Dorlan J. Kimbrough, Elias S. Sotirchos, James A. Wilson, Omar Al-Louzi, Amy Conger, Darrel Conger, Teresa C. Frohman, Shiv Saidha, Ari J. Green, Elliot M. Frohman, Laura J. Balcer and Peter A. Calabresi Retinal Damage and Vision Loss in African-American Multiple Sclerosis Patients Accepted manuscript online: 8 NOV 2014 03:29AM EST | DOI: 10.1002/ana.2430
Objective: To determine whether African-American (AA) multiple sclerosis (MS) patients exhibit more retinal damage and visual impairment compared to Caucasian-American (CA) MS patients.
Methods: 687 MS patients (81 AA) and 110 healthy control (HC) subjects (14 AA) were recruited at three academic hospitals between 2008 and 2012. We compared high and low contrast visual acuity (HCVA and LCVA) and high-definition spectral-domain optical coherence tomography (Cirrus-OCT) measures of retinal architecture between MS patients of self-identified AA and CA ancestry.
Results: In HC, baseline peripapillary retinal nerve fiber layer thickness (RNFL) was 6.1 μm greater in AA (p = 0.047), while ganglion cell / inner plexiform layer (GCIP) thickness did not differ by race. In MS patients, baseline RNFL did not differ by race, and GCIP was 3.98 µm thinner in AA (p = 0.004). AA had faster RNFL and GCIP thinning rates compared to CA (p = 0.004 and p= 0.046, respectively). AA MS patients had lower baseline HCVA (p = 0.02) and worse LCVA per year of disease duration (p= 0.039). Among patients with an acute optic neuritis (AON) history, AA had greater loss of HCVA than CA patients (p = 0.012).
Interpretation: This multicenter investigation provides objective evidence that AA MS patients exhibit accelerated retinal damage compared to CA MS patients. Self-identified AA ancestry is associated with worse MS-related visual disability, particularly in the context of an AON history, suggesting a more aggressive inflammatory disease course among AA MS patients or a subpopulation therein.
Genetics influences immune responsiveness and this is well known this study looks at American White and Black people with MS and see how they do after a bout of optic nerve inflammation. They find that more nerves are lost in the retina of African Americans.
They suggest that this is because the African Americans have a more aggressive inflammatory response and this is quite possible, but another alternative could be that they may not handle the inflammatory insult as well and so loose more nerves as a consequence the inflammatory response.
This happens in mice also. The C57BlackSix mouse strain looses more nerves compared to Swiss Caesarian derivation One mice.
This result may not be surprising as African Americans have a poorer disease course