The Contribution of Genetics and Epigenetics to Our Understanding of Health Disparities in Rheumatic Diseases

Advances in the management of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a severe multisystem autoimmune disease that can cause injury in almost every body system. While considered a classic example of autoimmunity, it is still relatively poorly understood. Treatment with immunosuppressive agents is challenging, as many agents are relatively non-specific, and the underlying disease is characterized by unpredictable flares and remissions. This State of The Art Review provides a comprehensive current summary of systemic lupus erythematosus based on recent literature. In basic and translational science, this summary includes the current state of genetics, epigenetics, differences by ancestry, and updates about the molecular and immunological pathogenesis of systemic lupus erythematosus. In clinical science, the summary includes updates in diagnosis and classification, clinical features and subphenotypes, and current guidelines and strategies for treatment. The paper also provides a comprehensive review of the large number of recent clinical trials in systemic lupus erythematosus. Current knowns and unknowns are presented, and potential directions for the future are suggested. Improved knowledge of immunological pathogenesis and the molecular differences that exist between patients should help to personalize treatment, minimize side effects, and achieve better outcomes in this difficult disease.

Race, Ethnicity, and Disparities in the Risk of End-Organ Lupus Manifestations Following a Systemic Lupus Erythematosus Diagnosis in a Multiethnic Cohort

OBJECTIVE

Data on the onset of lupus manifestations across multiple organ domains and in diverse populations are limited. The objective was to analyze racial and ethnic differences in the risk of end-organ lupus manifestations following systemic lupus erythematosus (SLE) diagnosis in a multiethnic cohort.

METHODS

The California Lupus Epidemiology Study (CLUES) is a longitudinal study of SLE. Data on major end-organ lupus manifestations were collected and categorized by organ system: renal, hematologic, neurologic, cardiovascular, and pulmonary. Multiorgan disease was defined as manifestations in ≥2 of these distinct organ systems. Kaplan-Meier curves assessed end-organ disease-free survival, and Cox proportional hazards regression estimated the rate of end-organ disease following SLE diagnosis, adjusting for age at diagnosis, sex, and self-reported race and ethnicity (White, Hispanic, Black, and Asian).

RESULTS

Of 326 participants, 89% were female; the mean age was 45 years. Self-reported race and ethnicity were 30% White, 23% Hispanic, 11% Black, and 36% Asian. Multiorgan disease occurred in 29%. Compared to White participants, Hispanic and Asian participants had higher rates, respectively, of renal (hazard ratio [HR] 2.9 [95% confidence interval (95% CI) 1.8-4.7], HR 2.9 [95% CI 1.9-4.6]); hematologic (HR 2.7 [95% CI 1.3-5.7], HR 2.1 [95% CI 1.0-4.2]); and multiorgan disease (HR 3.3 [95% CI 1.8-5.9], HR 2.5 [95% CI 1.4-4.4]) following SLE diagnosis.

CONCLUSION

We found heightened risks of developing renal, hematologic, and multiorgan disease following SLE diagnosis among Hispanic and Asian patients with SLE, as well as a high burden of multiorgan disease among CLUES participants.

Social Factors, Epigenomics and Lupus in African American Women (SELA) Study: protocol for an observational mechanistic study examining the interplay of multiple individual and social factors on lupus outcomes in a health disparity population

Introduction

Despite the disproportional impact of SLE on historically marginalised communities, the individual and sociocultural factors underlying these health disparities remain elusive. We report the design and methods for a study aimed at identifying epigenetic biomarkers associated with racism and resiliency that affect gene function and thereby influence SLE in a health disparity population.

Methods and analysis

The Social Factors, Epigenomics and Lupus in African American Women (SELA) Study is a cross-sectional, case–control study. A total of 600 self-reported African American women will be invited to participate. All participants will respond to questionnaires that capture detailed sociodemographic and medical history, validated measures of racial discrimination, social support, as well as disease activity and damage for cases. Participants who wish will receive their genetic ancestry estimates and be involved in research. Blood samples are required to provide peripheral blood mononuclear cell counts, DNA and RNA. The primary goals of SELA are to identify variation in DNA methylation (DNAm) associated with self-reported exposure to racial discrimination and social support, to evaluate whether social DNAm sites affect gene expression, to identify the synergistic effects of social factors on DNAm changes on SLE and to develop a social factors-DNAm predictive model for disease outcomes. This study is conducted in cooperation with the Sea Island Families Project Citizen Advisory Committee.

Discussion and dissemination

SELA will respond to the pressing need to clarify the interplay and regulatory mechanism by which various positive and negative social exposures influence SLE. Results will be published and shared with patients and the community. Knowledge of the biological impact of social exposures on SLE, as informed by the results of this study, can be leveraged by advocacy efforts to develop psychosocial interventions that prevent or mitigate risk exposures, and services or interventions that promote positive exposures. Implementation of such interventions is paramount to the closure of the health disparities gap.

Integrating genetic and social factors to understand health disparities in lupus

PURPOSE OF REVIEW

Both social and genetic factors are associated with health outcomes in systemic lupus erythematosus (SLE), thus playing a role in its health disparities. Despite the growing list of social and genetic factors associated with SLE outcomes, studies integrating sociocultural and individual determinants of health to understand health disparities in SLE are lacking. We review the contributions of different social and genetic factors to the disparities in SLE, and propose a socioecological model to integrate and examine the complex interactions between individual and social factors in SLE outcomes.

RECENT FINDINGS

Multiple studies collecting comprehensive social data and biospecimens from diverse populations are underway, which will contribute to the elucidation of the interplay and underlying mechanisms by which positive and negative social determinants of health influence epigenomic variation, and how the resulting biological changes may contribute to the lupus health disparities.

SUMMARY

There is growing awareness of the need to integrate genomic and health disparities research to understand how social exposures affect disease outcomes. Understanding the contributions of these factors to the SLE health disparity will inform the development of interventions to eliminate risk exposures and close the health disparity gap.