Pathogenesis of systemic sclerosis associated interstitial lung disease

Systemic sclerosis is an autoimmune disease leading to vasculopathy and fibrosis of skin and internal organs. Despite likely shared pathogenic mechanisms, the patterns of skin and lung fibrosis differ. Pathogenesis of interstitial lung disease, a major cause of death in systemic sclerosis, reflects the intrinsic disease pathobiology and is associated with distinct clinical phenotypes and laboratory characteristics. The commonest histological pattern of systemic sclerosis–interstitial lung disease is non-specific interstitial pneumonia. Systemic sclerosis–interstitial lung disease pathogenesis involves multiple components, including susceptibility and triggering factors, which could be genetic or environmental. The process is amplified likely through ongoing inflammation and the link between inflammatory activity and fibrosis with IL6 emerging as a key mediator. The disease is driven by epithelial injury, reflected by markers in the serum, such as surfactant proteins and KL-6. In addition, mediators that are produced by epithelial cells and that regulate inflammatory cell trafficking may be important, especially CCL2. Other factors, such as CXCL4 and CCL18, point towards immune-mediated damage or injury response. Monocytes and alternatively activated macrophages appear to be important. Transforming growth factor beta appears central to pathogenesis and regulates epithelial repair and fibroblast activation. Understanding pathogenesis may help to unravel the stages of systemic sclerosis–interstitial lung disease, risks of progression and determinants of outcome. With this article, we set out to review the multiple factors, including genetic, environmental, cellular and molecular, that may be involved in the pathogenesis of systemic sclerosis–interstitial lung disease and the mechanisms leading to sustained fibrosis. We propose a model for the pathogenesis of systemic sclerosis–interstitial lung disease, based on the available literature

Comparing paediatric- and adult-onset linear morphoea in a large tertiary-referral scleroderma centre

Background: Linear morphoea is a severe morphoea subtype associated with extracutaneous manifestations, potentially permanent disfigurement and functional impairment. Linear morphoea is more prevalent in paediatric patients, and knowledge of disease in adults is limited. The objective of this study was to compare paediatric- and adult-onset linear morphoea, in an exclusively adult population. / Methodology: This was a retrospective cohort study of adult patients with linear morphoea seen over a 3-year period at a single-site adult tertiary-referral Connective Tissue Disease centre. Clinical markers of disease severity and course, including anatomical distribution, extracutaneous manifestations, cutaneous symptoms, associated autoimmunity, inflammatory blood parameters, Dermatology Life Quality Index scores, treatment requirements and modified Localised Scleroderma Activity Tool were assessed and compared in paediatric- and adult-onset linear morphoea. / Results: Of 298 patients with morphoea seen during the study period, 135 had linear morphoea and 133 were included in the study. Most were female (78.9%), the mean age was 36.5 years and almost half (43.6%) had adult-onset disease. Disease was similarly severe between groups with regard to anatomical distribution, cutaneous symptoms (n = 89, 66.9%), extracutaneous manifestations (n = 76, 57.1%), antinuclear antibody–positivity (n = 40, 40.4%), raised erythrocyte sedimentation rate (n = 27, 25.0%) and associated autoimmune diagnoses (n = 15, 11.3%). Prescribed treatments were similar between groups; 73.7% receiving methotrexate and almost one-third (32.3%) requiring more than one steroid-sparing agent. Those with paediatric-onset had more disease-related damage, with a mean modified Localised Scleroderma Skin Damage Index score of 19.5 (95% confidence interval: 17.0–22.0) versus 8.1 (95% confidence interval: 4.4–11.8; p < 0.001). Significantly more patients with adult-onset linear morphoea had quiescent disease (p = 0.0332), and even after correcting for disease duration, paediatric-onset patients still had 2.6 times greater odds of active disease (odds ratio = 2.59, 95% confidence interval: 0.9–7.6; p = 0.083). / Conclusion: Linear morphoea in adults can be a severe disease with extracutaneous, autoimmune and systemic features. Adults with paediatric-onset disease appear to have more severe cumulative damage, greater functional impairment and ongoing disease activity. This patient subgroup may require particularly close monitoring and more aggressive therapy

Sustained benefit from intravenous immunoglobulin therapy for gastrointestinal involvement in systemic sclerosis

Objective. IVIG is known to confer significant benefit in rheumatologic conditions, including inflammatory myopathy. This study aimed to assess the efficacy of IVIG across different aspects of internal organ involvement in refractory active SSc, particularly the gastrointestinal (GI) system. / Methods. SSc patients with overlap polymyositis who remained active and unresponsive to conventional disease-modifying agents and who subsequently received IVIG were identified. GI symptoms were assessed using validated questionnaires. The Medical Research Council Sum Score for muscle strength and modified Rodnan skin score (mRSS) were assessed. Serial measurements were undertaken at baseline prior to the first IVIG treatment and post-treatment in the most recent assessment. / Results. Fifteen SSc patients were consecutively recruited into this observational study. The mean duration of IVIG treatment was 2.3 years, with treatment frequency ranging from every 6 weeks to 4 months. Compared with baseline, there was a significant reduction in gastro-oesophageal reflux frequency and intensity mean scores (P = 0.006 and P = 0.013, respectively). Significant improvement in the Gastrointestinal Tract (GIT) 2.0 score from a baseline mean score of 1.07 (s.d. 0.67) to 0.60 (0.46) (P = 0.002) was observed. There was regression in the markers of muscle disease with a reduction in the mean (s.d.) Medical Research Council sum score and the median creatine kinase level (P = 0.001 and P = 0.025, respectively). Significant amelioration of the mean basal modified Rodnan skin score from 21.5 (s.d. 13.8) to 10 (10.6) (P = 0.005) was observed. / Conclusion. IVIG may be a helpful adjunctive therapy in the amelioration of some key clinical aspects in refractory SSc. Sustained benefit from IVIG suggests a specific immunomodulatory effect on those with established SSc GI complications

Autoantibody predictors of gastrointestinal symptoms in systemic sclerosis

Objectives: To assess the prevalence and burden of SSc-related gastrointestinal dysfunction (SSc-GI) and to evaluate associations with demographic, clinical and serological characteristics. // Methods: Patients completed the UCLA SCTC GIT 2.0 questionnaire for SSc-GI disease to assess the burden of GI disease across multiple functional and psychological domains. Questionnaire scores were assessed using non-parametric and quantile regression analyses. // Results: Our cohort included 526 patients with SSc, with a typical distribution of disease-associated autoantibodies (ACA, ARA, ATA, PM-Scl, U1RNP, U3RNP). We demonstrated associations between hallmark antibodies and the domain-specific burden of GI disease. In particular, ACA, ARA and ENA-negative demonstrated increased SSc-GI disease burden, while PM-Scl conferred relative protection. In a distributional analysis, associations with autoantibodies were particularly marked in those with the highest burden of GI disease. // Conclusion: There is a significant burden of SSc-GI disease in patients with SSc; reflux and bloating symptoms are most prominent. SSc hallmark antibodies may predict increased risk of SSc-GI disease, in particular ACA and ARA, while PM-Scl may be protective

Outcomes linked to eligibility for stem cell transplantation trials in diffuse cutaneous systemic sclerosis

Objectives: The aim of this study was to explore outcomes in a cohort of diffuse cutaneous systemic sclerosis (dcSSc) patients fulfilling eligibility criteria for stem cell transplantation (SCT) studies but receiving standard immunosuppression. Methods: From a large single-centre dcSSc cohort (n = 636), patients were identified using the published SCT trials’ inclusion criteria. Patients meeting the trials’ exclusion criteria were excluded. Results: Of the 227 eligible patients, 214 met the inclusion criteria for ASTIS, 82 for SCOT and 185 for the UPSIDE trial, and 66 were excluded based on age > 65 years, low DLco, pulmonary hypertension or creatinine clearance <40ml/min. The mean follow-up time was 12 years (SD 7). Among the eligible patients, 103 (45.4%) died. Survival was 96% at 2-, 88% at 5-, 73% at 10- and 43% at 20 years. Compared with this ‘SCT-eligible’ cohort, those patients who would have been excluded from SCT trials had a worse long-term survival (97% at 2-, 77% at 5-, 52% at 10- and 15% at 20 years, log rank p< 0.001). Excluded patients also had a significantly worse long-term event free survival. Hazard of death was higher in patients with higher age at onset (HR 1.05, p< 0.001), higher ESR at baseline (HR 1.01, p= 0.025) and males (HR 2.12, p= 0.008). Conclusion: SCT inclusion criteria identify patients with poor outcome despite current best practice treatment. Patients meeting the inclusion criteria for SCT but who would have been excluded from the trials because of age, pulmonary hypertension, poor kidney function or DLco <40%, had worse outcomes

Using autoantibodies and cutaneous subset to develop outcome-based disease classification in systemic sclerosis

OBJECTIVE: To describe the associations between autoantibodies, presentation and outcome among systemic sclerosis (SSc) patients. We propose a new SSc classification incorporating antibodies and cutaneous subset. METHODS: Survival analysis was used to assess the effect of antibodies on organ disease and death. RESULTS: The study included 1325 subjects. The ACA+ limited cutaneous (lc)SSc group (n=374) had the highest 20-year survival (65.3%), lowest incidence of clinically-significant pulmonary fibrosis (csPF, 8.5%) and scleroderma renal crisis (SRC, 0.3%), low cardiac SSc incidence (4.9%), while pulmonary hypertension (PH) frequency was similar to the cohort average. The anti-Scl70+ lcSSc (n=138) and diffuse cutaneous (dc)SSc groups (n=149) had the highest csPF incidence (86.1% and 84% at 15 years). The dcSSc group had the lowest survival (32.4%) and the second highest incidence of cardiac SSc (12.9%) at 20 years, while in the lcSSc group other complications were rare, demonstrating the lowest incidence of PH (6.9%) and second highest survival (61.8%). The anti-RNA polymerase+ group (n=147) had the highest incidence of SRC (28.1%). The anti-U3RNP+ group (n=56) had the highest PH (33.8%) and cardiac SSc incidence (13.2%). Among lcSSc patients with other autoantibodies (n=295), risk of SRC and cardiac SSc was low, while other outcomes were similar to the cohort average. DcSSc patients with other antibodies (n=166) had poor prognosis, with the second lowest survival (33.6%) and frequent organ complications. CONCLUSION: We highlight the importance of autoantibodies, cutaneous subset and disease duration when assessing SSc morbidity and mortality. Our classification may benefit disease monitoring and clinical trial design

Derivation and External Validation of a Prediction Rule for Five-Year Mortality in Patients With Early Diffuse Cutaneous Systemic Sclerosis

OBJECTIVE: Although diffuse cutaneous systemic sclerosis (dcSSc) is associated with a reduction in life expectancy, there are no validated prognostic models for determining 5-year mortality in patients with dcSSc. The objective of this study was to derive and validate a rule for predicting 5-year mortality in patients with early dcSSc. METHODS: We studied an inception cohort of 388 US Caucasian patients with early dcSSc (<2 years from the appearance of the first symptom). Predefined baseline variables were analyzed in a stepwise logistic regression model in order to identify factors independently associated with 5-year all-cause mortality. We rounded the beta weights to the nearest integer and summed the points assigned to each variable in order to stratify patients into low-risk (<0 points), moderate-risk (1-2 points), and high-risk (≥3 points) groups. We then applied this rule to an external validation cohort of 144 Caucasian patients with early dcSSc from the Royal Free Hospital cohort and compared stratum-specific 5-year mortality. RESULTS: Six independent predictors (rounded beta weight) comprised the model: age at first visit (points allotted: -1, 0, or 1), male sex (points allotted: 0 or 1), tendon friction rubs (points allotted: 0 or 1), gastrointestinal involvement (points allotted: 0 or 1), RNA polymerase III antibodies (points allotted: 0 or 1), and anemia (points allotted: 0 or 1). The 3-level risk stratification model performed well, with no significant differences between the US derivation cohort and the UK validation cohort. CONCLUSION: We derived and externally validated, in US and UK cohorts, an easy-to-use 6-variable prediction rule that assigns low-risk, moderate-risk, and high-risk categories for 5-year mortality in patients with early dcSSc. Only history, physical examination, and basic laboratory assessments are required