Association of the CD226 Ser(307) variant with systemic sclerosis: evidence of a contribution of costimulation pathways in systemic sclerosis pathogenesis.

OBJECTIVE: The nonsynonymous polymorphism rs763361 of the CD226 gene, which encodes DNAX accessory molecule 1, which is involved in T cell costimulation pathways, has recently been identified as a genetic risk factor for autoimmunity. The purpose of this study was to test for association of the CD226 rs763361 polymorphism with systemic sclerosis (SSc) in European Caucasian populations. METHODS: CD226 rs763361 was genotyped in 3,632 individuals, consisting of a discovery sample (991 SSc patients and 1,008 controls) and a replication sample (999 SSc patients and 634 controls). All study subjects were of European Caucasian origin. Expression of CD226 was assessed on peripheral blood mononuclear cells obtained from 21 healthy donors genotyped for CD226 rs763361. RESULTS: The CD226 rs763361 T allele was found to be associated with SSc in both the discovery and the replication samples, showing the following results in the combined populations: odds ratio (OR) 1.22 (95% confidence interval [95% CI] 1.10-1.34), P = 5.69 × 10(-5) . The CD226 T allele was also associated with various SSc subsets, highlighting a potential contribution to disease severity. The most remarkable associations of the CD226 TT risk genotype were observed with the diffuse cutaneous SSc subtype, the anti-topoisomerase I antibody-positive, and SSc-related fibrosing alveolitis subsets: OR 1.86 (95% CI 1.42-2.43), P = 5.15 × 10(-6) , OR 1.82 (95% CI 1.38-2.40), P = 2.16 × 10(-5) , and OR 1.61 (95% CI 1.25-2.08), P = 2.73 × 10(-4) , respectively. CD226 expression was not significantly influenced by CD226 rs763361 genotypes whatever the T cell subtype investigated. CONCLUSION: Our results establish CD226 as a new SSc genetic susceptibility factor underlying the contribution of costimulation pathways in the pathogenesis of SSc. Further work is nevertheless needed to define the causal variant at the CD226 locus as well as the functional consequences.

NLRP1 influences the systemic sclerosis phenotype: a new clue for the contribution of innate immunity in systemic sclerosis-related fibrosing alveolitis pathogenesis.

BACKGROUND: Recent evidence has highlighted a potential role of interleukin 1ß (IL-1ß) in systemic sclerosis (SSc). NLRP1 provides a scaffold for the assembly of the inflammasome that promotes the processing and maturation of pro-IL-1ß. In addition, NLRP1 variants were found to confer susceptibility to autoimmune disorders. OBJECTIVE: /st> To study a possible association of the NLRP1 rs6502867, rs2670660 and rs8182352, rs12150220 and rs4790797 with SSc in the European Caucasian population. METHODS: NLRP1 single nucleotide polymorphisms were genotyped in 3227 individuals comprising a discovery set (870 SSc patients and 962 controls) and a replication set including individuals from Germany (532 SSc patients and 324 controls) and Italy (527 SSc patients and 301 controls), all individuals being of European Caucasian origin. RESULTS: Conditional analyses revealed a significant association for the NLRP1 rs8182352 variant with both anti-topoisomerase-positive and SSc-related fibrosing alveolitis (FA) subsets under an additive model: p=0.0042, OR 1.23 (95% CI 1.07 to 1.41) and p=0.0065 OR 1.19 (95% CI 1.05 to 1.36), respectively. Logistic regression analysis showed an additive effect of IRF5 rs2004640, STAT4 rs7574865 and NLRP1 rs8182352 risk alleles on SSc-related FA. CONCLUSIONS: Our results establish NLRP1 as a new genetic susceptibility factor for SSc-related pulmonary fibrosis and anti-topoisomerase-positive SSc phenotypes. This provides new insights into the pathogenesis of SSc, underlining the potential role of innate immunity in particular in the FA-positive SSc subphenotype, which represents a severe subset of the disease.

Association of a KCNA5 gene polymorphism with systemic sclerosis-associated pulmonary arterial hypertension in the European Caucasian population.

OBJECTIVE: Pulmonary arterial hypertension (PAH) has emerged as a leading cause of death in systemic sclerosis (SSc). The genetic basis of PAH has been unraveled in recent years, with a major role played by transforming growth factor ß receptors; however, some other candidate genes have also been advocated, including potassium voltage-gated channel, shaker-related subfamily, member 5 (KCNA5). We undertook this study to determine whether KCNA5 polymorphisms confer susceptibility to SSc and its vascular phenotype, including PAH. METHODS: Four KCNA5 single-nucleotide polymorphisms (SNPs), rs10744676, rs1860420, rs3741930, and rs2284136, were genotyped in a discovery set of 638 SSc patients and 469 controls. In addition, rs10744676 was genotyped in an independent replication sample (938 SSc patients and 564 controls) and in a cohort of 168 patients with different PAH subtypes. RESULTS: The KCNA5 rs10744676 variant was found to be associated with SSc in the discovery sample, with an odds ratio (OR) of 0.62 (95% confidence interval [95% CI] 0.48-0.79, adjusted P = 0.0003) in comparison with controls (C allele frequency 11.4% versus 17.2%). When subphenotypes were investigated, an association was found solely for PAH associated with SSc (OR 0.31 [95% CI 0.13-0.71], adjusted P = 0.04). The other KCNA5 SNPs tested were not associated with any SSc subset. The above association with PAH associated with SSc was replicated in the second set. In the combined population, rs10744676 was strongly associated with PAH associated with SSc in comparison with controls (OR 0.36 [95% CI 0.21-0.63], P = 0.0002). In the independent cohort of patients with PAH, after investigating PAH subtypes, only rs10744676 showed an association with PAH associated with SSc. CONCLUSION: Our results provide the first evidence for an association between the KCNA5 rs10744676 variant and PAH associated with SSc.

Prognostic factors for lung function in systemic sclerosis: prospective study of 105 cases.

The aims of the present study were to identify prognostic factors for systemic sclerosis (SSc)-related interstitial lung disease and to clarify the possible causative role of manometric oesophageal involvement. Consecutive SSc patients underwent pulmonary function tests and oesophageal manometry. They were included in the study if pulmonary function tests were repeated >12 months after baseline. The primary end-point was a decrease of >or=10% of the predicted value in forced vital capacity (FVC). The secondary end-points were a decrease of >or=15% pred in lung carbon monoxide diffusing capacity (D(L,CO)) and a decrease of >or=20% pred in FVC. Of the 105 patients (45 diffuse SSc; median disease duration 2.0 yrs), 23 (23%) had a FVC of <80% pred, 60 (59%) had a D(L,CO) of <80% pred and 57 (54%) showed severe oesophageal hypomotility at baseline. Over 72+/-46 months, 29 (28%) patients displayed a decrease of >or=10% pred in FVC, 39 (40%) of 98 patients displayed D(L,CO) decline and 19 (18%) patients displayed a decrease of >or=20% pred in FVC. On multivariate analysis, diffuse SSc was a significant predictor for a decrease of >or=10% pred in FVC (p = 0.01). No other predictor of a decrease in pulmonary function was identified. Only diffuse SSc was predictive of a decrease in pulmonary function in this early-SSc cohort. This does not support preliminary data suggestive of a causative role of oesophageal involvement.

Association of the TNFAIP3 rs5029939 variant with systemic sclerosis in the European Caucasian population.

BACKGROUND: TNFAIP3 encodes the ubiquitin-modifying enzyme, a key regulator of inflammatory signalling pathways. Convincing associations between TNFAIP3 variants and autoimmune diseases have been reported. OBJECTIVE: To investigate the association of TNFAIP3 polymorphisms with systemic sclerosis (SSc). METHODS: Three single nucleotide polymorphisms (SNPs) in a set of 1018 patients with SSc and 1012 controls of French Caucasian origin were genotyped. Two intergenic SNPs, rs10499194 and rs6920220, and one located in TNFAIP3 intron 2, rs5029939, were selected. The TNFAIP3 rs5029939 found to be associated with SSc in this first set was then genotyped in a second set of 465 patients with SSc and 182 controls from Germany and 184 patients with SSc and 124 controls from Italy. Pooled odd ratios were calculated by Mantel-Haenszel meta-analysis. RESULTS: The rs5029939 G allele was found to be significantly associated with SSc susceptibility (pooled OR=2.08 (95% CI 1.59 to 2.72); p=1.16×10⁻7), whereas the rs10499194 and rs6920220 variants displayed no association. Only one of the predicted haplotypes investigated in the French sample was significantly associated with SSc (p=8.91×10⁻8), and this haplotype was discriminating only in the presence of the rs5029939 risk allele, suggesting that this SNP tags the association signal. The strongest associations of rs5029939 with subphenotypes, having large magnitudes for complex genetic disorders, were observed for diffuse cutaneous SSc (pooled OR=2.71 (1.94 to 3.79), p=5.2×10⁻9), fibrosing alveolitis (pooled OR=2.26 (1.61 to 3.17), p=2.5×10⁻6) and pulmonary arterial hypertension (pooled OR=3.11 (1.86 to 5.17), p=1.3×10⁻5). CONCLUSION: These results suggest that TNFAIP3 is a genetic susceptibility factor for SSc.

Association of hypoxia-inducible factor 1A (HIF1A) gene polymorphisms with systemic sclerosis in a French European Caucasian population.

OBJECTIVE: Systemic sclerosis (SSc) is a connective tissue disease characterized by generalized microangiopathy leading to chronic hypoxia. The aim of this study was to determine whether polymorphisms of the hypoxia-inducible factor 1A gene (HIF1A) affects susceptibility to SSc in a large French European Caucasian population. METHODS: A case-control study was performed in 659 SSc patients and 511 healthy matched controls. Three tag single nucleotide polymorphisms (SNPs) of the HIF1A gene (rs12434438 A/G, rs1957757 C/T, and rs11549465 C/T) were genotyped allowing whole gene coverage according to HapMap data. RESULTS: The frequency of genotypes carrying at least one G allele (A/G and/or GG) of the rs12434438 SNP was significantly higher in SSc patients than in controls [p(corr) = 0.018, odds ratio (OR) 1.44, 95% confidence interval (CI) 1.08-1.91]. Regarding SSc subgroup analyses, the heterozygous genotype A/G was associated with SSc (p(corr) = 0.012, OR 1.47, 95% CI 1.13-1.9), with the limited cutaneous form of SSc (p(corr) = 0.04, OR 1.43, 95% CI 1.08-1.91), and with positive anti-centromere antibodies (ACA; p(corr) = 0.016, OR 1.61, 95% CI 1.16-2.23). No association was detected for the remaining two HIF1A SNPs tested. Haplotype analyses did not detect any association with SSc. CONCLUSIONS: We observed an association between the HIF1A gene and SSc in a European Caucasian population, supporting a role for HIF1 in the pathophysiology of SSc.

Effects of oral treatments on exercise capacity in systemic sclerosis related pulmonary arterial hypertension: a meta-analysis of randomised controlled trials.

OBJECTIVE: To determine the effects of recently available oral therapies, ie, endothelin receptor antagonists (ERAs) and phosphodiesterase-5 inhibitors (PDEIs), in patients with pulmonary arterial hypertension related to connective tissue disease (CTD), mostly systemic sclerosis (SSc). METHOD: A systematic literature search was conducted up to April 2007. All randomised controlled trials evaluating the efficacy of bosentan, sitaxsentan and sildenafil vs placebo on exercise capacity were selected. Effect size was calculated in each study to assess the magnitude of treatment effect. RESULTS: In all, 10 studies were analysed, giving a total of 613 participants (186 with CTD) who received the active treatment and 272 (72 with CTD) who received placebo. The effect sizes of bosentan, sitaxsentan and sildenafil for exercise capacity in the CTD subset of patients were non-significant; 0.31 (95% confidence interval (CI) -0.22 to 0.83), 0.26 (95% CI -0.06 to 0.57) and 0.53 (95% CI -0.02 to 0.89), respectively. In the whole PAH population, these values were significant; 0.61 (95% CI 0.38 to 0.84), 0.33 (95% CI 0.15 to 0.51) and 0.58 (95% CI 0.38 to 0.79), respectively. CONCLUSION: This meta-analysis suggests an absence of clinically relevant improvement on exercise capacity in patients with CTD/SSc after 12 to 18 weeks of treatment. A poor therapeutic response, insufficient power of studies or poor sensitivity to change of the 6-min walk test may explain these results. The promising preliminary data on survival of ERAs and the confounding effects of other comorbidities associated with CTD and SSc may support the latter hypothesis.

Circulating endothelial progenitor cells in systemic sclerosis: association with disease severity.

BACKGROUND: Heterogeneous data have been reported regarding the detection and number of circulating endothelial progenitor cells (EPCs) in systemic sclerosis (SSc). OBJECTIVE: We investigated the number of circulating EPCs using recent recommendations and we quantified their late outgrowth in patients with SSc and healthy controls. PATIENTS AND METHODS: EPCs, defined as Lin-/7AAD-/CD34+/CD133+/VEGFR-2+ cells, were quantified in 50 patients with SSc (mean age: 55 (16) years, disease duration: 9 (9) years) and 26 controls (mean age: 53 (19) years) by cell sorting/flow cytometry and by counting late outgrowth colony-forming units (CFU). RESULTS: Patients with SSc displayed higher circulating EPC counts than controls (median 86 (5-282) vs 49 (5-275)) EPCs for 1 million Lin- mononuclear cells; p = 0.01). Lower EPC counts were associated with the higher Medsger's severity score (p = 0.01) and with the presence of past and/or current digital ulcers (p = 0.026). There was no difference for the number of late outgrowth EPC-CFUs between patients with SSc and controls in cell culture evaluation. The formation of colonies was associated with higher levels of circulating EPCs (p = 0.02) and the number of colonies correlated with levels of EPCs (R = 0.73, p = 0.0004), validating our combination of fluorescence-activated cell sorter surface markers. CONCLUSIONS: We quantified circulating EPCs with an accurate combination of markers herein validated. Our data demonstrate increased circulating EPC levels in SSc, supporting their mobilisation from bone marrow. Furthermore, the subset of patients with digital vascular lesions and high severity score displayed low EPC counts, suggesting increased homing at this stage. The predictive value of this biomarker now warrants further evaluation.

Disturbed angiogenesis in systemic sclerosis: high levels of soluble endoglin.

OBJECTIVE: SSc is a CTD characterized by early generalized microangiopathy with disturbed angiogenesis. Soluble endoglin (sENG), a serum anti-angiogenic protein, has recently been described as a major actor in pre-eclampsia, another severe vascular disease with abnormal angiogenesis. The aim of this study was to investigate, in a cross-sectional study, sENG levels together with other serum vascular markers. METHODS: Serum levels of sENG were assessed by ELISA in consecutive SSc patients and controls matched for age and sex. We also measured by ELISA serum levels of VEGF and asymmetric dimethylarginine (ADMA), as respective markers of angiogenesis and endothelial dysfunction. RESULTS: We included 235 unrelated subjects: 187 SSc patients and 48 controls. Higher concentrations of sENG (P = 0.002) and sVEGF (P < 0.0001) were found in SSc patients compared with controls whereas there was no difference for ADMA. In multivariate analysis, sENG levels were significantly increased in SSc patients with cutaneous ulcerations (P = 0.0003), positive for ACAs (P = 0.009) and with abnormal diffusing capacity for carbon monoxide divided by alveolar volume (P = 0.03). Soluble ENG levels negatively correlated with ADMA, but no relationship was found between sENG and sVEGF. CONCLUSION: This study shows increased values of sENG in a large SSc cohort and a relevant association with a vascular phenotype. The predictive value of the biomarker sENG and its potential role on cellular endothelial disturbances remain to be determined.

Clinical outcome in children with chronic recurrent multifocal osteomyelitis.

OBJECTIVE: To determine the clinical outcome of children with chronic recurrent multifocal osteomyelitis (CRMO). METHODS: We retrospectively reviewed clinical, biological and radiological data of children with CRMO at five French paediatric centres. Outcome data were obtained through review of hospital charts and questionnaires sent to all patients to assess disease activity and educational and vocational achievement. RESULTS: Forty patients were assessed (34 females and 6 males) with a median age at diagnosis of 11.5 yrs (range 2-17). Median number of initial bony lesions was 2 at onset, and 3.5 over disease course. Median time since diagnosis was 3.5 yrs (range 0.5-15) and median duration of active disease 2.7 yrs (range 0.5-13.5). Nine (22.5%) patients had psychological or physical sequelae. Twenty-nine children (72.5%) responded to the questionnaire. Twenty-six had no physical disability as judged by the HAQ 0-1, two had moderate disability (HAQ: 1-2) and one had severe disability (HAQ: 2-3). Seventeen patients (58.6%) had active disease at follow-up (after 6 months to 15 yrs since diagnosis) and continued to have pain (median value of visual analogue scale: 10/100). CRMO had interfered with patient's education in two cases. CONCLUSIONS: Clinical outcome of children with CRMO is generally good, but a sizeable proportion of patients have active disease at follow-up, and a minority of patients can have a severe and prolonged disease course despite intensive treatments. Further studies are required to determine predictive factors for severe disease.

Predictors of hypogammaglobulinemia during rituximab maintenance therapy in rheumatoid arthritis: A 12-year longitudinal multi-center study.

OBJECTIVE: Rituximab (RTX) is an anti-CD20 monoclonal antibody that selectively depletes B-cell population. Thus, it presents a potential risk for the development of hypogammaglobulinemia and related infectious events. Our aim was to identify predictors of hypogammaglobulinemia in RA patients long-term treated with RTX. METHODS: Multicenter observational usual care study of patients with RA on RTX maintenance therapy (minimal exposition of 30 months). Serum protein electrophoresis was performed before each RTX infusion. Hypogammaglobulinemia and severe hypogammaglobulinemia were defined as total gammaglobulin <6g/L and <4g/L, respectively. The primary outcome was the occurrence within the follow-up period of hypogammaglobulinemia. RESULTS: 134 patients met inclusion criteria and were followed-up for 79.5 ± 24.6 months. Hypogammaglobulinemia occurred during the follow-up period in 23 patients (2.7 events per 100 pt-yrs). The mean time to development of hypogammaglobulinemia was 64 ± 23 months. Patients who developed hypogammaglobulinemia were more likely to experience severe infections (26.1% vs. 6.3%, P = 0.033). Multivariate Cox analysis identified gammaglobulin levels <8g/L at baseline as an independent predictor of hypogammaglobulinemia (HR 7.34 [95% CI: 2.00-26.90], P = 0.003). Concomitant methotrexate (MTX) intake was also predictive of a reduced risk of hypogammaglobulinemia occurrence (HR 0.26 [95% CI: 0.08-0.87], P = 0.03). CONCLUSION: Our results show that gammaglobulin levels of less than 8g/L at baseline is a strong independent risk factor for developing subsequent hypogammaglobulinemia, whereas concomitant MTX therapy seems to be a protective factor in RA patients treated long-term with RTX.

A large national cohort of French patients with chronic recurrent multifocal osteitis.

OBJECTIVE: To document more fully the characteristics of chronic recurrent multifocal osteomyelitis (CRMO) in pediatric patients, to collect data on the outcomes and management of the disease, and to define prognostic factors. METHODS: One hundred seventy-eight patients were included (123 female patients and 55 male patients), with a mean ± SD age at diagnosis of 10.9 ± 2.9 years. Inclusion criteria were a diagnosis of CRMO, evidence of at least one lesion of osteitis confirmed by imaging, and development of the syndrome before age 18 years. RESULTS: Longitudinal clinical and imaging studies revealed that only 12 of 178 CRMO patients (7%) had unifocal lesions at the last medical visit. We were able to apply the clinical chronic nonbacterial osteomyelitis score to 110 of 178 patients (62%), which indicated that bone biopsy could have been avoided in 27 cases (25%). At the last medical visit, disease was in remission in only 73 of 171 patients (43%) (41% receiving therapy) after a mean ± SD of 47.9 ± 38.9 months; 44 of 171 patients (26%) experienced sequelae. Using cluster analysis, the CRMO cohort was separated into 3 homogeneous phenotypes (severe, mild, and intermediate). Patients with the severe phenotype had the worst prognosis. This group was entirely composed of male patients, most of whom had the multifocal form of CRMO and inflammatory syndrome. Patients with the mild phenotype had the best prognosis. This group was primarily composed of female patients with a unifocal form of CRMO and infrequent clavicle involvement and inflammatory syndrome. Patients with the intermediate phenotype had a good prognosis but greater reliance on treatment. This group primarily included female patients with multifocal lesions and inflammatory syndrome. CONCLUSION: This is the largest CRMO cohort described in the literature to date. Clinical evolution and imaging investigations confirmed the multifocal pattern of the disease. Three distinct subgroups of CRMO patients were distinguished, with very different prognoses.

[Watermelon stomach in systemic sclerosis]. / Estomac pastèque au cours de la sclérodermie systémique.

Systemic sclerosis (SSc) is a connective tissue disorder characterized by microvascular involvement, which very frequently targets the digestive tract. Gastrointestinal involvement is noted in up to 90% of cases, the segment most frequently involved being the esophagus although the entire digestive tract may be affected. Gastroesophageal reflux is the most common symptom but other unusual complications may also occur. Gastric antral vascular ectasia (GAVE) or watermelon stomach is one such rare lesion; it relates to a disturbed capillary bed, which appears dilated, sometimes with thrombi under the mucosa. This lesion is one expression of generalized SSc microvasculopathy. Its prevalence is not precisely known but appears to be weak; however, it remains a cause of anemia clinicians should be aware of. Indeed, specific local treatment must be delivered and is usually efficient despite frequent recurrent events.

Association between the IRF5 rs2004640 functional polymorphism and systemic sclerosis: a new perspective for pulmonary fibrosis.

OBJECTIVE: There is now growing evidence that connective tissue diseases, including systemic sclerosis (SSc), share a common genetic background. Microarray studies support a pivotal role of type I interferon (IFN) in the pathophysiology of connective tissue diseases. Interferon regulatory factors coordinate the expression of type I IFNs, and the IRF5 gene has been identified as a susceptibility gene of systemic lupus and Sjögren's syndrome. The aim of this study was to determine whether the IRF5 rs2004640 single-nucleotide polymorphism is associated with SSc. METHODS: The IRF5 rs2004640 (GT) functional polymorphism was genotyped in 1,641 subjects of French European Caucasian origin: a discovery set comprising 427 patients with SSc and 380 control subjects and a replication set comprising 454 patients with SSc and 380 control subjects. RESULTS: In both the discovery set and the replication set, the TT genotype was significantly more common in patients with SSc than in control subjects, with an odds ratio (OR) for the combined populations of 1.58 (95% confidence interval [95% CI] 1.18-2.11 [P for trend 0.002]). Analyses of the whole SSc population showed a significant association between homozygosity for the T allele and the presence of antinuclear antibodies (corrected P [Pcorr]=0.04, OR 1.59, 95% CI 1.16-2.17) and fibrosing alveolitis (Pcorr=0.001, OR 2.07, 95% CI 1.38-3.11). In a multivariate analysis model including the diffuse cutaneous subtype of SSc and positivity for anti-topoisomerase I antibodies, the IRF5 rs2004640 TT genotype remained associated with fibrosing alveolitis (P=0.029, OR 1.92, 95% CI 1.07-3.44). CONCLUSION: The IRF5 rs2004640 GT substitution is associated with susceptibility to SSc. These data provide new insight into the pathogenesis of SSc, including clues to the mechanisms leading to fibrosing alveolitis.

STAT4 is a genetic risk factor for systemic sclerosis having additive effects with IRF5 on disease susceptibility and related pulmonary fibrosis.

OBJECTIVE: Systemic sclerosis (SSc) belongs to the group of connective tissue disorders (CTDs), among which are several disorders characterized by a type I interferon (IFN) signature. The recent identification of an association between IRF5 and SSc further highlights a key role for IFN. STAT4, which encodes STAT-4, contributes to IFN signaling, and its genetic variants were found to be associated with CTDs. The aim of this study was to determine whether the STAT4 rs7574865 single-nucleotide polymorphism is associated with SSc, and whether it interacts with IRF5. METHODS: Both the STAT4 rs7574865 and IRF5 rs2004640 polymorphisms were genotyped in 1,855 individuals of French Caucasian origin comprising a discovery set of 440 patients with SSc and 485 control subjects and a replication set of 445 patients with SSc and an additional 485 control subjects. RESULTS: STAT4 rs7574865 was shown to be associated with SSc (P=0.001, odds ratio [OR] 1.29, 95% confidence interval [95% CI] 1.11-1.51). This association was not restricted to a particular phenotype. An additive effect of the STAT4 rs7574865 T allele and the IRF5 rs2004640 T allele was observed, resulting in a multiple increased 1.28-fold risk of SSc. The OR for SSc was 2.72 (95% CI 1.86-3.99) for combinations of genotypes with >or=3 risk alleles. An additive effect was also detected for fibrosing alveolitis: carriage of at least 3 risk alleles appeared to be an independent risk factor (P=2.2x10(-4), OR 1.97, 95% CI 1.28-3.04). CONCLUSION: Our results establish STAT4 rs7574865 as a new SSc genetic susceptibility factor. STAT4 and IRF5 act with additive effects in terms of susceptibility to both SSc and SSc-related fibrosing alveolitis.

BANK1 is a genetic risk factor for diffuse cutaneous systemic sclerosis and has additive effects with IRF5 and STAT4.

OBJECTIVE: To determine whether the functional BANK1 variants rs3733197 and rs10516487 are associated with systemic sclerosis (SSc) in 2 European Caucasian populations and to investigate the putative gene-gene interactions between BANK1 and IRF5 as well as STAT4. METHODS: BANK1 single-nucleotide polymorphisms were genotyped in a total population of 2,432 individuals. The French cohort consisted of 874 SSc patients and 955 controls (previously genotyped for both IRF5 rs2004640 and STAT4 rs7574865). The German cohort consisted of 421 SSc patients and 182 controls. RESULTS: The BANK1 variants were found to be associated with diffuse cutaneous SSc (dcSSc) in both cohorts, providing an odds ratio (OR) of 0.77 for the rs10516487 T rare allele in the combined populations of dcSSc patients as compared with the combined populations of controls (95% confidence interval [95% CI] 0.64-0.93) and an OR of 0.73 (95% CI 0.61-0.87) for the rs3733197 A rare allele. BANK1 haplotype analysis found the A-T haplotype to be protective in dcSSc patients (OR 0.70 [95% CI 0.57-0.86], P = 3.39 x 10(-4)) and the G-C haplotype to be a risk factor (OR 1.25 [95% CI 1.06-1.47], P = 0.008). Significant differences were also observed when the limited cutaneous subset of SSc was compared with the dcSSc subset, both for the rare alleles and for the haplotypes. The BANK1, IRF5, and STAT4 risk alleles displayed a multiplicatively increased risk of dcSSc of 1.43-fold. CONCLUSION: Our results establish BANK1 as a new SSc genetic susceptibility factor and show that BANK1, IRF5, and STAT4 act with additive effects.

Angiogenesis in systemic sclerosis: impaired expression of vascular endothelial growth factor receptor 1 in endothelial progenitor-derived cells under hypoxic conditions.

OBJECTIVE: To assess angiogenesis and explore the expression and regulation of vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR-1), and VEGFR-2, the leading mediators of angiogenesis, in SSc patients and controls. METHODS: Late-outgrowth endothelial progenitor cells (EPCs), isolated from the peripheral blood of systemic sclerosis (SSc) patients and controls, and human umbilical vein endothelial cells (HUVECs) were assessed under normal and hypoxic conditions. Genomic background was evaluated in a large case-control study (including 659 patients with SSc and 511 controls) using tag single-nucleotide polymorphisms on VEGFR1 and VEGFR2 genes. RESULTS: EPCs from SSc patients had the phenotype of genuine endothelial cells and displayed in vitro angiogenic properties similar to those of HUVECs and control EPCs under basal conditions, as determined by flow cytometry, tube formation, and migration assay. However, after 6 hours of hypoxic exposure, EPCs from SSc patients exhibited lower induced expression of VEGFR-1 at the messenger RNA and protein levels, but similar VEGF and VEGFR-2 expression, compared with HUVECs or EPCs from healthy controls. There was no evidence of defective expression of hypoxia-inducible factor 1alpha. These results were supported by the lower serum levels of soluble VEGFR-1 found in SSc patients (n = 187) compared with healthy controls (n = 48) (mean +/- SD 163.7 +/- 98.5 versus 210.4 +/- 109.5 pg/ml; P = 0.0042). These abnormalities did not seem to be related to genomic background. CONCLUSION: Our findings shed new light on the possible role of VEGFR-1 in the main vascular disturbances that occur in SSc and lead to more severe disease.

The PTPN22 620W allele confers susceptibility to systemic sclerosis: findings of a large case-control study of European Caucasians and a meta-analysis.

OBJECTIVE: To determine whether genetic variants of the PTPN22 gene, including the R620W (1858C>T) missense single-nucleotide polymorphism (SNP), are associated with systemic sclerosis (SSc). Since PTPN22 is involved in multiple autoimmune diseases, we also examined the occurrence of a concomitant autoimmune disease. We then conducted a meta-analysis of the most recent studies of SSc in order to verify the association or lack of association between the PTPN22 1858C>T variant and SSc. METHODS: Seven PTPN22 SNPs were analyzed in a French Caucasian cohort of 659 SSc patients and 504 healthy controls. All SSc patient sera were tested for the presence of autoantibodies against topoisomerase I (anti-topo I) and for anticentromere antibodies (ACAs). RESULTS: The co-occurrence of an autoimmune disease was observed in 22% of the 416 SSc patients who were exhaustively screened. In 33 of the 416 patients (8%), the concomitant autoimmune disease was known to be associated with PTPN22 1858T; these patients were excluded prior to analysis. No association was detected for any of the SNPs tested. PTPN22 haplotype analysis identified a strong association between SSc and the presence of a risk haplotype carrying the 1858T allele (P = 1.52 x 10(-7)) and a protective haplotype carrying the 1858C allele (P = 2.20 x 10(-16)) in our French Caucasian population. The meta-analysis provided evidence that the PTPN22 1858T allele is involved in the genetic susceptibility to SSc in Caucasian (P = 8.39 x 10(-3), OR 1.08 [95% CI 1.02-1.15]) and mixed (P = 3.11 x 10(-3), OR 1.09 [95% CI 1.04-1.16]) populations, particularly in the anti-topo I-positive subset. CONCLUSION: Our results indicate that PTPN22, a shared genetic factor of multiple autoimmune diseases, also contributes to the genetic background of SSc.

Association between an endoglin gene polymorphism and systemic sclerosis-related pulmonary arterial hypertension.

UNLABELLED: Systemic sclerosis (SSc) is a connective tissue disorder characterized by early generalized microangiopathy with disturbed angiogenesis. Endoglin gene (ENG) encodes a transmembrane glycoprotein which acts as an accessory receptor for the transforming growth factor-beta (TGF-beta) superfamily, and is crucial for maintaining vascular integrity. A 6-base insertion in intron 7 (6bINS) of ENG has been reported to be associated with microvascular disturbance. OBJECTIVES: Our objective was to investigate the relationship between 6bINS and the vascular complication pulmonary arterial hypertension (PAH) in SSc in a French Caucasian population. METHODS: Two hundred eighty SSc cases containing 29/280 having PAH diagnosed by catheterism were compared with 140 patients with osteoarthritis. Genotyping was performed by polymerase-chain-reaction-based fluorescence and direct sequencing of genomic DNA. RESULTS: The polymorphism was in Hardy-Weinberg equilibrium. We observed a significant lower frequency of 6bINS allele in SSc patients with associated PAH compared with controls [10.3 vs 23.9%, P = 0.01; odds ratio (OR) 0.37, 95% confidence interval (CI) 0.15-0.89], and a trend in comparison with SSc patients without PAH (10.3 vs 20.3%, P = 0.05; OR: 0.45, 95% CI: 0.19-1.08). Genotypes carrying allele 6bINS were also less frequent in SSc patients with PAH than in controls (20.7 vs 42.9%, P = 0.02). CONCLUSIONS: Thus the frequency of 6bINS differs between SSc patients with or without PAH, suggesting the implication of ENG in this devastating vascular complication of SSc.