African American Multiple Sclerosis Research Articles

African American patients with Multiple Sclerosis (MS) have higher proportions of CD19+ and CD20+ B-cell lineage cells in their cerebrospinal fluid than White MS patients.

To compare proportions of B-cell lineage CD19+ and CD20+ cells in CSF of African-American (AA) and White (W) patients with MS. AA MS patients are more likely to have oligoclonal bands in CSF, higher IgG index in CSF, and higher circulating plasmablasts in blood than W MS patients. It is unknown whether the proportion of B-cells in CSF differs between AA and W patients in MS. Demographics, disease-related information, treatment history were retrospectively collected on patients with MS who self-identified as AA or W and underwent flow cytometry of CSF during diagnostic work-up. Proportion of B-lymphocytes, T-lymphocytes, NK cells, monocytes, and plasma cells were analyzed with flow cytometry. 20 AA and 56W MS patients fulfilled our inclusion criteria. The groups had similar demographics, CSF cell counts, protein and glucose CSF concentrations, and oligoclonal band number. IgG index was higher in AA compared to W (1.08vs. 0.85, p=0.031). AA had higher proportions of CD19+ (5.46% AA vs. 2.26% W, p=0.006) and CD20+ (4.64% AA vs. 1.91% W, p=0.004) cells but did not significantly differ in proportion of CD4+, CD8+, CD38+ bright B-cells, NK cells and monocytes. B-cells are overrepresented in the CSF of African American patients with MS relative to Whites.

Genetic susceptibility to multiple sclerosis in African Americans.

ObjectiveTo explore the nature of genetic-susceptibility to multiple sclerosis (MS) in African-Americans.BackgroundRecently, the number of genetic-associations with MS has exploded although the MS-associations of specific haplotypes within the major histocompatibility complex (MHC) have been known for decades. For example, the haplotypes HLA-DRB1*15:01~HLA-DQB1*06:02, and HLA-DRB1*03:01~ HLA-DQB1*02:01 have odds ratios (ORs) for an MS-association orders of magnitude stronger than many of these newly-discovered associations. Nevertheless, all these haplotypes are part of much larger conserved extended haplotypes (CEHs), which span both the Class I and Class II MHC regions. African-Americans are at greater risk of developing MS compared to a native Africans but at lesser risk compared to Europeans. It is the purpose of this manuscript to explore the relationship between MS-susceptibility and the CEH make-up of our African-American cohort.Design/methodsThe African-American (AA) cohort consisted of 1,305 patients with MS and 1,155 controls, who self-identified as being African-American. For comparison, we used the 18,492 controls and 11,144 MS-cases from the predominantly European Wellcome Trust Case Control Consortium (WTCCC) and the 28,557 phased native Africans from the multinational “Be the Match” registry. The WTCCC and the African-Americans were phased at each of five HLA loci (HLA-A, HLA-C, HLA-B, HLA-DRB1 and HLA-DQB1) and the at 11 SNPs (10 of which were in non-coding regions) surrounding the Class II region of the DRB1 gene using previously-published probabilistic phasing algorithms.ResultsOf the 32 most frequent CEHs, 18 (56%) occurred either more frequently or exclusively in Africans) whereas 9 (28%) occurred more frequently or exclusively in Europeans. The remaining 5 CEHs occurred in neither control group although, likely, these were African in origin. Eight of these CEHs carried the DRB1*15:03~DQB1*06:02~a36 haplotype and three carried the DRB1*15:01~DQB1*06:02~a1 haplotype. In African Americans, a single-copy of the European CEH (03:01_07:02_07:02_15:01_06:02_a1) was associated with considerable MS-risk (OR = 3.30; p = 0.0001)–similar to that observed in the WTCCC (OR = 3.25; p<10−168). By contrast, the MS-risk for the European CEH (02:01_07:02_07:02_15:01_06:02_a1) was less (OR = 1.49; ns)–again, similar to the WTCCC (OR = 2.2; p<10−38). Moreover, four African haplotypes were “protective” relative to a neutral reference, to three European CEHs, and also to the five other African CEHs.ConclusionsThe common CEHs in African Americans are divisible into those that are either African or European in origin, which are derived without modification from their source population. European CEHs, linked to MS-risk, in general, had similar impacts in African-Americans as they did in Europeans. By contrast, African CEHs had mixed MS-risks. For a few, the MS-risk exceeded that in a neutral-reference group whereas, for many others, these CEHs were “protective”–perhaps providing a partial rationale for the lower MS-risk in African-Americans compared to European-Americans.

African Americans experience disproportionate neurodegenerative changes in the medulla and upper cervical spinal cord in early multiple sclerosis

Objective: To compare the temporal changes in the 3-dimensional (3D) structure of the medulla-upper cervical spinal cord region in African American (AA) and white multiple sclerosis (MS) patients to identify early patterns of anatomical change prior to progressive symptom development.Methods: Standardized 3-Tesla 3D brain MRI studies were performed at two time points on AA and white MS patients along with controls. Longitudinal changes in volume, surface area, tissue compliance, and surface texture measured in total and within ventral and dorsal compartments were studied. Independent regression models were constructed to evaluate differences between groups.Results: Thirty-five individuals were studied, 10 AA with MS (female (F): 8; median age [IQR]=33.8 years (y) [10.9], median disease duration: 11.8y [11.3]), 20 white MS patients (F: 10; 35.6y [17.4], 7.23y [8.83], and 5 controls (F: 2, 51.8y [10.2]). Expanded Disability Status Scale scores were 0.0 at baseline and at the second MRI time point. Within the medulla-upper cervical spinal cord, AA versus white MS patients exhibited greater rates of atrophy in total (p<0.0001) and within the ventral (p<0.0001) and dorsal (p<0.0001) compartments, reduced surface area (p<0.0001), and reduced tissue compliance in the ventral (p=0.002) and dorsal (p=0.0005) compartments. The rate of change at the dorsal surface, but not the ventral surface, between MRI time points was also greater in AA relative to white MS patients (p<0.0001).Conclusion: Structural changes in distinct anatomical regions of the medulla-upper cervical spinal cord may be reflective of early and disproportionate neurodegeneration in AA MS as compared to whites.

Race and ethnicity on MS presentation and disease course

Multiple sclerosis (MS) has a strong racial and ethnic component and disproportionately affects whites of European background. Recent incidence reports suggest an increasing rate of MS among African Americans compared with whites. Despite this recent increase in MS in African Americans, Hispanics and Asians are significantly less likely to develop MS than whites of European ancestry. MS-specific mortality trends demonstrate distinctive disparities by race/ethnicity and age, suggesting that there is an unequal burden of disease. Inequalities in health along with differences in clinical characteristics that may be genetic, environmental, and social in origin may be contributing to disease variability and be suggestive of endophenotypes. The overarching goal of this review was to summarize the current understanding on the variability of disease that we observe in selected racial and ethnic populations: Hispanics and African Americans. Future challenges will be to unravel the genetic, environmental, and social determinants of the observed racial/ethnic disparities.

Cerebral Gray Matter Atrophy Is Associated with the CSF IgG index in African American with Multiple Sclerosis

African American (AA) patients with multiple sclerosis (MS) have been reported to have a more aggressive disease course compared to their white counterparts. We explored the relation of gray matter (GM) volume, a marker of tissue injury, and cerebrospinal fluid (CSF) IgG index in both AA and white MS patients. This was a cross-sectional study of 150 self-identified AA and 150 white patients with MS who underwent magnetic resonance imaging scan of brain and CSF sampling. Intrathecal IgG synthesis was quantified as IgG index. The Spearman test was used for univariate correlation analysis, followed by generalized linear model (GLM) to assess the effect of race on the correlation between IgG index and GM volume. The GM volume was inversely related to the IgG index for the entire group (rho = -.57, P < .0004). The AA group showed a stronger correlation (rho = -.893, P < .00004), as compared to whites (rho = -.019, P = .85), between GM and IgG index. Furthermore, GLM analysis showed a significant effect of race on the relation between IgG index and GM volume (P < .0005). AA patients with MS have lower GM volume and a stronger inverse correlation between GM volume and CSF IgG index, compared to the whites. These findings suggest a potentially prominent role of humoral immunity in mediating tissue injury in AA patients with MS.

The killer immunoglobulin-like receptor KIR3DL1 in combination with HLA-Bw4 is protective against multiple sclerosis in African Americans.

We investigated the role of the KIR loci and their HLA class I ligands in a large cohort of African American MS patients (N=907) and controls (N=1456). No significant differences in carrier frequencies for any KIR locus or haplotype were observed between cases and controls. However, examination of KIR in the context of their cognate HLA ligands revealed a strong protective effect for KIR3DL1 in combination with HLA-A and –B alleles bearing the Bw4 motif (p=10−8; OR=0.60, CI=0.50–0.71) and the Bw4 ligand alone (Table 3; p<10−6; OR=0.63, CI=0.53–0.75). The observed effect cannot be explained by either a specific HLA-B allele or by linkage disequilibrium with HLA-DRB1 or HLA-A. The protective effect was observed only in individuals who were not positive for the MS risk allele HLA-DRB1*15:01 (p<10−6; OR=0.61, CI=0.51–0.74). Our study, the first investigation of KIR and MS in African Americans, confirms and refines previous findings in a European cohort.

Newer multiple sclerosis drugs and disability scores-are key data analyses missing?

Keywords: expanded disability status scores (EDSS); multiple sclerosis (MS); immune-modulating drugs; no evidence of disease activity (NEDA); African American MS, disability metrics

Retinal damage and vision loss in African American multiple sclerosis patients.

To determine whether African American (AA) multiple sclerosis (MS) patients exhibit more retinal damage and visual impairment compared to Caucasian American (CA) MS patients. A total of 687 MS patients (81 AAs) and 110 healthy control (HC) subjects (14 AAs) were recruited at 3 academic hospitals between 2008 and 2012. Using mixed effects regression models, we compared high- and low-contrast visual acuity (HCVA and LCVA) and high-definition spectral domain optical coherence tomography measures of retinal architecture between MS patients of self-identified AA and CA ancestry. In HCs, baseline peripapillary retinal nerve fiber layer (RNFL) thickness was 6.1µm greater in AAs (p = 0.047), whereas 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 3.98µm thinner in AAs (p = 0.004). AAs had faster RNFL and GCIP thinning rates compared to CAs (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, AAs had greater loss of HCVA than CA patients (p = 0.012). 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.

Inadequacy of clinical trial designs and data to control for the confounding impact of race/ethnicity in response to treatment in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune demyelinating disease characterized by a complex mix of genetics and gene-environment interactions. As compared with white Americans, African Americans are thought to have a lower risk for developing MS but a greater risk of disability and more opticospinal MS. Data show that MS in African Americans follows a more severe course than in white Americans. The 6-tiered multiple sclerosis severity scale–based analysis demonstrates that African ancestry is a risk factor for a more rapidly disabling disease course. 1 While MS is rare in native Africans, it can be associated with a higher risk of cane dependency, a shorter time to cane, and a shorter duration from symptom onset to diagnosis. 2 In one study, African American patients with MS admitted to US nursing homes were 6 years younger than white American patients with MS on admission, but more disabled. 3

Genetic risk variants in African Americans with multiple sclerosis.

To assess the association of established multiple sclerosis (MS) risk variants in 3,254 African Americans (1,162 cases and 2,092 controls). Human leukocyte antigen (HLA)-DRB1, HLA-DQB1, and HLA-A alleles were typed by molecular techniques. Single nucleotide polymorphism (SNP) genotyping was conducted for 76 MS-associated SNPs and 52 ancestry informative marker SNPs selected throughout the genome. Self-declared ancestry was refined by principal component analysis of the ancestry informative marker SNPs. An ancestry-adjusted multivariate model was applied to assess genetic associations. The following major histocompatibility complex risk alleles were replicated: HLA-DRB1*15:01 (odds ratio [OR] = 2.02 [95% confidence interval: 1.54-2.63], p = 2.50e-07), HLA-DRB1*03:01 (OR = 1.58 [1.29-1.94], p = 1.11e-05), as well as HLA-DRB1*04:05 (OR = 2.35 [1.26-4.37], p = 0.007) and the African-specific risk allele of HLA-DRB1*15:03 (OR = 1.26 [1.05-1.51], p = 0.012). The protective association of HLA-A*02:01 was confirmed (OR = 0.72 [0.55-0.93], p = 0.013). None of the HLA-DQB1 alleles were associated with MS. Using a significance threshold of p < 0.01, outside the major histocompatibility complex region, 8 MS SNPs were also found to be associated with MS in African Americans. MS genetic risk in African Americans only partially overlaps with that of Europeans and could explain the difference of MS prevalence between populations.

Refining the association of MHC with multiple sclerosis in African Americans

Multiple sclerosis (MS) is a common demyelinating disease of the central nervous system mediated by autoimmune and neurodegenerative pathogenic mechanisms. Multiple genes account for its moderate heritability, but the only genetic region shown to have a large replicable effect on MS susceptibility is the major histocompatibility complex (MHC). Strong linkage disequilibrium (LD) across the MHC has made it difficult to fully characterize individual genetic contributions of this region to MS risk in previous studies. African Americans are at a lower risk for MS when compared with northern Europeans and Americans of European descent, but greater haplotypic diversity and distinct patterns of LD suggest that this population may be particularly informative for fine-mapping efforts. To examine the role of the MHC in African American MS, a case-control association study was performed with 499 African American MS patients and 750 African American controls that were genotyped for 6040 MHC region single nucleotide polymorphisms (SNPs). A replication data set consisting of 451 African American patients and 718 African American controls was genotyped for selected SNPs. Two MHC class II SNPs, rs2647040 and rs3135021, were significant in the replication cohort and partially tagged DRB1*15 alleles. Surprisingly, in comparison to similar studies of individuals of European descent, the MHC seems to play a smaller role in MS susceptibility in African Americans, consistent with pervasive genetic heterogeneity across ancestral groups, and may explain the difference in MS susceptibility between African Americans and individuals of European descent.

This week in Neurology ®

### Increased tissue damage and lesion volumes in African Americans with multiple sclerosis A cohort of 488 white American and 79 African American patients with multiple sclerosis were evaluated using clinical and MRI measures. African American patients showed greater tissue damage and faster lesion volume accumulation along with rapid clinical progression. The results suggest that the greater clinical progression of multiple sclerosis in African Americans may be related to increased tissue damage. See p. 538; Editorial, p. 532 ### Early imaging predicts later cognitive impairment in primary progressive multiple sclerosis Thirty-one patients recruited within 5 years of onset of primary progressive multiple sclerosis were …

Response to Mitoxantrone for Secondary Progressive Multiple Sclerosis in African Americans Compared with Whites

Mitoxantrone has been associated with the severe adverse effects of cardiotoxicity and myelocytic leukemia. Therefore, in considering mitoxantrone as a treatment option for people with multiple sclerosis (MS), it is important to determine whether the possible benefits outweigh the considerable risks. In a retrospective evaluation of patients who had received mitoxantrone in our MS center, we noted unexpectedly better outcomes in six African Americans with secondary progressive multiple sclerosis (SPMS) compared with six white patients with similar characteristics. Although this sample is small, if it is typical, the findings may provide support for the use of mitoxantrone in African American people with MS and indicate a need to evaluate MS patients' responses to treatment by ethnicity.

Uncoupling the Roles of HLA-DRB1 and HLA-DRB5 Genes in Multiple Sclerosis

Genetic susceptibility to multiple sclerosis (MS) is associated with the MHC located on chromosome 6p21. This signal maps primarily to a 1-Mb region encompassing the HLA class II loci, and it segregates often with the HLA-DQB1*0602, -DQA1*0102, -DRB1*1501, -DRB5*0101 haplotype. However, the identification of the true predisposing gene or genes within the susceptibility haplotype has been handicapped by the strong linkage disequilibrium across the locus. African Americans have greater MHC haplotypic diversity and distinct patterns of linkage disequilibrium, which make this population particularly informative for fine mapping efforts. The purpose of this study was to establish the telomeric boundary of the HLA class II region affecting susceptibility to MS by assessing genetic association with the neighboring HLA-DRB5 gene as well as seven telomeric single nucleotide polymorphisms in a large, well-characterized African American dataset. Rare DRB5*null individuals were previously described in African populations. Although significant associations with both HLA-DRB1 and HLA-DRB5 loci were present, HLA-DRB1*1503 was associated with MS in the absence of HLA-DRB5, providing evidence for HLA-DRB1 as the primary susceptibility gene. Interestingly, the HLA-DRB5*null subjects appear to be at increased risk for developing secondary progressive MS. Thus, HLA-DRB5 attenuates MS severity, a finding consistent with HLA-DRB5's proposed role as a modifier in experimental autoimmune encephalomyelitis. Additionally, conditional haplotype analysis revealed a susceptibility signal at the class III AGER locus independent of DRB1. The data underscore the power of the African American MS dataset to identify disease genes by association in a region of high linkage disequilibrium.

Phenotype and prognosis in African-Americans with multiple sclerosis: a retrospective chart review

Context There is an emerging body of literature regarding multiple sclerosis (MS) in African-Americans (AA) that suggests more rapid progression and a worse prognosis in this group. A phenotype of opticospinal MS has been proposed by some publications. Objective To determine whether AA with MS have a different clinical phenotype, different distribution of clinical subtypes, and/or different levels of disability than Caucasians (CA) with MS. Specifically, is the disability attributable to severe cerebellar disease, which limits ambulation and function? Design: Retrospective chart analyses of a patient cohort from an academic MS center. Patients A total of 86 AA were identified with MS, 79 were followed for ≥5 years. The control group consisted of 80 randomly-selected CA with MS and similar follow-up. Outcome measures EDSS at diagnosis, five-year follow-up, and last follow-up; time to walking assistance device; disease subtype; involved functional systems. Results AA MS patients displayed more cerebellar dysfunction, and worse EDSS scores at diagnosis, at four to six years follow-up from diagnosis, and at last follow-up compared to the CA MS patients with similar length of follow-up. AA MS patients had earlier and more frequent gait difficulty requiring use of a cane or wheelchair. AA MS patients had a higher prevalence of primary progressive (PP) MS (22 versus 9%) and a lower rate of relapsing-remitting (RR) MS (30 versus 52%) compared to CA. Conclusions Compared to CA patients, MS in AA is characterized by a higher incidence of cerebellar dysfunction and a more rapid accumulation of disabilities. In this cohort, AA patients had a relatively higher rate of the PPMS subtype. These data suggest the presence of fundamental differences in the clinical phenotype and the natural history of MS in AA.

Ethnicity-dependent association of HLA DRB1-DQA1-DQB1 alleles in Brazilian multiple sclerosis patients.

The present study focused on human leukocyte antigen (HLA) DQB1, DQA1 and DRB1 allelic variation according to ethnicity and analyzed whether susceptibility to multiple sclerosis (MS) depends on population characteristics. Eighty-eight healthy African-Brazilians and 92 healthy white Brazilians living in Rio de Janeiro City were selected and the HLA phenotype between the two ethnic groups was compared with 44 MS patients of African descent and 40 patients of European descent. HLA class II genes were performed using polymerase chain reaction (PCR) and PCR-sequence-specific primer amplification. DQA1*0201-0301 alleles were associated with the white Brazilian population (P < 0.001). The DRB*1501 allele was present in White Brazilians (P=0.003), and DRB1*03-1503 in African-Brazilians. The DRB1*1501 allele confers an ethnicity-dependent MS susceptibility in White patients and the DQB1*0602 allele confers genetic susceptibility regardless of ethnicity. Heterogeneous phenotypes occur in both Brazilian ethnic groups. Taking into account that the response to immunomodulator drugs for MS treatment changes according to the DRB1*1501 allele and African-American MS patients presented poor response to the interferons, phenotype heterogeneity of HLA loci found in this study could influence therapeutic decisions in the Brazilian MS population.

The influence of HLA-C alleles on multiple sclerosis in African Americans

The influence of HLA-C alleles on multiple sclerosis in African Americans