African Americans with multiple sclerosis (MS) are more likely to have paramagnetic rim lesions (PRLs) compared to Caucasians
Nara Michaelson1, Melanie Marcille1, Elizabeth Sweeney2, Ulrike Kaunzner1, Jai Perumal1, Nancy Nealon1, Thanh Nguyen1, Susan Gauthier1
1Weill Cornell Multiple Sclerosis, Department of Neurology, Weill Cornell Medicine, 2Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania
Objective:

To determine the prevalence of paramagnetic rim lesions (PRLs) in African American patients with multiple sclerosis (AAwMS) compared to Caucasian (CAwMS).

 

Background:
PRLs are a subset of chronic active MS lesions with a rim of iron-laden innate immune cells and their presence has been associated with higher disability. AAwMS have been clinically observed to have higher disability and more severe symptoms as compared to other racial groups.
Design/Methods:

In this retrospective study of 139 AAwMS and 132 CAwMS quantitative susceptibility mapping (QSM), an MRI approach sensitive to iron, was used to identify PRLs. A linear model assessed the relationship between EDSS and race, adjusting for total lesion number (TLN), sex, age and disease duration (DD). The association of PRL per patient and race was modeled, adjusting for clinical variables and total lesions, using a zero-inflated Poisson regression.

Results:

The cohorts were well matched on all clinical variables and TLN. In a linear model, AAwMS had a higher EDSS (p-value <0.001) with, on average, a 1.16-point higher EDSS (95% CI: [0.73, 1.60] than CAwMS. AAwMS had a mean of 1.3 (2.72) PRL whereas CAwMS had 0.82 (1.69), p=0.085. In the zero-inflated Poisson model, the log odds ratio of having no PRL was 0.53 (95% CI: [0.29, 0.97], p-value = 0.039) for AAwMS, indicating more patients have at least one PRL. In the Poisson model, only TLN (p = 0.021) and gender (p = 0.046) were found to be significant, which indicates that AAwMS were more likely to have one PRL, however among all patients with PRL, the total number of PRL did not depend on race.  

 

Conclusions:

This is the first study to explore racial differences in the occurrence of chronic active lesions and provides preliminary evidence that PRL could relate to racial specific differences in disease pathology, an area which has been significantly understudied.

10.1212/WNL.0000000000202858