated pathway-level analysis in order to provide insight into the deregulated peripheral immune response programs in MS. We found a remarkable elevated expression of a spectrum of genes known to be involved in immune defense in the PB of MS patients compared to healthy individuals. Cluster analysis revealed that the increased expression of these genes was characteristic for approximately half of the patients. In addition, the gene signature in this group of patients was comparable with a virus response program. We conclude that the transcriptional signature of the PB cells reflects the heterogeneity of MS and defines a sub-population of RRMS patients, who exhibit an activated immune defense program that resembles a virus response program, which is supportive for a link between viruses and MS.
Subject(s)
Multiple Sclerosis, Relapsing-Remitting/genetics , Multiple Sclerosis, Relapsing-Remitting/immunology , Case-Control Studies , Cluster Analysis , Gene Expression Regulation , Genetic Heterogeneity , Humans , Interferon Type I/immunology , Interferon Type I/metabolism , Multiple Sclerosis, Relapsing-Remitting/blood , Oligonucleotide Array Sequence Analysis , Poxviridae Infections/genetics , Signal Transduction , Up-RegulationABSTRACT
Interleukin-12 (IL-12) is a potent inducer of interferon-gamma production by T cells and is a major factor for the development of T-helper 1 (Th1) cells. It exerts its biological effects through binding to the IL-12 receptor (IL-12R), a heterodimer composed of a 1 and a beta2 subunits. The signaling beta2 chain is expressed on Th1 cells and to a lesser extent on Th0 cells, but not on Th2 cells, rendering these latter cells unresponsive to IL-12. Polymorphisms in the coding region of the IL-12Rbeta2 gene were shown to be associated with atopic disease. Here, we analyzed the 5'-regulatory region of the human IL-12Rbeta2 gene by denaturing high-performance liquid chromatography (Transgenomic WAVE system, San Jose, CA). We found five novel single-nucleotide polymorphisms (SNPs) in the proximal 1.2 kb IL-12Rbeta2 promoter region, i.e. -237C/T, -465A/G, -1023A/G, -1033T/C, and -1035A/G. SNP -465A/G is of particular interest as it determines the integrity of a GATA consensus site. By functional comparison of both -465 alleles in transient transfection assays, we show that promoter activity is increased in case of the -465G allele, disrupting the intact GATA site. Comparison of the prevalence of -465A/G SNP alleles in small cohorts of allergic asthmatic and healthy control individuals provided no evidence for an altered distribution in the asthmatic population. In conclusion, we have identified a novel polymorphic GATA site that may affect transciptional activity of the human IL-12Rbeta2 gene under GATA3-mediated, Th2-polarizing conditions.
Subject(s)
Promoter Regions, Genetic , Receptors, Interleukin/genetics , 5' Flanking Region , Asthma/genetics , Base Sequence , Consensus Sequence , Humans , Molecular Sequence Data , Polymorphism, Single Nucleotide , Receptors, Interleukin-12ABSTRACT
BACKGROUND: Expression of signal transducer and activator of transcription 1 (STAT1), the mediator of interferon (IFN) signalling, is raised in synovial tissue (ST) from patients with rheumatoid arthritis (RA). OBJECTIVES: To determine the extent to which this pathway is activated by phosphorylation in RA synovium. Additionally, to investigate the cellular basis of STAT1 activation in RA ST. METHODS: ST specimens from 12 patients with RA and 14 disease controls (patients with osteoarthritis and reactive arthritis) were analysed by immunohistochemistry, using antibodies to STAT1, tyrosine phosphorylated STAT1, and serine phosphorylated STAT1. Lysates of cultured fibroblast-like synoviocytes stimulated with IFNbeta were analysed by western blotting. Phenotypic characterisation of cells expressing STAT1 in RA ST was performed by double immunolabelling for STAT1 and CD3, CD22, CD55, or CD68. RESULTS: Raised levels of total STAT1 protein and both its activated tyrosine and serine phosphorylated forms were seen in RA synovium as compared with controls. STAT1 was predominantly abundant in T and B lymphocytes in focal inflammatory infiltrates and in fibroblast-like synoviocytes in the intimal lining layer. Raised levels of STAT1 are sustained in cultured RA compared with OA fibroblast-like synoviocytes, and STAT1 serine and tyrosine phosphorylation is rapidly induced upon stimulation with IFNbeta. CONCLUSION: These results demonstrate activation of the STAT1 pathway in RA synovium by raised STAT1 protein expression and concomitantly increased tyrosine (701) and serine (727) phosphorylation. High expression of STAT1 is intrinsic to RA fibroblast-like synoviocytes in the intimal lining layer, whereas activation of the pathway by phosphorylation is an active process.
Subject(s)
Arthritis, Rheumatoid/metabolism , DNA-Binding Proteins/analysis , Signal Transduction/physiology , Synovial Membrane/metabolism , Trans-Activators/analysis , Adult , Aged , Aged, 80 and over , Arthritis, Reactive/metabolism , Blotting, Western/methods , Cells, Cultured , Female , Humans , Immunohistochemistry/methods , Interferon-beta/pharmacology , Male , Microscopy, Fluorescence , Middle Aged , Osteoarthritis/metabolism , Phosphorylation , STAT1 Transcription Factor , Stimulation, ChemicalABSTRACT
Rheumatoid arthritis (RA) is a heterogeneous disease. We used cDNA microarray technology to subclassify RA patients and disclose disease pathways in rheumatoid synovium. Hierarchical clustering of gene expression data identified two main groups of tissues (RA-I and RA-II). A total of 121 genes were significantly higher expressed in the RA-I tissues, whereas 39 genes were overexpressed in the RA-II tissues. Among the 121 genes overexpressed in RA-I tissues, a relative majority of nine genes are located on chromosome 6p21.3. An interpretation of biological processes that take place revealed that the gene expression profile in RA-I tissues is indicative for an adaptive immune response. The RA-II group showed expression of genes suggestive for fibroblast dedifferentiation. Within the RA-I group, two subgroups could be distinguished; the RA-Ia group showed predominantly immune-related gene activity, while the RA-Ib group showed an additional higher activity of genes indicative for the classical pathway of complement activation. All tissues except the RA-Ia subgroup showed elevated expression of genes involved in tissue remodeling. These results confirm the heterogeneous nature of RA and suggest the existence of distinct pathogenic mechanisms that contribute to RA. The differences in expression profiles provide opportunities to stratify patients based on molecular criteria.
Subject(s)
Arthritis, Rheumatoid/genetics , Synovial Membrane/metabolism , Arthritis, Rheumatoid/classification , Arthritis, Rheumatoid/metabolism , Chromosome Mapping , Chromosomes, Human, Pair 6 , Fibroblasts/metabolism , Gene Expression Profiling , Humans , Oligonucleotide Array Sequence Analysis , PhylogenyABSTRACT
IL-13 is strongly implicated in the development of asthma and chronic obstructive pulmonary disease (COPD). We previously identified an IL-13 promoter polymorphism (-1055 C to T) that is associated with allergic asthma. We now report an increased frequency of the -1055 T allele in COPD patients compared to healthy controls (P=0.002) and compared to a second control group consisting of smoking individuals with normal lung function (P=0.01). A closely linked IL-13 exon polymorphism is present at normal allelic frequencies (P=0.3 and 0.4, respectively). In addition, we observed a normal distribution of two IL-4 polymorphisms at positions -590 and +33 (P=0.2 and 0.9, respectively). These results could implicate a functional role for the IL-13 promoter polymorphism in the enhanced risk to develop COPD.
Subject(s)
Genetic Predisposition to Disease , Interleukin-13/genetics , Promoter Regions, Genetic , Pulmonary Disease, Chronic Obstructive/genetics , Adult , Aged , Female , Humans , Immunoglobulin E/blood , Male , Middle Aged , Polymorphism, GeneticABSTRACT
BACKGROUND: Specific allergen immunotherapy (SIT) is effective for treatment of IgE-mediated diseases: however, the mechanisms of action still remain unclear. Earlier, we showed that IL-4 and IL-13 are produced in response to specific allergens. The aim of this study was to investigate whether these cytokine responses were affected by allergen SIT, and, furthermore, to evaluate the effect of SIT on allergen-specific IgE and IgG4 levels. METHODS: Blood samples from pollen-sensitized individuals were collected before the pollen season (before treatment) and during the pollen season (after SIT or placebo treatment). Peripheral blood mononuclear cells were activated in vitro with allergens and the numbers of IL-4-, IL-13-, IL-10-, and IFN-gamma-producing cells were determined by ELISPOT. Serum levels of allergen-specific IgE and IgG4 were measured by RAST and ELISA, respectively. RESULTS: The numbers of IL-4- and IL-13-producing cells were shown to be increased in the placebo group during the pollen season, an increment which was absent in patients receiving allergen SIT. We found an increase in allergen-specific IgG4 in the SIT-treated individuals, but not in the placebo group. Both groups displayed elevated specific IgE levels during the pollen season. CONCLUSIONS: Taken together, our data show a downregulation of IL-4- and IL-13-producing cells in peripheral blood after SIT, suggesting induction of nonresponsiveness/tolerance or a redistribution of these cells. Furthermore, we demonstrate that SIT acts on antibody production by increasing the specific IgG4 levels.
Subject(s)
Antibody-Producing Cells/drug effects , Antibody-Producing Cells/immunology , Desensitization, Immunologic , Interleukin-13/immunology , Interleukin-4/immunology , Pollen/adverse effects , Adult , Double-Blind Method , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin E/blood , Immunoglobulin E/drug effects , Immunoglobulin E/immunology , Immunoglobulin G/blood , Immunoglobulin G/drug effects , Immunoglobulin G/immunology , Interferon-gamma/drug effects , Interferon-gamma/immunology , Interleukin-10/immunology , Male , Middle Aged , SeasonsSubject(s)
Antigen-Presenting Cells/metabolism , Cell Polarity/immunology , Hypersensitivity, Immediate/physiopathology , T-Lymphocytes, Helper-Inducer/metabolism , Animals , Antigen-Presenting Cells/immunology , Humans , Hypersensitivity, Immediate/immunology , Interleukin-12/metabolism , Lymphocyte Activation/immunology , Mice , T-Lymphocytes, Helper-Inducer/immunology , Th2 Cells/metabolismABSTRACT
IL-13 plays a crucial role in the development of allergic asthma by several mechanisms, including induction of IgE antibodies, airway eosinophilia and hyper-reactivity. We previously established a deregulated production of IL-13 by T cells from allergic asthma patients. In this report we describe the identification of a novel IL-13 promoter polymorphism (C to T exchange) at position -1055. The IL-13 -1055 TT genotype is associated with allergic asthma (P = 0.002), altered regulation of IL-13 production (P < 0.002), and increased binding of nuclear proteins to this region. We postulate that the presence of this polymorphism predisposes to the development of allergic asthma.
Subject(s)
Asthma/genetics , Asthma/immunology , Interleukin-13/genetics , Polymorphism, Genetic , Promoter Regions, Genetic , Base Sequence , Case-Control Studies , DNA/genetics , DNA Primers/genetics , Genotype , Humans , Interleukin-13/biosynthesis , Risk FactorsABSTRACT
IL-12 is essential for T helper 1 (Th1) development and inhibits the induction of Th2 responses. Atopic diseases, which are characterized by Th2 responses, are associated with the overproduction of histamine. Here we present evidence that histamine, at physiological concentrations, strongly inhibits human IL-12 p40 and p70 mRNA and protein production by human monocytes. The use of specific histamine receptor antagonists reveals that this inhibition is mediated via the H2 receptor and induction of intracellular cAMP. The inhibition of IL-12 production is independent of IL-10 and IFN-gamma. The observation that histamine strongly reduces the production of the Th1-inducing cytokine IL-12 implies a positive feedback mechanism for the development of Th2 responses in atopic patients.
Subject(s)
Histamine/pharmacology , Interleukin-12/metabolism , Monocytes/immunology , Dinoprostone/pharmacology , Histamine Agonists/pharmacology , Histamine Antagonists/pharmacology , Histamine H2 Antagonists/pharmacology , Humans , Imidazoles/pharmacology , Interleukins/metabolism , Monocytes/drug effects , RNA, Messenger/metabolism , Ranitidine/pharmacology , Receptors, Histamine H2/drug effects , Receptors, Histamine H2/metabolism , Thiourea/analogs & derivatives , Thiourea/pharmacology , Triprolidine/pharmacologyABSTRACT
We have reported previously that allergen-specific serum IgE levels were correlated with allergen-induced interleukin (IL)-4 in type I allergic individuals. Here, we wanted to investigate whether IL-13, another switch factor for IgE, was induced by allergen in vitro and if so, whether this was correlated with the elevated serum IgE-levels seen in atopic individuals, and whether the cytokine profile changed during pollen season. Peripheral blood mononuclear cells from 14 atopic and 14 healthy individuals collected out of the pollen season were incubated in vitro with allergens (birch or timothy) and the number of IL-4, IL-13, IL-10 and IFN-gamma producing cells was determined by ELISPOT. In response to the specific allergen, IL-13-producing cells were seen in allergic but not in healthy individuals. The number of IL-13-producing cells was significantly correlated with the allergen-specific serum IgE levels. When the allergic individuals were tested during the pollen season, the number of allergen-specific IL-4- and IL-13-producing cells, as well as serum levels of specific IgE, increased. The IL-13 increase seen in ELISPOT was confirmed by a RT-PCR assay. No seasonal changes were seen in response to purified protein derivative (PPD) or the mitogen PHA. During the pollen season, the IL-4 and IL-13 responses were highly correlated. Taken together, our results support the roles of both IL-13 and IL-4 in the regulation of allergen-specific IgE levels in atopic individuals.
Subject(s)
Allergens/administration & dosage , Hypersensitivity/immunology , Interleukin-13/immunology , Leukocytes, Mononuclear/immunology , Pollen , Aged , Blood Cell Count , Humans , Hypersensitivity/blood , Immunoglobulin E/immunology , Interleukin-13/biosynthesis , Interleukins/biosynthesis , Interleukins/immunologyABSTRACT
AD is associated with a bias of the T helper cells to show increased IL-4 and reduced interferon-gamma (IFN-gamma) production. The production of IFN-gamma and IL-4 and the development of Th cells into either high IFN-gamma or high IL-4 producers is strongly influenced by factors produced by antigen-presenting cells (APC), like IL-12 and prostaglandin E2 (PGE2). IL-12 selectively enhances IFN-gamma production and favours the development of IFN-gamma-producing Th cells, whereas PGE2 selectively inhibits IFN-gamma production by Th cells. The aim of this study was to test whether the increased IL-4/IFN-gamma production ratio by Th cells in AD can be explained by an increased PGE2/IL-12 production ratio by the APC. Monocytes were used as APC source. PGE2 and IL-12 production by lipopolysaccharide (LPS)-stimulated monocytes from 12 AD patients and 12 non-atopic controls was determined using two complementary experimental systems, whole blood cultures and purified monocytes. In addition, we determined IL-6 production as a measure of monocyte activation, and IL-10 production because IL-12 production by monocytes is highly influenced by endogenously produced IL-10. The monocytes from AD patients showed normal production levels of IL-6 and IL-10, a two-fold, but non-significant decrease in IL-12 production, and a significantly (three-fold) higher PGE2 production than those from non-atopic controls. Here we show for the first time that enhanced PGE2 production by monocytes in AD is not accompanied by a general rise in cytokine production. We conclude that AD is indeed associated with an increased PGE2/IL-12 production ratio by monocytes.