Impact of JAK Inhibitors in Pediatric Patients with STAT1 Gain of Function (GOF) Mutations-10 Children and Review of the Literature.

INTRODUCTION: Since the first description of gain of function (GOF) mutations in signal transducer and activator of transcription (STAT) 1, more than 300 patients have been described with a broad clinical phenotype including infections and severe immune dysregulation. Whilst Jak inhibitors (JAKinibs) have demonstrated benefits in several reported cases, their indications, dosing, and monitoring remain to be established. METHODS: A retrospective, multicenter study recruiting pediatric patients with STAT1 GOF under JAKinib treatment was performed and, when applicable, compared with the available reports from the literature. RESULTS: Ten children (median age 8.5 years (3-18), receiving JAKinibs (ruxolitinib (n = 9) and baricitinib (n = 1)) with a median follow-up of 18 months (2-42) from 6 inborn errors of immunity (IEI) reference centers were included. Clinical profile and JAKinib indications in our series were similar to the previously published 14 pediatric patients. 9/10 (our cohort) and 14/14 patients (previous reports) showed partial or complete responses. The median immune deficiency and dysregulation activity scores were 15.99 (5.2-40) pre and 7.55 (3-14.1) under therapy (p = 0.0078). Infection, considered a likely adverse event of JAKinib therapy, was observed in 1/10 patients; JAKinibs were stopped in 3/10 children, due to hepatotoxicity, pre-HSCT, and absence of response. CONCLUSIONS: Our study supports the potentially beneficial use of JAKinibs in patients with STAT1 GOF, in line with previously published data. However, consensus regarding their indications and timing, dosing, treatment duration, and monitoring, as well as defining biomarkers to monitor clinical and immunological responses, remains to be determined, in form of international prospective multicenter studies using established IEI registries.

The ovarian reserve as measured by the anti-Müllerian hormone is not diminished in patients with rheumatoid arthritis compared to the healthy population.

OBJECTIVES: Rheumatoid arthritis (RA) is the most prevalent chronic inflammatory arthritis, affecting 0.5-1% worldwide population and predominates in females. Altered fertility has been reported due to a decrease in ovarian reserve secondary to sustained inflammation. The anti-Müllerian Hormone (AMH) is currently the most reliable biomarker of ovarian reserve. However, few and contradictory studies have been reported to analyse the relationship between fertility in RA female patients and AMH. The aim of present study is to determine the AMH serum concentrations in a long-standing RA patient group and control group. We also sought to determine the correlation between AMH serum levels and disease activity measured by different parameters and the effect of biological DMARDs. METHODS: Serum AMH levels were measured in 60 women with long-standing RA aged 20-50 y.o. and compared to 59 healthy women. AMH was assessed by an electrochemiluminescence immunoassay method (ECLIA, Roche Diagnostics) and a large data set of clinical and molecular data was annotated. Demographic parameters, RA disease activity measured by DAS28 score and inflammatory biomarkers such as ESR, CRP, lymphocyte CD4+, CD8+, NK cells, IL-10 and IL-6 were determined. A comprehensive gynaecological self-administered questionnaire was given. Serum AMH levels were age-correlated. Differences between groups were calculated using Student's t-test or Mann-Whitney U-test for continuous variables and Fisher's exact test for categorical variables. Multivariate analysis was conducted by the partial correlation coefficient. Linear regression analysis was performed to study the effect of different variables on proportional AMH change. p-values <0.005 were considered significant. RESULTS: The median age was similar in AR and control groups (37.4±6.23 vs. 37.3±6.27 p=0.937). Mean disease duration was 8.37±5.36 years. The number of previous treatments was <3 in 71.7% of patients and ≥3 in 28.3%. Disease activity measured by DAS28 was 2.89± 1.54. The age-adjusted mean serum concentration of AMH was 1.27 ng/ml [IQR 0.42; 2.24] in RA patients and 1.31 ng/ml [IQR 0.46; 3.09] in controls (p=0.608). Neither disease activity (p=0.862), nor current or previous bDMARDs treatments (p=0.871) were associated with AMH levels. However, a negative linear correlation was observed between AMH and IL-10 levels (p=0.033). CONCLUSIONS: Our study shows that ovarian reserve determined by AMH serum levels is not reduced in rheumatoid arthritis patients compared with healthy controls. In our series, AMH levels were not affected by disease activity, however, a significant correlation was observed between AMH and IL-10 levels. These results support the role of cytokines profile in the female reproductive system and will focus further investigations in this critical area, mainly once biological DMARDs have been recommended in RA pregnant patients.

Abatacept in interstitial lung disease associated with rheumatoid arthritis: national multicenter study of 263 patients.

OBJECTIVE: To assess the efficacy of abatacept (ABA) in RA patients with interstitial lung disease (ILD) (RA-ILD). METHODS: This was an observational, multicentre study of RA-ILD patients treated with at least one dose of ABA. ILD was diagnosed by high-resolution CT (HRCT). We analysed the following variables at baseline (ABA initiation), 12 months and at the end of the follow-up: Modified Medical Research Council (MMRC) scale (1-point change), forced vital capacity (FVC) or diffusion lung capacity for carbon monoxide (DLCO) (improvement or worsening ≥10%), HRCT, DAS on 28 joints evaluated using the ESR (DAS28ESR) and CS-sparing effect. RESULTS: We studied 263 RA-ILD patients [150 women/113 men; mean (s.d.) age 64.6 (10) years]. At baseline, they had a median duration of ILD of 1 (interquartile range 0.25-3.44) years, moderate or severe degree of dyspnoea (MMRC grade 2, 3 or 4) (40.3%), FVC (% of the predicted) mean (s.d.) 85.9 (21.8)%, DLCO (% of the predicted) 65.7 (18.3) and DAS28ESR 4.5 (1.5). The ILD patterns were: usual interstitial pneumonia (UIP) (40.3%), non-specific interstitial pneumonia (NSIP) (31.9%) and others (27.8%). ABA was prescribed at standard dose, i.v. (25.5%) or s.c. (74.5%). After a median follow-up of 12 (6-36) months the following variables did not show worsening: dyspnoea (MMRC) (91.9%); FVC (87.7%); DLCO (90.6%); and chest HRCT (76.6%). A significant improvement of DAS28ESR from 4.5 (1.5) to 3.1 (1.3) at the end of follow-up (P < 0.001) and a CS-sparing effect from a median 7.5 (5-10) to 5 (2.5-7.5) mg/day at the end of follow-up (P < 0.001) was also observed. ABA was withdrawn in 62 (23.6%) patients due to adverse events (n = 30), articular inefficacy (n = 27), ILD worsening (n = 3) and other causes (n = 2). CONCLUSION: ABA may be an effective and safe treatment for patients with RA-ILD.

Juvenile idiopathic arthritis in the young adult. Methodology, objectives, and initial data from the JUVENSER registry.

OBJECTIVES: To describe the methodology, objectives, and initial data of the registry of young adult patients diagnosed with Juvenile Idiopathic Arthritis (JIA), JUVENSER. The main objective of the project is to know the sociodemographic and clinical characteristics, and disease activity of patients with JIA reaching the transition to adulthood. MATERIAL AND METHOD: Longitudinal, prospective, multicentre study, including patients between 16 and 25 years old, with a diagnosis of JIA in any of its categories. The main objective is to determine the characteristics and activity of JIA in the young adult. It includes sociodemographic variables, clinical variables, disease activity and joint damage rates, data on the use of health resources, and treatments used. The total duration of the project will be 3 years. A cohort of 534 young adult patients was obtained. CONCLUSIONS: The JUVENSER registry will constitute a cohort of young adults with JIA, which will allow the evaluation of the clinical characteristics and response to treatment of patients with disease onset in childhood, moving to adult clinics.

Real-World Health Care Outcomes and Costs Among Patients With Juvenile Idiopathic Arthritis in Spain.

Background: Juvenile idiopathic arthritis (JIA) is the most frequent chronic rheumatic disease in children. If inflammation is not adequately treated, joint damage, long-term disability, and active disease during adulthood can occur. Identifying and implementing early and adequate therapy are critical for improving clinical outcomes. The burden of JIA on affected children, their families, and the healthcare system in Spain has not been adequately assessed. The greatest contribution to direct costs is medication, but other expenses contribute to the consumption of resources, negatively impacting healthcare cost and the economic conditions of affected families. Objective: To assess the direct healthcare, indirect resource utilization, and associated cost of moderate-to-severe JIA in children in routine clinical practice in Spain. Methods: Children were enrolled in this 24-month observational, multicentric, cross-sectional, retrospective study (N = 107) if they had been treated with biologic disease-modifying anti-rheumatic drugs (bDMARDs), had participated in a previous study (ITACA), and continued to be followed up at pediatric rheumatology units at 3 tertiary Spanish hospitals. Direct costs included medication, specialist and primary care visits, hospitalizations, emergency visits or consultations, surgeries, physiotherapy, and tests. Indirect costs included hospital travel expenses and loss of caregiver working hours. Unitary costs were obtained from official sources (€, 2020). Results: Overall, children had inactive disease/low disease activity according to JADAS-71 score and very low functional disability as measured by Childhood Health Assessment Questionnaire score. Up to 94.4% of children received treatment, mainly with bDMARDs as monotherapy (84.5%). Among anti-TNFα treatments, adalimumab (47.4%) and etanercept (40.2%) were used in similar proportions. Annual mean (SD) total JIA cost was €7516.40 (€5627.30). Average cost of pharmacological treatment was €3021.80 (€3956.20), mainly due to biologic therapy €2789.00 (€3399.80). Direct annual cost (excluding treatments) was €3654.60 (€3899.00). Indirect JIA cost per family was €747.20 (€1452.80). Conclusion: JIA causes significant costs to the Spanish healthcare system and affected families. Public costs are partly due to the high cost of biologic treatments, which nevertheless remain an effective long-term treatment, maintaining inactive disease/low disease activity state; a very low functional disability score; and a good quality of life.

Ultrasound in pediatric rheumatology: Highlighting the differences with adults.

Musculoskeletal ultrasound (MSUS) is a powerful tool of major importance in rheumatology. MSUS is ideally suited for the evaluation of pediatric patients because it is a safe technique with a high patient acceptability, it does not require sedation, and it is excellent for exploring multiple joints. It is also the most operator-dependent imaging modality, and assessing joints in patients with juvenile idiopathic arthritis (JIA) is particularly challenging due to the unique features of the growing skeleton. Years ago, MSUS was already extensively used to manage rheumatoid arthritis (RA), which allowed pediatric rheumatologists to apply the knowledge generated in adult studies. It was a good starting point to study the joints of healthy children and JIA patients. Luckily, there is increasing evidence regarding the possibilities of MSUS in the management of JIA patients, with recent definitions for synovitis, descriptions of the sonographic features of joints in healthy children, and a better understanding of the role of subclinical synovitis. This review highlights the differences in normality and in pathological findings between children and adults assessed by MSUS. Specifically, this provides a summary of the current information on characteristics, scores, and definitions that are frequently different between JIA and RA patients. Despite the existence of several unresolved questions in the field, the value that MSUS adds to clinical examination in JIA has already been demonstrated, and we believe that MSUS may be included in the near future in treatment to target strategies.

Effectiveness and safety of bisphosphonates therapy in secondary osteoporosis in children.

INTRODUCTION: There are few studies on effectiveness and safety of bisphosphonate therapy in secondary osteoporosis in children. The aim of this research was to analyse effectiveness and safety of bisphosphonates in secondary osteoporosis in children. PATIENTS AND METHODS: Multicentre retrospective study in patients younger than 18 suffering from secondary osteoporosis and who have received bisphosphonates. Clinical data were recorded. Bone mineral density (BMD) was assessed in terms of BMD Z-score in lumbar spine (ZBMDls) measured by dual-energy X-ray absorptiometry (DXA). Effectiveness was valued at changes in ZBMDls one and two years after the onset of bisphosphonates and at the decrese in the number of fractures a year. Adverse events reported were recorded. Descriptive and bivariant analysis was performed. RESULTS: 32 patients were recruited. ZBMDls increased one year after the onset of treatment ((-2.46 ± 0.96) vs. (-1.54 ± 1.38); p < .001). Fractures a year dicreased significantly (1 (1-2) vs. 0 (0-0.61); p < .001). ZBMDls increase was higher in patients who were able to walk (1.88 ± 0.72 vs. 0.55 ± 0.82; p = .07) and correlated positively with body mass index (BMI)- for- age percentile (rho: 0.564; p < .001). The decrease in the number of fractures a year was higher in patients with lower initial fracture rate (rho: -0,47; p = .006) and with higher initial ZBMDls (rho: -0.47; p = .07). 10 adverse events were reported in 7 patients (22%), all of them intravenous bisphosphonates related. No association was found between adverse events and studied variables. CONCLUSIONS: Bisphosphonates are effective in secondary osteoporosis in children. Response seems to be better in patients who are able to walk, well-nourished and in the early stages of the disease. Adverse events were frequent but mild.

Targeting of the CD80/86 proinflammatory axis as a therapeutic strategy to prevent severe COVID-19.

An excessive immune response known as cytokine storm is the hallmark of severe COVID-19. The cause of this cytokine rampage is yet not known. Based on recent epidemiological evidence, we hypothesized that CD80/86 signaling is essential for this hyperinflammation, and that blocking this proinflammatory axis could be an effective therapeutic approach to protect against severe COVID-19. Here we provide exploratory evidence that abatacept, a drug that blocks CD80/86 co-stimulation, produces changes at the systemic level that are highly antagonistic of the proinflammatory processes elicited by COVID-19. Using RNA-seq from blood samples from a longitudinal cohort of n = 38 rheumatic patients treated with abatacept, we determined the immunological processes that are significantly regulated by this treatment. We then analyzed available blood RNA-seq from two COVID19 patient cohorts, a very early cohort from the epicenter of the pandemic in China (n = 3 COVID-19 cases and n = 3 controls), and a recent and larger cohort from the USA (n = 49 severe and n = 51 mild COVD-19 patients). We found a highly significant antagonism between SARS-CoV-2 infection and COVID-19 severity with the systemic response to abatacept. Analysis of previous single-cell RNA-seq data from bronchoalveolar lavage fluid from mild and severe COVID-19 patients and controls, reinforce the implication of the CD80/86 proinflammatory axis. Our functional results further support abatacept as a candidate therapeutic approach to prevent severe COVID-19.

A young girl with severe polyarteritis nodosa successfully treated with tocilizumab: a case report.

BACKGROUND: Childhood Polyarteritis nodosa (PAN) is a systemic vasculitis with necrotizing inflammation of medium- and small-sized arteries. Disease evolution may be severe and refractory to standard treatment including prednisone, azathioprine and cyclophosphamide. CASE PRESENTATION: We present the case of a young girl with severe PAN resulting in progressive ischemia and necrosis of fingers and toes. Biological work-up revealed increased acute phase reactants and interleukin-6 levels. She was only partially controlled despite high-dose corticosteroids and cyclophosphamide infusions, and eventually achieved rapid improvement and sustained remission on tocilizumab. Further, we review the current evidence of the interleukin-6-inhibitor tocilizumab for the treatment of PAN. CONCLUSION: Tocilizumab may be an efficient therapeutic option in a subset of treatment-refractory children with PAN.

Overview of STING-Associated Vasculopathy with Onset in Infancy (SAVI) Among 21 Patients.

BACKGROUND: Gain-of-function mutations in STING1 underlie a type I interferonopathy termed SAVI (STING-associated vasculopathy with onset in infancy). This severe disease is variably characterized by early-onset systemic inflammation, skin vasculopathy, and interstitial lung disease (ILD). OBJECTIVE: To describe a cohort of patients with SAVI. METHODS: Assessment of clinical, radiological and immunological data from 21 patients (17 families) was carried out. RESULTS: Patients carried heterozygous substitutions in STING1 previously described in SAVI, mainly the p.V155M. Most were symptomatic from infancy, but late onset in adulthood occurred in 1 patient. Systemic inflammation, skin vasculopathy, and ILD were observed in 19, 18, and 21 patients, respectively. Extensive tissue loss occurred in 4 patients. Severity of ILD was highly variable with insidious progression up to end-stage respiratory failure reached at teenage in 6 patients. Lung imaging revealed early fibrotic lesions. Failure to thrive was almost constant, with severe growth failure seen in 4 patients. Seven patients presented polyarthritis, and the phenotype in 1 infant mimicked a combined immunodeficiency. Extended features reminiscent of other interferonopathies were also found, including intracranial calcification, glaucoma and glomerular nephropathy. Increased expression of interferon-stimulated genes and interferon α protein was constant. Autoantibodies were frequently found, in particular rheumatoid factor. Most patients presented with a T-cell defect, with low counts of memory CD8+ cells and impaired T-cell proliferation in response to antigens. Long-term follow-up described in 8 children confirmed the clinical benefit of ruxolitinib in SAVI where the treatment was started early in the disease course, underlying the need for early diagnosis. Tolerance was reasonably good. CONCLUSION: The largest worldwide cohort of SAVI patients yet described, illustrates the core features of the disease and extends the clinical and immunological phenotype to include overlap with other monogenic interferonopathies.

Expert panel consensus recommendations for diagnosis and treatment of secondary osteoporosis in children.

BACKGROUND: Osteoporosis incidence in children is increasing due to the increased survival rate of patients suffering from chronic diseases and the increased use of drugs that can damage bones. Recent changes made to the definition of childhood osteoporosis, along with the lack of guidelines or national consensuses regarding its diagnosis and treatment, have resulted in a wide variability in the approaches used to treat this disease. For these reasons, the Osteogenesis Imperfecta and Childhood Osteoporosis Working Group of the Spanish Society of Pediatric Rheumatology has sounded the need for developing guidelines to standardize clinical practice with regard to this pathology. METHODS: An expert panel comprised of 6 pediatricians and 5 rheumatologists carried out a qualitative literature review and provided recommendations based on evidence, when that was available, or on their own experience. The level of evidence was determined for each section using the Oxford Centre for Evidence-based Medicine (CEBM) system. A Delphi survey was conducted for those recommendations with an evidence level of IV or V. This survey was sent to all members of the SERPE. All recommendations that had a level of agreement higher or equal to 70% were included. RESULTS: Fifty-one recommendations, categorized into eight sections, were obtained. Twenty-four of them presented an evidence level 4 or 5, and therefore a Delphi survey was conducted. This was submitted electronically and received a response rate of 40%. All recommendations submitted to the Delphi round obtained a level of agreement of 70% or higher and were therefore accepted. CONCLUSION: In summary, we present herein guidelines for the prevention, diagnosis and treatment of secondary childhood osteoporosis based on the available evidence and expert clinical experience. We believe it can serve as a useful tool that will contribute to the standardization of clinical practice for this pathology. Prophylactic measures, early diagnosis and a proper therapeutic approach are essential to improving bone health, not only in children and adolescents, but also in the adults they will become in the future.

Incidence of COVID-19 in a cohort of adult and paediatric patients with rheumatic diseases treated with targeted biologic and synthetic disease-modifying anti-rheumatic drugs.

Objectives: To investigate the incidence of COVID-19 in a cohort of adult and paediatric patients with rheumatic diseases receiving targeted biologic and synthetic disease modifying anti-rheumatic drugs (tDMARDs) and to explore the possible effect of these treatments in the clinical expression of COVID-19. Methods: A cross-sectional study comprising of a telephone survey and electronic health records review was performed including all adult and paediatric patients with rheumatic diseases treated with tDMARDs in a large rheumatology tertiary centre in Barcelona, Spain. Demographics, disease activity, COVID-19 related symptoms and contact history data were obtained from the start of the 2020 pandemic. Cumulative incidence of confirmed cases (SARS-CoV-2 positive PCR test) was compared to the population estimates for the same city districts from a governmental COVID-19 health database. Suspected cases were defined following WHO criteria and compared to those without compatible symptoms. Results: 959 patients with rheumatic diseases treated with tDMARDs were included. We identified 11 confirmed SARS-CoV-2 positive cases in the adult cohort and no confirmed positive cases in the paediatric cohort. COVID-19 incidence rates of the rheumatic patient cohort were very similar to that of the general population [(0.48% (95% CI 0.09 to 0.87%)] and [0.58% (95% CI 0.56 to 0.60%)], respectively. We found significant differences in tDMARDs proportions between the suspected and non-suspected cases (p=0.002). Conclusion: Adult and paediatric patients with rheumatic diseases on tDMARDs do not seem to present a higher risk of COVID-19 or a more severe disease outcome when compared to general population.

A Combined Transcriptomic and Genomic Analysis Identifies a Gene Signature Associated With the Response to Anti-TNF Therapy in Rheumatoid Arthritis.

Background: Rheumatoid arthritis (RA) is the most frequent autoimmune disease involving the joints. Although anti-TNF therapies have proven effective in the management of RA, approximately one third of patients do not show a significant clinical response. The objective of this study was to identify new genetic variation associated with the clinical response to anti-TNF therapy in RA. Methods: We performed a sequential multi-omic analysis integrating different sources of molecular information. First, we extracted the RNA from synovial biopsies of 11 RA patients starting anti-TNF therapy to identify gene coexpression modules (GCMs) in the RA synovium. Second, we analyzed the transcriptomic association between each GCM and the clinical response to anti-TNF therapy. The clinical response was determined at week 14 using the EULAR criteria. Third, we analyzed the association between the GCMs and anti-TNF response at the genetic level. For this objective, we used genome-wide data from a cohort of 348 anti-TNF treated patients from Spain. The GCMs that were significantly associated with the anti-TNF response were then tested for validation in an independent cohort of 2,706 anti-TNF treated patients. Finally, the functional implication of the validated GCMs was evaluated via pathway and cell type epigenetic enrichment analyses. Results: A total of 149 GCMs were identified in the RA synovium. From these, 13 GCMs were found to be significantly associated with anti-TNF response (P < 0.05). At the genetic level, we detected two of the 13 GCMs to be significantly associated with the response to adalimumab (P = 0.0015) and infliximab (P = 0.021) in the Spain cohort. Using the independent cohort of RA patients, we replicated the association of the GCM associated with the response to adalimumab (P = 0.0019). The validated module was found to be significantly enriched for genes involved in the nucleotide metabolism (P = 2.41e-5) and epigenetic marks from immune cells, including CD4+ regulatory T cells (P = 0.041). Conclusions: These findings show the existence of a drug-specific genetic basis for anti-TNF response, thereby supporting treatment stratification in the search for response biomarkers in RA.

Abatacept in patients with rheumatoid arthritis and interstitial lung disease: A national multicenter study of 63 patients.

OBJECTIVE: Interstitial lung disease (ILD) is one of the most serious complications of rheumatoid arthritis (RA). In the present study, we aimed to assess the efficacy of abatacept (ABA) in patients with ILD associated to RA. METHODS: National multicenter, non-controlled, open-label registry study of RA patients with ILD treated with ABA. RESULTS: 63 patients (36 women) with RA-associated ILD undergoing ABA therapy were studied. The mean ± standard deviation age at the time of the study was 63.2 ± 9.8 years. The median duration of RA and ILD from diagnosis were 6.8 and 1 year, respectively. RA was seropositive in 55 patients (87.3%). In 15 (23.8%) of 63 patients the development of ILD was closely related to the administration of synthetic or biologic disease modifying anti-rheumatic drugs. After a follow-up of 9.4 ± 3.2 months, two-thirds of patients remained stable whereas one-quarter experienced improvement in the Modified Medical Research Council scale. At that time forced vital capacity remained stable in almost two-thirds of patents and improved in one out of five patients assessed. Also, diffusing capacity of the lung for carbon monoxide remained stable in almost two-thirds and showed improvement in a quarter of the patients assessed. At 12 months, 50% of the 22 patients in whom chest HRCT scan was performed due persistence of respiratory symptoms showed stabilization, 8 (36.4%) improvement and 3 worsening of the HRCT scan pattern. Eleven of 63 patients had to discontinue ABA, mainly due to adverse events. CONCLUSION: ABA appears to be an effective in RA-associated ILD.

Genome-wide pathway analysis identifies VEGF pathway association with oral ulceration in systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is a genetically complex rheumatic disease characterized by heterogeneous clinical manifestations of unknown etiology. Recent studies have suggested the existence of a genetic basis for SLE heterogeneity. The objective of the present study was to identify new genetic variation associated with the clinically relevant phenotypes in SLE. METHODS: A two-stage pathway-based approach was used to identify the genetic variation associated with the main clinical phenotypes in SLE. In the discovery stage, 482 SLE patients were genotyped using Illumina Human Quad610 microarrays. Association between 798 reference genetic pathways from the Molecular Signatures Database and 11 SLE phenotypes was tested using the set-based method implemented in PLINK software. Pathways significantly associated after multiple test correction were subsequently tested for replication in an independent cohort of 425 SLE patients. Using an in silico approach, we analyzed the functional effects of common SLE therapies on the replicated genetic pathways. The association of known SLE risk variants with the development of the clinical phenotypes was also analyzed. RESULTS: In the discovery stage, we found a significant association between the vascular endothelial growth factor (VEGF) pathway and oral ulceration (P value for false discovery rate (P FDR) < 0.05), and between the negative regulation signaling pathway of retinoic acid inducible gene-I/melanoma differentiation associated gene 5 and the production of antinuclear antibodies (P FDR < 0.05). In the replication stage, we validated the association between the VEGF pathway and oral ulceration. Therapies commonly used to treat mucocutaneous phenotypes in SLE were found to strongly influence VEGF pathway gene expression (P = 4.60e-4 to 5.38e-14). Analysis of known SLE risk loci identified a strong association between PTPN22 and the risk of hematologic disorder and with the development of antinuclear antibodies. CONCLUSIONS: The present study has identified VEGF genetic pathway association with the risk of oral ulceration in SLE. New therapies targeting the VEGF pathway could be more effective in reducing the severity of this phenotype. These findings represent a first step towards the understanding of the genetic basis of phenotype heterogeneity in SLE.