Racial Disparities in Systemic Sclerosis: Short- and Long-Term Outcomes Among African American Participants of SLS I and II

Racial variability in immune responses only partially explains differential systemic sclerosis disease severity

OBJECTIVE

To understand if autoantibodies account for racial variation in disease severity, we compared autoantibody distribution and associated phenotype between self-identified black and white systemic sclerosis (SSc) patients.

METHODS

803 black and 2178 white SSc patients had systematic testing for autoantibodies using Euroimmun (centromere (ACA), RNA-polymerase III (POLR3), Scl70, PM/Scl, NOR90, Th/To, Ku, U3RNP and Ro52) and commercial ELISA (U1RNP). In this observational study, logistic regression was performed to assess the association between self-identified race and outcomes, adjusting for autoantibodies. To estimate whether the effect of race was mediated by autoantibody status, race coefficients from multivariate models including and excluding autoantibodies were compared.

RESULTS

Anti-Scl70, anti-U1RNP, anti-U3RNP, anti-Th/To, anti-Ku and anti-NOR90 were more common in the black cohort than in the white cohort, which was enriched for ACA, anti-POLR3 and anti-PM/Scl. Black individuals had a higher prevalence of severe Raynaud's, skin, lung, gastrointestinal and renal disease whereas white individuals had a higher prevalence of severe heart and muscle disease. Adjusting for autoantibodies decreased the effect of race on outcome for telangiectasias, forced vital capacity <70%, pulmonary hypertension and severe lung, heart, muscle and gastrointestinal disease by 11%-44% and increased the association between race and renal crisis and severe kidney disease by 37%-52%.

CONCLUSIONS

This study is the largest systematic analysis of autoantibody responses in a geographically diverse population of black SSc patients. Black and white individuals with SSc have distinct autoantibody profiles. Autoantibodies explain only a fraction of the effect of race on clinical outcomes, suggesting other factors contribute to disparate outcomes between these groups.

The Impact of Progressive Pulmonary Fibrosis in Systemic Sclerosis-Associated Interstitial Lung Disease

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by immune dysregulation and progressive fibrosis, typically affecting the skin, with variable internal organ involvement. Interstitial lung disease (ILD), with a prevalence between 35 and 75%, is the leading cause of death in patients with SSc, indicating that all newly diagnosed patients should be screened for this complication. Some patients with SSc-ILD experience a progressive phenotype, which is characterized by worsening fibrosis on high-resolution computed tomography (HRCT), a decline in lung function, and premature mortality. To assess progression and guide therapeutic decisions, regular monitoring is essential and should include pulmonary function testing (PFT), symptom assessment, and repeat HRCT imaging when indicated. Multidisciplinary discussion allows a comprehensive evaluation of the available information and its consequences for management. There has been a shift in the approach to managing SSc-ILD, which includes the addition of targeted biologic and antifibrotic therapies to standard immunosuppressive therapy (particularly mycophenolate mofetil or cyclophosphamide), with autologous hematopoietic stem-cell transplantation and lung transplantation reserved for refractory cases.

[Characteristics of patients with systemic sclerosis who develop interstitial lung disease]

Background

Systemic sclerosis associated-interstitial lung disease (SSc-ILD) show a high mortality. The factors associated SSc-ILD have shown variability in different populations. There are few studies in Mexican mestizos.

Objective

To analyze the epidemiological, clinical and paraclinical factors associated with SSc-ILD.

Material and methods

Cross-sectional study, where patients > 18 years of age with a diagnosis of SSc according to EULAR/ACR 2013 criteria and diagnosis of ILD by forced vital capacity (FVC) < 70% and > 5% of affected lung area on tomography were included. The strength of association of the factors for ILD was measured by odds ratio (OR) with 95% confidence intervals (95% CI). The significant variables were analyzed by multiple logistic regression with adjustment.

Results

Of the 80 patients with SSc, 38 (47.5%) had ILD. Risk factors such as smoking, higher activity index, lower FVC, anti-topoisomerase I antibodies, and protective factors such as a limited SSc, early capillaroscopic pattern, and anti-centromere antibodies (ACA) were associated with ILD. In the multivariate analysis, a higher activity index with OR 4.17, (95% CI 2.01-8.65) persisted as a risk factor, while ACA with OR 0.17, (95% CI 0.03-0.85) persisted as a protective factor associated with SSc-ILD.

Conclusions

A higher index of activity and ACA persisted as factors associated with SSc-ILD.

Combining Clinical and Biological Data to Predict Progressive Pulmonary Fibrosis in Patients With Systemic Sclerosis Despite Immunomodulatory Therapy

OBJECTIVE

Progressive pulmonary fibrosis (PPF) is the leading cause of death in systemic sclerosis (SSc). This study aimed to develop a clinical prediction nomogram using clinical and biological data to assess risk of PPF among patients receiving treatment of SSc-related interstitial lung disease (SSc-ILD).

METHODS

Patients with SSc-ILD who participated in the Scleroderma Lung Study II (SLS II) were randomized to treatment with either mycophenolate mofetil (MMF) or cyclophosphamide (CYC). Clinical and biological parameters were analyzed using univariable and multivariable logistic regression, and a nomogram was created to assess the risk of PPF and validated by bootstrap resampling.

RESULTS

Among 112 participants with follow-up data, 22 (19.6%) met criteria for PPF between 12 and 24 months. An equal proportion of patients randomized to CYC (n = 11 of 56) and mycophenolate mofetil (n = 11 of 56) developed PPF. The baseline severity of ILD was similar for patients who did, compared to those who did not, experience PPF in terms of their baseline forced vital capacity percent predicted, diffusing capacity for carbon monoxide percent predicted, and quantitative radiological extent of ILD. Predictors in the nomogram included sex, baseline CXCL4 level, and baseline gastrointestinal reflux score. The nomogram demonstrated moderate discrimination in estimating the risk of PPF, with a C-index of 0.72 (95% confidence interval 0.60-0.84).

CONCLUSION

The SLS II data set provided a unique opportunity to investigate predictors of PPF and develop a nomogram to help clinicians identify patients with SSc-ILD who require closer monitoring while on therapy and potentially an alternative treatment approach. This nomogram warrants external validation in other SSc-ILD cohorts to confirm its predictive power.

Distinct genome-wide DNA methylation and gene expression signatures in classical monocytes from African American patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a multisystem autoimmune disorder that has an unclear etiology and disproportionately affects women and African Americans. Despite this, African Americans are dramatically underrepresented in SSc research. Additionally, monocytes show heightened activation in SSc and in African Americans relative to European Americans. In this study, we sought to investigate DNA methylation and gene expression patterns in classical monocytes in a health disparity population.

METHODS

Classical monocytes (CD14+ + CD16-) were FACS-isolated from 34 self-reported African American women. Samples from 12 SSc patients and 12 healthy controls were hybridized on MethylationEPIC BeadChip array, while RNA-seq was performed on 16 SSc patients and 18 healthy controls. Analyses were computed to identify differentially methylated CpGs (DMCs), differentially expressed genes (DEGs), and CpGs associated with changes in gene expression (eQTM analysis).

RESULTS

We observed modest DNA methylation and gene expression differences between cases and controls. The genes harboring the top DMCs, the top DEGs, as well as the top eQTM loci were enriched for metabolic processes. Genes involved in immune processes and pathways showed a weak upregulation in the transcriptomic analysis. While many genes were newly identified, several other have been previously reported as differentially methylated or expressed in different blood cells from patients with SSc, supporting for their potential dysregulation in SSc.

CONCLUSIONS

While contrasting with results found in other blood cell types in largely European-descent groups, the results of this study support that variation in DNA methylation and gene expression exists among different cell types and individuals of different genetic, clinical, social, and environmental backgrounds. This finding supports the importance of including diverse, well-characterized patients to understand the different roles of DNA methylation and gene expression variability in the dysregulation of classical monocytes in diverse populations, which might help explaining the health disparities.

Worsening premature death burden gap from systemic sclerosis in men and black persons: A US nationwide population-based study

Objective

Male sex and black race incur poor prognosis in systemic sclerosis (SSc). There is no nationwide population-based assessment of premature SSc death burden by sex and race.

Methods

This is a population-based study comprising all recorded SSc deaths across the United States. We constructed histograms depicting the number of SSc deaths for each age by sex and race, and calculated the cumulative percent death at each age and the median age of death. We determined the odds ratios for the risk of premature death from SSc by sex and race. We then calculated the percent of total SSc deaths for different age groups by sex and race from 1970 to 2015. We performed chi-square test with Yates's correction and quantified the odds ratio (OR) with 95% confidence interval (CI).

Results

The median age of SSc death was 63 years in males versus 68 years in females, and 57 years in blacks versus 70 years in whites. The odds for SSc death before 65 years age was 1.8 (95% CI, 1.6-2.0) for males compared with females and 5.1 (95% CI, 4.4-6.0) for blacks compared with whites. The higher odds for premature death in males than in females was similar for both races. Differences in the proportions of premature deaths from 1970 to 2015 increased between males and females (-5% to 17%) and between blacks and whites (14% to 36%).

Conclusion

Males and black persons die of SSc at younger ages. The worsening premature death burden gap between the two sexes and races over the last five decades is troublesome.

Systemic sclerosis

Systemic sclerosis, also known as scleroderma, is a rare and complex autoimmune connective-tissue disease. Once considered an untreatable and unpredictable condition, research advancements have improved our understanding of its disease pathogenesis and clinical phenotypes and expanded our treatment armamentarium. Early and accurate diagnosis is essential, while ongoing efforts to risk stratify patients have a central role in predicting both organ involvement and disease progression. A holistic approach is required when choosing the optimal therapeutic strategy, balancing the side-effect profile with efficacy and tailoring the treatment according to the goals of care of the patient. This Seminar reviews the multiple clinical dimensions of systemic sclerosis, beginning at a precursor very early stage of disease, with a focus on timely early detection of organ involvement. This Seminar also summarises management considerations according to the pathological hallmarks of systemic sclerosis (eg, inflammation, fibrosis, and vasculopathy) and highlights unmet needs and opportunities for future research and discovery.

Systemic sclerosis

Systemic sclerosis, also known as scleroderma, is a rare and complex autoimmune connective-tissue disease. Once considered an untreatable and unpredictable condition, research advancements have improved our understanding of its disease pathogenesis and clinical phenotypes and expanded our treatment armamentarium. Early and accurate diagnosis is essential, while ongoing efforts to risk stratify patients have a central role in predicting both organ involvement and disease progression. A holistic approach is required when choosing the optimal therapeutic strategy, balancing the side-effect profile with efficacy and tailoring the treatment according to the goals of care of the patient. This Seminar reviews the multiple clinical dimensions of systemic sclerosis, beginning at a precursor very early stage of disease, with a focus on timely early detection of organ involvement. This Seminar also summarises management considerations according to the pathological hallmarks of systemic sclerosis (eg, inflammation, fibrosis, and vasculopathy) and highlights unmet needs and opportunities for future research and discovery.