Mutation screening of the macrophage migration inhibitory factor gene: positive association of a functional polymorphism of macrophage migration inhibitory factor with juvenile idiopathic arthritis

OBJECTIVE: To determine if polymorphisms of the macrophage migration inhibitory factor (MIF) gene are associated with juvenile idiopathic arthritis (JIA). METHODS: Denaturing high-performance liquid chromatography was used to screen the MIF gene in 32 UK Caucasian controls and 88 UK Caucasian JIA patients. Ninety-two healthy UK Caucasian controls were then genotyped for each of the polymorphic positions identified. A panel of 526 UK Caucasian JIA patients and 259 UK Caucasian controls were subsequently genotyped for a single-nucleotide polymorphism (SNP) identified in the 5'-flanking region of the gene, using SNaPshot ddNTP primer extension and capillary electrophoresis. The functional significance of this polymorphism was also studied using luciferase-based reporter gene assays in human T lymphoblast and epithelial cell lines. RESULTS: A tetranucleotide repeat CATT((5-7)) beginning at nucleotide position -794 and 3 SNPs at positions -173 (G to C), +254 (T to C), and +656 (C to G) of the MIF gene were identified. No JIA-specific mutations were found. Allele and genotype frequencies differed significantly between the controls and the JIA patients for the MIF-173 polymorphism. Individuals possessing a MIF-173*C allele had an increased risk of JIA (34.8% versus 21.6%) (odds ratio 1.9, 95% confidence interval 1.4-2.7; P = 0.0002). Furthermore, the MIF-173* G and C variants resulted in altered expression of MIF in a cell type-specific manner. Serum levels of MIF were also significantly higher in individuals who carried a MIF-173*C allele (P = 0.04). CONCLUSION: The -173-MIF*C allele confers increased risk of susceptibility to JIA. Our data suggest a cell type-specific regulation of MIF, which may be central to understanding its role in inflammation.     

Functional and prognostic relevance of the -173 polymorphism of the macrophage migration inhibitory factor gene in systemic-onset juvenile idiopathic arthritis

OBJECTIVE: To address the functional and prognostic relevance of the -173 single-nucleotide G-to-C polymorphism of the macrophage migration inhibitory factor (MIF) gene in patients with systemic-onset juvenile idiopathic arthritis (systemic-onset JIA) by evaluating its association with serum and synovial fluid levels of MIF, with glucocorticoid requirement, and with the outcome of the disease. METHODS: A total of 136 patients with systemic-onset JIA were studied, including 98 patients from the British Paediatric Rheumatology Study Group's National Repository for JIA and 38 patients who were followed up at the IRCCS Policlinico San Matteo (Pavia, Italy) and the IRCCS G. Gaslini (Genoa, Italy). The MIF-173 polymorphism was genotyped using SnaPshot ddNTP primer extension and capillary electrophoresis. MIF levels were measured by enzyme-linked immunosorbent assay. The evaluation of the association of the MIF-173 polymorphism with outcome was performed only in Italian patients who were followed up for >5 years, by analyzing retrospectively 1) the number of joints with active arthritis and the number of joints with limited range of motion; 2) the score, at the last visit, on the Italian version of the Childhood Health Assessment Questionnaire (C-HAQ); and 3) data concerning the treatment regimens during the disease course. RESULTS: Systemic-onset JIA patients carrying a MIF-173*C allele had serum and synovial fluid levels of MIF significantly higher than those in patients with the GG genotype. The duration of glucocorticoid treatment on a daily regimen was significantly longer in patients carrying a MIF-173*C allele than in MIF-173 GG homozygous patients. Moreover, the duration of clinical response to intraarticular injection of triamcinolone hexacetonide was significantly shorter in patients carrying a MIF-173*C allele. At the last visit, the numbers of joints with active arthritis, the C-HAQ scores, and the numbers of joints with limited range of motion were significantly higher in patients carrying the MIF-173*C allele. CONCLUSION: Our study shows the functional relevance of the MIF-173 polymorphism and suggests that the MIF-173*C allele is a predictor of poor outcome in systemic-onset JIA.     

Serum macrophage migration inhibitory factor (MIF) in the intercritical phase of hereditary periodic fevers and its relationship with the MIF-173G/C polymorphism

OBJECTIVES: To examine the association of the -173 single-nucleotide G/C polymorphism of the macrophage migration inhibitory factor gene (MIF) and serum macrophage migration inhibitory factor (MIF) concentrations in a group of Italian patients with hereditary periodic fevers (HPF), tested during a symptom-free phase of their disease. METHODS: Genomic DNA for MIF and serum MIF were evaluated in 22 patients with HPF and compared with healthy controls of the same ethnic group. The MIF-173G/C polymorphism was genotyped using polymerase chain reaction (PCR) and visualized by ethidium bromide staining. Serum MIF levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: MIF-173*C allele frequency and MIF serum concentrations were significantly higher in patients with HPF than in controls, with no statistically significant difference between familial Mediterranean fever (FMF) and hyperimmunoglobulinaemia D/periodic fever syndrome (HIDS) and no correlation with specific MIF genotypes. CONCLUSIONS: The MIF-173*C allele was found more frequently in patients with HPF than in controls and MIF serum concentrations were considerably elevated in attack-free phases, suggesting a persistent state of subclinical cytokine activation with MIF involvement in the autoinflammatory cascade.     

A functional promoter haplotype of macrophage migration inhibitory factor is linked and associated with juvenile idiopathic arthritis

OBJECTIVE: To establish linkage and replicate the association of macrophage migration inhibitory factor (MIF) with juvenile idiopathic arthritis (JIA). METHODS: Three hundred twenty-one Caucasian simplex families from the UK were genotyped for polymorphisms of MIF using SNaPshot ddNTP primer extension, or by a fluorescently labeled primer method, and capillary gel electrophoresis. The functional significance of the promoter polymorphisms was studied using luciferase-based reporter gene assays in human T lymphoblast and epithelial cell lines. RESULTS: MIF was linked and associated with JIA (P = 0.0016). Specifically, a 2-point promoter haplotype, CATT(7)-MIF-173*C, was found to be transmitted in excess (38 transmitted: 21 not transmitted) in the JIA patients. Conditional extended transmission disequilibrium test and pairwise extended transmission disequilibrium test predicted functional interaction between the 2 polymorphic positions. The interaction of the CATT repeat with MIF-173*G/C was found to be specific to the cell type. CONCLUSION: Replication of an association and linkage of MIF with JIA has been established. Functional interaction between the polymorphic positions on the linked haplotype has also been shown. The molecular mechanism of this interaction is currently being investigated.     

Macrophage migration inhibitory factor in patients with juvenile idiopathic arthritis

OBJECTIVE: To evaluate serum and synovial fluid (SF) levels of macrophage migration inhibitory factor (MIF) and in vitro MIF production by peripheral blood mononuclear cells (PBMCs) in patients with juvenile idiopathic arthritis (JIA). METHODS: Serum, SF, and culture supernatant levels of MIF were measured by enzyme-linked immunosorbent assay. Production of MIF by PBMCs was investigated by culturing PBMCs in the absence or presence of 2 different concentrations of concanavalin A. RESULTS: Serum MIF levels were increased in patients with JIA, and the highest levels were present in patients with systemic-onset JIA. In systemic-onset JIA, serum levels of MIF correlated with the persistence of systemic features and the number of active joints. PBMCs from patients with systemic-onset JIA, when cultured under unstimulated conditions or at suboptimal stimulation, released higher amounts of MIF compared with those from patients with oligoarticular-onset JIA or healthy controls. MIF levels in the SF of patients with systemic-onset JIA were significantly higher than those in patients with oligoarticular-onset JIA. In individual joints, in both systemic-onset JIA and oligoarticular-onset JIA, SF MIF levels were inversely correlated with the duration of the clinical remission induced by intraarticular administration of triamcinolone hexacetonide. CONCLUSION: MIF appears to be a relevant cytokine in the pathogenesis of JIA, particularly in systemic-onset JIA.     

Macrophage migration inhibitory factor (MIF) and oligoarticular juvenile idiopathic arthritis (o-JIA): association of MIF promoter polymorphisms with response to intra-articular glucocorticoids

OBJECTIVES: To address the clinical relevance of macrophage migration inhibitory factor (MIF) promoter polymorphisms in oligoarticular juvenile idiopathic arthritis (o-JIA) by evaluating their associations with serum and SF MIF levels, with response to intra-articular glucocorticoid injections and with outcome of the disease. METHODS: Seventy-five Caucasian patients with o-JIA were studied. Alleles of the -794 CATT variable number of tandem repeats (VNTR) and of the -173 G/C single nucleotide polymorphism (SNP) were identified by capillary electrophoresis following fluorescently labelled PCR and by allelic discrimination assay, respectively. MIF levels were measured by ELISA. The association of MIF promoter polymorphisms with polyarticular extension, Childhood Health Assessment Questionnaire (CHAQ) score at the last follow-up visit and occurrence of chronic anterior uveitis was evaluated only in patients with a follow up > 5 years. RESULTS: Neither of the MIF promoter polymorphisms was associated with serum MIF levels, nor with the long-term outcome of o-JIA. The -173 G/C SNP was significantly associated with both SF MIF levels and duration of response to intra-articular glucocorticoid injection. Carriers of a MIF -173 C allele were 4 times more likely to relapse within 3 months. No association was found between the different MIF CATT alleles and both SF MIF levels and duration of response to intra-articular glucocorticoids. CONCLUSION: Our study shows the clinical relevance of the MIF -173 G/C SNP in o-JIA and suggests that the -173 C allele may represent a predictor of poor response to intra-articular glucocorticoid treatment.     

Lack of association between macrophage migration inhibitory factor gene (-173 G/C) polymorphism and cutaneous vasculitis

OBJECTIVE: To assess whether polymorphism of the macrophage migration inhibitory factor (MIF) gene at position -173 was implicated in the incidence of Henoch-Sch?nlein purpura (HSP) and cutaneous leukocytoclastic angiitis (CLA). A further objective was to determine if any relationship existed with severe systemic complications of HSP, in particular with severe renal involvement and permanent renal dysfunction. METHODS: Unselected patients from Northwest Spain with primary cutaneous vasculitis classified as HSP or hypersensitivity vasculitis (HV) according to proposed criteria were studied. Patients with HV were included in this study if they fulfilled the Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitis definitions for CLA. Patients and controls were genotyped for a single nucleotide polymorphism (SNP) in the 5'-flanking region at position -173 of the MIF gene, using SNapshot ddNTP primer extension, followed by capillary electrophoresis (ABI 3100). RESULTS: Ninety-five Caucasian patients (57 classified as having HSP and 38 who fulfilled definitions for CLA) and 122 healthy controls were studied. No allele or genotype differences between the whole group of HSP or CLA patients and controls were observed. This was also the case when HSP patients were stratified by the presence of gastrointestinal complications, nephritis, and permanent renal involvement (renal sequelae). CONCLUSION: The polymorphism in MIF gene promoter (-173 G/C) does not appear to be genetic risk factors for cutaneous vasculitis in Northwest Spain.     

Macrophage migration inhibitory factor gene polymorphism is associated with sarcoidosis in biopsy proven erythema nodosum

OBJECTIVE: To assess whether polymorphism of the macrophage migration inhibitory factor (MIF) gene at the position -173 is implicated in the development of sarcoidosis. METHODS: Twenty-eight patients with biopsy proven erythema nodosum (EN) associated with sarcoidosis, 70 patients with biopsy proven EN related to other etiologies, and 122 healthy matched controls from the Lugo region of Northwest Spain were studied. Patients and controls were genotyped for a single nucleotide polymorphism in the 5'-flanking region at position -173 of the MIF gene, using SNapshot ddNTP primer extension, followed by capillary electrophoresis (ABI 3100). RESULTS: A significantly increased frequency of the C mutant allele was observed in patients with EN secondary to sarcoidosis compared to controls (p = 0.0016; p(corr) = 0.0032; OR 2.78, 95% CI 1.45, 5.35) and also compared to patients with EN unrelated to sarcoidosis (p = 0.0004; p(corr) = 0.0008; OR 3.72, 95% CI 1.75, 7.87). Patients with EN carrying an MIF 173 C allele were found to have an increased risk of sarcoidosis (57% in EN secondary to sarcoidosis vs 24% in patients with EN related to other etiologies; p = 0.002; p(corr) = 0.004; OR 4.16, 95% CI 1.64, 10.50). CONCLUSION: This is the first attempt to assess the influence of MIF genetic polymorphism at position -173 in the development of sarcoidosis. The MIF 173 C allele is associated with a significantly increased risk of developing sarcoidosis in patients with EN.     

A polymorphism in the macrophage migration inhibitory factor gene is involved in the genetic predisposition of Crohn's disease and associated with cumulative steroid doses

BACKGROUND/AIMS: Macrophage migration inhibitory factor (MIF) is an important cytokine involved in the regulation of the innate immune system in IBD. Secreted MIF is able to induce the production of pro-inflammatory cytokines and counteracts anti-inflammatory effects of steroids. We evaluated whether the single nucleotide polymorphism (SNP) G/C at position -173 of the MIF gene contributes to the predisposition to IBD and higher amounts of steroid therapy. METHODOLOGY: We genotyped the SNP G/C at position -173 of the MIF gene in 157 patients with Crohn's disease (CD), 102 patients with ulcerative colitis (UC) and 489 healthy controls. Allele frequencies and cumulative steroid doses were compared. RESULTS: C allele and CC genotype frequencies were significantly decreased in CD patients compared to controls (p < 0.012 and p < 0.022, respectively). No significant differences were found in UC patients compared to controls. Cumulative corticosteroid dose was significantly higher in CD patients with the CC genotype [12300mg/yr (0-40000mg/yr), p < 0.021] compared with the GC genotype [220mg/yr (0-450mg/yr) and the GG genotype (310mg/yr (100-500mg/yr)]. In contrast, there were no significant differences between the genotypes in UC patients. CONCLUSIONS: Our data demonstrate the counterregulatory effects of MIF in CD patients and indicate the important role of the SNP G/C at position -173 of the MIF gene for the anti-inflammatory therapy with glucocorticoids.     

Lack of association between macrophage migration inhibitory factor gene polymorphism and giant cell arteritis

OBJECTIVE: To investigate the role of macrophage migration inhibitory factor (MIF) gene polymorphism in giant cell arteritis (GCA). METHODS: Eighty-three patients with biopsy-proven GCA, 20 of them with visual ischemic complications, and 122 healthy matched controls from the Lugo region of Northwest Spain were studied. Patients and controls were genotyped for a single nucleotide polymorphism in the 5'-flanking region at position -173 of the MIF gene, using SNapshot ddNTP primer extension, followed by capillary electrophoresis (ABI 3100). RESULTS: No significant differences in MIF gene polymorphism were observed in patients with biopsy-proven GCA compared to controls. This was also the case when GCA patients with or without visual ischemic complications were compared. CONCLUSION: Polymorphism in MIF gene promoter -173 G/C does not appear to be a genetic risk factor for GCA in Northwest Spain.     

Macrophage migration inhibitory factor gene polymorphisms in inflammatory bowel disease: An association study in New Zealand Caucasians and meta-analysis

AIM:To investigate the association of macrophage migration inhibitory factor(MIF)promoter polymorphisms with inflammatory bowel disease(IBD)risk.METHODS:One thousand and six New Zealand Caucasian cases and 540 Caucasian controls were genotyped for the MIF SNP-173G>C(rs755622)and the repeat polymorphism CATT5-8(rs5844572)using a predesigned TaqMan SNP assay and capillary electrophoresis,respectively.Data were analysed for single site and haplotype association with IBD risk and phenotype.Meta-analysis was employed,to assess cumulative evidence of association of MIF-173G>C with IBD.All published genotype data for MIF-173G>C in IBD were identified using PubMed and subsequently searching the references of all PubMed-identified studies.Imputed genotypes for MIF-173G>C were generated from the Wellcome Trust Case Control Consortium(and National Institute of Diabetes and Digestive and Kidney Diseases).Separate meta-analyses were performed on Caucasian Crohn’s disease(CD)(3863 patients,6031controls),Caucasian ulcerative colitis(UC)(1260 patients,1987 controls),and East Asian UC(416 patients and 789 controls)datasets using the Mantel-Haenszel method.The New Zealand dataset had 93%power,and the meta-analyses had 100%power to detect an effect size of OR=1.40 atα=0.05,respectively.RESULTS:In our New Zealand dataset,single-site analysis found no evidence of association of MIF polymorphisms with overall risk of CD,UC,and IBD or disease phenotype(all P values>0.05).Haplotype analysis found the CATT5/-173C haplotype occurred at a higher frequency in New Zealand controls compared to IBD patients(0.6 vs 0.01;P=0.03,OR=0.22;95%CI:0.05-0.99),but this association did not survive bonferroni correction.Meta-analysis of our New Zealand MIF-173G>C data with data from seven additional Caucasian datasets using a random effects model found no association of MIF polymorphisms with CD,UC,or overall IBD.Similarly,meta-analysis of all published MIF-173G>C data from East Asian datasets(416UC patients,789 controls)found no     

Genetic loci contributing to hemophagocytic lymphohistiocytosis do not confer susceptibility to systemic-onset juvenile idiopathic arthritis

OBJECTIVE: To investigate whether single-nucleotide polymorphisms (SNPs) within the genes PRF1, GZMB, UNC13D, and Rab27a, which are involved in natural killer cell dysfunction and known to contribute to the risk of hemophagocytic lymphohistiocytosis (HLH), confer an increased risk of susceptibility to systemic-onset juvenile idiopathic arthritis (JIA). METHODS: Four SNPs across the PRF1 gene locus, 5 for GZMB, 7 for UNC13D, and 11 for Rab27a were investigated using MassArray genotyping in 133 UK Caucasian patients with systemic-onset JIA and 384 ethnically matched unrelated control subjects. Additional control genotypes were accessed from the data generated by the Wellcome Trust Case Control Consortium. RESULTS: No significant association was found between any SNP within the 4 selected loci and systemic-onset JIA, by either single-point or haplotype analysis. CONCLUSION: The results of this study demonstrate that genes involved in HLH do not confer a significant risk of association with systemic-onset JIA.     

Tumour necrosis factor receptor II polymorphism and juvenile idiopathic arthritis

OBJECTIVES: Juvenile idiopathic arthritis (JIA) is a complex polygenic disorder. The encouraging outcome of anti-tumour necrosis factor (TNF) treatment, as well as serological studies, has implicated TNF and its receptors (TNFRI and TNFRII, or TNFRSF1B) in the pathogenesis of JIA. The purpose of this study was to investigate the exon 6 TNFRII single nucleotide polymorphism (SNP) in a well-defined UK cohort of JIA patients, using case-control association analysis. METHODS: A total of 435 patients, spanning seven JIA subgroups, and 261 healthy individuals were screened for the polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: No significant differences were observed between the SNP allelic or genotypic frequencies of patients and controls, or between JIA subgroups. CONCLUSIONS: This TNFRII exon 6 SNP does not seem to be associated with susceptibility to JIA.     

Macrophage migration inhibitory factor (MIF) -173G/C promoter polymorphism influences upper gastrointestinal tract involvement and disease activity in patients with Crohn's disease

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with increased expression in inflammatory bowel disease. The aim of the study was to analyze the role of the MIF -173G/C single nucleotide polymorphism in Crohn's disease (CD). METHODS: Using restriction fragment length polymorphism analysis, genomic DNA of 198 patients with CD and 159 unrelated controls was analyzed for the -173G/C SNP in the MIF promoter region. Colonic MIF mRNA expression was measured by quantitative polymerase chain reaction (PCR), serum MIF levels by enzyme-linked immunosorbent assay (ELISA). RESULTS: Thirty-six of the 146 G/G wildtype carriers (24.7%) but only 3 of the 45 G/C heterozygotes (6.7%) and only 1 of the C/C homozygotes (14.3%) were diagnosed with upper gastrointestinal tract involvement (P = 0.009, odds ratio [OR] = 0.22, 95% confidence interval [CI], 0.06-0.75 for wildtype versus hetero- and homozygous carriers). This result was confirmed in a second prospective study, in which all patients diagnosed with upper gastrointestinal involvement (n = 13) were G/G wildtype carriers (P = 0.01 versus controls). All patients (n = 12; 100%) with a Crohn's disease activity index (CDAI) > 300 were G/G wildtype carriers compared to only 65.6% wildtype carriers in the group with a CDAI < 150 (P = 0.016). MIF is expressed in the colonic mucosa of CD patients and intestinal epithelial cells but its mRNA expression does not correlate with the degree of inflammation and is not upregulated by proinflammatory cytokines. In CD, MIF serum levels are not influenced by the MIF -173G/C polymorphism. CONCLUSIONS: The MIF -173G/C polymorphism appears to be a factor contributing to a particular CD phenotype characterized by protection against upper gastrointestinal tract involvement and severe disease activity.     

Association between rheumatoid arthritis and polymorphism of tumor necrosis factor receptor II, but not tumor necrosis factor receptor I, in Caucasians

OBJECTIVE: Tumor necrosis factor (TNF) is a powerful mediator of inflammation in rheumatoid arthritis (RA). In vivo, its acute effects are limited by binding to soluble receptors (TNFR), suggesting that TNFR genes could be important candidate risk factors. The present study was undertaken to investigate association of polymorphisms of TNFRI and TNFRII with RA in subjects in the UK. METHODS: Unrelated Caucasian RA patients (n = 291) and healthy Caucasian controls (n = 143) were genotyped for A/G polymorphism in exon 1 of TNFRI. From this sample, 240 of the patients and 137 controls were also typed for a single-nucleotide polymorphism (SNP) in exon 6 of the TNFRII gene. In followup studies, DNA samples from UK Caucasian RA patients with a positive family history (n = 149) and UK Caucasian patients with sporadic RA (n = 208) were also typed for the exon 6 TNFRII polymorphism. RESULTS: TNFRI polymorphism was not associated with RA (odds ratio [OR] for GG genotype 0.93, 95% confidence interval [95% CI] 0.54-1.60). For TNFRII, in the initial study group, patients with RA were significantly more likely to be positive for both the G allele and GG genotype than were controls (OR for GG genotype 2.55, 95% CI 1.11-5.86). The association appeared to be confined to those with a family history of RA. This finding was replicated in an independent cohort of patients with familial RA. CONCLUSION: The results of this study provide evidence of association between an SNP in the TNFRII gene and RA, the strongest association being observed in patients with a family history. No evidence of association between RA and TNFRI was demonstrated.     

Macrophage migration inhibitory factor polymorphisms do not predict therapeutic response to glucocorticoids or to tumour necrosis factor alpha-neutralising treatments in rheumatoid arthritis

BACKGROUND: Macrophage migration inhibitory factor (MIF) is an inflammatory mediator associated with RA severity. In various diseases, MIF polymorphisms are associated with clinical response glucocorticoid (GC) treatment. It is unclear whether MIF polymorphisms determine GC response in rheumatoid arthritis (RA) and to other RA treatments. Therefore, the question of whether two functional variants in MIF are associated with the response to tumour necrosis factor (TNF)alpha-neutralising and GC treatments in RA was investigated. METHODS: Data from two cohorts of an RA registry were used. For patients who started with TNFalpha-neutralising (infliximab) or GC treatment, courses with a duration of at least 3 months were included and response to TNFalpha blockers or GC was calculated according to the European League Against Rheumatism response criteria. MIF -173G-->C genotyping was achieved using an assay-on-demand allelic discrimination assay, and alleles of the CATT repeat element were identified using a fluorescently labelled PCR primer and capillary electrophoresis. Logistic-regression modelling was used for the statistical analysis. RESULTS: In total, 192 courses of oral prednisone or methylprednisolone injections in 98 patients with RA and 90 patients with RA who were on TNFalpha-neutralising treatments were documented. In all, 27% of the patients with RA were found to be heterozygous for seven CATT repeats (CATT(7)) and 31% were heterozygous for -173C. Respectively, 4% and 6% of the patients with RA were homozygous for the MIF CATT(7) repeat or the MIF -173C allele. Carrier status and homozygosity for CATT(7 )repeat and the MIF -173C allele were not associated with response to GC (odds ratios (ORs) close to 1) or to TNFalpha-neutralising treatment (ORs close to 2). CONCLUSION: The MIF-CATT(7) repeat and the MIF-173G-->C functional variant are not strongly associated with a decreased clinical response to TNFalpha-neutralising or GC treatment in RA.     

Functional and prognostic relevance of the −173 polymorphism of the macrophage migration inhibitory factor gene in systemic‐onset juvenile idiopathic arthritis

Objective

To address the functional and prognostic relevance of the −173 single‐nucleotide G‐to‐C polymorphism of the macrophage migration inhibitory factor (MIF) gene in patients with systemic‐onset juvenile idiopathic arthritis (systemic‐onset JIA) by evaluating its association with serum and synovial fluid levels of MIF, with glucocorticoid requirement, and with the outcome of the disease.

Methods

A total of 136 patients with systemic‐onset JIA were studied, including 98 patients from the British Paediatric Rheumatology Study Group's National Repository for JIA and 38 patients who were followed up at the IRCCS Policlinico San Matteo (Pavia, Italy) and the IRCCS G. Gaslini (Genoa, Italy). The MIF‐173 polymorphism was genotyped using SnaPshot ddNTP primer extension and capillary electrophoresis. MIF levels were measured by enzyme‐linked immunosorbent assay. The evaluation of the association of the MIF‐173 polymorphism with outcome was performed only in Italian patients who were followed up for >5 years, by analyzing retrospectively 1) the number of joints with active arthritis and the number of joints with limited range of motion; 2) the score, at the last visit, on the Italian version of the Childhood Health Assessment Questionnaire (C‐HAQ); and 3) data concerning the treatment regimens during the disease course.

Results

Systemic‐onset JIA patients carrying a MIF‐173*C allele had serum and synovial fluid levels of MIF significantly higher than those in patients with the GG genotype. The duration of glucocorticoid treatment on a daily regimen was significantly longer in patients carrying a MIF‐173*C allele than in MIF‐173 GG homozygous patients. Moreover, the duration of clinical response to intraarticular injection of triamcinolone hexacetonide was significantly shorter in patients carrying a MIF‐173*C allele. At the last visit, the numbers of joints with active arthritis, the C‐HAQ scores, and the numbers of joints with limited range of motion were significantly higher in patients carrying the MIF‐173*C allele.

Conclusion

Our study shows the functional relevance of the MIF‐173 polymorphism and suggests that the MIF‐173*C allele is a predictor of poor outcome in systemic‐onset JIA.

     

Tumor necrosis factor alpha promoter polymorphisms in patients with juvenile idiopathic arthritis

OBJECTIVE: To investigate the potential association of tumor necrosis factor-alpha (TNF) promoter alleles within subtypes of juvenile idiopathic arthritis (JIA) compared to healthy controls in a Caucasian population. METHODS: TNF-alpha promoter polymorphisms at positions -163, -238, -244, -308, -376 were determined in 228 patients with JIA and 196 healthy individuals. Genomic DNA was isolated and a PCR fragment of about 500 base pairs of the TNF gene promoter were amplified by PCR. Detection of polymorphisms was achieved by a single sequencing procedure. RESULTS: The TNF -238A allele was more frequent in the psoriatic arthritis JIA subgroup compared to healthy controls as well as to non-psoriatic JIA patients (p < 0.001, chi-square-test) and was associated with the more frequent occurrence of joint erosion (p < 0.05, chi-square-test). The frequency of the TNF -308A allele was significantly lower in patients with rheumatoid factor negative polyarthritis JIA patients compared to healthy controls, respectively (p < 0.05, chi-square-test). Joint erosions were detectable more often in rheumatoid factor negative polyarthritis JIA patients with the G/A genotype (80%) than in those with the G/G genotype (45%) (p = 0.20). The rare alleles at position -376 or at positions -163 and -244 were found very infrequently. CONCLUSION: TNF promoter polymorphisms may play a role in the pathogenesis of JIA. The TNF-238A allele seems to be associated with juvenile psoriatic arthritis. The TNF-308A allele is less frequently found in rheumatoid factor negative but not in rheumatoid factor positive polyarthritis and may therefore be associated with a more severe disease, while the more common TNF-308G allele may be protective.     

Association between the PTPN22 gene and rheumatoid arthritis and juvenile idiopathic arthritis in a UK population: further support that PTPN22 is an autoimmunity gene

OBJECTIVE: The protein tyrosine phosphatase N22 (PTPN22) gene exhibits regulatory activities for both T cells and B cells. A missense single-nucleotide polymorphism (SNP) within this gene (rs2476601) has recently been associated with 4 autoimmune diseases: rheumatoid arthritis (RA), systemic lupus erythematosus, autoimmune thyroid disease, and type 1 diabetes mellitus, all of which are T cell-mediated and associated with the elaboration of autoantibody. The aim of this study was to investigate associations of the missense SNP of PTPN22 in a number of autoimmune diseases in the UK population, including RA, juvenile idiopathic arthritis (JIA), psoriasis, psoriatic arthritis (PsA), and multiple sclerosis (MS), some of which have not been examined previously. METHODS: The PTPN22 missense SNP was genotyped in 886 RA, 661 JIA, 279 psoriasis, 455 PsA, and 379 MS patients and in 595 healthy controls. Association with the PTPN22 SNP was analyzed by chi-square test as implemented in Stata software. RESULTS: There was a significant association between the PTPN22 SNP and RA (P = 1.8 x 10(-8)) and JIA (P = 0.0005). In contrast, no association with psoriasis, PsA, or MS was detected. CONCLUSION: We replicated the findings of a previous association with RA and identified a novel association with JIA. Together with previous data showing associations with other autoimmune diseases, our findings provide further evidence that the PTPN22 gene plays a role in the pathogenesis of a subgroup of autoimmune diseases.