The HLA DRB1*03:01 allele is associated with NMO regardless of the NMO-IgG status in Brazilian patients from Rio de Janeiro

HLA-transgenic mouse models to study autoimmune central nervous system diseases

It is known that certain human leukocyte antigen (HLA) genes are associated with autoimmune central nervous system (CNS) diseases, such as multiple sclerosis (MS), but their exact role in disease susceptibility and etiopathogenesis remains unclear. The best studied HLA-associated autoimmune CNS disease is MS, and thus will be the primary focus of this review. Other HLA-associated autoimmune CNS diseases, such as autoimmune encephalitis and neuromyelitis optica will be discussed. The lack of animal models to accurately capture the complex human autoimmune response remains a major challenge. HLA transgenic (tg) mice provide researchers with powerful tools to investigate the underlying mechanisms promoting susceptibility and progression of HLA-associated autoimmune CNS diseases, as well as for elucidating the myelin epitopes potentially targeted by T cells in autoimmune disease patients. We will discuss the potential role(s) of autoimmune disease-associated HLA alleles in autoimmune CNS diseases and highlight information provided by studies using HLA tg mice to investigate the underlying pathological mechanisms and opportunities to use these models for development of novel therapies.

Prevalence of neuromyelitis optica spectrum disorder in Colombia: Analysis of the official Ministry of Health administrative registry

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare entity with severe inflammatory demyelinating events of the central nervous system with debilitating sequelae. Its global prevalence ranges between 0.5 and 4/100,000 individuals, with variations by region and ethnicity. Latin America lacks epidemiological data on the disease, and Colombian prevalence is unknown.

OBJECTIVE

Prevalence of NMOSD in Colombia was estimated between 2017 and 2021 using the official Ministry of Health administrative database (SISPRO).

METHODS

This is an observational, cross-sectional retrospective study, using data between January 2017 and December 2021 in the SISPRO database using the International Classification of Disease code for NMOSD G36.0. Prevalence by gender, age and geographic distribution was estimated using official government statistics for 2019. World Health Organization (WHO) standard population was used to adjust using the direct method.

RESULTS

2,650 patients were diagnosed with NMOSD; the average age was 44.9 years with an overall unadjusted prevalence of 5.3/100,000 individuals, higher for females (7.8) than for males (2.8). No significant changes (from 5.3 to 5.4) were seen after adjusting to the WHO standard.

CONCLUSION

According to this study Colombia has one of the highest prevalence rates of NMOSD in Latin America, further studies are needed to elucidate the contributing factors.

Neuromyelitis optica spectrum disorders: a review with a focus on children and adolescents

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and severe inflammatory disorder of the central nervous system (CNS). It is strongly associated with anti-aquaporin 4 antibodies (AQP4-IgG), and it mainly affects young women from non-white ethnicities. However, ∼ 5 to 10% of all cases have onset during childhood. Children and adolescents share the same clinical, radiologic, and laboratory presentation as adults. Thus, the same NMOSD diagnostic criteria are also applied to pediatric-onset patients, but data on NMOSD in this population is still scarce. In seronegative pediatric patients, there is a high frequency of the antibody against myelin oligodendrocyte glycoprotein (MOG-IgG) indicating another disease group, but the clinical distinction between these two diseases may be challenging. Three drugs (eculizumab, satralizumab, and inebilizumab) have been recently approved for the treatment of adult patients with AQP4-IgG-positive NMOSD. Only satralizumab has recruited adolescents in one of the two pivotal clinical trials. Additional clinical trials in pediatric NMOSD are urgently required to evaluate the safety and efficacy of these drugs in this population.

Sequence similarity between SARS-CoV-2 nucleocapsid and multiple sclerosis-associated proteins provides insight into viral neuropathogenesis following infection

The novel coronavirus SARS-CoV-2 continues to cause death and disease throughout the world, underscoring the necessity of understanding the virus and host immune response. From the start of the pandemic, a prominent pattern of central nervous system (CNS) pathologies, including demyelination, has emerged, suggesting an underlying mechanism of viral mimicry to CNS proteins. We hypothesized that immunodominant epitopes of SARS-CoV-2 share homology with proteins associated with multiple sclerosis (MS). Using PEPMatch, a newly developed bioinformatics package which predicts peptide similarity within specific amino acid mismatching parameters consistent with published MHC binding capacity, we discovered that nucleocapsid protein shares significant overlap with 22 MS-associated proteins, including myelin proteolipid protein (PLP). Further computational evaluation demonstrated that this overlap may have critical implications for T cell responses in MS patients and is likely unique to SARS-CoV-2 among the major human coronaviruses. Our findings substantiate the hypothesis of viral molecular mimicry in the pathogenesis of MS and warrant further experimental exploration.

Genetics behind Cerebral Disease with Ocular Comorbidity: Finding Parallels between the Brain and Eye Molecular Pathology

Cerebral visual impairments (CVIs) is an umbrella term that categorizes miscellaneous visual defects with parallel genetic brain disorders. While the manifestations of CVIs are diverse and ambiguous, molecular diagnostics stand out as a powerful approach for understanding pathomechanisms in CVIs. Nevertheless, the characterization of CVI disease cohorts has been fragmented and lacks integration. By revisiting the genome-wide and phenome-wide association studies (GWAS and PheWAS), we clustered a handful of renowned CVIs into five ontology groups, namely ciliopathies (Joubert syndrome, Bardet–Biedl syndrome, Alstrom syndrome), demyelination diseases (multiple sclerosis, Alexander disease, Pelizaeus–Merzbacher disease), transcriptional deregulation diseases (Mowat–Wilson disease, Pitt–Hopkins disease, Rett syndrome, Cockayne syndrome, X-linked alpha-thalassaemia mental retardation), compromised peroxisome disorders (Zellweger spectrum disorder, Refsum disease), and channelopathies (neuromyelitis optica spectrum disorder), and reviewed several mutation hotspots currently found to be associated with the CVIs. Moreover, we discussed the common manifestations in the brain and the eye, and collated animal study findings to discuss plausible gene editing strategies for future CVI correction.

Association Analysis Between HLA-DQA1 Loci and Neuromyelitis Optica Spectrum Disorder in a Han Chinese Population

BACKGROUND

Genome-wide association studies for neuromyelitis optica spectrum disorder (NMOSD) have established an association between HLA-DQ alpha 1 (DQA1) and risk for NMOSD. Though ethnicity is generally considered a major influencing factor in genetic analyses, little is known regarding the association of HLA-DQA1 polymorphisms with NMOSD in the Han population, especially the single-nucleotide polymorphisms (SNPs) at HLA-DQA1 .

METHODS

We genotyped SNP at loci rs28383224 in a case-control study consisting of 137 subjects (51 patients with NMOSD and 86 unrelated controls were recruited) of Han ethnicity. Logistic regression was used to test the association of SNP with NMOSD susceptibility, the sex and age were adjusted, odds ratios and 95% confidence intervals were estimated.

RESULTS

The rs28383224 polymorphism and susceptibility to NMOSD were not statistically associated ( P >0.05) in the Han population in the current study. No significant difference was found in allelic frequencies or genotypic distributions among different subsets of NMOSD patients ( P >0.05).

CONCLUSION

In the current study, there is no evidence that polymorphism of rs28383224 in the HLA-DQA1 gene is associated with the risk of NMOSD in the Han Chinese population.

A Comprehensive Review on the Role of Genetic Factors in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorders (NMOSD) comprise a variety of disorders being described by optic neuritis and myelitis. This disorder is mostly observed in sporadic form, yet 3% of cases are familial NMO. Different series of familial NMO cases have been reported up to now, with some of them being associated with certain HLA haplotypes. Assessment of HLA allele and haplotypes has also revealed association between some alleles within HLA-DRB1 or other loci and sporadic NMO. More recently, genome-wide SNP arrays have shown some susceptibility loci for NMO. In the current manuscript, we review available information about the role of genetic factors in NMO.

Exome-Wide Search for Genes Associated With Central Nervous System Inflammatory Demyelinating Diseases Following CHIKV Infection: The Tip of the Iceberg

Chikungunya virus (CHIKV) is a re-emergent arbovirus that causes a disease characterized primarily by fever, rash and severe persistent polyarthralgia, although <1% of cases develop severe neurological manifestations such as inflammatory demyelinating diseases (IDD) of the central nervous system (CNS) like acute disseminated encephalomyelitis (ADEM) and extensive transverse myelitis. Genetic factors associated with host response and disease severity are still poorly understood. In this study, we performed whole-exome sequencing (WES) to identify HLA alleles, genes and cellular pathways associated with CNS IDD clinical phenotype outcomes following CHIKV infection. The cohort includes 345 patients of which 160 were confirmed for CHIKV. Six cases presented neurological manifestation mimetizing CNS IDD. WES data analysis was performed for 12 patients, including the CNS IDD cases and 6 CHIKV patients without any neurological manifestation. We identified 29 candidate genes harboring rare, pathogenic, or probably pathogenic variants in all exomes analyzed. HLA alleles were also determined and patients who developed CNS IDD shared a common signature with diseases such as Multiple sclerosis (MS) and Neuromyelitis Optica Spectrum Disorders (NMOSD). When these genes were included in Gene Ontology analyses, pathways associated with CNS IDD syndromes were retrieved, suggesting that CHIKV-induced CNS outcomesmay share a genetic background with other neurological disorders. To our knowledge, this study was the first genome-wide investigation of genetic risk factors for CNS phenotypes in CHIKV infection. Our data suggest that HLA-DRB1 alleles associated with demyelinating diseases may also confer risk of CNS IDD outcomes in patients with CHIKV infection.

Whole-exome sequencing reveals the major genetic factors contributing to neuromyelitis optica spectrum disorder in Chinese patients with aquaporin 4-IgG seropositivity

BACKGROUND AND OBJECTIVE

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease. Although genetic factors are involved in its pathogenesis, limited evidence is available in this area. The aim of the present study was to identify the major genetic factors contributing to NMOSD in Chinese patients with aquaporin 4 (AQP4)-IgG seropositivity.

METHODS

Whole-exome sequencing (WES) was performed on 228 Chinese NMOSD patients seropositive for AQP4-IgG and 1400 healthy controls in Guangzhou, South China. Human leukocyte antigen (HLA) sequencing was also utilized. Genotype model and haplotype, gene burden, and enrichment analyses were conducted.

RESULTS

A significant region of the HLA composition is on chromosome 6, and great variation was observed in DQB1, DQA2 and DQA1. HLA sequencing confirmed that the most significant allele was HLA-DQB1*05:02 (p < 0.01, odds ratio [OR] 3.73). The genotype model analysis revealed that HLA-DQB1*05:02 was significantly associated with NMOSD in the additive effect model and dominant effect model (p < 0.05). The proportion of haplotype "HLA-DQB1*05:02-DRB1*15:01" was significantly greater in the NMOSD patients than the controls, at 8.42% and 1.23%, respectively (p < 0.001, OR 7.39). The gene burden analysis demonstrated that loss-of-function mutations in NOP16 were more common in the NMOSD patients (11.84%) than the controls (5.71%; p < 0.001, OR 2.22). The IgG1-G390R variant was significantly more common in NMOSD, and the rate of the T allele was 0.605 in patients and 0.345 in the controls (p < 0.01, OR 2.92). The enrichment analysis indicated that most of the genetic factors were mainly correlated with nervous and immune processes.

CONCLUSIONS

Human leukocyte antigen is highly correlated with NMOSD. NOP16 and IgG1-G390R play important roles in disease susceptibility.

Neuromyelitis optica is an HLA associated disease different from Multiple Sclerosis: a systematic review with meta-analysis

Neuromyelitis Optica and Multiple Sclerosis are idiopathic inflammatory demyelinating diseases of the central nervous system that currently are considered distinct autoimmune diseases, so differences in genetic susceptibility would be expected. This study aimed to investigate the HLA association with Neuromyelitis Optica by a systematic review with meta-analysis. The STROBE instrument guided research paper assessments. Thirteen papers published between 2009 and 2020 were eligible. 568 Neuromyelitis Optica patients, 41.4% Asians, 32.4% Latin Americans and 26.2% Europeans were analyzed. Only alleles of the DRB1 locus were genotyped in all studies. Neuromyelitis Optica patients have 2.46 more chances of having the DRB1*03 allelic group than controls. Ethnicity can influence genetic susceptibility. The main HLA association with Neuromyelitis Optica was the DRB1*03:01 allele in Western populations and with the DPB1*05:01 allele in Asia. Differences in the Multiple Sclerosis and Neuromyelitis Optica genetic susceptibility was confirmed in Afro descendants. The DRB1*03 allelic group associated with Neuromyelitis Optica has also been described in other systemic autoimmune diseases.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

Native American ancestry significantly contributes to neuromyelitis optica susceptibility in the admixed Mexican population

Neuromyelitis Optica (NMO) is an autoimmune disease with a higher prevalence in non-European populations. Because the Mexican population resulted from the admixture between mainly Native American and European populations, we used genome-wide microarray, HLA high-resolution typing and AQP4 gene sequencing data to analyze genetic ancestry and to seek genetic variants conferring NMO susceptibility in admixed Mexican patients. A total of 164 Mexican NMO patients and 1,208 controls were included. On average, NMO patients had a higher proportion of Native American ancestry than controls (68.1% vs 58.6%; p = 5 × 10^-6). GWAS identified a HLA region associated with NMO, led by rs9272219 (OR = 2.48, P = 8 × 10^-10). Class II HLA alleles HLA-DQB1*03:01, -DRB1*08:02, -DRB1*16:02, -DRB1*14:06 and -DQB1*04:02 showed the most significant associations with NMO risk. Local ancestry estimates suggest that all the NMO-associated alleles within the HLA region are of Native American origin. No novel or missense variants in the AQP4 gene were found in Mexican patients with NMO or multiple sclerosis. To our knowledge, this is the first study supporting the notion that Native American ancestry significantly contributes to NMO susceptibility in an admixed population, and is consistent with differences in NMO epidemiology in Mexico and Latin America.

HLA association in MOG-IgG- and AQP4-IgG-related disorders of the CNS in the Dutch population

Objective

To investigate the possible human leukocyte antigen (HLA) association of both myelin oligodendrocyte glycoprotein (MOG-IgG)-associated diseases (MOGAD) and aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (NMOSDs) in the Dutch population with European ancestry to clarify similarities or differences in the immunogenetic background of both diseases.

Methods

Blood samples from patients in the Dutch national MS/NMOSD expert clinic were tested for MOG-IgG and AQP4-IgG using a cell-based assay. HLA Class I and II genotyping was performed in 43 MOG-IgG–seropositive and 42 AQP4-IgG–seropositive Dutch patients with European ancestry and compared with those of 5,604 Dutch healthy blood donors.

Results

No significant HLA association was found in MOG-IgG–seropositive patients. The AQP4-IgG–seropositive patients had a significant higher frequency of HLA-A*01 (61.9% vs 33.7%, OR 3.16, 95% CI, 1.707–5.863, p after correction [pc] = 0.0045), HLA-B*08 (61.9% vs 25.6%, OR 4.66, 95% CI, 2.513–8.643, pc < 0.0001), and HLA-DRB1*03 (51.2% vs 27.6%, OR 2.75, 95% CI, 1.495–5.042, pc = 0.0199) compared with controls.

Conclusions

The present study demonstrates differences in the immunogenetic background of MOGAD and AQP4-IgG–positive NMOSD. The strong positive association with HLA-A*01, -B*08, and -DRB1*03 is suggestive of a role of this haplotype in the etiology of AQP4-IgG–positive NMOSD in patients with European ancestry, whereas in MOGAD no evidence was found for any HLA association in these disorders.

HLA-alleles class I and II associated with genetic susceptibility to neuromyelitis optica in Brazilian patients

OBJECTIVE

To study the genetic susceptibility to neuromyelitis optica (NMO) as well as the relationship between HLA genotypes and susceptibility to the disease in the southern Brazilian population.

METHODS

We analyzed patients with NMO, who met criteria for Wingerchuk's diagnosis of NMO, with detected serum anti-AQP4-IgG antibody. The HLA genotyping was performed by high-resolution techniques (Sanger sequencing) in patients and controls. The HLA genotypes were statistically compared with a paired control population.

RESULTS

The HLA genotyping revealed the diversity of the southern Brazilian population whose HLA profile resembled European and Asian populations. Some alleles had statistical correlations with a positive association (increased susceptibility) with NMO, particularly the HLA-DRB1*04:05 and *16:02.

CONCLUSIONS

In our study, the HLA genotype was different to that previously reported for other Brazilian populations. Although our study had a small cohort, HLA genotypes were associated with increased susceptibility to NMO for HLA-DRB1*04:05 and *16:02. The alleles of HLA class I HLA-A*02:08 and *30:09, HLA-B*08:04 and *35:04 showed an association before the Bonferroni correction.

Associations between HLA and autoimmune neurological diseases with autoantibodies

Recently, several autoimmune neurological diseases have been defined by the presence of autoantibodies against different antigens of the nervous system. These autoantibodies have been demonstrated to be specific and useful biomarkers, and most of them are also pathogenic. These aspects have increased the value of autoantibodies in neurological practice, as they enable to establish more accurate diagnosis and to better understand the underlying mechanisms of the autoimmune neurological diseases when they are compared to those lacking them. Nevertheless, the exact mechanisms leading to the autoimmune response are still obscure. Genetic predisposition is likely to play a role in autoimmunity, HLA being the most reported genetic factor. Herein, we review the current knowledge about associations between HLA and autoimmune neurological diseases with autoantibodies. We report the main alleles and haplotypes, and discuss the clinical and pathogenic implications of these findings.

Identifying the culprits in neurological autoimmune diseases

The target organ of neurological autoimmune diseases (NADs) is the central or peripheral nervous system. Multiple sclerosis (MS) is the most common NAD, whereas Guillain-Barré syndrome (GBS), myasthenia gravis (MG), and neuromyelitis optica (NMO) are less common NADs, but the incidence of these diseases has increased exponentially in the last few years. The identification of a specific culprit in NADs is challenging since a myriad of triggering factors interplay with each other to cause an autoimmune response. Among the factors that have been associated with NADs are genetic susceptibility, epigenetic mechanisms, and environmental factors such as infection, microbiota, vitamins, etc. This review focuses on the most studied culprits as well as the mechanisms used by these to trigger NADs.

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Neurological autoimmune diseases are caused by a complex interaction between genes, environmental factors, and epigenetic deregulation.

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Infectious agents can cause an autoimmune reaction to myelin epitopes through molecular mimicry and/or bystander activation.

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Gut microbiota dysbiosis contributes to neurological autoimmune diseases.

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Smoking increases the risk of NADs through inflammatory signaling pathways, oxidative stress, and Th17 differentiation.

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Deficiency in vitamin D favors NAD development through direct damage to the central and peripheral nervous system.

Familial multiple sclerosis in a Brazilian sample: Is HLA-DR15 involved in susceptibility to the disease?

BACKGROUND

The HLA-DR15 extended haplotype HLA-DRB1*15:01-DQA1*01:02-DQB1*06:02 comprises the strongest genetic risk factor for multiple sclerosis (MS). The aim of this work was to investigate whether HLA-DR15 alleles were significantly associated with the susceptibility to MS familial forms (MSf) in an admixed Brazilian population.

METHODS

Association analyses between DR15 and the clinical and demographic variables were made.

RESULTS

We have genotyped 25 familial cases. The DR15 was detected in 11/25 (44%) of them and in none of controls (P < .00001). DR15 was significantly associated to a foreign ancestor background (P = .029) and later age of onset (P = .018).

Epidemiology of neuromyelitis optica in Latin America

A major development over the past two decades was the recognition of recurrent neuromyelitis optica (NMO) as a particular central nervous system disorder different from multiple sclerosis (MS). Here we reviewed the epidemiology of NMO in Latin America (LATAM). A predominance of a mixed population is found in this region. Recurrent NMO in black women was described in the Caribbean Islands and in Rio de Janeiro. The prevalence of NMO in LATAM varied from 0.37/100,000 (Volta Redonda city) to 4.2/100,000 inhabitants (Caribbean Islands). NMO differs significantly from MS with respect to gender, ethnicity, morbidity and genetic susceptibility. An association of the HLA DRB1*03 alleles with NMO was described in the French Antilles, Ribeirão Preto, Rio de Janeiro and Mexico. It is not common to find familial forms of NMO. NMO represents 11.8% of all inflammatory idiopathic diseases in South America (SA). In SA, the highest frequency of NMO occurs in African Brazilian young women. The overall relative frequency of NMO among MS cases in this region was 14%, decreasing following a north-south gradient, which parallels the percentage of nonwhite people.