Prediction of pulmonary hypertension related to systemic sclerosis bu an index based on simple clinical observations

To develop a score to estimate the risk of developing pulmonary hypertension (PH) in patients with systemic sclerosis (SSc). METHODS: We first examined the prevalence and characteristics of precapillary PH confirmed by right-heart catheterization in a cross-sectional (derivation) sample of 1,165 SSc patients, and we developed a risk prediction score (RPS) based on simple clinical observations associated with PH. We next prospectively tested the 3-year predictive power of the "Cochin RPS" in a separate (validation) sample of 443 patients presenting with PH-free SSc at baseline. RESULTS: In the derivation sample, age, forced vital capacity, and diffusing capacity for carbon monoxide/alveolar volume were independently associated with the presence of PH and were used to create the Cochin RPS. PH developed during followup in 20 patients in the validation sample. The area under the receiver operating characteristic curve of the Cochin RPS was 0.87 (95% confidence interval 0.79-0.95). With a cutoff value of 2.73, patients at risk of PH during followup could be identified with 89.5% sensitivity and 74.1% specificity. PH occurred in 0.6% of patients in the lowest 2 quintiles of the Cochin RPS, in 1.7% of patients in the third and fourth quintiles, and in 17.1% of patients in the highest quintile (P35-fold higher risk of developing PH compared with patients in the 2 lowest quintiles (P=0.001). CONCLUSION: Using routine clinical observations, we developed a simple score that accurately predicted the risk of PH in SSc

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

Recent evidence has highlighted a potential role of interleukin 1\u3b2 (IL-1\u3b2) in systemic sclerosis (SSc). NLRP1 provides a scaffold for the assembly of the inflammasome that promotes the processing and maturation of pro-IL-1\u3b2. In addition, NLRP1 variants were found to confer susceptibility to autoimmune disorders. OBJECTIVE: 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

Brief report: candidate gene study in systemic sclerosis identifies a rare and functional variant of the TNFAIP3 locus as a risk factor for polyautoimmunity

Systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) share some pathophysiologic bases as evidenced by individual and familial polyautoimmunity and common susceptibility genetic factors. With regard to the latter, there has been a recent shift from the "common variant" to the "rare variant" paradigm, since rare variants of TNFAIP3 and TREX1 with large effect sizes have recently been discovered in SLE. The present study was undertaken to investigate whether rare variants of TNFAIP3 and TREX1 are also associated with SSc. METHODS: TREX1 single-nucleotide polymorphisms (SNPs) rs3135946, rs7626978, rs3135943, and rs11797 and TNFAIP3 SNPs rs9494883, rs72063345, rs5029939, rs2230926, rs117480515, and rs7749323 were genotyped in a discovery set (985 SSc patients and 1,011 controls), and replication analysis of the most relevant results was performed in a second set (622 SSc patients and 493 controls). RESULTS: No association between TREX1 variants and SSc was observed. For TNFAIP3, we first demonstrated that a low-frequency variant, rs117480515, tagged the recently identified TT>A SLE dinucleotide. In the discovery sample, we observed that all tested TNFAIP3 variants were in linkage disequilibrium and were associated with SSc and various SSc subsets, including the polyautoimmune phenotype. We subsequently genotyped rs117480515 in the replication sample and found it to be associated solely with the SSc polyautoimmune subset (odds ratio 3.51 [95% confidence interval 2.28-5.41], P = 8.58 7 10(-9) ) in the combined populations. Genotype-messenger RNA (mRNA) expression correlation analysis revealed that the TNFAIP3 rs117480515 risk allele was associated with decreased mRNA expression. CONCLUSION: The present findings establish the TNFAIP3 locus as a susceptibility factor for the subset of SSc with a polyautoimmune phenotype. Our results support the implication of rare/low-frequency functional variants and the critical role of A20 in autoimmunity

Evidence for caveolin-1 as a new susceptibility gene regulating tissue fibrosis in systemic sclerosis

Caveolin-1 (CAV1) is an inhibitor of tissue fibrosis and has been implicated in the pathogenesis of systemic sclerosis (SSc). The aim of the study was to analyse the possible association of CAV1 gene single nucleotide polymorphisms (SNP) with SSc. METHODS: A total population of 3974 individuals (1355 SSc patients, 2619 controls) was studied. Genotype data for 23 SNP spanning the CAV1-CAV2 gene locus were obtained from a genome-wide scan conducted in a French population (564 SSc patients, 1776 controls). Three CAV1 SNP (rs926198, rs959173, rs9920) displaying the most significant associations with SSc and/or clinical phenotypes were then genotyped in an Italian population (791 SSc patients, 843 controls). CAV1 protein expression in skin biopsies was investigated by immunohistochemistry and western blotting. RESULTS: In the French population, the CAV1 rs959173 C minor allele showed a significant protective association with susceptibility to SSc (OR 0.71, 95% CI 0.59 to 0.86, p(adjusted)=0.009), and with the subset of patients with limited cutaneous SSc (OR 0.71, 95% CI 0.56 to 0.89, p(adjusted)=0.018). The association was replicated in the Italian population and strengthened in the combined populations through Cochran-Mantel-Haenszel meta-analysis (SSc: pooled OR 0.81, 95% CI 0.71 to 0.92, p=0.0018; limited cutaneous SSc: pooled OR 0.80, 95% CI 0.69 to 0.93, p=0.0053). Genotype/protein expression correlations revealed that the rs959173 C protective allele was associated with increased CAV1 protein expression. CONCLUSIONS: These results add CAV1 to the list of SSc susceptibility genes and provide further evidence for the contribution of this pathway in the fibrotic process that characterises SSc pathogenesis

TGFbeta receptor gene variants in systemic sclerosis-related pulmonary arterial hypertension: results from a multicentre EUSTAR study of European Caucasian patients

: Systemic sclerosis (SSc)-related pulmonary arterial hypertension (PAH) has emerged as a major mortality prognostic factor. Mutations of transforming growth factor beta (TGF\u3b2) receptor genes strongly contribute to idiopathic and familial PAH. OBJECTIVE: To explore the genetic bases of SSc-PAH, we combined direct sequencing and genotyping of candidate genes encoding TGF\u3b2 receptor family members. MATERIALS AND METHODS: TGF\u3b2 receptor genes, BMPR2, ALK1, TGFR2 and ENG, were sequenced in 10 SSc-PAH patients, nine SSc and seven controls. In addition, 22 single-nucleotide polymorphisms (SNP) of these four candidate genes were tested for association in a first set of 824 French Caucasian SSc patients (including 54 SSc-PAH) and 939 controls. The replication set consisted of 1516 European SSc (including 219 SSc-PAH) and 3129 controls from the European League Against Rheumatism Scleroderma Trials and Research group network. RESULTS: No mutation was identified by direct sequencing. However, two repertoried SNP, ENG rs35400405 and ALK1 rs2277382, were found in SSc-PAH patients only. The genotyping of 22 SNP including the latter showed that only rs2277382 was associated with SSc-PAH (p=0.0066, OR 2.13, 95% CI 1.24 to 3.65). Nevertheless, this was not replicated with the following result in combined analysis: p=0.123, OR 0.79, 95% CI 0.59 to 1.07. CONCLUSIONS: This study demonstrates the lack of association between these TGF\u3b2 receptor gene polymorphisms and SSc-PAH using both sequencing and genotyping methods