Clinical trait-specific genetic analysis in Behçet's disease identifies novel loci associated with ocular and neurological involvement.

Behçet's disease is a complex inflammatory vasculitis with a broad spectrum of clinical manifestations. The purpose of this study was to investigate the genetics underlying specific clinical features of Behçet's disease. A total of 436 patients with Behçet's disease from Turkey were studied. Genotyping was performed using the Infinium ImmunoArray-24 BeadChip. After imputation and quality control measures, logistic regressions adjusting for sex and the first five principal components were performed for each clinical trait using a case-case genetic analysis approach. A weighted genetic risk score was calculated for each clinical feature. Genetic association analyses of previously identified susceptibility loci in Behçet's disease revealed a genetic association between ocular lesions and HLA-B/MICA (rs116799036: OR = 1.85 [95% CI = 1.35-2.52], p-value = 1.1 × 10-4). The genetic risk score was significantly higher in Behçet's disease patients with ocular lesions compared to those without ocular involvement, which is explained by the genetic variation in the HLA region. New genetic loci predisposing to specific clinical features in Behçet's disease were suggested when genome-wide variants were evaluated. The most significant associations were observed in ocular involvement with SLCO4A1 (rs6062789: OR = 0.41 [95% CI = 0.30-0.58], p-value = 1.92 × 10-7), and neurological involvement with DDX60L (rs62334264: OR = 4.12 [95% CI 2.34 to 7.24], p-value = 8.85 × 10-7). Our results emphasize the role of genetic factors in predisposing to specific clinical manifestations in Behçet's disease, and might shed additional light into disease heterogeneity, pathogenesis, and variability of Behçet's disease presentation across populations.

Sex-specific analysis in Behçet's disease reveals higher genetic risk in male patients.

OBJECTIVES: Behçet's disease tends to be more severe in men than women. This study was undertaken to investigate sex-specific genetic effects in Behçet's disease. METHODS: A total of 1762 male and 1216 female patients with Behçet's disease from six diverse populations were studied, with the majority of patients of Turkish origin. Genotyping was performed using an Infinium ImmunoArray-24 BeadChip, or extracted from available genotyping data. Following imputation and extensive quality control measures, genome-wide association analysis was performed comparing male to female patients in the Turkish cohort, followed by a meta-analysis of significant results in all six populations. In addition, a weighted genetic risk score for Behçet's disease was calculated and compared between male and female patients. RESULTS: Genetic association analysis comparing male to female patients with Behçet's disease from Turkey revealed an association with male sex in HLA-B/MICA within the HLA region with a GWAS level of significance (rs2848712, OR = 1.46, P = 1.22 × 10-8). Meta-analysis of the effect in rs2848712 across six populations confirmed these results. Genetic risk score for Behçet's disease was significantly higher in male compared to female patients from Turkey. Higher genetic risk for Behçet's disease was observed in male patients in HLA-B/MICA (rs116799036, OR = 1.45, P = 1.95 × 10-8), HLA-C (rs12525170, OR = 1.46, P = 5.66 × 10-7), and KLRC4 (rs2617170, OR = 1.20, P = 0.019). In contrast, IFNGR1 (rs4896243, OR = 0.86, P = 0.011) was shown to confer higher genetic risk in female patients. CONCLUSIONS: Male patients with Behçet's disease are characterized by higher genetic risk compared to female patients. This genetic difference, primarily derived from our Turkish cohort, is largely explained by risk within the HLA region. These data suggest that genetic factors might contribute to differences in disease presentation between men and women with Behçet's disease.

Genetic Association of a Gain-of-Function IFNGR1 Polymorphism and the Intergenic Region LNCAROD/DKK1 With Behçet's Disease.

OBJECTIVE: Behçet's disease is a complex systemic inflammatory vasculitis of incompletely understood etiology. This study was undertaken to investigate genetic associations with Behçet's disease in a diverse multiethnic population. METHODS: A total of 9,444 patients and controls from 7 different populations were included in this study. Genotyping was performed using an Infinium ImmunoArray-24 v.1.0 or v.2.0 BeadChip. Analysis of expression data from stimulated monocytes, and epigenetic and chromatin interaction analyses were performed. RESULTS: We identified 2 novel genetic susceptibility loci for Behçet's disease, including a risk locus in IFNGR1 (rs4896243) (odds ratio [OR] 1.25; P = 2.42 × 10-9 ) and within the intergenic region LNCAROD/DKK1 (rs1660760) (OR 0.78; P = 2.75 × 10-8 ). The risk variants in IFNGR1 significantly increased IFNGR1 messenger RNA expression in lipopolysaccharide-stimulated monocytes. In addition, our results replicated the association (P < 5 × 10-8 ) of 6 previously identified susceptibility loci in Behçet's disease: IL10, IL23R, IL12A-AS1, CCR3, ADO, and LACC1, reinforcing the notion that these loci are strong genetic factors in Behçet's disease shared across ancestries. We also identified >30 genetic susceptibility loci with a suggestive level of association (P < 5 × 10-5 ), which will require replication. Finally, functional annotation of genetic susceptibility loci in Behçet's disease revealed their possible regulatory roles and suggested potential causal genes and molecular mechanisms that could be further investigated. CONCLUSION: We performed the largest genetic association study in Behçet's disease to date. Our findings reveal novel putative functional variants associated with the disease and replicate and extend the genetic associations in other loci across multiple ancestries.

Identification of susceptibility loci for Takayasu arteritis through a large multi-ancestral genome-wide association study.

Takayasu arteritis is a rare inflammatory disease of large arteries. We performed a genetic study in Takayasu arteritis comprising 6,670 individuals (1,226 affected individuals) from five different populations. We discovered HLA risk factors and four non-HLA susceptibility loci in VPS8, SVEP1, CFL2, and chr13q21 and reinforced IL12B, PTK2B, and chr21q22 as robust susceptibility loci shared across ancestries. Functional analysis proposed plausible underlying disease mechanisms and pinpointed ETS2 as a potential causal gene for chr21q22 association. We also identified >60 candidate loci with suggestive association (p < 5 × 10-5) and devised a genetic risk score for Takayasu arteritis. Takayasu arteritis was compared to hundreds of other traits, revealing the closest genetic relatedness to inflammatory bowel disease. Epigenetic patterns within risk loci suggest roles for monocytes and B cells in Takayasu arteritis. This work enhances understanding of the genetic basis and pathophysiology of Takayasu arteritis and provides clues for potential new therapeutic targets.

Intestinal Behçet Disease: Evaluation With MR Enterography-A Case-Control Study.

OBJECTIVE: The purposes of this study were to discern imaging findings that distinguish Behçet disease from small-bowel Crohn disease, to find initial performance estimates for these findings, and to evaluate the diagnostic value of MR enterography (MRE) for detecting intestinal Behçet disease. MATERIALS AND METHODS: The MRE examinations of 30 consecutively registered patients with established intestinal Behçet disease were reviewed by two blinded readers. The frequencies of MRE findings were compared with those obtained for 30 control subjects with small-bowel Crohn disease who were matched for sex and age. The performance estimates were generated with ileocolonoscopic and histopathologic findings as the reference standard. RESULTS: Polypoid pattern and homogeneous mural enhancement were the findings seen more frequently in Behçet disease (p = 0.000) than in Crohn disease (p = 0.003). Stricture formation, long-segment disease, and involvement of more proximal ileal segments favored small-bowel Crohn disease. The ROC AUCs for polypoid pattern and homogeneous mural enhancement in the detection of intestinal Behçet disease were 0.806 and 0.779. The accuracy of MRE was 70.00% (95% CI, 50.60-85.27%); sensitivity, 57.14% (95% CI, 34.02-78.18%), and specificity, 100% (95% CI, 66.37-100%). CONCLUSION: MRE has potential for use as a radiation-free alternative for clarifying the cause of nonspecific gastrointestinal symptoms in patients with known Behçet disease. However, additional studies are needed to determine the actual value of MRE in patients with Behçet disease and to validate the clinical usefulness of the technique in the detection of unknown intestinal Behçet disease.

An analysis of the relationship between autoantibodies and clinical findings in patients with systemic sclerosis

Background/aim: We aimed to investigate the prevalence of anti-RNA polymerase (RNAP) III and other autoantibodies in a group of Turkish patients with systemic sclerosis (SSc) and their relation with clinical features. Materials and methods: The prevalence of anti-RNAP III and other autoantibodies was analyzed in 93 patients with SSc and control groups including 86 patients with systemic lupus erythematosus (SLE) and 65 healthy subjects, respectively. Their relationship with diseases findings was assessed in a cross-sectional manner. Results: Prevalences of anti-RNAP III were 2/93 (2.2%) in SSc, 1/86 (1.2%) in SLE, and 1/65 (1.5%) in the healthy group and there was no difference among groups (P > 0.999). Anti-Sm was significantly more common in SLE patients (P < 0.001), whereas antitopoisomerase I and anticentromere protein B were significantly more common in SSc patients (P < 0.001). There was a significant association between antitopoisomerase I positivity and interstitial lung disease (P < 0.001), and interestingly there was also a significant association between anti-SS-A 52 positivity and the presence of digital ulcers in patients with SSc. Conclusion: Our data show that anti-RNAP III in SSc patients was low in frequency in a Turkish population.

Criteria sets for primary Sjogren's syndrome are not adequate for those presenting with extraglandular organ involvements as their dominant clinical features.

Patients with primary Sjogren's syndrome (pSS) may go undiagnosed or be misclassified due to the insidious nature and wide spectrum of the disease. The available several classification criteria emphasize glandular findings. We aimed to analyze the efficiency of various classification criteria sets in patients diagnosed on the clinical basis by expert opinion and to compare those pSS patients who fulfilled these criteria with those who did not. This is a multicenter study in which 834 patients from 22 university-based rheumatology clinics are included. Diagnosis of pSS was made on the clinical basis by the expert opinion. In this study, we only interviewed patients once and collected available data from the medical records. The European criteria, American-European Consensus Group (AECG) and American College of Rheumatology (ACR) Sjogren's criteria were applied. Majority of the patients were women (F/M was 20/1). The median duration from the first pSS-related symptom to diagnosis was significantly shorter in men (2.5 ± 2.3 vs 4.3 ± 5.9 years) (p = 0 < 0.016). When the European, AECG and ACR Sjogren's criteria were applied, 666 patients (79.9%) satisfied at least one of them. In total, 539 patients (64.4%) satisfied the European, 439 (52.6%) satisfied the AECG, and 359 (43%) satisfied the ACR criteria. Among the entire group, 250 patients (29.9%) satisfied all and 168 (20.1%) met none of the criteria. The rates of extraglandular organ involvements were not different between patients who met at least one of the criteria sets and those who met none. There is an urgent need for the modification of the pSS criteria sets to prevent exclusion of patients with extraglandular involvements as the dominant clinical features.

Anti-angiotensin II type 1 receptor autoantibodies (AT1R-AAs) in patients with systemic sclerosis: lack of association with disease manifestations.

Angiotensin II type 1 receptor autoantibodies (AT1R-AAs) are known to be associated with malignant hypertension, preeclampsia, and vascular rejection in kidney transplantation. They were also suspected to have pathogenetic role in vasculopathic changes in systemic sclerosis (SSc). Clinical data regarding AT1R-AAs in SSc are scarce. In this work, we will examine the relationship between serum levels of AT1R-AAs and disease manifestations. Serum samples from SSc patients and healthy controls were analyzed for AT1R-AAs by using a commercial ELISA kit. We examined the association of serum levels of AT1R-AA with disease duration, systolic pulmonary artery pressure (sPAP) measurements, and disease manifestations like cutaneous, lung and esophageal involvements, and the presence of digital ulcers in a cross-sectional manner. There was no statistically significant difference in levels of AT1R-AAs between SSc (n = 93) patients and healthy controls (n = 66) (p = 0.23). Serum levels of AT1R-AAs were not correlated with disease duration, sPAP measurements, and showed no association with disease manifestations like lung involvement, esophageal involvement, digital ulcers, and cutaneous fibrosis. In our SSc cohort, AT1R-AA serum levels were not different from healthy subjects and higher levels were not associated with any disease manifestation neither.

Low serum fibroblast growth factor 2 levels not accompanied by increased serum pentraxin 3 levels in patients with systemic sclerosis.

There are scarce clinical data regarding serum pentraxin 3 (PTX3) and fibroblast growth factor 2 (FGF2) in patients with systemic sclerosis (SSc). Study was conducted to evaluate serum levels in our SSc cohort. Serum PTX3 and FGF2 concentrations were compared among SSc, disease control (systemic lupus erythematosus (SLE)), and healthy control groups. We also examined the association of serum levels of PTX3 and FGF2 with disease manifestations. Serum PTX3 levels were similarly distributed among SSc (n = 93) and healthy groups (n = 66) (p = 1.00) while PTX3 levels were higher in SLE controls (n = 86) compared to both SSc and healthy groups. PTX3 levels were higher in limited SSc cases compared to diffuse cases (p = 0.016). Median PTX3 levels in SSc cases with lung involvement were lower compared to cases with no lung involvement (p = 0.006). Patients with SSc had significantly lower serum levels of FGF2 compared to SLE and healthy groups. Serum FGF2 concentration was undetectable in 61.3% of cases with SSc while 30.2% of SLE and only 4.5% of healthy cases had undetectable FGF2 levels (p < 0.01). Diffuse and limited SSc cases, as well as cases with and without lung involvement, had similar rates of undetectable serum FGF2 levels (p = 0.15 and p = 0.59, respectively). FGF2 levels were mostly undetectably low in patients with SSc, and serum PTX3 was lower in diffuse SSc and in cases with lung involvement compared to limited SSc and cases with no lung involvement, respectively, in our cohort.

Association between single nucleotide polymorphisms in prospective genes and susceptibility to ankylosing spondylitis and inflammatory bowel disease in a single centre in Turkey.

BACKGROUND/AIMS: To establish the prevalence of the single nucleotide polymorphisms (SNPs) of endoplasmic reticulum aminopeptidase 1 (ERAP1), IL-23 receptor (IL-23R), signal transducer and activator of transcription 3 (STAT-3) and Janus kinase 2 (JAK-2) in ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) in a Turkish population. MATERIALS AND METHODS: A total of 562 subjects who presented at the Ankara University internal medicine departments of rheumatology and gastroenterology outpatient clinics were recruited in this study, including 365 patients with AS, 197 patients with IBD and 230 healthy controls. ERAP1, IL-23R, STAT-3 and JAK-2) were genotyped in competitive allele-specific polymerase chain reactions. RESULTS: The ERAP1 (rs26653) polymorphism was found to increase the disease risk in patients with AS and IBD compared with the control group (p=0.02 and p=0.01, respectively). In addition, this polymorphism revealed a significant relationship with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath AS Functional Index (BASFI) in patients with AS (r=0.829, p < 0.001 and r=0.731, p < 0.001, respectively). CONCLUSION: The ERAP1 gene polymorphism might be a risk factor in the pathogenesis of AS and IBD. In contrast, IL-23R gene polymorphisms may serve a protective role in AS and IBD.

Association of serum KL-6 levels with interstitial lung disease in patients with connective tissue disease: a cross-sectional study.

It was aimed to evaluate KL-6 glycoprotein levels to determine if it may be a diagnostic marker for the connective tissue diseases (CTDs) predicting CTD-related interstitial lung diseases (ILDs) (CTD-ILD) development and to examine if there was a difference between patients and healthy controls. The study included 113 patients with CTD (45 CTD without lung involvement, 68 CTD-ILD) and 45 healthy control subjects. KL-6 glycoprotein levels were analyzed with ELISA in patients and the control group. The relationship between KL-6 glycoprotein levels and CTD-ILD was assessed. In the comparison of all the groups in the study, significantly higher levels of KL-6 were determined in the CTD-ILD group than in either the CTD without pulmonary involvement group or the healthy control group (p < 0.008 and p < 0.001, respectively). There was no statistically significant difference between the KL-6 levels in the healthy control group and the CTD without pulmonary involvement group (p = 0.289). The KL-6 levels did not differ significantly according to the connective tissue diseases in the diagnostic groups (systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, mixed connective tissue disease, scleroderma, polymyositis/ dermatomyositis). In the healthy control group, there was a statistically significant difference between KL-6 levels in smokers and non-smokers. Smokers had significantly higher serum KL-6 levels compared with non-smokers (p < 0.05). There was no statistically significant difference between smoking status (pack-year) and serum KL-6 levels. There was no statistically significant correlation between serum KL-6 levels and time since diagnosis of CTD and CTD-ILD. The level of KL-6 as a predictive factor could be used to identify the clinical development of ILD before it is detected on imaging modality. Further prospective clinical studies are needed to define whether levels of KL-6 might have prognostic value or might predict progressive ILD.

The Assessment of Tp-e Interval and Tp-e/QT Ratio in Patients With Systemic Sclerosis.

OBJECTIVES: This study aims to investigate ventricular repolarization using T-peak to T-end (Tp-e) intervals and Tp-e/QT ratios in patients with systemic sclerosis (SSc). PATIENTS AND METHODS: Totally 65 patients (8 males, 57 females; mean age 49.8 years; range 20 to 77 years) with SSc and 63 control subjects (8 males, 55 females; mean age 49.3 years; range 20 to 77 years) were enrolled. Tp-e intervals, Tp-e/QT, and Tp-e/corrected QT (QTc) ratios were measured from the 12-lead electrocardiogram. RESULTS: Tp-e intervals, QT intervals, QTc intervals, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in patients with SSc than control subjects (all p<0.01). There was no difference between patients with diffuse and limited cutaneous SSc in terms of electrocardiogram and echocardiographic findings. Correlation analysis revealed no correlation between Tp-e intervals, Tp-e/QT, and Tp-e/QTc ratios with disease duration and anti-Sjögren's syndrome antigen A antibody levels in patients with SSc (all p>0.05). CONCLUSION: Our study showed that Tp-e intervals, Tp-e/QT, and Tp-e/QTc ratios were increased in patients with SSc than control subjects. The increased frequency of ventricular arrhythmias can be clarified by increased indexes of ventricular repolarization parameters in patients with SSc.

Identification of Susceptibility Loci in IL6, RPS9/LILRB3, and an Intergenic Locus on Chromosome 21q22 in Takayasu Arteritis in a Genome-Wide Association Study.

OBJECTIVE: Takayasu arteritis is a rare large vessel vasculitis with incompletely understood etiology. This study was undertaken to perform the first unbiased genome-wide association analysis of Takayasu arteritis. METHODS: Two independent cohorts of patients with Takayasu arteritis from Turkey and North America were included in our study. The Turkish cohort consisted of 559 patients and 489 controls, and the North American cohort consisted of 134 patients and 1,047 controls of European ancestry. Genotyping was performed using the Omni1-Quad and Omni2.5 genotyping arrays. Genotyping data were subjected to rigorous quality control measures and subsequently analyzed to discover genetic susceptibility loci for Takayasu arteritis. RESULTS: We identified genetic susceptibility loci for Takayasu arteritis with a genome-wide level of significance in IL6 (rs2069837) (odds ratio [OR] 2.07, P = 6.70 × 10(-9)), RPS9/LILRB3 (rs11666543) (OR 1.65, P = 2.34 × 10(-8)), and an intergenic locus on chromosome 21q22 (rs2836878) (OR 1.79, P = 3.62 × 10(-10)). The genetic susceptibility locus in RPS9/LILRB3 lies within the leukocyte receptor complex gene cluster on chromosome 19q13.4, and the disease risk variant in this locus correlates with reduced expression of multiple genes including the inhibitory leukocyte immunoglobulin-like receptor gene LILRB3 (P = 2.29 × 10(-8)). In addition, we identified candidate susceptibility genes with suggestive levels of association (P < 1 × 10(-5)) with Takayasu arteritis, including PCSK5, LILRA3, PPM1G/NRBP1, and PTK2B. CONCLUSION: Our findings indicate novel genetic susceptibility loci for Takayasu arteritis and uncover potentially important aspects of the pathophysiology of this form of vasculitis.

Churg-Strauss syndrome: a new endotype of severe asthma? Results of 14 Turkish patients.

INTRODUCTION: Churg-Strauss syndrome (CSS) is a rare multisystem vasculitis. Considering the variation of autoimmune diseases in different races, it is of interest to determine whether any outstanding features exist for Turkish patients with CSS. OBJECTIVE: The aim of this study was to evaluate the clinical and serological features of the disease, the treatment, and long-term follow-up details, and to investigate possible etiological factors of Turkish CSS patients. METHODS: The study included 14 patients who were diagnosed with CSS, and followed by our department between 2004 and 2012. Possible etiological factors, initial symptoms, clinical presentations, treatment, as well as outcomes were documented. The study was approved by the local ethics. RESULTS: All patients fulfilled the American College of Rheumatology criteria. Initial symptoms were worsening asthma (n = 14; 100%) and skin lesions (n = 6; 43%). All patients had a diagnosis of asthma and nasal polyps, whereas 57.1% had aspirin hypersensitivity at the time of diagnosis. The lungs (100%) and skin (43%) were most commonly involved. Peripheral eosinophilia dominated on initial presentations of all patients. Initial treatments included oral methyl prednisolone in all cases, whereas cyclophosphamide and azathioprine were used in three cases. Relapses were detected in five cases. None of the cases were able to stop the oral corticosteroid treatment. No fatalities were observed. CONCLUSION: We herein describe a new severe asthma endotype in connection with CSS. We suggest that physicians who deal with uncontrolled severe asthma cases should consider CSS in the presence of nasal polyps, aspirin hypersensitivity, and especially peripheral blood eosinophilia over 10%.

Response to rituximab in a case of lupus associated digital ischemia.

We report the case of a 38-year-old female patient with systemic lupus erythematosus (SLE) and Jaccoud arthritis (JA) that sequentially developed digital ischemic lesions of the hands. In spite of follow-up treatment with glucocorticoids, immunosuppressant, antiaggregant, and potent vasodilatator agents, a serious progression to digital gangrene over a one-month period was observed. Surprisingly, her nonhealing digital lesions improved after two cycles of rituximab (RTX) administration.

TIR-domain-containing adaptor protein gene TIRAP S180L polymorphism is not increased in Behçet's disease patients in two ethnic cohorts.

OBJECTIVES: The single nucleotide polymorphism (SNP) of TIRAP (Serine 180 leucine, S180L) that is shown to be associated with Behçet's disease (BD) in a European-derived cohort, but not in Middle Eastern patients is investigated in two other populations. METHODS: Two cohorts of BD patients and controls from Turkey (n=797) and Italy (n=633) were genotyped by sequence specific primer-polymerase chain reaction (SSP-PCR) or TaqMan q-PCR assays. RESULTS: Genotype and allele frequencies in TIRAP S180L (rs8177374) were not different between BD patients and controls in either ethnicity. Furthermore, a meta-analysis between the Turkish and the Italian BD cohorts did not reveal an association between this non-synonymous SNP in TIRAP and BD (meta-analysis OR=0.94, meta-analysis p=0.61, Q statistic heterogeneity p=0.11). CONCLUSIONS: TIRAP S180L gene polymorphism, which was previously shown to be associated with BD in a Caucasian population, has been replicated in either Turkish or Italian population in our study.