Local Ancestry at the Major Histocompatibility Complex Region is Not a Major Contributor to Disease Heterogeneity in a Multiethnic Lupus Cohort.

OBJECTIVE: Systemic lupus erythematosus (SLE) is an autoimmune disease resulting in debilitating clinical manifestations that vary in severity by race and ethnicity with a disproportionate burden in African American, Mestizo, and Asian populations compared with populations of European descent. Differences in global and local genetic ancestry may shed light on the underlying mechanisms contributing to these disparities, including increased prevalence of lupus nephritis, younger age of symptom onset, and presence of autoantibodies. METHODS: A total of 1,139 European, African American, and Mestizos patients with SLE were genotyped using the Affymetrix LAT1 World array. Global ancestry proportions were estimated using ADMIXTURE, and local ancestry was estimated using RFMIXv2.0. We investigated associations between lupus nephritis, age at onset, and autoantibody status with both global and local ancestry proportions within the Major Histocompatibility Complex region. RESULTS: Our results showed small effect sizes that did not meet the threshold for statistical significance for global or local ancestry proportions in either African American or Mestizo patients with SLE who presented with the clinical manifestations of interest compared with those who did not. CONCLUSION: These findings suggest that local genetic ancestry within the Major Histocompatibility Complex region is not a major contributor to these SLE manifestations among patients with SLE from admixed populations.

Prevalence of cardiovascular disease and major risk factors in patients with rheumatoid arthritis: a multinational cross-sectional study.

To compare the prevalence of cardiovascular disease (CVD) and major CVD risk factors among rheumatoid arthritis (RA) patients enrolled in a large US and multinational registry. We compared CVD and CVD risk factor prevalence from 11 countries enrolled in the CORRONA US and CORRONA International registries; patients from the 10 ex-US participating countries were grouped by region (Eastern Europe, Latin America, and India). Unadjusted summary data were presented for demographics and disease characteristics; comparisons for prevalence of CVD risk factors and CVD were age/gender standardized to the age/gender distribution of the US enrolled patients. Overall, 25,987 patients were included in this analysis. Compared to patients from the ex-US regions, US participants had longer disease duration and lower disease activity, yet were more likely to receive a biologic agent. Additionally, CORRONA US participants had the highest body mass index (BMI). Enrolled patients in India had the lowest BMI, were more rarely smokers, and had a low prevalence of hyperlipidemia, hypertension, and prior CVD compared to the US and other ex-US regions. Participants from Eastern Europe had a higher prevalence of hypertension and hyperlipidemia and highest prevalence of all manifestations of CVD. Differences in the prevalence of both CVD and major CVD risk factors were observed across the four regions investigated. Observed differences may be influenced by variations in both non-modifiable/modifiable characteristics of patient populations, and may contribute to heterogeneity on the observed safety of investigational and approved therapies in studies involving RA patients from different origins.