Association of polymorphism in the transforming growth factor {beta}1 gene with disease outcome and mortality in rheumatoid arthritis

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Inappropriate treatment response to DMARDs: A pathway to difficult-to-treat rheumatoid arthritis

In recent years, difficult-to-treat rheumatoid arthritis (D2T RA) has attracted significant attention from rheumatologists due to its poor treatment response and the persistent symptoms or signs experienced by patients. The therapeutic demands of patients with D2T RA are not properly met due to unclear pathogenic causes and a lack of high-quality data for current treatment options, creating considerable management difficulties with this patient population. This review describes the clinical challenges associated with disease-modifying antirheumatic drugs (DMARDs) and explores contributing factors associated with inappropriate response to DMARDs that may lead to D2T RA and related immunological dysregulation. It is now understood that D2T RA is a highly heterogeneous pathological status that involves multiple factors. These factors include but are not limited to genetics, environment, immunogenicity, comorbidities, adverse drug reactions, inappropriate drug application, poor adherence, and socioeconomic status. Besides, these factors may manifest in the selection and utilization of specific DMARDs, either individually or in combination, thereby contributing to inadequate treatment response. Finding these variables may offer hints for enhancing DMARD therapy plans and bettering the condition of D2T RA patients.

Identification of potential genetic causal variants for rheumatoid arthritis by whole-exome sequencing

Rheumatoid arthritis (RA) is a highly prevalent chronic autoimmune disease. However, genetic and environmental factors involved in RA pathogenesis are still remained largely unknown. To identify the genetic causal variants underlying pathogenesis and disease progression of RA patients, we undertook the first comprehensive whole-exome sequencing (WES) study in a total of 124 subjects including 58 RA cases and 66 healthy controls in Han Chinese population. We identified 378 novel genes that were enriched with deleterious variants in RA patients using a gene burden test. The further functional effects of associated genetic genes were classified and assessed, including 21 newly identified genes that were involved in the extracellular matrix (ECM)-receptor interaction, protein digestion and absorption, focal adhesion and glycerophospholipid metabolism pathways relevant to RA pathogenesis. Moreover, six pathogenic variants were investigated and structural analysis predicted their potentially functional alteration by homology modeling. Importantly, five novel and rare homozygous variants (NCR3LG1, RAP1GAP, CHCHD5, HIPK2 and DIAPH2) were identified, which may exhibit more functional impact on RA pathogenesis. Notably, 7 genes involved in the olfactory transduction pathway were enriched and associated with RA disease progression. Therefore, we performed an efficient and powerful technique WES in Chinese RA patients and identified novel, rare and common disease causing genes that alter innate immunity pathways and contribute to the risk of RA. Findings in this study may provide potential diagnostic tools and therapeutic strategies for RA patients.

TGFB1 Functional Gene Polymorphisms (C-509T and T869C) in the Maternal Susceptibility to Pre-eclampsia in South Indian Women

Pre-eclampsia (PE), a pregnancy-specific vascular disorder characterized by hypertension and proteinuria, is hypothesized to be the result of inadequate placental angiogenesis with attendant systemic inflammation. The pleiotropic cytokine, Transforming Growth Factor-β1 (TGF-β1), is considered to be a key candidate gene in the molecular pathogenesis of PE by virtue of its ability to not only regulate angiogenesis and apoptosis of target cells, but also by acting as a master controller of Th1/Th2 cytokine balance and production of the anti-inflammatory peripheral regulatory T cells (FOXP3+ Tregs). Based on this presumption, we screened a total of 469 pregnant women from South India that include 239 patients with PE and 230 healthy controls for the two functional polymorphisms of TGFB1 gene (C-509T and T869C). The genotype frequencies of these two polymorphisms differed significantly between the PE and control groups (P = 0.01 and P = 0.002, for the TGFB1 C-509T and T869C polymorphisms, respectively). Under the over-dominant model, the CT genotype of the TGFB1 C509T polymorphism showed a high protective effect (P = 3e-04), while the TT genotype of the same variant appeared to be the predisposing genotype (P = 0.003). The T-T and C-C haplotypes were found to be the risk haplotypes blocks towards PE (OR = 4.72; P = 0.031, OR = 5.39; P = 0.03), respectively. Strong linkage disequilibrium was seen between the two polymorphisms. Our investigations revealed a significant influence of TGFB1 C-509T and T869C polymorphisms on the PE risk in South Indian women. The study represents one of the first of its kind from the Indian subcontinent.

Effect of MTHFR, TGFβ1, and TNFB polymorphisms on osteoporosis in rheumatoid arthritis patients

Diseases of the immune and the skeletal systems should be studied together for the deep interaction between them. Many studies consider osteoporosis (OP) as a risk factor for the prediction of disease progression in rheumatoid arthritis (RA). The aim of this research is to study the effect of four single nucleotide polymorphisms (SNPs) on RA patients with and without OP. The examined SNPs (MTHFR (C677T, and A1298C), TGFβ1 (T869C), and TNFB (A252G)) were tested by genotyping 17 RA patients with OP and 72 RA patients without OP. Associations were tested using four models (multiplicative, dominant, recessive, and co-dominant). The studied SNPs were not significantly associated with the risk of OP in RA. MTHFR, TGFβ1, and TNFB polymorphisms don't appear to be clinically useful genetic markers for predicting RA severity in Egyptian women population.

A functional polymorphism C-509T in TGFβ-1 promoter contributes to susceptibility and prognosis of lone atrial fibrillation in Chinese population

Transforming growth factor-β1 (TGF-β1) is an important mediator of atrial fibrosis and atrial fibrillation (AF). But the involved genetic mechanism is unknown. Herein, the TGF-β1 C-509 T polymorphism (rs1800469) was genotyped in a case-control study of 840 patients and 845 controls in Chinese population to explore the association between the polymorphism and susceptibility and prognosis of lone AF. As a result, the CT and/or TT genotypes had an increased lone AF risk [adjusted odds ratio (OR) = 1.50 for CT, OR = 3.72 for TT, and OR = 2.15 for CT/TT], compared with the TGF-β1CC genotype. Moreover, patients carrying CT/TT genotypes showed a higher possibility of AF recurrence after catheter ablation, compared with patients carrying CC genotype. In a genotype-phenotype correlation analysis using 24 normal left atrial appendage samples, increasing gradients of atrial TGF-β1 expression levels positively correlated with atrial collagen volume fraction were identified in samples with CC, CT and TT genotypes. The in vitro luciferase assays also showed a higher luciferase activity of the -509 T allele than that of the -509 C allele. In conclusion, the TGF-β1 C-509 T polymorphism is involved in the etiology of lone AF and thus may be a marker for genetic susceptibility to lone AF and predicting prognosis after catheter ablation in Chinese populations. Therefore, we provide new information about treatment strategies and our understanding of TGF-β1 in AF.

Interleukins and interleukin receptors in rheumatoid arthritis: Research, diagnostics and clinical implications

Rheumatoid arthritis (RA) is an autoimmune disease, resulting in a chronic, systemic inflammatory disorder. It may affect many tissues and organs, but it primarily affects the flexible joints. In clinical practice patient care generates many questions about diagnosis, prognosis, and treatment. It is challenging for health care specialists to keep up to date with the medical literature. This review summarizes the pathogenesis, the polymorphisms of interleukin and interleukin genes and the standard available and possible future immunologic targets for RA treatment. The identification of disease-associated interleukin and interleukin receptor genes can provide precious insight into the genetic variations prior to disease onset in order to identify the pathways important for RA pathogenesis. The knowledge of the complex genetic background may prove useful for developing novel therapies and making personalized medicine based on the individual’s genetics.

Higher expression of latency-associated peptide on the surface of peripheral blood monocytes in patients with rheumatoid arthritis may be protective against articular erosions

Latency-associated peptide (LAP) forms small latent complexes with transforming growth factor beta 1 (TGF-β1). TGF-β-LAP complexes can be detected on the surfaces of immune cells and have been recently shown to play a role in immune regulation through TGF-β1-mediated functions. A study was undertaken to investigate the correlation of LAP expression on the surface of immune cells and presence of articular erosions in patients with rheumatoid arthritis (RA). Venous blood was obtained from patients with severe RA as well as from healthy control subjects. Surface expression of LAP on peripheral blood mononuclear cells was analyzed by flow cytometry, measured as flow cytometric intensity separately on CD14(+) and CD14(-) cells, and compared between RA patients and healthy subjects. Patients with RA demonstrated higher surface expression of LAP on both CD14(+) and CD14(-) mononuclear cells than healthy individuals. Patients with erosive RA had significantly reduced intensity of anti-LAP staining on the CD14(+) cells when compared to RA patients without erosions (p = 0.01). The intensity of anti-LAP staining on CD14(-) cells was not different between groups of RA patients. Higher expression of LAP on the surface of the cells of monocyte lineage may be protective of formation of articular erosions in RA. Further studies are needed to elaborate the mechanism of this phenomenon.

Combined anti-tumor necrosis factor-α therapy and DMARD therapy in rheumatoid arthritis patients reduces inflammatory gene expression in whole blood compared to DMARD therapy alone

Periodic assessment of gene expression for diagnosis and monitoring in rheumatoid arthritis (RA) may provide a readily available and useful method to detect subclinical disease progression and follow responses to therapy with disease modifying anti-rheumatic agents (DMARDs) or anti-TNF-α therapy. We used quantitative real-time PCR to compare peripheral blood gene expression profiles in active (“unstable”) RA patients on DMARDs, stable RA patients on DMARDs, and stable RA patients treated with a combination of a disease-modifying anti-rheumatoid drug (DMARD) and an anti-TNF-α agent (infliximab or etanercept) to healthy human controls. The expression of 48 inflammatory genes were compared between healthy controls (N = 122), unstable DMARD patients (N = 18), stable DMARD patients (N = 26), and stable patients on combination therapy (N = 20). Expression of 13 genes was very low or undetectable in all study groups. Compared to healthy controls, patients with unstable RA on DMARDs exhibited increased expression of 25 genes, stable DMARD patients exhibited increased expression of 14 genes and decreased expression of five genes, and combined therapy patients exhibited increased expression of six genes and decreased expression of 10 genes. These findings demonstrate that active RA is associated with increased expression of circulating inflammatory markers whereas increases in inflammatory gene expression are diminished in patients with stable disease on either DMARD or anti-TNF-α therapy. Furthermore, combination DMARD and anti-TNF-α therapy is associated with greater reductions in circulating inflammatory gene expression compared to DMARD therapy alone. These results suggest that assessment of peripheral blood gene expression may prove useful to monitor disease progression and response to therapy.

Transforming growth factor beta1 gene variation Leu10Pro affects secretion and function in hepatic cells

BACKGROUND

Our previous work revealed transforming growth factor beta1 (TGFβ1) gene polymorphisms are associated with susceptibility to hepatocellular carcinoma and liver cirrhosis. However, no further study of functional substitution in hepatic cells has yet been reported.

AIMS

This study was designed to uncover the functional mechanisms of TGFβ1 gene polymorphisms in the pathogenesis of liver diseases.

METHODS

Two recombinant TGFβ1 expression plasmids containing TGFβ1 codon 10 Leu/Pro variation were constructed with CMV promoter and transfected into human hepatoma cell lines (HepG2 and SMMU 7721), hepatic stellate cells (LX-2), and immortalized hepatocytes (L02). The secretion capacities of TGFβ1 protein in the transfected cells were determined by ELISA. Apoptosis, proliferative activity, and expression of CD 105, CD83, and CD80 were also measured by use of flow cytometry.

RESULTS

The ELISA results showed that cells transfected with CMV-Pro10 were more capable of TGFβ1 secretion than those transfected with CMV-Leu10. Functionally, CMV-Pro10 was more apoptosis-protective and induced more proliferation than CMV-Leu10 in transfected hepatic cells. Pro10 up-regulated expression of CD105 and down-regulated expression of CD83.

CONCLUSIONS

TGFβ1 gene Leu10Pro variation in signal peptide has significant effects on TGFβ1 secretion and functions in hepatic cells.

Gene network analysis of small molecules with autoimmune disease associated genes predicts a novel strategy for drug efficacy

Numerous genes/SNPs in autoimmune diseases (ADs) are identified through genome-wide association studies (GWAS) and likely to contribute in developing autoimmune phenotypes. Constructions of biologically meaningful pathways are necessary to determine how these genes interact with each other and with other small molecules to develop various complex AD phenotypes prior to beginning time-consuming rigorous experimentation. We have constructed biological pathways with genetically identified genes leading to shared AD phenotypes. Various environmental and endogenous factors interact with these AD associated genes suggesting their critical role in developing diseases and further association studies could be designed for assessing the role of these factors with risk allele in a specific gene. Additionally, existing drugs that have been used long before the identification of these genetically associated genes also interact with these newly associated genes. Thus advanced therapeutic strategies could be designed by grouping patients with risk allele(s) in particular genes that directly or closely interact with the specified drugs. This drug-susceptible gene network will not only increase our understanding about the additional molecular basis for effectiveness against these diseases but also indicate which drug could be more effective for those patients carrying risk allele(s) in that gene. Additionally, we have also identified several interlinking genes in the pathways that could be used for designing future association studies.

Interaction between smoking and functional polymorphism in the TGFB1 gene is associated with ischaemic heart disease and myocardial infarction in patients with rheumatoid arthritis: a cross-sectional study

INTRODUCTION

Transforming growth factor-beta1 (TGF-beta1) is a pleiotropic cytokine that plays important roles in immunity and inflammation. Some studies have suggested that polymorphism in the TGFB1 gene is associated with heart disease in the general population. The purpose of the present study was to determine whether common single-nucleotide polymorphisms (SNP) in the TGFB1 gene are associated with ischaemic heart disease (IHD) and/or myocardial infarction (MI) in patients with rheumatoid arthritis (RA), and to investigate the influence of smoking on any association.

METHODS

PCR-based assays were used to determine the genotypes of TGFB1 SNPs including TGFB1-509 C/T (rs1800469, in the promoter region), +868 T/C (rs1800470, in exon 1) and +913 G/C (rs1800471, in exon 1) in 414 subjects with established RA. Genotyping for the +868 SNP was also carried out on a second study population of RA patients (n = 259) with early disease. Serum levels of TGF-beta1 were measured using a commercial ELISA kit. Smoking history and IHD/MI status were obtained on each patient. Associations with IHD/MI were assessed using contingency tables and logistic regression analyses.

RESULTS

The heterozygous genotype of TGFB+868 was associated with an increased risk of IHD (OR 2.14, 95% CI 1.30 - 3.55) and MI (OR 2.42, 95% CI 1.30-4.50), compared to the homozygous genotypes combined. Smoking was an independent risk for IHD and MI, and evidence of interaction between smoking and TGFB+868 was found. Multivariate analyses indicated that the strongest associations with IHD and MI were due to the combined effect of the TGFB1+868 TC genotype and smoking (OR 2.75, 95% CI 1.59-4.75; and OR 2.58 95% CI 1.33-4.99, respectively), independent of other cardiovascular risk factors. The association of the +868 TC genotype and evidence of +868 TC-smoking interaction with IHD were replicated in a second population of RA patients with early disease. Serum TGF-beta1 levels were not associated with TGFB1 genetic variations, smoking or IHD/MI status.

CONCLUSIONS

Interaction between smoking and polymorphism in the TGFB1 gene may influence the risk of IHD and MI in patients with RA.

Transforming growth factor β 869C/T and interleukin 6 -174G/C polymorphisms relate to the severity and progression of bone-erosive damage detected by ultrasound in rheumatoid arthritis

Introduction

Single nucleotide polymorphisms (SNPs) of transforming growth factor β (TGF-β) and IL-6 genes (respectively, 869C/T and -174G/C) have been associated with radiographic severity of bone-erosive damage in patients with rheumatoid arthritis (RA). Musculoskeletal ultrasound (US) is more sensitive than radiography in detecting bone erosion. We analyzed the association between TGF-β 869C/T and IL-6 -174G/C SNPs and bone-erosive damage, evaluated by US, in a cohort of patients with severely active RA.

Methods

Seventy-seven patients were enrolled before beginning anti-TNF treatment. Disease activity was measured using the disease activity score in 28 joints, and the clinical response was evaluated according to the European League Against Rheumatism response criteria. Rheumatoid factor (RF) and anticitrullinated protein/peptide antibodies (ACPAs) were detected. The 869C/T TGF-β and -174G/C IL-6 SNPs were analyzed by PCR amplification. US was performed to assess the bone surfaces of metacarpophalengeal (MCP), proximal interphalangeal (PIP) and metatarsophalangeal (MTP) joints by obtaining multiplanar scans. According to the number of erosions per joint, a semiquantitative score ranging from 0 to 3 was calculated in each anatomical site to obtain a MCP total erosion score (TES), a PIP TES and a MTP TES, all ranging from 0 to 30, and a global patient TES calculated as the sum of these scores (range, 0 to 90).

Results

Patients carrying the TGF-β 869TT genotype showed a statistically significant lower MTP TES than those with the CC or CT genotype (mean MTP TES ± standard deviation for 869TT 6.3 ± 5.7 vs. 869CC/CT 11.7 ± 7.8; P = 0.011). Interestingly, patients with the TT genotype showed dichotomous behavior that was dependent on autoantibody status. In the presence of ACPAs and/or RF, the TT genotype was associated with lower erosion scores at all anatomical sites compared with the CC and CT genotypes. Conversely, the same 869TT patients showed higher erosion scores in the absence of ACPAs or RF.

Conclusions

In RA patients, TGF-β 869C/T SNPs could influence the bone-erosive damage as evaluated by US. The serological autoantibody status (ACPAs and RF) can modulate this interaction.

Platelet function in rheumatoid arthritis: arthritic and cardiovascular implications

Patients with rheumatoid arthritis (RA) are at high risk of cardiovascular events. Platelet biomarkers are involved in inflammation, atherosclerosis and thrombosis. Cardiovascular and RA-associated factors can alter the structure and function of platelets, starting from megakaryocytopoiesis. Reactive megakaryocytopoiesis increases circulating platelets count and triggers hyperactivity. Hyperactive platelets target synovial membranes with subsequent local rheumatoid inflammation. Hyperactive platelets interact with other cells, and target the vascular wall. Accumulating evidence suggests that disease modifying anti-rheumatic drugs (DMARD) decrease platelet activity.

Platelet function in rheumatoid arthritis: arthritic and cardiovascular implications

Patients with rheumatoid arthritis (RA) are at high risk of cardiovascular events. Platelet biomarkers are involved in inflammation, atherosclerosis and thrombosis. Cardiovascular and RA-associated factors can alter the structure and function of platelets, starting from megakaryocytopoiesis. Reactive megakaryocytopoiesis increases circulating platelets count and triggers hyperactivity. Hyperactive platelets target synovial membranes with subsequent local rheumatoid inflammation. Hyperactive platelets interact with other cells, and target the vascular wall. Accumulating evidence suggests that disease modifying anti-rheumatic drugs (DMARD) decrease platelet activity.

An overview on the genetic of rheumatoid arthritis: a never-ending story

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory, multi-factorial disease sustained by environmental and genetic factors. These seem to be necessary but not sufficient in the disease development, nonetheless they can be responsible of different clinical pictures and response to therapy, and they can represent potential therapeutic targets. Several genes have been indicated so far in the pathogenesis of RA. The most important region is the Human Leukocyte Antigen (HLA) that contributes to approximately half of the genetic susceptibility for RA. The association seems to be stronger or specific for anti-citrullinated protein antibodies positive disease. Several alleles in the epitope-recognition part of the HLA molecule that show the highest association with RA susceptibility, also share a common string of amminoacid residues (the so-called shared-epitope hypothesis). Other variants in potentially pathogenic genes located in non-MHC regions have been implicated by recently performed genome wide analysis studies. These genes include PTPN22, TRAF1-C5, PADI4, STAT4. Other polymorphisms seem to be responsible for more aggressive disease phenotype such as those located at TNF, IL-1, IL-6, IL-4, IL-5, OPN, PRF1. However, still nowadays, the genetic background of RA remains to be clearly depicted, and the efforts in the post-genomic era can bring to an estimation of the real likelihood of the genetic effect on RA. Finally, the discovery of new genes associated with the disease can be relevant in finding potential biomarkers, potentially useful in disease diagnosis and treatment.

The functional class evaluated in rheumatoid arthritis is associated with soluble TGF-β1 serum levels but not with G915C (Arg25Pro) TGF-β1 polymorphism

The influence of genetic factors in rheumatoid arthritis (RA) has been described, including several cytokine genes such as transforming growth factor β (TGF-β) with regulatory effects on lymphocytes, dendritic cells, macrophages, chondrocytes, and osteoblasts, which are important in the RA pathogenesis. The G915C TGF-β1 polymorphism has been associated with soluble TGF-β1 (sTGF-β) serum levels. Thus, we studied the association of G915C (Arg25Pro) TGF-β1 polymorphism with sTGF-β1 serum levels in RA. We enrolled 120 RA patients and 120 control subjects (CS). The G915C TGF-β1 polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and sTGF-β1 serum levels were quantified using an ELISA kit. The genotype frequency of G915C TGF-β1 polymorphism in RA and CS was G/G (91.7%), G/C (8.3%), C/C (0%) and G/G (85.8%), G/C (14.2%), C/C (0%), respectively, without significant differences. Moreover, the G/G TGF-β1 genotype carriers presented the highest disability index evaluated for the Spanish HAQ-DI score (P < 0.001). In addition, the sTGF-β1 serum levels were higher in RA (182.2 ng/mL) than CS (160.2 ng/mL), there was not significant difference. However, we found a positive correlation between the sTGF-β1 serum levels and the functional class (r = 0.472, P = 0.023). In conclusion, the G915C (Arg25Pro) TGF-β1 polymorphism is not associated with RA, but the sTGF-β1 serum levels are related with the functional class in RA.

Functional polymorphisms and methotrexate treatment outcome in recent-onset rheumatoid arthritis

AIMS

Clinical response to methotrexate (MTX) treatment differs among rheumatoid arthritis patients. Genetic variation can partly account for this phenomenon. In this study, functional polymorphisms in genes related to the mechanism of action of MTX or immunopathogenesis of rheumatoid arthritis were studied for association with treatment outcome in a Dutch cohort of patients with early rheumatoid arthritis. Furthermore, tests for replication of previous research on these genetic variants were performed according to reported end points.

MATERIALS & METHODS

Seven polymorphisms in seven genes were analyzed in 205 genotyped patients with active rheumatoid arthritis. All patients received standardized MTX treatment (< or =25 mg per week orally) combined with folic acid. MTX treatment outcome was evaluated by disease activity score criteria and adverse drug events. The following genetic variants were analyzed and correlated: ABCB1 3435C>T, ITPA IVS2 +21A>C, HLA-G (-14 bp >+14 bp), TGFB1 +869T>C and TLR4 +896A>G. In case of significant differences, regression analyses were applied. Since carriers of the minor alleles of the SNPs DHFR 829C>T and IMPDH2 +787C>T were not observed, no statistical analyses could be performed.

RESULTS

No significant associations or replications of these genetic variants with MTX efficacy were demonstrated. Regarding toxicity, patients carrying the ABCB1 3435T-allele and TLR4 +896G-allele were 2.5-times more likely to develop adverse drug events at 6 months (odds ratio: 2.6; 95% CI: 1.1-6.2, and odds ratio: 2.5; 95% CI: 1.1-6.1, respectively). Additionally, this chance increased almost fourfold in patients with the two unfavorable genotypes (odds ratio: 3.9; 95% CI: 1.5-10.3). However, none of these associations remained significant after correction for multiple testing (p < 0.004).

CONCLUSION

Our data indicate that MTX toxicity was potentially associated with ABCB1 3435C>T and TLR4 +896A>G. However, after correction, none of these associations remained significant. Furthermore, no significant associations or replications of these functional variants with efficacy were found.

Transforming growth factor-beta1 869T/C, but not interleukin-6 -174G/C, polymorphism associates with hypertension in rheumatoid arthritis

OBJECTIVES

Part of the deleterious effects of systemic inflammation on the cardiovascular system of patients with RA may be exerted via increased propensity to hypertension. IL-6 and TGF-beta1 are important regulators of the inflammatory response. In some, but not all, studies, IL6 -174G/C (rs1800795) and TGFB1 869T/C (rs1982073) gene polymorphisms have been associated with hypertension in the general population. The present study addressed their potential association with hypertension in RA patients.

METHODS

TGFB1 869T/C and IL6 -174G/C were identified in 400 RA patients and 422 local, non-RA controls using real-time PCR and melting curve analysis. Binary logistic and linear regression models were used to identify the independence of the effects of the polymorphisms on hypertension.

RESULTS

Genotypic and allelic frequencies of the two polymorphisms were similar in RA and controls. Within the RA group, there was no significant association between IL6 -174G/C and hypertension, but TGF 869T-allele carriers had significantly increased prevalence of hypertension compared with CC homozygotes (70.2 vs 55.2%; P = 0.023). This association remained significant after adjustment for other hypertension risk factors and medication (odds ratio = 1.96; 95% CI 1.02, 3.77; P = 0.044), and was more pronounced in patients with increased systemic inflammation.

CONCLUSIONS

This study suggests an association of TGFB1 869T/C, but not of IL6 -174G/C, with hypertension in RA patients. If this finding is confirmed in prospective studies, this polymorphism could be used as a screening tool for RA patients with higher risk of developing hypertension and lead to increased surveillance and earlier treatment.

Promoter polymorphism of transforming growth factor-β1 gene and ulcerative colitis

AIM: To elucidate the possible difference in two promoter polymorphisms of the transforming growth factor-β1 (TGF-β1) gene (-800G > A, -509C > T) between ulcerative colitis (UC) patients and normal subjects.

METHODS: A total of 155 patients with established ulcerative colitis and 139 normal subjects were selected as controls. Two single nucleotide polymorphisms within the promoter region of TGF-β1 gene (-509C > T and -800G > A) were genotyped using PCR-RFLP.

RESULTS: There was a statistically significant difference in genotype and allele frequency distributions between UC patients and controls for the -800G > A polymorphism of the TGF-β1 gene (P < 0.05). The frequency of the TGF-β1 gene polymorphism at position -800 showed that the AA genotype and the allele A frequencies significantly differed between the patients and healthy controls (P < 0.05). At position -509, there was no statically significant difference in genotype and allele frequency between the patients and control subjects.

CONCLUSION: The results of our study indicate that there is a significant difference in both allele and genotype frequency at position -800G > A of TGF-β1 gene promoter between Iranian patients with UC and normal subjects.

Cells of the synovium in rheumatoid arthritis. Macrophages

The multitude and abundance of macrophage-derived mediators in rheumatoid arthritis and their paracrine/autocrine effects identify macrophages as local and systemic amplifiers of disease. Although uncovering the etiology of rheumatoid arthritis remains the ultimate means to silence the pathogenetic process, efforts in understanding how activated macrophages influence disease have led to optimization strategies to selectively target macrophages by agents tailored to specific features of macrophage activation. This approach has two advantages: (a) striking the cell population that mediates/amplifies most of the irreversible tissue destruction and (b) sparing other cells that have no (or only marginal) effects on joint damage.

Genetic epidemiology of rheumatoid arthritis

PURPOSE OF REVIEW

This review aims to summarize articles published between October 2004 and November 2005 that have investigated the genetic epidemiology of rheumatoid arthritis.

RECENT FINDINGS

The consistent replication of an association between the R620W single nucleotide polymorphism in PTPN22 and rheumatoid arthritis clearly establishes this polymorphism as an important risk factor for rheumatoid arthritis.

SUMMARY

Genetic investigations of rheumatoid arthritis have predominantly been single nucleotide polymorphism-based candidate gene association studies searching for markers of susceptibility, severity or treatment response. Studies of the human leukocyte antigen region have refined and added to our understanding of the complex associations to polymorphisms with this locus. PTPN22 has emerged strongly as a genuine rheumatoid arthritis susceptibility gene with replications of the association to the R620W single nucleotide polymorphism. Many investigations have been conducted on the genetics of treatment response -- some 'generic' and others specific in terms of identifying genetic influences to the mode of action and metabolism of particular agents.

Pathogenesis of Parvovirus B19 Infection: Host Gene Variability, and Possible Means and Effects of Virus Persistence

Since conducting follow-up studies of patients with acute symptomatic parvovirus B19 infection which showed that a significant proportion of patients develop prolonged arthritis and chronic fatigue syndrome (CFS), we have become interested in the mechanisms of this phenomenon. We showed that these cases have high levels of pro-inflammatory cytokines in their circulation and that this correlates with the symptoms. However, the underlying mechanisms were not apparent, and we have used various approaches to begin studying this phenomenon. DNA polymorphisms were looked for and several were shown to be more common in these subjects compared with controls; these occur within genes of both the immune response [human leucocyte antigen (HLA)-DRB1, HLA-B, transforming growth factor (TGF)-beta1] and those involved in several other cellular functions (predominantly the cytoskeleton and cell adhesion). Interestingly, one particular single-nucleotide polymorphism (SNP) which is associated with symptomatic B19 infection occurs in the Ku80 gene which has recently been shown to be a B19 co-receptor. B19 persistence is probably the key to this phenomenon, and some new data are presented on short regions of sequence homology (17-26 bp) between human, mouse and rat parvoviruses and their respective hosts which occur in many host genes. This homology may provide a foothold for virus persistence and may also play a role in the genesis of disease through gene disruption. Finally, we used microarrays and TaqMan real-time polymerase chain reaction in 108 normal persons to study human gene expression in persons who are B19-seropositive versus B19-seronegative (age- and sex-matched) to examine the hypothesis that gene regulation may be altered in subjects harbouring the B19 virus DNA. Six genes were found to be differentially expressed with roles in the cytoskeleton (SKIP, MACF1, SPAG7, FLOT1), integrin signalling (FLOT1, RASSF5), HLA class III (c6orf48), and tumour suppression (RASSF5). These results have implications not only for B19 but also for other persistent viruses as well and confirmation is required. In conclusion, these disparate findings contribute to our understanding of the pathogenesis of B19 disease. We are using these studies as a starting point to study the phenomenon of chronic immune activation following B19 infection.