Ariane L. Herrick

2013 Classification Criteria for Systemic Sclerosis: An American College of Rheumatology/European League Against Rheumatism Collaborative Initiative

OBJECTIVE The 1980 American College of Rheumatology (ACR) classification criteria for systemic sclerosis (SSc) lack sensitivity for early SSc and limited cutaneous SSc. The present work, by a joint committee of the ACR and the European League Against Rheumatism (EULAR), was undertaken for the purpose of developing new classification criteria for SSc. METHODS Using consensus methods, 23 candidate items were arranged in a multicriteria additive point system with a threshold to classify cases as SSc. The classification system was reduced by clustering items and simplifying weights. The system was tested by 1) determining specificity and sensitivity in SSc cases and controls with scleroderma-like disorders, and 2) validating against the combined view of a group of experts on a set of cases with or without SSc. RESULTS It was determined that skin thickening of the fingers extending proximal to the metacarpophalangeal joints is sufficient for the patient to be classified as having SSc; if that is not present, 7 additive items apply, with varying weights for each: skin thickening of the fingers, fingertip lesions, telangiectasia, abnormal nailfold capillaries, interstitial lung disease or pulmonary arterial hypertension, Raynauds phenomenon, and SSc-related autoantibodies. Sensitivity and specificity in the validation sample were, respectively, 0.91 and 0.92 for the new classification criteria and 0.75 and 0.72 for the 1980 ACR classification criteria. All selected cases were classified in accordance with consensus-based expert opinion. All cases classified as SSc according to the 1980 ACR criteria were classified as SSc with the new criteria, and several additional cases were now considered to be SSc. CONCLUSION The ACR/EULAR classification criteria for SSc performed better than the 1980 ACR criteria for SSc and should allow for more patients to be classified correctly as having the disease.

2013 classification criteria for systemic sclerosis: an American college of rheumatology/European league against rheumatism collaborative initiative

Objective The 1980 American College of Rheumatology (ACR) classification criteria for systemic sclerosis (SSc) lack sensitivity for early SSc and limited cutaneous SSc. The present work, by a joint committee of the ACR and the European League Against Rheumatism (EULAR), was undertaken for the purpose of developing new classification criteria for SSc. Methods Using consensus methods, 23 candidate items were arranged in a multicriteria additive point system with a threshold to classify cases as SSc. The classification system was reduced by clustering items and simplifying weights. The system was tested by (1) determining specificity and sensitivity in SSc cases and controls with scleroderma-like disorders, and (2) validating against the combined view of a group of experts on a set of cases with or without SSc. Results It was determined that skin thickening of the fingers extending proximal to the metacarpophalangeal joints is sufficient for the patient to be classified as having SSc; if that is not present, seven additive items apply, with varying weights for each: skin thickening of the fingers, fingertip lesions, telangiectasia, abnormal nailfold capillaries, interstitial lung disease or pulmonary arterial hypertension, Raynauds phenomenon, and SSc-related autoantibodies. Sensitivity and specificity in the validation sample were, respectively, 0.91 and 0.92 for the new classification criteria and 0.75 and 0.72 for the 1980 ACR classification criteria. All selected cases were classified in accordance with consensus-based expert opinion. All cases classified as SSc according to the 1980 ACR criteria were classified as SSc with the new criteria, and several additional cases were now considered to be SSc. Conclusions The ACR/EULAR classification criteria for SSc performed better than the 1980 ACR criteria for SSc and should allow for more patients to be classified correctly as having the disease.

Genome-wide association study of systemic sclerosis identifies CD247 as a new susceptibility locus

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs that leads to profound disability and premature death. To identify new SSc susceptibility loci, we conducted the first genome-wide association study in a population of European ancestry including a total of 2,296 individuals with SSc and 5,171 controls. Analysis of 279,621 autosomal SNPs followed by replication testing in an independent case-control set of European ancestry (2,753 individuals with SSc (cases) and 4,569 controls) identified a new susceptibility locus for systemic sclerosis at CD247 (1q22–23, rs2056626, P = 2.09 × 10−7 in the discovery samples, P = 3.39 × 10−9 in the combined analysis). Additionally, we confirm and firmly establish the role of the MHC (P = 2.31 × 10−18), IRF5 (P = 1.86 × 10−13) and STAT4 (P = 3.37 × 10−9) gene regions as SSc genetic risk factors.

Identification of novel genetic markers associated with clinical phenotypes of systemic sclerosis through a genome-wide association strategy

The aim of this study was to determine, through a genome-wide association study (GWAS), the genetic components contributing to different clinical sub-phenotypes of systemic sclerosis (SSc). We considered limited (lcSSc) and diffuse (dcSSc) cutaneous involvement, and the relationships with presence of the SSc-specific auto-antibodies, anti-centromere (ACA), and anti-topoisomerase I (ATA). Four GWAS cohorts, comprising 2,296 SSc patients and 5,171 healthy controls, were meta-analyzed looking for associations in the selected subgroups. Eighteen polymorphisms were further tested in nine independent cohorts comprising an additional 3,175 SSc patients and 4,971 controls. Conditional analysis for associated SNPs in the HLA region was performed to explore their independent association in antibody subgroups. Overall analysis showed that non-HLA polymorphism rs11642873 in IRF8 gene to be associated at GWAS level with lcSSc (P = 2.32×10−12, OR = 0.75). Also, rs12540874 in GRB10 gene (P = 1.27 × 10−6, OR = 1.15) and rs11047102 in SOX5 gene (P = 1.39×10−7, OR = 1.36) showed a suggestive association with lcSSc and ACA subgroups respectively. In the HLA region, we observed highly associated allelic combinations in the HLA-DQB1 locus with ACA (P = 1.79×10−61, OR = 2.48), in the HLA-DPA1/B1 loci with ATA (P = 4.57×10−76, OR = 8.84), and in NOTCH4 with ACA P = 8.84×10−21, OR = 0.55) and ATA (P = 1.14×10−8, OR = 0.54). We have identified three new non-HLA genes (IRF8, GRB10, and SOX5) associated with SSc clinical and auto-antibody subgroups. Within the HLA region, HLA-DQB1, HLA-DPA1/B1, and NOTCH4 associations with SSc are likely confined to specific auto-antibodies. These data emphasize the differential genetic components of subphenotypes of SSc.

The pathogenesis, diagnosis and treatment of Raynaud phenomenon

The past 10 years have seen the publication of results from several multicentre clinical trials in primary and systemic sclerosis (SSc)-related Raynaud phenomenon. The publication of these studies has occurred as a result of new insights into the pathogenesis of Raynaud phenomenon, which are directing new treatment approaches, and increased international collaboration between clinicians and scientists. Although the pathogenesis of Raynaud phenomenon is complex, abnormalities of the blood vessel wall, of neural control mechanisms and of intravascular (circulating) factors are known to interact and contribute. Key players relevant in drug development include nitric oxide, endothelin-1, alpha adrenergic receptor activation, abnormal signal transduction in vascular smooth muscle, oxidative stress and platelet activation. The main advances in diagnosis have been a clearer understanding of autoantibodies and of abnormal nailfold capillary patterns as independent predictors of SSc, and widespread use and increased availability of capillaroscopy. The ultimate aim is to translate the advances made in the pathophysiology and early diagnosis into development of treatments to prevent and reverse digital vascular dysfunction and injury. This Review provides an update of the pathogenesis, diagnosis and treatment of Raynaud phenomenon. Current and future treatment approaches are discussed, and some key unanswered questions are highlighted.

Vascular function in systemic sclerosis.

Raynaud phenomenon is often the earliest manifestation of systemic sclerosis. This fact highlights the role of vascular dysfunction early on in the disease process. Although this review deals primarily with digital vasculature, recent research confirms that vascular dysfunction is widespread, and affects large as well as small vessels. Abnormalities of vascular function and structure are interdependent, and together result in the ischemic atrophy so characteristic of SSc. Key areas of research include the pathophysiology of the imbalance between vasodilation and vasoconstriction, with particular interest in understanding the relative contributions of endothelial-dependent and endothelial-independent vasodilation, and the development of new methodologies by which to quantify vascular function.

Quantifying digital vascular disease in patients with primary Raynaud’s phenomenon and systemic sclerosis

In primary and secondary Raynaud’s phenomenon, measurement of activity or severity, or both, of the digital vascular disease is a major challenge. We need to identify objective measures of digital vascular disease that are helpful in predicting those patients with Raynaud’s who have underlying connective tissue disease, and to measure reliably digital vascular disease progression, and responses to treatment. None of the various physiological measurement techniques used in the assessment of patients with primary or secondary Raynaud’s are ideal. In this review we outline these techniques, highlighting their applications and limitations. The discussion concentrates on the physiological assessment of patients with primary Raynaud’s phenomenon (PRP) and systemic sclerosis (SSc), but is also applicable to other connective tissue diseases. We have not included biochemical markers of vascular injury or measurement of tissue oxygen levels. In PRP, episodic ischaemia in response to cold exposure or to emotional stimuli is entirely reversible: absence of tissue damage is a defining feature.1 In contrast, SSc may be associated with irreversible tissue damage with ulceration, scarring and sometimes gangrene, and structural change occurs in the vasculature.2 3 Indeed, SSc is probably primarily a disease of the vasculature, although it is not clear how this interrelates with collagen and other connective tissue matrix metabolism.4 5 Assessment of digital vascular disease needs to take into account: (a) Digital vasospasm. This is best assessed by dynamic testing with standard stimuli, such as a standard cold stress. (b) Structural vascular disease. This may affect basal blood flow in addition to vascular responses to standard stimuli. In the patient presenting with Raynaud’s phenomenon, we must assess both the microvasculature and the digital arteries. Different physiological measurement techniques may be used in combination, especially if investigators wish to examine both digital artery and microvascular flow.6 On widefield capillaroscopy, …

Immunochip Analysis Identifies Multiple Susceptibility Loci for Systemic Sclerosis

In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci.

Endothelial expression of nitric oxide synthases and nitrotyrosine in systemic sclerosis skin.

Although a multisystem disease, systemic sclerosis (SSc) most commonly affects the skin. The skin lesion is characterized by progressive changes, chief amongst which are vascular abnormalities, including endothelial cell (EC) injury and death, and dermal fibrosis. The pathogenesis of the vascular changes, and their relationship to dermal fibrosis, is poorly understood. The purpose of this study was to examine the potential role of nitric oxide (NO)‐related free radical production, as part of an assessment of mechanisms leading to endothelial damage. Histologically graded skin biopsies from 33 patients with SSc (ten grade 0, ten grade 1, eight grade 2, and five grade 3) and eight healthy controls were reacted with antibodies against constitutive (eNOS) and inducible (iNOS) forms of nitric oxide synthase and nitrotyrosine. The degree of staining was assessed using a semi‐quantitative system and a staining score was developed for the ECs of different vessel types in different areas of dermis at all grades. In biopsies from patients with SSc, superficial microvessel ECs showed a peak of eNOS expression in grade 1 skin which fell as the grade increased. By contrast, iNOS staining increased with the grade of skin lesion, a pattern paralleled by endothelial nitrotyrosine expression. From these findings, it is concluded that a metabolic switch occurs in dermal ECs from endothelial to cytokine inducible forms of NOS during the progression of the skin lesion of SSc. iNOS is a potent inducer of NO production which, in turn, can mediate NO free radical production. At a time of development of the SSc skin lesion when previous studies report evidence of EC damage, the cells express immunodetectable nitrotyrosine, a marker of NO‐mediated free radical injury. The data suggest a role for iNOS‐induced NO production in EC damage in SSc. Copyright

Noninvasive imaging techniques in the assessment of scleroderma spectrum disorders

OBJECTIVE Systemic sclerosis (SSc) affects both microvascular structure and function. Laser Doppler imaging (LDI) and thermal imaging can be used to measure cutaneous blood vessel function. Nailfold capillaroscopy (NC) measures capillary morphology. The aim of this study was to investigate the relationship between capillary morphology and blood flow, and to determine which combination of techniques allows the best discrimination between patients with SSc, primary Raynauds phenomenon (RP), and healthy controls. METHODS NC was performed in 16 patients with SSc, 14 patients with primary RP, and 16 healthy controls. In addition, participants underwent cold stimulus with cold water. Hands were imaged to monitor rewarming and reperfusion. Nailfold morphologic features were measured and baseline images and rewarming curves were analyzed. RESULTS Significant differences were found between groups (analysis of variance) for capillary morphologic features and rewarming curve characteristics. A correlation (P < 0.001) was found between LDI and thermal imaging at baseline (0.667) and maximum (0.729) blood flow and skin temperature, and for the areas under the rewarming curves (0.684). Receiver operating characteristic curves indicated that NC, thermal imaging, and LDI allowed 89%, 74%, and 72%, respectively, of SSc patient data to be correctly classified versus primary RP patients and controls. CONCLUSION NC, LDI, and thermal imaging each independently provide good discrimination between patients with SSc and those with primary RP and healthy controls (NC being the most suitable technique for classifying patient groups). However, a combination of all 3 techniques improves classification. LDI and thermal imaging give equivalent information on dynamic changes in the cutaneous microcirculation; however, these only weakly correspond to capillary morphology.