Julien Wipff

Genome-Wide Scan Identifies TNIP1, PSORS1C1, and RHOB as Novel Risk Loci for Systemic Sclerosis

Systemic sclerosis (SSc) is an orphan, complex, inflammatory disease affecting the immune system and connective tissue. SSc stands out as a severely incapacitating and life-threatening inflammatory rheumatic disease, with a largely unknown pathogenesis. We have designed a two-stage genome-wide association study of SSc using case-control samples from France, Italy, Germany, and Northern Europe. The initial genome-wide scan was conducted in a French post quality-control sample of 564 cases and 1,776 controls, using almost 500 K SNPs. Two SNPs from the MHC region, together with the 6 loci outside MHC having at least one SNP with a P<10−5 were selected for follow-up analysis. These markers were genotyped in a post-QC replication sample of 1,682 SSc cases and 3,926 controls. The three top SNPs are in strong linkage disequilibrium and located on 6p21, in the HLA-DQB1 gene: rs9275224, P = 9.18×10−8, OR = 0.69, 95% CI [0.60–0.79]; rs6457617, P = 1.14×10−7 and rs9275245, P = 1.39×10−7. Within the MHC region, the next most associated SNP (rs3130573, P = 1.86×10−5, OR = 1.36 [1.18–1.56]) is located in the PSORS1C1 gene. Outside the MHC region, our GWAS analysis revealed 7 top SNPs (P<10−5) that spanned 6 independent genomic regions. Follow-up of the 17 top SNPs in an independent sample of 1,682 SSc and 3,926 controls showed associations at PSORS1C1 (overall P = 5.70×10−10, OR:1.25), TNIP1 (P = 4.68×10−9, OR:1.31), and RHOB loci (P = 3.17×10−6, OR:1.21). Because of its biological relevance, and previous reports of genetic association at this locus with connective tissue disorders, we investigated TNIP1 expression. A markedly reduced expression of the TNIP1 gene and also its protein product were observed both in lesional skin tissue and in cultured dermal fibroblasts from SSc patients. Furthermore, TNIP1 showed in vitro inhibitory effects on inflammatory cytokine-induced collagen production. The genetic signal of association with TNIP1 variants, together with tissular and cellular investigations, suggests that this pathway has a critical role in regulating autoimmunity and SSc pathogenesis.

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 Sjögrens 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.

Cardiac involvement in systemic sclerosis assessed by tissue-doppler echocardiography during routine care: A controlled study of 100 consecutive patients.

OBJECTIVE To assess the prevalence of primary cardiac complications in a large population of patients with systemic sclerosis (SSc), using recently developed echocardiographic techniques. METHODS We prospectively studied 100 consecutive patients (mean +/- SD age 54 +/- 14 years; 86 women) presenting with SSc without pulmonary arterial hypertension or clinical manifestations of heart failure. All patients underwent standard echocardiography, along with measurements of longitudinal velocities by tissue Doppler imaging (TDI) to assess left ventricular (LV) and right ventricular (RV) contractility and LV diastolic function. Results were compared with those in 26 age- and sex-matched healthy controls. RESULTS Patients with SSc had a wider mean left atrial diameter and impaired relaxation compared with the controls. A trend was observed toward a smaller LV ejection fraction (EF) in the patients (mean +/- SD 64.9 +/- 0.6%) than in the controls (67.2 +/- 0.7%), as well as higher pulmonary artery pressure (mean +/- SD 33.3 +/- 0.6 mm Hg versus 30.8 +/- 1.0 mm Hg). LVEF was <55% in 7 patients versus none of the controls. Peak systolic mitral annular velocity as measured by TDI was <7.5 cm/second in 14 patients versus none of the controls (P = 0.040). Mitral annulus early diastolic velocity was <10 cm/second in 30 patients versus 2 of the controls (P = 0.022). Fifteen patients and none of the controls had reduced peak systolic tricuspid annular velocity (P = 0.039). The TDI results correlated with each other, but not with lung abnormalities or other disease characteristics. CONCLUSION Depression of LV and RV systolic and LV diastolic function is common in patients with SSc and is due to primary myocardial involvement. Considering the major contributions of TDI, the addition of this simple technique to standard measurements may improve the detection of heart involvement in patients with SSc.

Radiological hand involvement in systemic sclerosis

Background: The osteoarticular and soft tissue structures of the hand may be involved in systemic sclerosis (SSc), causing functional disability. Objective: To assess radiological hand features in a cross sectional study of SSc patients and in controls. Methods: Hand radiology was done systematically in patients with SSc seen over a two year period and in unselected controls with rheumatoid arthritis or digital trauma. Two independent investigators blind to the diagnosis carried out the radiological assessment. Results: 120 consecutive SSc patients (median (range) age, 56.5 (20 to 90) years; disease duration, 6 (0 to 42) years) and 42 controls (22 with rheumatoid arthritis and 20 with digital trauma) were studied. Radiological abnormalities in SSc patients included erosion (21%), joint space narrowing (28%), arthritis (defined by concomitant erosion and joint space narrowing) (18%), radiological demineralisation (23%), acro-osteolysis (22%), flexion contracture (27%), and calcinosis (23%). In univariate and multivariate analysis, the resorption of distal phalanges was significantly associated with digital ulcers, extra-articular calcification, and pulmonary arterial hypertension; flexion contracture was associated with the diffuse cutaneous form and high HAQ (Health Assessment Questionnaire) disability score. Calcinosis was most often seen in patients with digital ulcers, but was similarly observed in patients with the diffuse or limited cutaneous subtypes. Conclusions: Flexion contracture was associated with disability and occurred in patients with the diffuse cutaneous subtype of SSc, consistent with the tendency towards fibrosis and functional impairment of this subtype. Calcinosis and acro-osteolysis were both associated with vascular complications, highlighting a potential role of vascular injury in such lesions.

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.

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.

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 patients 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.

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.

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.

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.