HLA-DR15 haplotype and multiple sclerosis: a HuGE review

Macrophages and HLA-Class II Alleles in Multiple Sclerosis: Insights in Therapeutic Dynamics

Antigen presentation is a crucial mechanism that drives the T cell-mediated immune response and the development of Multiple Sclerosis (MS). Genetic alterations within the highly variable Major Histocompatibility Complex Class II (MHC II) have been proven to result in significant changes in the molecular basis of antigen presentation and the clinical course of patients with both Adult-Onset MS (AOMS) and Pediatric-Onset MS (POMS). Among the numerous polymorphisms of the Human Leucocyte Antigens (HLA), within MHC II complex, HLA-DRB1*15:01 has been labeled, in Caucasian ethnic groups, as a high-risk allele for MS due to the ability of its structure to increase affinity to Myelin Basic Protein (MBP) epitopes. This characteristic, among others, in the context of the trimolecular complex or immunological synapsis, provides the foundation for autoimmunity triggered by environmental or endogenous factors. As with all professional antigen presenting cells, macrophages are characterized by the expression of MHC II and are often implicated in the formation of MS lesions. Increased presence of M1 macrophages in MS patients has been associated both with progression and onset of the disease, each involving separate but similar mechanisms. In this critical narrative review, we focus on macrophages, discussing how HLA genetic alterations can promote dysregulation of this population's homeostasis in the periphery and the Central Nervous System (CNS). We also explore the potential interconnection in observed pathological macrophage mechanisms and the function of the diverse structure of HLA alleles in neurodegenerative CNS, seen in MS, by comparing available clinical with molecular data through the prism of HLA-immunogenetics. Finally, we discuss available and experimental pharmacological approaches for MS targeting the trimolecular complex that are based on cell phenotype modulation and HLA genotype involvement and try to reveal fertile ground for the potential development of novel drugs.

Probing the basis of disease heterogeneity in multiple sclerosis using genetically diverse mice

Multiple sclerosis (MS) is a complex disease with significant heterogeneity in disease course and progression. Genetic studies have identified numerous loci associated with MS risk, but the genetic basis of disease progression remains elusive. To address this, we leveraged the Collaborative Cross (CC), a genetically diverse mouse strain panel, and experimental autoimmune encephalomyelitis (EAE). The thirty-two CC strains studied captured a wide spectrum of EAE severity, trajectory, and presentation, including severe-progressive, monophasic, relapsing remitting, and axial rotary (AR)-EAE, accompanied by distinct immunopathology. Sex differences in EAE severity were observed in six strains. Quantitative trait locus analysis revealed distinct genetic linkage patterns for different EAE phenotypes, including EAE severity and incidence of AR-EAE. Machine learning-based approaches prioritized candidate genes for loci underlying EAE severity ( Abcc4 and Gpc6 ) and AR-EAE ( Yap1 and Dync2h1 ). This work expands the EAE phenotypic repertoire and identifies novel loci controlling unique EAE phenotypes, supporting the hypothesis that heterogeneity in MS disease course is driven by genetic variation.

Summary

The genetic basis of disease heterogeneity in multiple sclerosis (MS) remains elusive. We leveraged the Collaborative Cross to expand the phenotypic repertoire of the experimental autoimmune encephalomyelitis (EAE) model of MS and identify loci controlling EAE severity, trajectory, and presentation.

HLA Associations of Intrathecal IgG Production against Specific Viruses in Multiple Sclerosis

OBJECTIVE

Specific human leucocyte antigen (HLA) alleles are not only associated with higher risk to develop multiple sclerosis (MS) and other autoimmune diseases, but also with the severity of various viral and bacterial infections. Here, we analyzed the most specific biomarker for MS, that is, the polyspecific intrathecal IgG antibody production against measles, rubella, and varicella zoster virus (MRZ reaction), for possible HLA associations in MS.

METHODS

We assessed MRZ reaction from 184 Swiss patients with MS and clinically isolated syndrome (CIS) and 89 Swiss non-MS/non-CIS control patients, and performed HLA sequence-based typing, to check for associations of positive MRZ reaction with the most prevalent HLA alleles. We used a cohort of 176 Swedish MS/CIS patients to replicate significant findings.

RESULTS

Whereas positive MRZ reaction showed a prevalence of 38.0% in MS/CIS patients, it was highly specific (97.7%) for MS/CIS. We identified HLA-DRB1*15:01 and other tightly linked alleles of the HLA-DR15 haplotype as the strongest HLA-encoded risk factors for a positive MRZ reaction in Swiss MS/CIS (odds ratio [OR], 3.90, 95% confidence interval [CI] 2.05-7.46, padjusted = 0.0004) and replicated these findings in Swedish MS/CIS patients (OR 2.18, 95%-CI 1.16-4.02, padjusted = 0.028). In addition, female MS/CIS patients had a significantly higher probability for a positive MRZ reaction than male patients in both cohorts combined (padjusted <0.005).

INTERPRETATION

HLA-DRB1*15:01, the strongest genetic risk factor for MS, and female sex, 1 of the most prominent demographic risk factors for developing MS, predispose in MS/CIS patients for a positive MRZ reaction, the most specific CSF biomarker for MS. ANN NEUROL 2024;95:1112-1126.

Validation of tag SNPs for multiple sclerosis HLA risk alleles across the 1000 genomes panel

Currently, the genetic variants strongly associated with risk for Multiple Sclerosis (MS) are located in the Major Histocompatibility Complex. This includes DRB1*15:01 and DRB1*15:03 alleles at the HLA-DRB1 locus, the latter restricted to African populations; the DQB1*06:02 allele at the HLA-DQB1 locus which is in high linkage disequilibrium (LD) with DRB1*15:01; and protective allele A*02:01 at the HLA-A locus. HLA allele identification is facilitated by co-inherited ('tag') single nucleotide polymorphisms (SNPs); however, SNP validation is not typically done outside of the discovery population. We examined 19 SNPs reported to be in high LD with these alleles in 2,502 healthy subjects included in the 1000 Genomes panel having typed HLA data. Examination of 3 indices (LD R2 values, sensitivity and specificity, minor allele frequency) revealed few SNPs with high tagging performance. All SNPs examined that tag DRB1*15:01 were in perfect LD in the British population; three showed high tagging performance in 4 of the 5 European, and 2 of the 4 American populations. For DQB1*06:02, with no previously validated tag SNPs, we show that rs3135388 has high tagging performance in one South Asian, one American, and one European population. We identify for the first time that rs2844821 has high tagging performance for A*02:01 in 5 of 7 African populations including African Americans, and 4 of the 5 European populations. These results provide a basis for selecting SNPs with high tagging performance to assess HLA alleles across diverse populations, for MS risk as well as for other diseases and conditions.

Ophthalmological and Neurological Findings in Patients with Idiopathic Uveitis Associated with Retinal Vasculitis and the Relation with the HLA DR15 Allele

PURPOSE

In 15 patients with idiopathic uveitis associated with retinal vasculitis, HLA DRB1 gene testing was performed to detect a possible association. 11 patients tested positive and 4 negative for the HLA DRB1 × 15 allele. The presence of the HLA DRB1 × 15 haplotype might be associated with a higher susceptibility to develop Multiple Sclerosis (MS).

METHODS

In this case series, we describe the ophthalmological and neurological findings in 10 HLA DR15-positive patients and 4 HLA DR15-negative patients that had neurological workup, including Magnetic Resonance Imaging (MRI) of the brain.

RESULTS

All patients had granulomatous ocular inflammation with either panuveitis or intermediate uveitis. MRI of the brain showed white matter lesions in 13 patients (9/10 and 4/4 respectively) of which 4 patients were eventually diagnosed with MS (3/10 and 1/4 respectively).

CONCLUSION

Although the majority of tested patients was carrying at least one HLA DRB1-15 allele, there was no difference in ophthalmological and neurological findings in both groups.

Berberine: A natural modulator of immune cells in multiple sclerosis

Berberine is a benzylisoquinoline alkaloid found in such plants as Berberis vulgaris, Berberis aristata, and others, revealing a variety of pharmacological properties as a result of interacting with different cellular and molecular targets. Recent studies have shown the immunomodulatory effects of Berberine which result from its impacts on immune cells and immune response mediators such as diverse T lymphocyte subsets, dendritic cells (DCs), and different inflammatory cytokines. Multiple sclerosis (MS) is a chronic disabling and neurodegenerative disease of the central nervous system (CNS) characterized by the recruitment of autoreactive T cells into the CNS causing demyelination, axonal damage, and oligodendrocyte loss. There have been considerable changes discovered in MS regards to the function and frequency of T cell subsets such as Th1 cells, Th17 cells, Th2 cells, Treg cells, and DCs. In the current research, we reviewed the outcomes of in vitro, experimental, and clinical investigations concerning the modulatory effects that Berberine provides on the function and numbers of T cell subsets and DCs, as well as important cytokines that are involved in MS.

Origins and immunopathogenesis of autoimmune central nervous system disorders

The field of autoimmune neurology is rapidly evolving, and recent discoveries have advanced our understanding of disease aetiologies. In this article, we review the key pathogenic mechanisms underlying the development of CNS autoimmunity. First, we review non-modifiable risk factors, such as age, sex and ethnicity, as well as genetic factors such as monogenic variants, common variants in vulnerability genes and emerging HLA associations. Second, we highlight how interactions between environmental factors and epigenetics can modify disease onset and severity. Third, we review possible disease mechanisms underlying triggers that are associated with the loss of immune tolerance with consequent recognition of self-antigens; these triggers include infections, tumours and immune-checkpoint inhibitor therapies. Fourth, we outline how advances in our understanding of the anatomy of lymphatic drainage and neuroimmune interfaces are challenging long-held notions of CNS immune privilege, with direct relevance to CNS autoimmunity, and how disruption of B cell and T cell tolerance and the passage of immune cells between the peripheral and intrathecal compartments have key roles in initiating disease activity. Last, we consider novel therapeutic approaches based on our knowledge of the immunopathogenesis of autoimmune CNS disorders.

Citrullinated human and murine MOG35-55 display distinct biophysical and biochemical behavior

The peptide spanning residues 35 to 55 of the protein myelin oligodendrocyte glycoprotein (MOG) has been studied extensively in its role as a key autoantigen in the neuroinflammatory autoimmune disease multiple sclerosis. Rodents and nonhuman primate species immunized with this peptide develop a neuroinflammatory condition called experimental autoimmune encephalomyelitis, often used as a model for multiple sclerosis. Over the last decade, the role of citrullination of this antigen in the disease onset and progression has come under increased scrutiny. We recently reported on the ability of these citrullinated MOG35-55 peptides to aggregate in an amyloid-like fashion, suggesting a new potential pathogenic mechanism underlying this disease. The immunodominant region of MOG is highly conserved between species, with the only difference between the murine and human protein, a polymorphism on position 42, which is serine in mice and proline for humans. Here, we show that the biophysical and biochemical behavior we previously observed for citrullinated murine MOG35-55 is fundamentally different for human and mouse MOG35-55. The citrullinated human peptides do not show amyloid-like behavior under the conditions where the murine peptides do. Moreover, we tested the ability of these peptides to stimulate lymphocytes derived from MOG immunized marmoset monkeys. While the citrullinated murine peptides did not produce a proliferative response, one of the citrullinated human peptides did. We postulate that this unexpected difference is caused by disparate antigen processing. Taken together, our results suggest that further study on the role of citrullination in MOG-induced experimental autoimmune encephalomyelitis is necessary.

Confirmation of CD19+ B-Lymphocyte Depletion Prior to Intake of the Second Dose of Ocrelizumab in Multiple Sclerosis Patients

The aim of the retrospective study was to compare the immunophenotyping of T-lymphocytes, B-lymphocytes, and natural killer cells before the administration of the first and the second dose of ocrelizumab in 22 patients with multiple sclerosis in a three-year period (2019-2021) at the Department of Neurology of the University Hospital of Split. The values of cell immunophenotyping and protein electrophoresis, as well as laboratory parameters, were investigated. There was no significant decrease in serum albumin and globulins before the second dose of ocrelizumab (p > 0,05). A decrease in the number of T-lymphocytes before administration of the second dose of ocrelizumab was observed, but without statistical significance (p = 0.274). Significant depletion occurred in median CD19+ B-lymphocytes (p < 0.001) before the intake of the second dose of ocrelizumab confirming the primary action of ocrelizumab on the B cell lineage.

Age-related blood transcriptional regulators affect disease progression in pediatric multiple sclerosis

BACKGROUND

Pediatric onset multiple sclerosis patients (POMS) are defined as multiple sclerosis with an onset before the age of 18 years. Compared to adult onset multiple sclerosis (AOMS), POMS has more severe disease activity at onset, but better recovery. Little is known about the molecular mechanism responsible for the differences in the clinical presentations.

METHODS

Peripheral Blood Mononuclear Cells samples were taken from 22 POMS patients (mean age 14.1 ± 2.4 years, 15 females, 7 male), and 16 AOMS patients, (mean age 30.8 ± 6.1 years,10 females, 6 males), and gene-expression were analyzed using Affymetrix Inc. HU-133-A2 microarrays. Differentially Expressed Genes (DEGs) that significantly distinguished between POMS and AOMS with pvalue <0.05 after false discovery rate correction were evaluated using Partek software. Twenty-one matched age and gender control was applied to clarify age-related changes. Clinical assessment was performed by analysis of expanded disability status scale (EDSS) and brain MRI lesion loads. Gene functional analysis was performed by Ingenuity Pathway Analysis software.

RESULTS

Compared to AOMS, POMS had higher EDSS (3.0 IQR 2.0-3.0 and 2.0 IQR 2.0-3.0, p = 0.005), volume of T1 (2.72 mm³, IQR 0.44-8.39 mm³ and 0.5 mm³ IQR 0-1.29 mm³ respectively, p = 0.04) and T2 (3.70 mm³, IQR 1.3-9.6 and 0.96 mm³, IQR 0.24-4.63 respectively, p = 0.02) brain MRI lesions. The POMS transcriptional profile was characterized by 551 DEGs, enriched by cell cycling, B lymphocyte signaling and senescent pathways (p < 0.02). Of these, 183 DEGs significantly correlated with T2 lesions volume. The POMS MRI correlated DEGs (n = 183) and their upstream regulators (n = 718) has overlapped with age related DEGs obtained from healthy subjects (n = 497). This evaluated common DEGs (n = 29) defined as POMS age-related regulators, suggesting to promote effect on disease severity.

CONCLUSION

Our finding of higher transcriptional levels of genes involved in cell cycle, cell migration and B cell proliferation that promoted by transcriptional level of age-associated genes and transcription factors allows better understanding of the more aggressive clinical course that defines the POMS.

Autoreactive lymphocytes in multiple sclerosis: Pathogenesis and treatment target

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by destruction of the myelin sheath structure. The loss of myelin leads to damage of a neuron’s axon and cell body, which is identified as brain lesions on magnetic resonance image (MRI). The pathogenesis of MS remains largely unknown. However, immune mechanisms, especially those linked to the aberrant lymphocyte activity, are mainly responsible for neuronal damage. Th1 and Th17 populations of lymphocytes were primarily associated with MS pathogenesis. These lymphocytes are essential for differentiation of encephalitogenic CD8⁺ T cell and Th17 lymphocyte crossing the blood brain barrier and targeting myelin sheath in the CNS. B-lymphocytes could also contribute to MS pathogenesis by producing anti-myelin basic protein antibodies. In later studies, aberrant function of Treg and Th9 cells was identified as contributing to MS. This review summarizes the aberrant function and count of lymphocyte, and the contributions of these cell to the mechanisms of MS. Additionally, we have outlined the novel MS therapeutics aimed to amend the aberrant function or counts of these lymphocytes.

High-resolution HLA class II sequencing of Swedish multiple sclerosis patients

Multiple sclerosis (MS) is a chronic neurological disease believed to be caused by autoimmune pathogenesis. The aetiology is likely explained by a complex interplay between inherited and environmental factors. Genetic investigations into MS have been conducted for over 50 years, yielding >100 associations to date. Globally, the strongest linkage is with the human leukocyte antigen (HLA) HLA-DRB5*01:01:01-DRB1*15:01:01-DQA1*01:02:01-DQB1*06:02:01 haplotype. Here, high-resolution sequencing of HLA was used to determine the alleles of DRB3, DRB4, DRB5, DRB1, DQA1, DQB1, DPA1 and DPB1 as well as their extended haplotypes and genotypes in 100 Swedish MS patients. Results were compared to 636 population controls. The heterogeneity in HLA associations with MS was demonstrated; among 100 patients, 69 extended HLA-DR-DQ genotypes were found. Three extended HLA-DR-DQ genotypes were found to be correlated to MS; HLA-DRB5*01:01:01-DRB1*15:01:01-DQA1*01:02:01-DQB1*06:02:01 haplotype together with (A) HLA-DRB4*01:01:01//DRB4*01:01:01:01-DRB1*07:01:01-DQA1*02:01//02:01:01-DQB1*02:02:01, (B) HLA-DRBX*null-DRB1*08:01:01-DQA1*04:01:01-DQB1*04:02:01, and (C) HLA-DRB3*01:01:02-DRB1*03:01:01-DQA1*05:01:01-DQB1*02:01:01. At the allelic level, HLA-DRB3*01:01:02 was considered protective against MS. However, when combined with HLA-DRB3*01:01:02-DRB1*03:01:01-DQA1*05:01:01-DQB1*02:01:01, this extended haplotype was considered a predisposing risk factor. This highlights the limitations as included with investigations of single alleles relative to those of extended haplotypes/genotypes. In conclusion, with 69 genotypes presented among 100 patients, high-resolution sequencing was conducted to underscore the wide polymorphisms present among MS patients. Additional studies in larger cohorts will be of importance to define MS among the patient group not associated with HLA-DRB5*01:01:01-DRB1*15:01:01-DQA1*01:02:01-DQB1*06:02:01.

Alzheimer's Disease Risk Variant rs3865444 in the CD33 Gene: A Possible Role in Susceptibility to Multiple Sclerosis

Polymorphisms in genes encoding receptors that modulate the activity of microglia and macrophages are attractive candidates for participation in genetic susceptibility to multiple sclerosis (MS). The aims of the study were to (1) investigate the association between Alzheimer’s disease-linked variant rs3865444:C>A in the CD33 gene and MS risk, (2) assess the effect of the strongest MS risk allele HLA-DRB1*15:01 on this association, and (3) analyze the correlation of rs3865444 with selected clinical phenotypes, i.e., age of onset and disease severity. CD33 rs3865444 was genotyped in a cohort of 579 patients and 1145 controls and its association with MS risk and clinical phenotypes was analyzed by logistic and linear regression analysis, respectively. Statistical evaluation revealed that rs3865444 reduces the risk of MS in the HLA-DRB1*15:01-positive subpopulation but not in the cohort negative for HLA-DRB1*15:01. A significant antagonistic epistasis between rs3865444 A and HLA-DRB1*15:01 alleles in the context of MS risk was detected by the interaction synergy factor analysis. Comparison of allele and genotype distribution between relapsing-remitting MS, secondary progressive MS, and control groups revealed that rs3865444 C to A substitution may also be associated with a decreased risk of transition of MS to its secondary progressive form, irrespective of the HLA-DRB1*15:01 carrier status. On the other hand, no correlation could be found between rs3865444 and the age of disease onset or MS severity score. Future studies are required to shed more light on the role of CD33 in MS pathogenesis.

Association of HLA DRB1-DQB1 Haplotypes with the Risk for Neuromyelitis Optica among South Indians

Background

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder, mainly characterized by severe optic neuritis, transverse myelitis and the high levels of antibodies against NMO-immunoglobulin G (IgG) or aquaporin-4 (AQP4). HLA-DR and HLA-DQ alleles within the HLA class II region on chromosome 6p21 are known to play a significant role in several autoimmune diseases including NMO. The rationale of the current case-control study is to explore the association of HLA-DRB1 and HLA-DQB1 alleles with the risk of NMO and its association with the clinical and serological markers.

Methods

A total of 158 samples (38 NMO cases and 120-age and ethnicity matched controls) were genotyped for the HLA-DRB1 and HLA-DQB1 alleles by using PCR-SSP method.

Results

Our analysis showed significant association of HLA-DRB1*10 allele (OR 2.63, 95% CI: 1.18-5.83, p=0.02) with NMO whereas DRB1*14 showed protective role against NMO (OR 0.33: 95% CI: 0.11-0.94, p=0.043). HLA-DRB1*10 allele also showed significant association in patients with NMO-IgG positive antibody (OR 3.28: 95% CI: 1.42-7.5, p=0.006). There was no association of HLA DQB1 alleles with NMO and also with NMO-IgG antibody. Among the haplotypes groups, HLA-DRB1*10-DQB1*05 (OR 2.61, 95% CI: 1.11-6.1, p=0.03), HLA-DRB1*15-DQB1*03 (OR 4.5, 95% CI: 1.81-11.5, p=0.001) were strongly associated with the risk of NMO, whereas DRB1*14-DQB1*05 (OR 0.20, 95% CI: 0.060-0.721, p=0.008) showed negative association with NMO.

Conclusion

From this study, it is concluded that the HLA-DRB1*10 and DRB1*10-DQB1*05 and HLA-DRB1*15-DQB1*03 haplotypes may influence the susceptibility to NMO among the South Indians. Additionally we found DRB1*14 allele and DRB1*14-DQB1*05 haplotype showed protective role for NMO.

FutureMS cohort profile: a Scottish multicentre inception cohort study of relapsing-remitting multiple sclerosis

PURPOSE

Multiple sclerosis (MS) is an immune-mediated, neuroinflammatory disease of the central nervous system and in industrialised countries is the most common cause of progressive neurological disability in working age persons. While treatable, there is substantial interindividual heterogeneity in disease activity and response to treatment. Currently, the ability to predict at diagnosis who will have a benign, intermediate or aggressive disease course is very limited. There is, therefore, a need for integrated predictive tools to inform individualised treatment decision making.

PARTICIPANTS

Established with the aim of addressing this need for individualised predictive tools, FutureMS is a nationally representative, prospective observational cohort study of 440 adults with a new diagnosis of relapsing-remitting MS living in Scotland at the time of diagnosis between May 2016 and March 2019.

FINDINGS TO DATE

The study aims to explore the pathobiology and determinants of disease heterogeneity in MS and combines detailed clinical phenotyping with imaging, genetic and biomarker metrics of disease activity and progression. Recruitment, baseline assessment and follow-up at year 1 is complete. Here, we describe the cohort design and present a profile of the participants at baseline and 1 year of follow-up.

FUTURE PLANS

A third follow-up wave for the cohort has recently begun at 5 years after first visit and a further wave of follow-up is funded for year 10. Longer-term follow-up is anticipated thereafter.

Risk Factors from Pregnancy to Adulthood in Multiple Sclerosis Outcome

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Haematopoietic Stem Cell Transplantation Results in Extensive Remodelling of the Clonal T Cell Repertoire in Multiple Sclerosis

Autologous haematopoietic stem cell transplantation (AHSCT) is a vital therapeutic option for patients with highly active multiple sclerosis (MS). Rates of remission suggest AHSCT is the most effective form of immunotherapy in controlling the disease. Despite an evolving understanding of the biology of immune reconstitution following AHSCT, the mechanism by which AHSCT enables sustained disease remission beyond the period of lymphopenia remains to be elucidated. Auto-reactive T cells are considered central to MS pathogenesis. Here, we analyse T cell reconstitution for 36 months following AHSCT in a cohort of highly active MS patients. Through longitudinal analysis of sorted naïve and memory T cell clones, we establish that AHSCT induces profound changes in the dominant T cell landscape of both CD4+ and CD8+ memory T cell clones. Lymphopenia induced homeostatic proliferation is followed by clonal attrition; with only 19% of dominant CD4 (p <0.025) and 13% of dominant CD8 (p <0.005) clones from the pre-transplant repertoire detected at 36 months. Recovery of a thymically-derived CD4 naïve T cell repertoire occurs at 12 months and is ongoing at 36 months, however diversity of the naïve populations is not increased from baseline suggesting the principal mechanism of durable remission from MS after AHSCT relates to depletion of putative auto-reactive clones. In a cohort of MS patients expressing the MS risk allele HLA DRB1*15:01, public clones are probed as potential biomarkers of disease. AHSCT appears to induce sustained periods of disease remission with dynamic changes in the clonal T cell repertoire out to 36 months post-transplant.

Sex-Specific Environmental Impacts on Initiation and Progression of Multiple Sclerosis

The immunological mechanisms that contribute to multiple sclerosis (MS) differ between males and females. Females are 2–3 times more likely to develop MS compared to males, however the reason for this discrepancy is unknown. Once MS is established, there is a more inflammatory yet milder form of disease in females whereas males generally suffer from more severe disease and faster progression, neural degradation, and disability. Some of these differences relate to genetics, including genetic control of immune regulatory genes on the X-chromosome, as well as immune modulatory properties of sex hormones. Differences in MS development may also relate to how sex interacts with environmental risk factors. There are several environmental risk factors for MS including late-onset Epstein Barr virus infection, low serum vitamin D levels, low UV radiation exposure, smoking, obesity, and lack of physical activity. Most of these risk factors impact males and females differently, either due to biological or immunological processes or through behavioral differences. In this review, we explore these differences further and focus on how the interaction of environmental risk factors with sex hormones may contribute to significantly different prevalence and pathology of MS in males and females.

Associations between m-type phospholipase A2 receptor,human leukocyte antigen gene polymorphisms and idiopathic membranous nephropathy

Primary membranous nephropathy, also known as idiopathic membranous nephropathy, is an autoimmune disease. As an autoimmune disease, genetic factors are essential in the pathogenesis of IMN. People pay more and more attention to genetics and bioinformatics. With the continuous improvement and development of high-throughput gene sequencing and genotyping technology, it has been confirmed that many genes and their single nucleotide polymorphisms are strongly correlated with IMN disease susceptibility. However, there are few studies on HLA-DQA1 and PLA2R gene polymorphisms and IMN susceptibility in China. The purpose of this study was to investigate whether PLA2R rs2715928 and rs16844715 are related to IMN, the correlation between five SNP loci of PLA2R and HLA-DQA1 and IMN, and the effect of gene-gene interaction among different genotypes of each locus on disease. In this study, 86 patients with IMN confirmed by renal biopsy in the first hospital of Harbin Medical University and 90 healthy controls were selected. All subjects were excluded from secondary membranous nephropathy, pregnant or breastfeeding women, severe primary disease of vital organs, severe infection, major surgery, and severe trauma. Seven selected SNP loci were genotyped using the IMLDR multiple SNP typing kit. Chi-square test and logistic regression were used to analyze the correlation between each SNP and IMN. The general clinical data and laboratory indicators of each subject were recorded, and the relationship between different genotypes and clinical manifestations was analyzed. Among the 7 SNP loci included in the study, except HLA-DQA1 rs2187668, the other 6 loci all met Hardy-Weiberg equilibrium test (P > 0.05). The allele distribution of PLA2R rs2715928 and rs16844715 was significantly different between the IMN group and the healthy control group, and it was closely related to IMN (P < 0.05). There was no statistical difference in the distribution of alleles of rs2715918 between the IMN group and the control group (P* > 0.05), and there was also statistical difference in the distribution of alleles of rs35771982, rs3749117, and rs4664308 between the IMN group and the healthy control group (P < 0.05).The C allele of rs16844715 (OR = 2.03, 95%CI: 1.29–3.19, P* = 0.0140) and the A allele of rs2715928 (OR = 3.18, 95%CI: 1.94–5.24, P* = 3.54E-5), G allele of rs35771982 (OR = 4.07, 95%CI: 2.34–7.08, P* = 4.96E-6), T allele of rs3749117 (OR = 4.07, 95%CI: 2.34–7.08, P* = 4.96E-6), the A allele of rs4664308 (OR = 2.63, 95%CI: 1.54–4.49, P* = 0.0028) was the risk gene of IMN.Through the establishment of different genetic models, we found that,in the additive model, the three SNPs of PLA2R rs2715928 (OR = 5.40, 95%CI: 1.77–16.50, P* = 0.0217) and rs35771982 (OR = 15.15, 95%CI: 2.92–78.48, P* = 0.0084), rs3749117 (OR = 15.15, 95%CI: 2.92–78.48, P* = 0.0084) had a strong correlation with IMN. In the stealth model,homozygous gene risk type of the five SNPs,PLA2R rs16844715 (OR = 2.52, 95%CI: 1.38–4.61, P* = 0.0189) and rs2715928 (OR = 4.30, 95%CI: 2.31–8.03, P* = 3.14E-5), rs35771982 (OR = 4.85, 95%CI: 5.53–9.31, P* = 1.42E-5), rs3749117 (OR = 4.85, 95%CI: 5.53–9.31, P* = 1.42E-5) and rs4664308 (OR = 3.16, 95%CI: 1.67–5.97, P* = 0.0028) had a strong correlation with IMN. The distribution of GT haplotypes and CC haplotypes of rs35771982 and rs3749117 and CA haplotypes and TG haplotypes of rs16844715 and rs4664308 were significantly different between IMN group and control group (P < 0.05). When GMDR software was used to establish a model to analyze the interaction between various SNP sites, it was found that the combination of GG genotype at rs35771982 and AA genotype at rs2715928 was the highest risk of disease. The risk genotypes of rs16844715, rs2715928 and rs4664308 had no effect on the clinical manifestations of IMN (P > 0.05). PLA2R rs2715928 and rs16844715 are associated with susceptibility to IMN. The C allele of rs16844715, the A allele of rs2715928, the G allele of rs35771982, the T allele of rs3749117, and the A allele of rs4664308 are the dangerous genes of IMN. The combination of GG genotype at rs35771982 and AA genotype at rs2715928 poses the greatest risk of disease. Haplotype may affect susceptibility to IMN. The risk genotype had no effect on the clinical manifestations of IMN.

Genome-wide association study identifies five risk loci for pernicious anemia

Pernicious anemia is a rare condition characterized by vitamin B12 deficiency anemia due to lack of intrinsic factor, often caused by autoimmune gastritis. Patients with pernicious anemia have a higher incidence of other autoimmune disorders, such as type 1 diabetes, vitiligo, and autoimmune thyroid issues. Therefore, the disease has a clear autoimmune basis, although the genetic susceptibility factors have thus far remained poorly studied. We conduct a genome-wide association study meta-analysis in 2166 cases and 659,516 European controls from population-based biobanks and identify genome-wide significant signals in or near the PTPN22 (rs6679677, p = 1.91 × 10-24, OR = 1.63), PNPT1 (rs12616502, p = 3.14 × 10-8, OR = 1.70), HLA-DQB1 (rs28414666, p = 1.40 × 10-16, OR = 1.38), IL2RA (rs2476491, p = 1.90 × 10-8, OR = 1.22) and AIRE (rs74203920, p = 2.33 × 10-9, OR = 1.83) genes, thus providing robust associations between pernicious anemia and genetic risk factors.

High Resolution Haplotype Analyses of Classical HLA Genes in Families With Multiple Sclerosis Highlights the Role of HLA-DP Alleles in Disease Susceptibility

Multiple sclerosis (MS) susceptibility shows strong genetic associations with HLA alleles and haplotypes. We genotyped 11 HLA genes in 477 non-Hispanic European MS patients and their 954 unaffected parents using a validated next-generation sequencing (NGS) methodology. HLA haplotypes were assigned unequivocally by tracing HLA allele transmissions. We explored HLA haplotype/allele associations with MS using the genotypic transmission disequilibrium test (gTDT) and multiallelic TDT (mTDT). We also conducted a case-control (CC) study with all patients and 2029 healthy unrelated ethnically matched controls. We performed separate analyses of 54 extended multi-case families by reviewing transmission of haplotype blocks. The haplotype fragment including DRB5*01:01:01~DRB1*15:01:01:01 was significantly associated with predisposition (gTDT: p < 2.20e-16; mTDT: p =1.61e-07; CC: p < 2.22e-16) as reported previously. A second risk allele, DPB1*104:01 (gTDT: p = 3.69e-03; mTDT: p = 2.99e-03; CC: p = 1.00e-02), independent from the haplotype bearing DRB1*15:01 was newly identified. The allele DRB1*01:01:01 showed significant protection (gTDT: p = 8.68e-06; mTDT: p = 4.50e-03; CC: p = 1.96e-06). Two DQB1 alleles, DQB1*03:01 (gTDT: p = 2.86e-03; mTDT: p = 5.56e-02; CC: p = 4.08e-05) and DQB1*03:03 (gTDT: p = 1.17e-02; mTDT: p = 1.16e-02; CC: p = 1.21e-02), defined at two-field level also showed protective effects. The HLA class I block, A*02:01:01:01~C*03:04:01:01~B*40:01:02 (gTDT: p = 5.86e-03; mTDT: p = 3.65e-02; CC: p = 9.69e-03) and the alleles B*27:05 (gTDT: p = 6.28e-04; mTDT: p = 2.15e-03; CC: p = 1.47e-02) and B*38:01 (gTDT: p = 3.20e-03; mTDT: p = 6.14e-03; CC: p = 1.70e-02) showed moderately protective effects independently from each other and from the class II associated factors. By comparing statistical significance of 11 HLA loci and 19 haplotype segments with both untruncated and two-field allele names, we precisely mapped MS candidate alleles/haplotypes while eliminating false signals resulting from ‘hitchhiking’ alleles. We assessed genetic burden for the HLA allele/haplotype identified in this study. This family-based study including the highest-resolution of HLA alleles proved to be powerful and efficient for precise identification of HLA genotypes associated with both, susceptibility and protection to development of MS.

An impact of air pollution on moderate to severe relapses among multiple sclerosis patients

BACKGROUND

Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system with both a genetic and environmental component.

OBJECTIVE

In the current study, we examined an association between incidence of MS moderate to severe relapses and exposure to air pollutants and meteorological exposures.

METHODS

We enrolled MS patients in Southern Israel during 2000-2017. Exposure assessment relied on satellite-based model of exposure to particulate matter of size <2.5 and 10 microns (PM_2.5, PM₁₀) and temperature at a spatial resolution of 1 km (Kloog et al., 2015). The information on exposure to nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃) levels was completed from the database of the monitoring stations. We analyzed the data using a semi-ecological approach. The monthly incidence of MS-related relapses requiring hospitalization as a function of environmental factors was analyzed by time-series technique, adjusting to sex, age and smoking. We also used a case-crossover approach to compare environmental exposure of a patient on the day of the relapse with the exposure on the relapse-free days. All estimates were adjusted to the heat index and were divided by IQR.

RESULTS

There were 287 MS patients in the study, with an average age of 52.8 ± 16.7 years, 37% of them (107) being under 40. Mostly female (66.2%), and 13.6% of the patients smoking (47% non-smoking and 39.4% unknown). PM_2.5 was independently associated with MS relapses within the non-smoking population [Relative Risk (RR)=1.28, 95%CI:1.01-1.62]. O₃ was found adversely associated with MS relapses among patients younger than 40 [RR=1.58, 95%CI 1.03-4.43]. Based on the case-crossover approach, relapses were associated with elevated levels of PM₁₀ and NO₂ in all subjects [Odds Ratio (OR)=1.05, 95%CI:1.00-1.11; OR=1.85, 95%CI: 1.28-2.68, respectively]. An adverse association with PM_2.5 was observed in non-smokers [OR 1.12, 95%CI 1.00-1.25].

CONCLUSIONS

The findings show that MS relapses are adversely associated with an ambient exposure to PM and NO₂.

Immunological tests and their interpretation in uveitis

Uveitis is a complex disorder including both infectious and non-infectious etiologies. Clinical diagnosis is a challenge because many diseases share common clinical signs. Laboratory support is crucial for confirming the clinical diagnosis. Laboratory diagnosis includes direct tests and indirect tests. For example smear, culture, and molecular diagnostics demonstrate the pathogens, hence they are direct tests. Immunologic tests employ an antigen to detect presence of antibodies to a pathogen, or an antibody to detect the presence of an antigen, of the pathogen in the specimens. The immunological tests used in laboratories are made by producing artificial antibodies that exactly “match” the pathogen in question. When these antibodies come into contact with a sample they bind to the matching pathogen if found in the sample. Hence they are grouped under indirect evidence. There are several investigations in uveitis to reach the confirmed diagnosis including microbiological, immunological, imaging and molecular diagnostic testing. In this section we will discuss immunological investigations of infectious and non-infectious uveitis.

Major histocompatibility complex (MHC) associations with diseases in ethnic groups of the Arabian Peninsula

Since the discovery of human leukocyte antigens (HLAs), the function of major histocompatibility complex (MHC) gene families in a wide range of diseases have been the subject of research for decades. In particular, the associations of autoimmune disorders to allelic variants and candidate genes encoding the MHC are well documented. However, despite decades of research, the knowledge of MHC associations with human disease susceptibility have been predominantly studied in European origin, with limited understanding in different populations and ethnic groups. This is particularly evident in countries and ethnic populations of the Arabian Peninsula. Human MHC haplotypes, and its association with diseases, of the variable ethnic groups of this region are poorly studied. This review compiled published manuscripts that have reported a list of autoimmune diseases (insulin-dependent diabetes mellitus, systemic lupus erythematosus, myasthenia gravis, rheumatoid arthritis, psoriasis vulgaris, and multiple sclerosis) associated with MHC class I and class II in the populations of the Arabian Peninsula, specifically Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates, and Yemen. Data available was compared with other three ethnic groups, namely Caucasians, Asians, and Africans. The limited data available in the public domain on the association between MHC gene and autoimmune diseases highlight the challenges in the Middle Eastern region.

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.

Clinical and transcriptional recovery profiles in pediatric and adult multiple sclerosis patients

OBJECTIVE

To determine whether pediatric-onset multiple sclerosis (POMS) and adults-onset multiple sclerosis (AOMS) patients are different in initial disease severity and recovery and to investigate the associations with peripheral blood mononuclear cells (PBMCs) transcriptional profiles.

METHODS

Clinical and radiological severity of first and second relapses and 6-month recovery were analyzed in 2153 multiple sclerosis (MS) patients and compared between POMS (onset at 8-18years old) and AOMS (onset at 19-40 years old) patients. PBMCs transcriptomes of 15 POMS and 15 gender-matched AOMS patients were analyzed 6 months after the first relapse and compared to 55 age-matched healthy controls. Differentially Expressed Genes (DEGs) with a false discovery rate ≤ 10% were evaluated using the Partek software.

RESULTS

POMS had increased Expanded Disability Status Scale (EDSS) score at first and second relapses, higher brain gadolinium-enhancing T1-lesions volume at first relapse, and more complete recovery after both relapses compared to AOMS. POMS patients, who recovered completely from the first relapse, were characterized by 19 DEGs that were mainly related to suppression of antigen presentation. Six upstream regulators of these genes were differentially expressed between pediatric and adult healthy controls. POMS patients, who showed no recovery from the first relapse, were characterized by 28 DEGs that were mainly associated with B-cell activation. Five upstream regulators of these genes were differentially expressed between pediatric and adult healthy controls.

INTERPRETATION

POMS patients may have more severe first and second relapses than AOMS. However, most often, POMS have better recovery that may be attributed to PBMCs age-related transcriptional profiles associated with antigen presentation and B-cell activation.

HLA Class II Genotype Does Not Affect the Myelin Responsiveness of Multiple Sclerosis Patients

Background: When aiming to restore myelin tolerance using antigen-specific treatment approaches in MS, the wide variety of myelin-derived antigens towards which immune responses are targeted in multiple sclerosis (MS) patients needs to be taken into account. Uncertainty remains as to whether the myelin reactivity pattern of a specific MS patient can be predicted based upon the human leukocyte antigen (HLA) class II haplotype of the patient. Methods: In this study, we analyzed the reactivity towards myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP) and proteolipid protein (PLP) peptides using direct interferon (IFN)-γ enzyme-linked immune absorbent spot (ELISPOT). Next, the HLA class II haplotype profile was determined by next-generation sequencing. In doing so, we aimed to evaluate the possible association between the precursor frequency of myelin-reactive T cells and the HLA haplotype. Results: Reactivity towards any of the analyzed peptides could be demonstrated in 65.0% (13/20) of MS patients and in 60.0% (6/10) of healthy controls. At least one of the MS risk alleles HLA-DRB1*15:01, HLA-DQA1*01:02 and HLA-DQB1*06:02 was found in 70.0% (14/20) of patients and in 20.0% (2/10) of healthy controls. No difference in the presence of a myelin-specific response, nor in the frequency of myelin peptide-reactive precursor cells could be detected among carriers and non-carriers of these risk alleles. Conclusion: No association between HLA haplotype and myelin reactivity profile was present in our study population. This complicates the development of antigen-specific treatment approaches and implies the need for multi-epitope targeting in an HLA-unrestricted manner to fully address the wide variation in myelin responses and HLA profiles in a heterogeneous group of MS patients.

Elevated Concentrations of Soluble Fas and FasL in Multiple Sclerosis Patients with Antinuclear Antibodies

Antinuclear antibodies (ANA) are currently considered as an epiphenomenon of apoptotic processes, possibly in control of autoreactivity in patients with multiple sclerosis (MS). Apoptosis of reactive lymphocytes by the Fas/FasL system is described as an effective control mechanism for autoreactivity in MS. We aimed to provide a context to the potential link between ANA and peripheral lymphocyte apoptosis in MS. The presence of ANA was detected in sera by immunofluorescence assay, and concentrations of sFas and sFasL were determined in the sera of 44 and cerebrospinal fluid (CSF) of 11 relapsing-remitting (RR) MS patients using cytometric bead-based array, and their association with the disease characteristics was determined. ANA were detected in the sera of 43.2% of RRMS patients, and their frequency was the highest in patients with disease duration of less than one year (88,89%). In addition, the number of experienced relapses was lower in ANA-positive patients. Concentrations of sFasL were inversely associated with patients' expanded disability status scale (EDSS) scores. Low concentrations of both soluble factors strongly discriminated patients with moderate to severe disability, from patients with mild or absent disability only in a group of patients with prolonged disease duration (>10 years). Both soluble mediators were significantly higher in ANA-positive patients. FasL concentrations were inversely associated with the number of relapses. There is a potential link between the presence of ANA and peripheral lymphocyte apoptosis mediated by Fas/FasL system in MS, whose precise role and significance needs to be determined by future mechanistic studies.

Association of multiple sclerosis with vitiligo: a systematic review and meta-analysis

Polyautoimmunity implicates that some autoimmune diseases share common etiopathogenesis. Some studies have reported an association between multiple sclerosis (MS) and vitiligo; meanwhile, other studies have failed to confirm this association. We performed a systemic review and meta-analysis to examine the association of MS with vitiligo. We searched the MEDLINE and Embase databases on March 8, 2020 for relevant case–control, cross-sectional, and cohort studies. The Newcastle–Ottawa Scale was used to evaluate the risk of bias of the included studies. Where applicable, we performed a meta-analysis to calculate the pooled odds ratio (OR) for case–control/cross-sectional studies and risk ratio for cohort studies with 95% confidence interval (CI). Our search identified 285 citations after removing duplicates. Six case–control studies with 12,930 study subjects met our inclusion criteria. Our meta-analysis found no significant association of MS with prevalent vitiligo (pooled OR 1.33; 95% CI 0.80‒2.22). Analysis of the pooled data failed to display any increase of prevalent vitiligo in MS patients compared with controls. Ethnic and genetic factors may play an important role for sporadically observed associations between MS and vitiligo. Future studies of this association should therefore consider stratification by ethnic or genetic factors.

Epigenetics in Multiple Sclerosis

Multiple sclerosis (MS) is an aggravating autoimmune disease that cripples young patients slowly with physical, sensory and cognitive deficits. The break of self-tolerance to neuronal antigens is the key to the pathogenesis of MS, with autoreactive T cells causing demyelination that subsequently leads to inflammation-mediated neurodegenerative events in the central nervous system. The exact etiology of MS remains elusive; however, the interplay of genetic and environmental factors contributes to disease development and progression. Given that genetic variation only accounts for a fraction of risk for MS, extrinsic risk factors including smoking, infection and lack of vitamin D or sunshine, which cause changes in gene expression, contribute to disease development through epigenetic regulation. To date, there is a growing body of scientific evidence to support the important roles of epigenetic processes in MS. In this chapter, the three main layers of epigenetic regulatory mechanisms, namely DNA methylation, histone modification and microRNA-mediated gene regulation, will be discussed, with a particular focus on the role of epigenetics on dysregulated immune responses and neurodegenerative events in MS. Also, the potential for epigenetic modifiers as biomarkers and therapeutics for MS will be reviewed.

High-resolution melting curve analysis of polymorphisms within CD58, CD226, HLA-G genes and association with multiple sclerosis susceptibility in a subset of Iranian population: a case-control study

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with unknown etiology, which typically is manifested in early to middle adulthood. Recently, genome-wide association studies have identified susceptibility of immune-related genes to be involved in MS predisposition. The goal of the current study was to investigate the association of single nucleotide polymorphisms (SNP) with the immunologically related genes responsible for the disease, composed of CD58 (rs2300747 A>G), CD226 (rs763361 C>T), and HLA-G (rs1611715 A>C), with MS susceptibility. In this case-control study, a total of 200 patients suffering from relapsing-remitting multiple sclerosis and 200 healthy individuals were recruited. DNA was extracted from blood and then all subjects were genotyped for the polymorphism within mentioned genes by high-resolution melting (HRM) real-time PCR method. Statistical analyses were performed using SPSS software (version 20; SPSS, Chicago, IL, USA). Our finding showed that there are significant differences in genotype and allele frequencies between two groups regarding rs763361 (P = 0.035, OR 0.64, CI 95% for C allele) and rs1611715 (P = 0.038, OR 1.57, CI 95% for AA genotype) polymorphisms within CD226 and HLA-G genes, respectively. Concerning rs2300747 polymorphism on CD58 gene, no significant differences were found between cases and controls. In general, results from the current study indicate that CD226 and HLA-G, but not CD58 genetic polymorphisms are associated with increased risk of MS in Isfahan population similar to European populations. However, to elucidate how these SNPs contribute to MS pathogenesis, functional studies are needed.

Replication analysis of variants associated with multiple sclerosis risk

Multiple Sclerosis (MS) is a complex chronic neurodegenerative disorder resulting from an autoimmune reaction against myelin. So far, many genetic variants have been reported to associate with MS risk however their association is inconsistent across different populations. Here we investigated the association of the most consistently reported genetic MS risk variants in the Kuwaiti MS population in a case-control study designs. Of the 94 reported MS risk variants four variants showed MS risk association in Arabs exome analysis (EVI5 rs11808092 p = 0.0002; TNFRSF1A rs1800693 p = 0.00003; MTHFR rs1801131 p = 0.038; and CD58 rs1414273 p = 0.00007). Replication analysis in Kuwaiti MS cases and healthy controls confirmed EVI5 rs11808092A (OR: 1.6, 95%CI: 1.19–2.16, p = 0.002) and MTHFR rs1801131G (OR: 1.79, 95%CI: 1.3–2.36, p = 0.001) as MS risk genetic factors, while TNFRSF1A rs1800693C had a marginal MS risk association (OR: 1.36, 95%CI: 1.04–1.78, p = 0.025) in the Kuwaiti population. CD58 rs1414273 did not sustain risk association (p = 0.37). In conclusion, EVI5 rs11808092A, TNFRSF1A rs1800693C and MTHFR rs1801131G are MS risk factors in the Kuwaiti population. Further investigations into their roles in MS pathogenesis and progression are merited.

ANCA-associated life-threatening systemic vasculitis after alemtuzumab treatment for multiple sclerosis

Alemtuzumab is highly effective in relapsing remitting multiple sclerosis (RRMS), but autoimmune adverse events are of concern. In contrast to rare cases of immune-mediated cutaneous vasculitis, systemic vasculitis after alemtuzumab has not yet been described. We report the case of a 29-year-old man with RRMS who developed fever, auricular chondritis, cutaneous vasculitis and life-threatening diffuse alveolar haemorrhage, 12 months after alemtuzumab. Antibodies to myeloperoxidase appeared 9 months after alemtuzumab and were extremely high at the time of vasculitis. Outcome was favourable after glucocorticoids, plasma exchanges and rituximab. Thus, alemtuzumab may induce life-threatening vasculitis in patients treated for RRMS.

Peptide mimotopes alter T cell function in cancer and autoimmunity

T cells recognize and respond to self antigens in both cancer and autoimmunity. One strategy to influence this response is to incorporate amino acid substitutions into these T cell-specific epitopes. This strategy is being reconsidered now with the goal of increasing time to regression with checkpoint blockade therapies in cancer and antigen-specific immunotherapies in autoimmunity. We discuss how these amino acid substitutions change the interactions with the MHC class I or II molecule and the responding T cell repertoire. Amino acid substitutions in epitopes that are the most effective in therapies bind more strongly to T cell receptor and/or MHC molecules and cross-react with the same repertoire of T cells as the natural antigen.

Immune-mediated genesis of multiple sclerosis

Multiple sclerosis (MS) is widely acknowledged to be an autoimmune disease affecting the neuronal myelin structure of the CNS. Autoantigens recognized as the target of this autoimmune process are: myelin basal protein, anti-proteolipid protein, antimyelin-associated glycoprotein and antimyelin-based oligodendrocytic basic protein. Ample evidence supports the idea of a dysregulation of immunological tolerance towards self-antigens of neuronal myelin structure triggered by one or more viral or bacterial microbial agents in predisposed HLA gene subjects. Genetic predisposition to MS has been highlighted by numerous studies associating the disease to specific HLA haplotypes. Moreover, a wide range of evidence supports the fact that MS may be consequence of one or more viral or bacterial infections such as measles virus, EBV, HHV6, HZV, Chlamydia pneumoniae, Helicobacter Pylori, and other microbial agents. Microbiota elements also seems to have a role on the determinism of the disease as a pathogenic or protective factor. The autoimmune pathogenetic process could arise when a molecular mimicry between a foreign microbial antigen and an auto-antigen occurs in an HLA gene subject competent for that particular antigen. The antigen-presenting cells in this case would induce the activation of a specific Th clone causing a cross-reaction between a foreign antigen and an autoantigen resulting in an autoimmune response.

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A multifactorial ethiopathogenetic model based on immunomediation is a reliable hypothesis for multiple sclerosis.

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Evidence found in the scientific literature makes it possible to reconstruct this etiopathogenetic hypothesis for MS.

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HLA gene predisposition, correlation with infections, molecular mimicry and other immunological data are reported.

Biomarkers of Multiple Sclerosis

The search for an ideal multiple sclerosis biomarker with good diagnostic value, prognostic reference and an impact on clinical outcome has yet to be realized and is still ongoing. The aim of this review is to establish an overview of the frequent biomarkers for multiple sclerosis that exist to date. The review summarizes the results obtained from electronic databases, as well as thorough manual searches. In this review the sources and methods of biomarkers extraction are described; in addition to the description of each biomarker, determination of the prognostic, diagnostic, disease monitoring and treatment response values besides clinical impact they might possess. We divided the biomarkers into three categories according to the achievement method: laboratory markers, genetic-immunogenetic markers and imaging markers. We have found two biomarkers at the time being considered the gold standard for MS diagnostics. Unfortunately, there does not exist a single solitary marker being able to present reliable diagnostic value, prognostic value, high sensitivity and specificity as well as clinical impact. We need more studies to find the best biomarker for MS.

TNFR2 limits proinflammatory astrocyte functions during EAE induced by pathogenic DR2b-restricted T cells

Multiple sclerosis (MS) is an autoimmune neuroinflammatory disease where the underlying mechanisms driving disease progression have remained unresolved. HLA-DR2b (DRB1*15:01) is the most common genetic risk factor for MS. Additionally, TNF and its receptors TNFR1 and TNFR2 play key roles in MS and its preclinical animal model, experimental autoimmune encephalomyelitis (EAE). TNFR2 is believed to ameliorate CNS pathology by promoting remyelination and Treg function. Here, we show that transgenic mice expressing the human MHC class II (MHC-II) allele HLA-DR2b and lacking mouse MHC-II and TNFR2 molecules, herein called DR2bΔR2, developed progressive EAE, while disease was not progressive in DR2b littermates. Mechanistically, expression of the HLA-DR2b favored Th17 cell development, whereas T cell-independent TNFR2 expression was critical for restraining of an astrogliosis-induced proinflammatory milieu and Th17 cell responses, while promoting remyelination. Our data suggest the TNFR2 signaling pathway as a potentially novel mechanism for curtailing astrogliosis and promoting remyelination, thus providing new insights into mechanisms limiting progressive MS.

Endosomal Toll-Like Receptors Mediate Enhancement of Interleukin-17A Production Triggered by Epstein-Barr Virus DNA in Mice

We previously demonstrated that Epstein-Barr virus (EBV) DNA increases the production of the proinflammatory cytokine interleukin-17A (IL-17A) in mice. This property may contribute to the established association between EBV and autoimmune diseases. The objective of the present study was to elucidate mechanisms through which EBV DNA modulates IL-17A levels in mice. To determine whether endosomal Toll-like receptors (TLRs) played a role in this pathway, the expression of TLR3, -7, or -9 was assessed by real-time reverse transcription-PCR in mouse spleens after injection of EBV DNA. Moreover, specific inhibitors were used for these TLRs in mouse peripheral blood mononuclear cells (PBMCs) cultured with EBV DNA and in mice injected with this viral DNA; IL-17A levels were then assessed using an enzyme-linked immunosorbent assay. The expression of the endosomal receptors TLR3, -7, and -9 was increased in mice injected with EBV DNA. When mouse immune cells were cultured with EBV DNA and a TLR3, -7, or -9 inhibitor or when mice were injected with the viral DNA along with either of these inhibitors, a significant decrease in IL-17A levels was detected. Therefore, endosomal TLRs are involved in the EBV DNA-mediated triggering of IL-17A production in mice. Targeting these receptors in EBV-positive subjects with autoimmunity may be useful pending investigations assessing whether they play a similar role in humans.IMPORTANCE Epstein-Barr virus is a pathogen that causes persistent infection with potential consistent viral DNA shedding. The enhancement of production of proinflammatory cytokines by viral DNA itself may contribute to autoimmune disease development or exacerbation. In this project, we identified that endosomal Toll-like receptors are involved in triggering proinflammatory mediators in response to viral DNA. Pathways and receptors involved may serve as future therapeutic targets for autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus.

The Transcriptional Landscape of Microglial Genes in Aging and Neurodegenerative Disease

Microglia, the brain-resident myeloid cells, are strongly implicated in Alzheimer's disease (AD) pathogenesis by human genetics. However, the mechanisms by which microglial gene expression is regulated in a region-specific manner over the course of normal aging and in neurodegenerative disease are only beginning to be deciphered. Herein, we used a specific marker of microglia (TMEM119) and a cell-type expression profiling tool (CellMapper) to identify a human microglial gene expression module. Surprisingly, we found that microglial module genes are robustly expressed in several healthy human brain regions known to be vulnerable in AD, in addition to other regions affected only later in disease or spared in AD. Surveying the microglial gene set for differential expression over the lifespan in mouse models of AD and a related tauopathy revealed that the majority of microglial module genes were significantly upregulated in cortex and hippocampus as a function of age and transgene status. Extending these results, we also observed significant upregulation of microglial module genes in several AD-affected brain regions in addition to other regions using postmortem brain tissue from human AD samples. In pathologically confirmed AD cases, we found preliminary evidence that microglial genes may be dysregulated in a sex-specific manner. Finally, we identified specific and significant overlap between the described microglial gene set—identified by unbiased co-expression analysis—and genes known to impart risk for AD. Our findings suggest that microglial genes show enriched expression in AD-vulnerable brain regions, are upregulated during aging and neurodegeneration in mice, and are upregulated in pathologically affected brain regions in AD. Taken together, our data-driven findings from multiple publicly accessible datasets reemphasize the importance of microglial gene expression alterations in AD and, more importantly, suggest that regional and sex-specific variation in microglial gene expression may be implicated in risk for and progression of neurodegenerative disease.

Rationally designed small molecules to prevent type 1 diabetes

PURPOSE OF REVIEW

To review the recent findings that small 'drug-like' compounds block disease-specific human leukocyte antigen (HLA) molecules in type 1 diabetes (T1D).

RECENT FINDINGS

The predominant genetic risk for developing T1D, the immune-mediated form of diabetes, is conferred through HLA genes. One such gene, termed HLA-DQ8, is present in 50-60% of patients with T1D and those at-risk. DQ8 presents disease-relevant peptides to T cells, which mediate tissue-specific destruction of pancreatic islets. Using a structure-based approach to evaluate the 'druggability' of the DQ8 molecule, methyldopa, a clinically well-established oral antihypertensive agent, was discovered to bind DQ8. Methyldopa blocked the activation of DQ8-specific T cells responding to self-antigens such as insulin but not influenza. In a proof-of-concept clinical trial (NCT01883804), methyldopa was administered to recent-onset T1D patients with the DQ8 gene that confirmed the mechanism of action and diminished inflammatory T cell responses toward insulin.

SUMMARY

Methyldopa blocks the diabetes-specific function of HLA-DQ8, which represents a personalized medicine approach to treat the underlying autoimmunity in T1D. Clinical trials are warranted and underway to evaluate methyldopa in potentially preserving residual β-cell function in those with new onset and at risk for T1D.

High resolution HLA analysis reveals independent class I haplotypes and amino-acid motifs protective for multiple sclerosis

We investigated association between HLA class I and class II alleles and haplotypes, and KIR loci and their HLA class I ligands, with multiple sclerosis (MS) in 412 European American MS patients and 419 ethnically matched controls, using next-generation sequencing. The DRB1*15:01~DQB1*06:02 haplotype was highly predisposing (odds ratio (OR) = 3.98; 95% confidence interval (CI) = 3-5.31; p-value (p) = 2.22E-16), as was DRB1*03:01~DQB1*02:01 (OR = 1.63; CI = 1.19-2.24; p = 1.41E-03). Hardy-Weinberg (HW) analysis in MS patients revealed a significant DRB1*03:01~DQB1*02:01 homozyote excess (15 observed; 8.6 expected; p = 0.016). The OR for this genotype (5.27; CI = 1.47-28.52; p = 0.0036) suggests a recessive MS risk model. Controls displayed no HW deviations. The C*03:04~B*40:01 haplotype (OR = 0.27; CI = 0.14-0.51; p = 6.76E-06) was highly protective for MS, especially in haplotypes with A*02:01 (OR = 0.15; CI = 0.04-0.45; p = 6.51E-05). By itself, A*02:01 is moderately protective, (OR = 0.69; CI = 0.54-0.87; p = 1.46E-03), and haplotypes of A*02:01 with the HLA-B Thr80 Bw4 variant (Bw4T) more so (OR = 0.53; CI = 0.35-0.78; p = 7.55E-04). Protective associations with the Bw4 KIR ligand resulted from linkage disequilibrium (LD) with DRB1*15:01, but the Bw4T variant was protective (OR = 0.64; CI = 0.49-0.82; p = 3.37-04) independent of LD with DRB1*15:01. The Bw4I variant was not associated with MS. Overall, we find specific class I HLA polymorphisms to be protective for MS, independent of the strong predisposition conferred by DRB1*15:01.

Genetic meta-analysis of diagnosed Alzheimer's disease identifies new risk loci and implicates Aβ, tau, immunity and lipid processing

Risk for late-onset Alzheimer's disease (LOAD), the most prevalent dementia, is partially driven by genetics. To identify LOAD risk loci, we performed a large genome-wide association meta-analysis of clinically diagnosed LOAD (94,437 individuals). We confirm 20 previous LOAD risk loci and identify five new genome-wide loci (IQCK, ACE, ADAM10, ADAMTS1, and WWOX), two of which (ADAM10, ACE) were identified in a recent genome-wide association (GWAS)-by-familial-proxy of Alzheimer's or dementia. Fine-mapping of the human leukocyte antigen (HLA) region confirms the neurological and immune-mediated disease haplotype HLA-DR15 as a risk factor for LOAD. Pathway analysis implicates immunity, lipid metabolism, tau binding proteins, and amyloid precursor protein (APP) metabolism, showing that genetic variants affecting APP and Aβ processing are associated not only with early-onset autosomal dominant Alzheimer's disease but also with LOAD. Analyses of risk genes and pathways show enrichment for rare variants (P = 1.32 × 10-7), indicating that additional rare variants remain to be identified. We also identify important genetic correlations between LOAD and traits such as family history of dementia and education.

Biomarkers in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease with a complex clinical course characterized by inflammation, demyelination, and axonal degeneration. Diagnosis of MS most commonly includes finding lesions in at least two separate areas of the central nervous system (CNS), including the brain, spinal cord, and optic nerves. In recent years, there has been a remarkable increase in the number of available treatments for MS. An optimal treatment is usually based on a personalized approach determined by an individual patient's prognosis and treatment risks. Biomarkers that can predict disability progression, monitor ongoing disease activity, and assess treatment response are integral in making important decisions regarding MS treatment. This review describes MS biomarkers that are currently being used in clinical practice; it also reviews and consolidates published findings from clinically relevant potential MS biomarkers in recent years. The work also discusses the challenges of validating and application of biomarkers in MS clinical practice.

The role of ERAP1 in autoinflammation and autoimmunity

Autoimmune and autoinflammatory diseases affect millions worldwide. These classes of disease involve abnormal immune activation of both the innate and adaptive immune systems. While both classes of disease represent a spectrum of aberrant immune activation, excessive activation of the innate immune system has been considered causal for the inflammation and tissue damage found in autoinflammatory diseases, while excessive activation of the adaptive immune system has been thought to primarily contribute to end-organ symptoms noted in autoimmune diseases. Interestingly, the endoplasmic reticulum aminopeptidase 1 (ERAP1) protein, well known for its aminopeptidase function as a "molecular ruler", trimming peptides prior to their loading onto MHC-I molecules for antigen presentation in the ER, has also been shown to be genetically associated with both autoinflammatory and autoimmune diseases. Indeed, this multifaceted protein has been found to have many functions that affect both the innate and adaptive immune responses. In this review, we summarize these findings, with an attempt to identify the possible ERAP1 dependent mechanisms responsible for the pathogenesis of multiple, ERAP1 associated diseases.

Association of SHMT1, MAZ, ERG, and L3MBTL3 Gene Polymorphisms with Susceptibility to Multiple Sclerosis

Multiple sclerosis (MS) is the most common inflammatory and chronic disease of the central nervous system (CNS). A complex interaction between genetic, environmental, and epigenetic factors is involved in the pathogenesis of MS. With the advancement of GWAS, various variants associated with MS have been identified. This study aimed to evaluate the association of single-nucleotide polymorphisms (SNPs) rs4925166 and rs1979277 in the SHMT1, MAZ rs34286592, ERG rs2836425, and L3MBTL3 rs4364506 with MS. In this case-control study, the association of five SNPs in SHMT1, MAZ, ERG, and L3MBTL3 genes with relapsing-remitting MS (RR-MS) was investigated in 190 patients and 200 healthy individuals. Four SNPs including SHMT1 rs4925166, SHMT1 rs1979277, MAZ rs34286592, and L3MBTL3 rs4364506 were genotyped using PCR-RFLP and genotyping of ERG rs2836425 was performed by tetra-primer ARMS PCR. Our findings showed a significant difference in the allelic frequencies for the four SNPs of SHMT1 rs4925166, SHMT1 rs1979277, MAZ rs34286592, and ERG rs2836425, while there were no differences in the allele and genotype frequencies for L3MBTL3 rs4364506. These significant associations were observed for the following genotypes: TT and GG genotypes of SHMT1 rs4925166 (OR 0.47 and 1.90, respectively) genotype GG of SHMT1 rs1979277 (OR 0.63), genotype GG of MAZ rs34286592 (OR 0.61), TC and CC genotypes of ERG rs2836425 (OR 1.89 and 0.50, respectively). Our study highlighted that people who are carrying genotypes including GG (SHMT1 rs4925166) and TC (ERG rs2836425) have the highest susceptibility chance for MS, respectively. However, genotypes TT (SHMT1 rs4925166), CC (ERG rs2836425), GG (MAZ rs34286592), and GG (SHMT1 rs1979277) had the highest negative association (protective effect) with MS, respectively. L3MBTL3 rs4364506 was found neither as a predisposing nor a protective variant.

Distinct HLA class I and II genotypes and haplotypes are associated with multiple sclerosis in Bahrain

Multiple sclerosis (MS) has become prevalent in the Arabian Gulf area with high incidence in Bahrain due to environmental influences and genetic susceptibilities, but there is a lack of study into human leukocyte antigen (HLA) types in patients with MS in Bahrain. The present study aimed to study the HLA types expressed in MS patients compared with in control subjects. Blood samples from 50 Bahraini patients with MS and 50 Bahraini control subjects' were subjected to HLA tissue typing by polymerase chain reaction using sequence-specific primers. In comparison with those in control subjects, the allele frequencies of HLA class-I antigens A2, A9, A19, B5, B35 and B40 were higher in MS patients. For class II antigens, the allele frequencies of DR3, DR4 and DR16 were higher in MS patients. The allele frequency of DR15 was lower in MS patients than in control subjects but the difference was not statistically significant (P=0.138). The higher prevalence of the HLA-ABDR allele was common among the female patients with MS, in relapse remission stage, in cases with higher expanded disability status scale scores and with disease duration between 4 and 9 years. Haplotype HLA-A2-B40-DR2 exhibited significantly higher frequency in MS patients compared with in control subjects (P=0.03). In conclusion, the results indicated different alleles associated with MS compared with previous reviews. The present study supports the importance of identifying genetic susceptibilities and targets for therapies in specific populations and individuals, to personalize disease management in terms of prediction, protective measures and treatment.

The role of polymorphic ERAP1 in autoinflammatory disease

Autoimmune and autoinflammatory conditions represent a group of disorders characterized by self-directed tissue damage due to aberrant changes in innate and adaptive immune responses. These disorders possess widely varying clinical phenotypes and etiology; however, they share a number of similarities in genetic associations and environmental influences. Whilst the pathogenic mechanisms of disease remain poorly understood, genome wide association studies (GWAS) have implicated a number of genetic loci that are shared between several autoimmune and autoinflammatory conditions. Association of particular HLA alleles with disease susceptibility represents one of the strongest genetic associations. Furthermore, recent GWAS findings reveal strong associations with single nucleotide polymorphisms in the endoplasmic reticulum aminopeptidase 1 (ERAP1) gene and susceptibility to a number of these HLA-associated conditions. ERAP1 plays a major role in regulating the repertoire of peptides presented on HLA class I alleles at the cell surface, with the presence of single nucleotide polymorphisms in ERAP1 having a significant impact on peptide processing function and the repertoire of peptides presented. The impact of this dysfunctional peptide generation on CD8+ T-cell responses has been proposed as a mechanism of pathogenesis diseases where HLA and ERAP1 are associated. More recently, studies have highlighted a role for ERAP1 in innate immune-mediated pathways involved in inflammatory responses. Here, we discuss the role of polymorphic ERAP1 in various immune cell functions, and in the context of autoimmune and autoinflammatory disease pathogenesis.

Familial multiple sclerosis in Greece: Distinct clinical and imaging characteristics in comparison with the sporadic disease

OBJECTIVE

Few studies are available worldwide concerning clinical, imaging and genetic/immunogenetic profile of familial multiple sclerosis (fMS). Recent but not systematic data concerning fMS, without direct comparison to sporadic MS (sMS) drove our aim towards further research in the field, given the total lack of information for the Greek population as well. Thus, in this case-control study we examined the clinical and imaging characteristics of 102 fMS-patients, compared to 282 patients suffering sMS.

PATIENTS AND METHODS

Patients recruited underwent medical interview (demographic, clinical and family history data collected). They were also assessed for disability and their MRI-scans were analyzed for lesion distribution. Statistical analyses were performed using SPSS v.21.0 software.

RESULTS

49% of unrelated fMS cases had at least one 1^st degree relative affected, while the rest had also at least one relative with MS, 3^rd degree or closer. Only the former subgroup (1^st degree relative) and not the entire fMS sample, had significantly younger age at onset (AAO) compared to sMS cases (mean AAO 28.08 vs 31.33 years, p = 0.036). AAO anticipation was noted in younger generation fMS patients (mean AAO 24.67 years in younger generation vs 37 years in older generation, p = 0.001). With regard to our MRI findings, subcortical lesions were less frequent in fMS (71% in fMS vs 81.9% in sMS patients, p = 0.028), whereas cervical cord lesions more frequent (93% in fMS vs 79.9% in sMS patients, p = 0.033, only in the 1^st degree relative subgroup). Double vision was a less common first symptom in fMS (4.1% in fMS vs 14.8% in sMS patients, p = 0.005). 1^st degree relatives of fMS patients were more often diagnosed with Hashimoto's (8.9% in fMS relatives vs 3.3% in sMS relatives, p = 0.033).

CONCLUSION

Younger AAO and different lesion distribution in brain and possibly spinal cord was observed in fMS in comparison to sMS patients. The hypothesis of increased genetic burden in fMS could offer some explanation for these differences, which needs though further validation as a next step, through genetic/immunogenetic testing in larger cohorts, of different ethnic groups.

TNFRSF1A polymorphisms and their role in multiple sclerosis susceptibility and severity in the Slovak population

Tumour necrosis factor (TNF)-mediated signalling plays a key role in inflammatory and neurodegenerative processes leading to the development of multiple sclerosis (MS). Recent studies have highlighted the role of tumour necrosis factor receptor superfamily member 1A (TNFRSF1A) gene encoding the type 1 TNF receptor in the genetic predisposition to MS. This study aimed to validate the association of TNFRSF1A rs1800693 and rs4149584 polymorphisms with susceptibility to MS in the Slovak population and analyse their influence on age at disease onset, severity, and disability progression. Polymerase chain reaction-restriction fragment length polymorphism method was used to genotype both TNFRSF1A polymorphisms in 541 MS patients and 724 healthy controls. Logistic regression analysis revealed a significantly increased risk of developing MS for the carriers of rs1800693 C allele (TC + CC vs. TT: pcorr = 0.005; OR = 1.61; 95% CI = 1.23-2.12), irrespective of sex and carriage of the major MS risk allele HLA-DRB1*15:01. On the other hand, no association could be found between rs4149584 and MS risk (GA + AA vs. GG: pcorr = 1.00; OR = 1.25; 95% CI = 0.71-2.21). Moreover, neither polymorphism was significantly associated with age at disease onset, MS Severity Score (MSSS) or MS Progression Index (PI) in any of the inheritance models. In conclusion, our results provide support for a sex- and HLA-DRB1*15:01-independent association of TNFRSF1A rs1800693 SNP with MS susceptibility, but not with age at disease onset, severity or rate of disability accumulation.