Thickness of the ganglion cell inner plexiform layer (GCIPL) may help predict atrophy of gray matter in white patients with relapsing-remitting multiple sclerosis (RRMS) but not in African Americans with RRMS, according to a study published in Multiple Sclerosis and Related Disorders.

A total of 59 patients with RRMS who were enrolled in 2 prospective studies at the Wayne State University School of Medicine were included in the retrospective analysis. In the first study, patients were receiving only glatiramer acetate, whereas the second study was comprised of patients receiving only fingolimod. Participants underwent optical coherence tomography and magnetic resonance imaging brain scans and were taking disease-modifying therapies (DMT) for ≤3 months. The researchers explored the effect of race on the association between gray matter fraction (GMF) and GCIPL thickness in analyses adjusted for age, sex, DMT, and disease duration. Comparisons were made between 32 white Americans with MS and 27 African Americans with MS.

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Although African Americans with MS exhibited significantly greater white matter fraction compared with white Americans with MS (median, 35.39 [range, 22.22-38.80] vs 32.46 [range, 22.43-37.12], respectively; P =.0020), there was no difference between the groups in terms of GMF and GCIPL volume (r =0.148; P =.127).

When evaluating the correlation between GMF and GCIPL for each race separately, patients in the white Americans with MS group demonstrated a significant association between GMF and GCIPL (r =0.434; P =.0004), but no correlation between these 2 measures was found in the African Americans with MS group (r =-0.201; P =.187). After correction for age, sex, disease duration, and DMT, the General Estimating Equations analysis supported the initial linear regression results.

Limitations of the study include its retrospective nature, the small sample size, the single-center design, and the inclusion of only patients with RRMS.

“As there is a growing interest in personalized medicine, the correlation between GCIPL and GMF deserves further attention and may lead to potentially new biomarkers for the [African Americans with MS] that are more strongly associated with GMF than the GCIPL, and eventually result in tailoring of DMT to the patient’s background,” the researchers wrote. “Our findings reiterate the importance of considering race in studies to reveal differences in disease biology and enable optimization of an individualized therapeutic approach.”

Disclosure: This work was supported by an investigator-initiated grant from Novartis and Teva pharmaceuticals.

Reference

Samuela LM, Saraa R, Kalyan Y, et al. Racial differences in retinal neurodegeneration as a surrogate marker for cortical atrophy in multiple sclerosis. Mult Scler Relat Disord. 2019;31:141-147.