Optimisation of tocilizumab therapy in giant cell arteritis. A multicentre real-life study of 471 patients.

OBJECTIVES: Tocilizumab (TCZ) is the only biologic therapy approved for giant cell arteritis (GCA). There is general agreement on the initial/maintenance dose, duration of TCZ therapy is not well established. In GiACTA trial, after one year on TCZ, most patients had GCA relapse after withdrawal. The aim of this study is to assess the effectiveness and safety of TCZ therapy optimisation in a large unselected series of patients with GCA in a clinical practice scenario. METHODS: We carried out a multicentre study on 471 GCA patients treated with TCZ. Once prolonged remission was achieved (n=231) and based on a decision between patient and physician, TCZ was optimised (n=125). We compared optimised (TCZOPT) and not optimised (TCZNON-OPT) groups. Prolonged remission defined as normalisation of clinical and laboratory data for 6 months. Optimisation was carried out by decreasing TCZ dose and/or increasing dosing interval. RESULTS: We evaluated 231 GCA patients on TCZ in prolonged remission. At TCZ onset, no differences in demographic, clinical, or laboratory data were observed. First TCZ optimisation was performed after a median follow-up of 12[6-17] months. Intravenous TCZ was optimised from 8 to 4mg/kg/4weeks in 44% patients, while subcutaneous TCZ was optimised from 162mg/w to 162mg/every-other-week in 65% cases. At the end of follow-up, prolonged remission (78.2% vs. 84.2%; p=0.29) and relapses (5.6% vs. 10.4%, p=0.177) were similar in TCZOPT vs. TCZNON-OPT. Severe infections were more frequent in TCZNON-OPT (12.9% vs. 6.6%; p=0.009). CONCLUSIONS: TCZ optimisation may be done once complete remission is achieved by reducing dose or increasing dosing interval. This seems to be effective, safe and cost-effective therapeutic scheme.

SARS-CoV-2 infection in patients with primary Sjögren syndrome: characterization and outcomes of 51 patients.

OBJECTIVE: To analyse the prognosis and outcomes of SARS-CoV-2 infection in patients with primary SS. METHODS: We searched for patients with primary SS presenting with SARS-CoV-2 infection (defined following and according to the European Centre for Disease Prevention and Control guidelines) among those included in the Big Data Sjögren Registry, an international, multicentre registry of patients diagnosed according to the 2002/2016 classification criteria. RESULTS: A total of 51 patients were included in the study (46 women, mean age at diagnosis of infection of 60 years). According to the number of patients with primary SS evaluated in the Registry (n = 8211), the estimated frequency of SARS-CoV-2 infection was 0.62% (95% CI 0.44, 0.80). All but two presented with symptoms suggestive of COVID-19, including fever (82%), cough (57%), dyspnoea (39%), fatigue/myalgias (27%) and diarrhoea (24%), and the most frequent abnormalities included raised lactate dehydrogenase (LDH) (88%), CRP (81%) and D-dimer (82%) values, and lymphopenia (70%). Infection was managed at home in 26 (51%) cases and 25 (49%) required hospitalization (five required admission to ICU, four died). Compared with patients managed at home, those requiring hospitalization had higher odds of having lymphopenia as laboratory abnormality (adjusted OR 21.22, 95% CI 2.39, 524.09). Patients with comorbidities had an older age (adjusted OR 1.05, 95% CI 1.00, 1.11) and showed a risk for hospital admission six times higher than those without (adjusted OR 6.01, 95% CI 1.72, 23.51) in the multivariate analysis. CONCLUSION: Baseline comorbidities were a key risk factor for a more complicated COVID-19 in patients with primary SS, with higher rates of hospitalization and poor outcomes in comparison with patients without comorbidities.

Patterns of drug therapy in newly diagnosed Spanish patients with systemic lupus erythematosus.

OBJECTIVES: This is the first Spanish multicentric inception lupus cohort, formed by SLE patients attending Spanish Internal Medicine Services since January 2009. We aimed to analyse drug therapy during the first year of follow-up according to disease severity. METHODS: 223 patients who had at least one year of follow-up were enrolled upon diagnosis of SLE. Therapy with prednisone, pulse methyl-prednisolone, hydroxychloroquine, immunosuppressives and calcium/vitamin D was analysed. RESULTS: Prednisone was given to 65% patients, at a mean (SD) daily dose of 11 (10) mg/d. 38% patients received average doses >7.5 mg/d during the first year. Patients with nephritis and with a SLEDAI ≥6 were treated with higher doses of prednisone. 81% of patients were treated with hydroxychloroquine, with higher frequency among those with a SLEDAI ≥6 (88% vs. 68%, p<0.001). The use of immunosuppressive drugs and methyl-prednisolone pulses was higher in patients with a baseline SLEDAI ≥6, however, differences were no longer significant when patients with lupus nephritis were excluded. The use of calcium/vitamin D increased with the dose of prednisone, however, 43% of patients on medium-high doses of prednisone did not take any calcium or vitamin D. CONCLUSIONS: This study gives a real-world view of the current therapeutic approach to early lupus in Spain. The generalised use of hydroxychloroquine is well consolidated. There is still a tendency to use prednisone at medium to high doses. Pulse methyl-prednisolone and immunosuppressive drugs were used in more severe cases, but not as steroid sparing agents. Vitamin D use was suboptimal.

A GWAS follow-up study reveals the association of the IL12RB2 gene with systemic sclerosis in Caucasian populations.

A single-nucleotide polymorphism (SNP) at the IL12RB2 locus showed a suggestive association signal in a previously published genome-wide association study (GWAS) in systemic sclerosis (SSc). Aiming to reveal the possible implication of the IL12RB2 gene in SSc, we conducted a follow-up study of this locus in different Caucasian cohorts. We analyzed 10 GWAS-genotyped SNPs in the IL12RB2 region (2309 SSc patients and 5161 controls). We then selected three SNPs (rs3790567, rs3790566 and rs924080) based on their significance level in the GWAS, for follow-up in an independent European cohort comprising 3344 SSc and 3848 controls. The most-associated SNP (rs3790567) was further tested in an independent cohort comprising 597 SSc patients and 1139 controls from the USA. After conditional logistic regression analysis of the GWAS data, we selected rs3790567 [P(MH)= 1.92 × 10(-5) odds ratio (OR) = 1.19] as the genetic variant with the firmest independent association observed in the analyzed GWAS peak of association. After the first follow-up phase, only the association of rs3790567 was consistent (P(MH)= 4.84 × 10(-3) OR = 1.12). The second follow-up phase confirmed this finding (P(χ2) = 2.82 × 10(-4) OR = 1.34). After performing overall pooled-analysis of all the cohorts included in the present study, the association found for the rs3790567 SNP in the IL12RB2 gene region reached GWAS-level significant association (P(MH)= 2.82 × 10(-9) OR = 1.17). Our data clearly support the IL12RB2 genetic association with SSc, and suggest a relevant role of the interleukin 12 signaling pathway in SSc pathogenesis.

Systemic involvement in primary Sjogren's syndrome evaluated by the EULAR-SS disease activity index: analysis of 921 Spanish patients (GEAS-SS Registry).

OBJECTIVE: To evaluate systemic involvement in primary SS in a large cohort of Spanish patients using the EULAR-SS disease activity index (ESSDAI) definitions. METHODS: Systemic involvement was characterized using ESSDAI definitions for the 10 clinical domains (constitutional, lymphadenopathy, glandular, articular, cutaneous, pulmonary, renal, peripheral nervous system, central nervous system and muscular). ESSDAI scores at diagnosis, during follow-up and cumulated at the last visit were calculated. RESULTS: The cohort consisted of 921 patients. After a mean follow-up of 75 months, 77 (8%) patients still had an ESSDAI score of zero at the last visit. Organ by organ, the percentage of patients who developed activity during the follow-up (ESSDAI score ≥ 1 at any time) ranged between 1.4% and 56%, with articular, pulmonary and peripheral neurological involvement being the most common. Logistic multivariate regression analysis showed the following features at diagnosis and had the closest association with systemic activity (statistically significant independent variables in at least two domains): cryoglobulinaemia in five domains; anaemia, lymphopenia and low C3 levels in three domains each and age <35 years in two domains. Sicca features, ANA and RF at diagnosis were not associated with a higher cumulated activity score in any clinical domain. CONCLUSION: Primary SS is undeniably a systemic disease, with the joints, lungs, skin and peripheral nerves being the most frequently involved organs. Cytopenias, hypocomplementaemia and cryoglobulinaemia at diagnosis strongly correlated with higher cumulated ESSDAI scores in the clinical domains. Clinically the ESSDAI provides a reliable picture of systemic involvement in primary SS.

Identification of Mechanisms by Which Genetic Susceptibility Loci Influence Systemic Sclerosis Risk Using Functional Genomics in Primary T Cells and Monocytes.

OBJECTIVE: Systemic sclerosis (SSc) is a complex autoimmune disease with a strong genetic component. However, most of the genes associated with the disease are still unknown because associated variants affect mostly noncoding intergenic elements of the genome. We used functional genomics to translate the genetic findings into a better understanding of the disease. METHODS: Promoter capture Hi-C and RNA-sequencing experiments were performed in CD4+ T cells and CD14+ monocytes from 10 SSc patients and 5 healthy controls to link SSc-associated variants with their target genes, followed by differential expression and differential interaction analyses between cell types. RESULTS: We linked SSc-associated loci to 39 new potential target genes and confirmed 7 previously known SSc-associated genes. We highlight novel causal genes, such as CXCR5, as the most probable candidate gene for the DDX6 locus. Some previously known SSc-associated genes, such as IRF8, STAT4, and CD247, showed cell type-specific interactions. We also identified 15 potential drug targets already in use in other similar immune-mediated diseases that could be repurposed for SSc treatment. Furthermore, we observed that interactions were directly correlated with the expression of important genes implicated in cell type-specific pathways and found evidence that chromatin conformation is associated with genotype. CONCLUSION: Our study revealed potential causal genes for SSc-associated loci, some of them acting in a cell type-specific manner, suggesting novel biologic mechanisms that might mediate SSc pathogenesis.

Genetic and physical interaction of the B-cell systemic lupus erythematosus-associated genes BANK1 and BLK.

OBJECTIVES: Altered signalling in B cells is a predominant feature of systemic lupus erythematosus (SLE). The genes BANK1 and BLK were recently described as associated with SLE. BANK1 codes for a B-cell-specific cytoplasmic protein involved in B-cell receptor signalling and BLK codes for an Src tyrosine kinase with important roles in B-cell development. To characterise the role of BANK1 and BLK in SLE, a genetic interaction analysis was performed hypothesising that genetic interactions could reveal functional pathways relevant to disease pathogenesis. METHODS: The GPAT16 method was used to analyse the gene-gene interactions of BANK1 and BLK. Confocal microscopy was used to investigate co-localisation, and immunoprecipitation was used to verify the physical interaction of BANK1 and BLK. RESULTS: Epistatic interactions between BANK1 and BLK polymorphisms associated with SLE were observed in a discovery set of 279 patients and 515 controls from northern Europe. A meta-analysis with 4399 European individuals confirmed the genetic interactions between BANK1 and BLK. As BANK1 was identified as a binding partner of the Src tyrosine kinase LYN, the possibility that BANK1 and BLK could also show a protein-protein interaction was tested. The co-immunoprecipitation and co-localisation of BLK and BANK1 were demonstrated. In a Daudi cell line and primary naive B cells endogenous binding was enhanced upon B-cell receptor stimulation using anti-IgM antibodies. CONCLUSION: This study shows a genetic interaction between BANK1 and BLK, and demonstrates that these molecules interact physically. The results have important consequences for the understanding of SLE and other autoimmune diseases and identify a potential new signalling pathway.

Adalimumab for the treatment of Behçet's disease: experience in 19 patients.

OBJECTIVE: To describe the experience of two tertiary Spanish centres (Hospital Clínico San Cecilio, Granada and Hospital Clínic, Barcelona) with the use of adalimumab for the treatment of severe clinical manifestations in patients with Behçet's disease (BD) in whom immunosuppressive therapy had failed. METHODS: Retrospective chart review from patients with BD treated with adalimumab in two specialized Spanish centres (Hospital Clínico San Cecilio, Granada and Hospital Clínic, Barcelona). RESULTS: From November 2006 to February 2011, 19 patients with BD were treated with adalimumab. The reason to initiate adalimumab was refractory disease in 17 (89.5%) patients and adverse events to CSA and infliximab in two (10.5%) patients, respectively. The main clinical manifestations leading to adalimumab administration were panuveitis in eight patients, severe bipolar aphthosis in eight, retinal vasculitis in three and severe folliculitis in three. Overall, adalimumab achieved clinical improvement in 17 of the 19 patients. Of note, ocular manifestations (panuveitis and retinal vasculitis) responded rapidly in all cases. In addition to clinical improvement, treatment with adalimumab was associated with reduction in the number and dose of standard immunosuppressive agents. Of interest, seven patients had received TNF-α inhibitors before adalimumab, five infliximab and the remaining two etanercept. Adalimumab was withdrawn in only one patient due to severe infusional reaction in the form of urticaria and angioedema. CONCLUSION: Adalimumab is a valid option for patients with BD and recalcitrant non-controlling manifestations with good safety profile.

Complement component C4 structural variation and quantitative traits contribute to sex-biased vulnerability in systemic sclerosis.

Copy number (CN) polymorphisms of complement C4 play distinct roles in many conditions, including immune-mediated diseases. We investigated the association of C4 CN with systemic sclerosis (SSc) risk. Imputed total C4, C4A, C4B, and HERV-K CN were analyzed in 26,633 individuals and validated in an independent cohort. Our results showed that higher C4 CN confers protection to SSc, and deviations from CN parity of C4A and C4B augmented risk. The protection contributed per copy of C4A and C4B differed by sex. Stronger protection was afforded by C4A in men and by C4B in women. C4 CN correlated well with its gene expression and serum protein levels, and less C4 was detected for both in SSc patients. Conditioned analysis suggests that C4 genetics strongly contributes to the SSc association within the major histocompatibility complex locus and highlights classical alleles and amino acid variants of HLA-DRB1 and HLA-DPB1 as C4-independent signals.

Hemophagocytic lymphohistiocytosis associated with Leishmania: A hidden passenger in endemic areas.

INTRODUCTION: Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and life-threatening syndrome characterized by excessive immune activation. We analyzed the presentation, diagnosis and prognosis of our cohort of HLH-Leishmania cases. METHODS: We studied HLH cases in patients over 14 years of age in the province of Granada (Spain), from January 2008 to November 2019. RESULTS: In this study, Leishmania was the predominant trigger of adult HLH in our region. There were no differences in the clinical-analytical presentation between HLH triggered by Leishmania and those initiated by a different cause. RT-PCR was the best tool to identify Leishmania as the trigger of HLH, given that the other microbiological tests showed low sensitivity to detect the parasite in our HLH-Leishmania cases. CONCLUSION: A comprehensive search for Leishmania is mandatory in HLH cases. Based on our findings, we propose that RT-PCR for Leishmania in bone marrow samples must be included in HLH differential diagnostic protocols.

Coexistence of immune-mediated diseases in sarcoidosis. Frequency and clinical significance in 1737 patients.

OBJECTIVE: To analyze whether immune-mediated diseases (IMDs) occurs in sarcoidosis more commonly than expected in the general population, and how concomitant IMDs influence the clinical presentation of the disease. METHODS: We searched for coexisting IMDs in patients included in the SARCOGEAS-cohort, a multicenter nationwide database of consecutive patients diagnosed according to the ATS/ESC/WASOG criteria. Comparisons were made considering the presence or absence of IMD clustering, and odds ratios (OR) and their 95% confidence intervals (CI) were calculated as the ratio of observed cases of every IMD in the sarcoidosis cohort to the observed cases in the general population. RESULTS: Among 1737 patients with sarcoidosis, 283 (16%) patients presented at least one associated IMD. These patients were more commonly female (OR: 1.98, 95% CI: 1.49-2.62) and were diagnosed with sarcoidosis at an older age (49.6 vs. 47.5years, P<0.05). The frequency of IMDs in patients with sarcoidosis was nearly 2-fold higher than the frequency observed in the general population (OR: 1.64, 95% CI: 1.44-1.86). Significant associations were identified in 17 individual IMDs. In comparison with the general population, the IMDs with the strongest strength of association with sarcoidosis (OR>5) were common variable immunodeficiency (CVID) (OR: 431.8), familial Mediterranean fever (OR 33.9), primary biliary cholangitis (OR: 16.57), haemolytic anemia (OR: 12.17), autoimmune hepatitis (OR: 9.01), antiphospholipid syndrome (OR: 8.70), immune thrombocytopenia (OR: 8.43), Sjögren syndrome (OR: 6.98), systemic sclerosis (OR: 5.71), ankylosing spondylitis (OR: 5.49), IgA deficiency (OR: 5.07) and psoriatic arthritis (OR: 5.06). Sex-adjusted ORs were considerably higher than crude ORs for eosinophilic digestive disease in women, and for immune thrombocytopenia, systemic sclerosis and autoimmune hepatitis in men. CONCLUSION: We found coexisting IMDs in 1 out of 6 patients with sarcoidosis. The strongest associations were found for immunodeficiencies and some systemic, rheumatic, hepatic and hematological autoimmune diseases.

Clinical characterization and outcomes of 85 patients with neurosarcoidosis.

To analyze the frequency and clinical phenotype of neurosarcoidosis (NS) in one of the largest nationwide cohorts of patients with sarcoidosis reported from southern Europe. NS was evaluated according to the Diagnostic Criteria for Central Nervous System and Peripheral Nervous System Sarcoidosis recently proposed by Stern et al. Pathologic confirmation of granulomatous disease was used to subclassify NS into definite (confirmation in neurological tissue), probable (confirmation in extraneurological tissue) and possible (no histopathological confirmation of the disease). Of the 1532 patients included in the cohort, 85 (5.5%) fulfilled the Stern criteria for NS (49 women, mean age at diagnosis of NS of 47.6 years, 91% White). These patients developed 103 neurological conditions involving the brain (38%), cranial nerves (36%), the meninges (3%), the spinal cord (10%) and the peripheral nerves (14%); no patient had concomitant central and peripheral nerve involvements. In 59 (69%) patients, neurological involvement preceded or was present at the time of diagnosis of the disease. According to the classification proposed by Stern et al., 11 (13%) were classified as a definite NS, 61 (72%) as a probable NS and the remaining 13 (15%) as a possible NS. In comparison with the systemic phenotype of patients without NS, patients with CNS involvement presented a lower frequency of thoracic involvement (82% vs 93%, q = 0.018), a higher frequency of ocular (27% vs 10%, q < 0.001) and salivary gland (15% vs 4%, q = 0.002) WASOG involvements. In contrast, patients with PNS involvement showed a higher frequency of liver involvement (36% vs 12%, p = 0.02) in comparison with patients without NS. Neurosarcoidosis was identified in 5.5% of patients. CNS involvement prevails significantly over PNS involvement, and both conditions do not overlap in any patient. The systemic phenotype associated to each involvement was clearly differentiated, and can be helpful not only in the early identification of neurological involvement, but also in the systemic evaluation of patients diagnosed with neurosarcoidosis.

Comparison of the Birmingham Vasculitis Activity Score and the Five-Factor Score to Assess Survival in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Study of 550 Patients From Spain (REVAS Registry).

OBJECTIVE: To compare the accuracy of the Birmingham Vasculitis Activity Score (BVAS), version 3, and the Five Factor Score (FFS), version 1996 and version 2009, to assess survival in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). METHODS: A total of 550 patients with AAV (41.1% with granulomatosis with polyangiitis, 37.3% with microscopic polyangiitis, and 21.6% with eosinophilic granulomatosis with polyangiitis), diagnosed between 1990 and 2016, were analyzed. Receiver operating characteristic (ROC) curves and multivariable Cox analysis were used to assess the relationships between the outcome and the different scores. RESULTS: Overall mortality was 33.1%. The mean ± SD BVAS at diagnosis was 17.96 ± 7.82 and was significantly higher in nonsurvivors than in survivors (mean ± SD 20.0 ± 8.14 versus 16.95 ± 7.47, respectively; P < 0.001). The mean ± SD 1996 FFS and 2009 FFS were 0.81 ± 0.94 and 1.47 ± 1.16, respectively, and were significantly higher in nonsurvivors than in survivors (mean ± SD 1996 FFS 1.17 ± 1.07 versus 0.63 ± 0.81 [P < 0.001] and 2009 FFS 2.13 ± 1.09 versus 1.15 ± 1.05 [P < 0.001], respectively). Mortality rates increased according to the different 1996 FFS and 2009 FFS categories. In multivariate analysis, BVAS, 1996 FFS, and 2009 FFS were significantly related to death (P = 0.007, P = 0.020, P < 0.001, respectively), but the stronger predictor was the 2009 FFS (hazard ratio 2.9 [95% confidence interval 2.4-3.6]). When the accuracy of BVAS, 1996 FFS, and 2009 FFS to predict survival was compared in the global cohort, ROC analysis yielded area under the curve values of 0.60, 0.65, and 0.74, respectively, indicating that 2009 FFS had the best performance. Similar results were obtained when comparing these scores in patients diagnosed before and after 2001 and when assessing the 1-year, 5-year, and long-term mortality. Correlation among BVAS and 1996 FFS was modest (r = 0.49; P < 0.001) but higher than between BVAS and the 2009 FFS (r = 0.28; P < 0.001). CONCLUSION: BVAS and FFS are useful to predict survival in AAV, but the 2009 FFS has the best prognostic accuracy at any point of the disease course.

Early- versus late-onset systemic sclerosis: differences in clinical presentation and outcome in 1037 patients.

Peak age at onset of systemic sclerosis (SSc) is between 20 and 50 years, although SSc is also described in both young and elderly patients. We conducted the present study to determine if age at disease onset modulates the clinical characteristics and outcome of SSc patients. The Spanish Scleroderma Study Group recruited 1037 patients with a mean follow-up of 5.2 ± 6.8 years. Based on the mean ± 1 standard deviation (SD) of age at disease onset (45 ± 15 yr) of the whole series, patients were classified into 3 groups: age ≤ 30 years (early onset), age between 31 and 59 years (standard onset), and age ≥ 60 years (late onset). We compared initial and cumulative manifestations, immunologic features, and death rates. The early-onset group included 195 patients; standard-onset group, 651; and late-onset, 191 patients. The early-onset group had a higher prevalence of esophageal involvement (72% in early-onset compared with 67% in standard-onset and 56% in late-onset; p = 0.004), and myositis (11%, 7.2%, and 2.9%, respectively; p = 0.009), but a lower prevalence of centromere antibodies (33%, 46%, and 47%, respectively; p = 0.007). In contrast, late-onset SSc was characterized by a lower prevalence of digital ulcers (54%, 41%, and 34%, respectively; p < 0.001) but higher rates of heart conduction system abnormalities (9%, 13%, and 21%, respectively; p = 0.004). Pulmonary hypertension was found in 25% of elderly patients and in 12% of the youngest patients (p = 0.010). After correction for the population effects of age and sex, standardized mortality ratio was shown to be higher in younger patients. The results of the present study confirm that age at disease onset is associated with differences in clinical presentation and outcome in SSc patients.

A genome-wide association study follow-up suggests a possible role for PPARG in systemic sclerosis susceptibility.

INTRODUCTION: A recent genome-wide association study (GWAS) comprising a French cohort of systemic sclerosis (SSc) reported several non-HLA single-nucleotide polymorphisms (SNPs) showing a nominal association in the discovery phase. We aimed to identify previously overlooked susceptibility variants by using a follow-up strategy. METHODS: Sixty-six non-HLA SNPs showing a P value <10⁻4 in the discovery phase of the French SSc GWAS were analyzed in the first step of this study, performing a meta-analysis that combined data from the two published SSc GWASs. A total of 2,921 SSc patients and 6,963 healthy controls were included in this first phase. Two SNPs, PPARG rs310746 and CHRNA9 rs6832151, were selected for genotyping in the replication cohort (1,068 SSc patients and 6,762 healthy controls) based on the results of the first step. Genotyping was performed by using TaqMan SNP genotyping assays. RESULTS: We observed nominal associations for both PPARG rs310746 (PMH = 1.90 × 10⁻6, OR, 1.28) and CHRNA9 rs6832151 (PMH = 4.30 × 10⁻6, OR, 1.17) genetic variants with SSc in the first step of our study. In the replication phase, we observed a trend of association for PPARG rs310746 (P value = 0.066; OR, 1.17). The combined overall Mantel-Haenszel meta-analysis of all the cohorts included in the present study revealed that PPARG rs310746 remained associated with SSc with a nominal non-genome-wide significant P value (PMH = 5.00 × 10⁻7; OR, 1.25). No evidence of association was observed for CHRNA9 rs6832151 either in the replication phase or in the overall pooled analysis. CONCLUSION: Our results suggest a role of PPARG gene in the development of SSc.

The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis.

Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P  = 1.34×10(-8), OR  = 1.22, CI 95%  = 1.14-1.30; rs2004640: P  = 4.60×10(-7), OR  = 0.84, CI 95%  = 0.78-0.90; rs10488631: P  = 7.53×10(-20), OR  = 1.63, CI 95%  = 1.47-1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P  = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P  = 9.04×10(-22), OR  = 1.75, CI 95%  = 1.56-1.97) better explained the observed association (likelihood P-value  = 1.48×10(-4)), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific.

Evaluation of a shared autoimmune disease-associated polymorphism of TRAF6 in systemic sclerosis and giant cell arteritis.

OBJECTIVE: We evaluated whether a single-nucleotide polymorphism (SNP) of the TRAF6 gene previously associated with systemic lupus erythematosus and rheumatoid arthritis may be a common risk factor for systemic sclerosis (SSc) and giant cell arteritis (GCA). METHODS: A total of 1185 patients with SSc, 479 patients with biopsy-proven GCA, and 1442 unrelated healthy controls of white Spanish origin were genotyped for the rs540386 variant using a specifically designed TaqMan(©) allele discrimination assay. RESULTS: No significant associations of this SNP with global SSc or GCA were found. This was also the case when the potential associations of the TRAF6 polymorphism with the main clinical phenotypes of the 2 diseases (e.g., limited cutaneous and diffuse cutaneous SSc, or presence of polymyalgia rheumatica and visual ischemic manifestations in GCA) were assessed. CONCLUSION: Our data do not support a role of the rs540386 TRAF6 variant as a key component of the genetic network underlying SSc and GCA.