Mediterranean and Amerindian MHC class II alleles are associated with multiple sclerosis in Mexicans

Genetic Variant HLA-DRB1*0403 and Therapeutic Response to Disease-Modifying Therapies in Multiple Sclerosis: A Case-Control Study

Multiple sclerosis (MS) is a chronic and demyelinating disease with an autoimmune origin, which leads to neurodegeneration and progressive disability. Approximately 30 to 50% of patients do not respond optimally to disease-modifying therapies (DMTs), and therapeutic response may be influenced by genetic factors such as genetic variants. Therefore, our study aimed to investigate the association of the HLA-DRB1*0403 genetic variant and therapeutic response to DMTs in MS. We included 105 patients with MS diagnosis. No evidence of disease activity based on the absence of clinical relapse, disability progression or radiological activity (NEDA-3) was used to classify the therapeutic response. Patients were classified as follows: (a) controls: patients who achieved NEDA-3; (b) cases: patients who did not achieve NEDA-3. DNA was extracted from peripheral blood leukocytes. HLA-DRB1*0403 genetic variant was analyzed by quantitative polymerase chain reaction (qPCR) using TaqMan probes. NEDA-3 was achieved in 86.7% of MS patients treated with DMTs. Genotype frequencies were GG 50.5%, GA 34.3%, and AA 15.2%. No differences were observed in the genetic variant AA between patients who achieved NEDA-3 versus patients who did not achieve NEDA-3 (48.7% vs. 43.1%, p = 0.6). We concluded that in Mexican patients with MS, HLA-DRB1*0403 was not associated with the therapeutic response to DMTs.

Ancestral risk modification for multiple sclerosis susceptibility detected across the Major Histocompatibility Complex in a multi-ethnic population

The Major Histocompatibility Complex (MHC) makes the largest genetic contribution to multiple sclerosis (MS) susceptibility, with 32 independent effects across the region explaining 20% of the heritability in European populations. Variation is high across populations with allele frequency differences and population-specific risk alleles identified. We sought to identify MHC-specific MS susceptibility variants and assess the effect of ancestral risk modification within 2652 Latinx and Hispanic individuals as well as 2435 Black and African American individuals. We have identified several novel susceptibility alleles which are rare in European populations including HLA-B*53:01, and we have utilized the differing linkage disequilibrium patterns inherent to these populations to identify an independent role for HLA-DRB1*15:01 and HLA-DQB1*06:02 on MS risk. We found a decrease in Native American ancestry in MS cases vs controls across the MHC, peaking near the previously identified MICB locus with a decrease of ~5.5% in Hispanics and ~0.4% in African Americans. We have identified several susceptibility variants, including within the MICB gene region, which show global ancestry risk modification and indicate ancestral differences which may be due in part to correlated environmental factors. We have also identified several susceptibility variants for which MS risk is modified by local ancestry and indicate true ancestral genetic differences; including HLA-DQB1*06:02 for which MS risk for European allele carriers is almost two times the risk for African allele carriers. These results validate the importance of investigating MS susceptibility at an ancestral level and offer insight into the epidemiology of MS phenotypic diversity.

Onychomycosis in patients with multiple sclerosis: prevalence, clinical description, mycological, and dermoscopic study in a Mexican population

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating disease related to HLA-DR8. Susceptibility to onychomycosis has been found in Mexican mestizos with HLA-DR8. The frequency of onychomycosis in this neurological disease is unknown.

OBJECTIVES

To determine the frequency of onychomycosis and its clinical, mycological, and dermoscopic characteristics in patients with MS in comparison with the general population.

METHODS

Observational, cross-sectional, case-control study in patients with MS from October 2017 to February 2018. Age, gender, MS type, and time of progression from diagnosis to date and baseline treatment were collected after signed informed consent. A neurological exploration and clinical examination of fingernails and toenails for onychomycosis was conducted. Mycological and dermoscopic studies of the infected nails were performed on patients with clinical diagnosis of onychomycosis. A healthy control group was taken for each case (1:1), paired by age and gender.

RESULTS

The frequency of onychomycosis in patients with MS was higher than the healthy population (32% vs. 26%, P = 0.509). A higher frequency of non-dermatophyte fungi was found, although it was not statistically significant. The clinical manifestations and dermoscopic findings in patients with MS and onychomycosis were similar to those of the general population.

CONCLUSION

The frequency of onychomycosis in patients with MS is slightly higher than that of the general population. A possible association of HLA-DR8 as a susceptibility factor for onychomycosis is proposed. The etiology of opportunistic fungi in MS patients with onychomycosis may be related to immunosuppressive treatment.

Comprehensive meta-analysis reveals an association of the HLA-DRB1*1602 allele with autoimmune diseases mediated predominantly by autoantibodies

The human leukocytes antigen (HLA)-DRB1*16:02 allele has been suggested to be associated with many autoimmune diseases. However, a validation of the results of the different studies by a comprehensive analysis of the corresponding meta data is lacking. In this study, we performed a meta-analysis of the association between HLA-DRB1*16:02 allele with various autoimmune disorders. Our analysis shows that HLA-DRB1*16:02 allele was associated with systemic lupus erythematosus, anti-N-Methyl-d-Aspartate receptor (NMDAR) encephalitis, Graves' disease, myasthenia gravis, neuromyelitis optica and antibody-associated systemic vasculitis with microscopic polyangiitis (AASV-MPA). However, no such association was found for multiple sclerosis, autoimmune hepatitis type 1, rheumatoid arthritis, type 1 diabetes and Vogt-Koyanagi-Harada syndrome. Re-analysis of the studies after their categorization into autoantibody-dependent and T cell-dependent autoimmune diseases revealed that the HLA-DRB1*16:02 allele was strongly associated with disorder predominantly mediated by autoantibodies (OR = 1.93; 95% CI = 1.63-2.28, P = 1.95 × 10^-14) but not with those predominantly mediated by T cells (OR = 1.08; 95% CI = 0.87-1.34, P = .474). In addition, amino acid sequence alignment of common HLA-DRB1 subtypes demonstrated that HLA-DRB1*16:02 carries a unique motif of amino acid residues at position 67-74 which encodes the third hypervariable region. Taken together, the distinct pattern of disease association and the unique amino acid sequence of the third hypervariable region of the HLA-DRB1 provide some hints on how HLA-DRB1*16:02 is involved in the pathogenesis of autoimmune diseases.

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).

MS in self-identified Hispanic/Latino individuals living in the US

Self-identified Hispanic/Latino individuals living with multiple sclerosis (MS) in the continental United States (US) are a diverse group that represents different cultural and ancestral backgrounds. A marked variability in the way MS affects various subgroups of Hispanics in the US has been observed. We reviewed and synthesized available data about MS in Hispanics in the US. There are likely a host of multifactorial elements contributing to these observations that could be explained by genetic, environmental, and social underpinnings. Barriers to adequate MS care in Hispanics are likely to include delivery of culturally competent care and social and economic disadvantages. Considerable efforts, including the formation of a national consortium known as the Alliance for Research in Hispanic Multiple Sclerosis (ARHMS), are underway to help further explore these various factors.

The immunogenetics of multiple sclerosis. The frequency of HLA-alleles class 1 and 2 is lower in Southern Brazil than in the European population

ABSTRACT Objective To study the HLA of class 1and 2 in a multiple sclerosis (MS) population to verify the susceptibility for the disease in the Southern Brazil. Methods We analyzed patients with MS and controls, by direct sequencing of the genes related to HLA DRB1, DQB1, DPB1, A, B and C alleles with high resolution techniques. Results We found a lower frequency of all HLA alleles class 1 and 2 in MS and controls comparing to the European population. Several alleles had statistical correlation, but after Bonferroni correction, the only allele with significance was the HLA-DQB1*02:03, which has a positive association with MS. Conclusions Our data have different frequency of HLA-alleles than the previous published papers in the Southeast Brazil and European population, possible due to several ethnic backgrounds.

Multiple sclerosis in First Nations Canadians: A pilot comparison study

Background

Genetic and clinical characteristics associated with multiple sclerosis (MS) may differ by ethnicity but few studies have evaluated whether characteristics of MS differ between individuals according to First Nations (FN) ethnicity.

Objective

Using a cross-sectional observational design, we compared clinical and genetic characteristics between people with MS of FN and non-FN ethnicity.

Methods

We recruited participants of FN ethnicity with MS. We conducted a medical records review for each participant followed by a standardized interview and drawing of blood samples. The blood underwent genetic analyses for several HLA alleles. We compared the study sample with 127 non-FN MS participants from another study conducted in the same region using the same data collection procedures.

Results

We included 144 participants with MS, of whom 17 (11.8%) self-identified as FN. The age of symptom onset was earlier and the diagnostic delay shorter among FN participants although these differences did not reach statistical significance. As compared to non-FN participants, FN participants with MS had increased odds of comorbid psychiatric disease (OR 5.38; 95% CI: 1.84–15.8), and were less likely to be HLA-DRB1*1501 positive (OR 0.32; 95% CI: 0.11–0.96).

Conclusion

Genetic and clinical characteristics of MS differ among Canadians of FN and non-FN ethnicity.

HLA-DRB1*14 is a protective allele for multiple sclerosis in an admixed Colombian population

OBJECTIVE

The aim of this study was to determine ancestry informative markers, mitochondrial DNA haplogroups, and the association between HLA-DRB1 alleles and multiple sclerosis (MS) in a group of patients from Bogotá, Colombia.

METHODS

In this case-control study, genomic DNA was isolated and purified from blood samples. HLA-DRB1 allele genotyping was done using PCR. Mitochondrial hypervariable region 1 was amplified and haplogroups were determined using HaploGrep software. Genomic ancestry was estimated by genotyping a panel of ancestry informative markers. To test the association of HLA polymorphisms and MS, we ran separate multivariate logistic regression models. Bonferroni correction was used to account for multiple regression tests.

RESULTS

A total of 100 patients with MS (mean age 40.4 ± 12 years; 70% females) and 200 healthy controls (mean age 37.6 ± 11 years; 83.5% females) were included in the analysis. Ancestry proportions and haplogroup frequencies did not differ between patients and controls. HLA-DRB1*15 was present in 31% of cases and 13.5% of controls, whereas HLA-DRB1*14 was present in 5% of cases and 15.5% of controls. In the multivariate model, HLA-DRB1*15 was significantly associated with MS (odds ratio [OR] = 3.05, p < 0.001), whereas HLA-DRB1*14 was confirmed as a protective factor in our population (OR = 0.16, p = 0.001).

CONCLUSIONS

This study provides evidence indicating that HLA-DRB1*15 allele confers susceptibility to MS and HLA-DRB1*14 allele exerts resistance to MS in a highly admixed population. This latter finding could partially explain the low prevalence of MS in Bogotá, Colombia.

The influence of the HLA-DRB1 and HLA-DQB1 allele heterogeneity on disease risk and severity in Iranian patients with multiple sclerosis

Multiple sclerosis (MS) is a common autoimmune disorder of the central nervous system. Recent studies have shown that the HLA-DRB1 and DQB1 alleles are associated with MS susceptibility and severity. However, this is controversial in different population studies. In the present study, the roles of HLA-DRB1 and DQB1 alleles and the amino acids were investigated on disease risk and severity in 120 Iranian patients with MS and 120 controls. Our findings indicate that the DRB1*1501 allele (OR = 3.203 P = 0.001), the DRB1*1501-DQB1*0602 haplotype (OR = 7.792 P = 0.003) and the DRB1*1501/0701- genotype (OR = 3.320 P = 0.006) and amino acid Leu26 (OR = 1.645 P = 0.005) and Phe9 (OR = 1.893 P = 0.009) on the DQβ1 chain are significantly associated with MS susceptibility. DRB1*1001 was the only allele that had a protective effect against MS (P = 0.0004). We also found that the DQB1*0303 allele was significantly associated with disease severity (mean Multiple Sclerosis Severity Score difference = 1.979, P = 0.002). However, protective effect of the DRB1*1001 against MS and also association of DQB1*0303 allele with MS severity need to be confirmed by larger sample size.

Multiple sclerosis in Caucasians and Latino Americans

Epidemiological and genetic studies suggest that the prevalence, median age of onset, and specific phenotypes of multiple sclerosis (MS) are different in Caucasians and Latino Americans. Recent epidemiological studies indicate an increase in MS prevalence in Latin America (LA), where the south-north gradient of latitude described for Nordic countries does not exist. Analysis of MS epidemiological and specific aspects in LA suggests that susceptibility and clinical behavior of the disease are related to mixtures and admixtures of genes in the population. MS is not present in Amerindians with Mongoloid genes, such as occurs in other pure ethnic groups. Surely, future studies will be carried out to obtain more reliable information. In this review, we contrast and analyze the available data of MS in LA and endemic countries.

Multiple sclerosis risk markers in HLA-DRA, HLA-C, and IFNG genes are associated with sex-specific childhood leukemia risk

Previous epidemiologic studies showed four times increased risk of acute lymphoblastic leukemia (ALL) in children of women with multiple sclerosis (MS). MS shows a risk association with Human leukocyte antigens (HLA)-DRA single nucleotide polymorphism (SNP) rs3135388, which is a proxy marker for DRB1*1501. We examined the relevance of rs3135388 in childhood ALL risk along with two other HLA-DRA SNPs in two case-control groups: 114 cases and 388 controls from South Wales (UK) and 100 Mexican Mestizo cases and 253 controls. We first confirmed the correlation between rs3135388 and DRB1*1501 in HLA-typed reference cell lines. We noted a female-specific risk association in childhood ALL (pooled odds ratio (OR) = 2.6, 95% confidence interval (CI) = 1.5-4.5, Mantel-Haenszel P = 0.0009) similar to the stronger association of DRB1*1501 in females with MS. Examination of an HLA-C 5' flanking region SNP rs9264942, known to correlate with HLA-C expression, showed a protective association in girls (OR = 0.4, 95% CI = 0.2-0.7, Mantel-Haenszel P = 0.0003) similar to the protective HLA-Cw*05 association in MS. In a reference cell line panel, HLA-Cw5 homozygous samples (n = 8) were also homozygous for the minor allele of the SNP. Likewise, the male-specific protective association of interferon-gamma (IFNG) SNP rs2069727 in MS was replicated with the same sex specificity in childhood ALL (OR = 0.6, 95% CI = 0.4-1.0, Mantel-Haenszel P = 0.03). Two other SNPs in superkiller viralicidic activity 2-like and tenascin XB that are markers for systemic lupus erythematosus susceptibility showed female-specific associations but due to linkage disequilibrium with HLA-DRB1*15. Our observations supported the epidemiologic link between MS and childhood ALL and added the sex effect to this connection. It appears that only girls born to mothers with MS may have an increased risk of ALL. Investigating the mechanism of these sex-specific associations may help understand the pathogenesis of MS and ALL.

Early treatment of multiple sclerosis: a Latin American experts meeting

Patients with clinically isolated syndrome (CIS) by definition do not have multiple sclerosis (MS) but are at risk of developing it. While studies show earlier immunomodulating drug use is effective, treatment must consider likely patient prognosis. In this paper we review current diagnosis, prognosis, and treatment literature for patients with CIS within Latin American clinical settings. Latin American MS experts, convened by ACINDES (The Civil Association for Research and Development in Health), reviewed current CIS (and early MS) literature and drew consensus conclusions. Three subgroups addressed separate questionnaires on CIS issues: prognosis, diagnosis, and treatment. MRI can contribute to predicting MS risk in patients with CIS; in Latin America, investigation of haplotype presence associated with CIS would be appropriate. McDonald's criteria and subsequent revisions enable earlier, more accurate MS diagnosis. Type A evidence exists supporting all leading immunomodulating MS drugs for effective treatment of CIS with a high risk of conversion to MS. In conclusion, patients with CIS are usually young, with often-limited symptomatic manifestations, and must be adequately prepared to receive preventive treatment. This consensus review should contribute to the dialogue between physicians and patients.

Association of narcolepsy-cataplexy with HLA-DRB1 and DQB1 in Mexican patients: a relationship between HLA and gender is suggested

Background

Narcolepsy-cataplexy is characterized by excessive daytime sleepiness with recurrent episodes of irresistible sleep, cataplexy, hallucinations and sleep paralysis. Its aetiology is unknown, but it is positively associated with the human leukocyte antigens (HLA) in all studied populations. The purpose of the present study was to investigate the association of HLA class II DRB1/DQB1 alleles with narcolepsy-cataplexy in Mexican Mestizo patients.

Methods

This is a case-control study of consecutive patients and ethnically matched controls. We included 32 patients diagnosed with typical narcolepsy-cataplexy, of the National Institute of Neurology, of the Institute of Psychiatry and at the Center of Narcolepsy at Stanford University. As healthy controls, 203 Mexican Mestizos were included. DRB1 alleles were identified using sequence based typing. A PCR-SSOP reverse dot blot was used for DQB1 typing. Allele frequency was calculated by direct counting and the significance of the differences was assessed using the Yates Chi square. Odds ratio and confidence intervals were evaluated.

Results

HLA-DRB1*1501 (OR = 8.2; pc < 0.0001) and DQB1*0602 (OR = 8.4; pc < 0.0001) were found positively associated with narcolepsy. When deleting DQB1*0602+ patients from the analysis, DQB1*0301 was also found increased (OR = 2.7; p = 0.035; pc = NS). DQB1*0602/DQB1*0301 genotype was present in 15.6% of the cases (OR = 11.5; p = 0.00035), conferring a high risk. DRB1*0407 (OR = 0.2; p = 0.016 pc = NS) and DQB1*0302(OR = 0.4; p = 0.017, pc = NS) were found decreased in the patients. The gender stratification analysis showed a higher risk in females carrying DRB1*1501 (OR = 15.8, pc < 0.0001) and DQB1*0602 (OR = 19.8, pc < 0.0001) than in males (OR = 5.0 for both alleles; p = 0.012, pc = NS for DRB1 & p = 0.0012, pc = 0.017 for DQB1). The susceptibility alleles found in Mexicans with narcolepsy are also present in Japanese and Caucasians; DRB1*04 linked protection has also been shown in Koreans. A stronger HLA association is suggested in females, in accordance with the sexual dimorphism claimed previously.

Conclusion

This knowledge may contribute to a better understanding of the disease pathogenesis in different populations. The evaluation of the risk to develop narcolepsy-cataplexy in carriers of the described alleles/genotypes may also be possible. A larger sample should be analysed in Mexican and in other Hispanic patients to confirm these results.

Defining the role of the MHC in autoimmunity: a review and pooled analysis

The major histocompatibility complex (MHC) is one of the most extensively studied regions in the human genome because of the association of variants at this locus with autoimmune, infectious, and inflammatory diseases. However, identification of causal variants within the MHC for the majority of these diseases has remained difficult due to the great variability and extensive linkage disequilibrium (LD) that exists among alleles throughout this locus, coupled with inadequate study design whereby only a limited subset of about 20 from a total of approximately 250 genes have been studied in small cohorts of predominantly European origin. We have performed a review and pooled analysis of the past 30 years of research on the role of the MHC in six genetically complex disease traits - multiple sclerosis (MS), type 1 diabetes (T1D), systemic lupus erythematosus (SLE), ulcerative colitis (UC), Crohn's disease (CD), and rheumatoid arthritis (RA) - in order to consolidate and evaluate the current literature regarding MHC genetics in these common autoimmune and inflammatory diseases. We corroborate established MHC disease associations and identify predisposing variants that previously have not been appreciated. Furthermore, we find a number of interesting commonalities and differences across diseases that implicate both general and disease-specific pathogenetic mechanisms in autoimmunity.

Western and Asian features of multiple sclerosis in Mexican Mestizos

OBJECTIVES

The objective of this study was to compare the clinical expression of MS in Mexican Mestizos with that of patients of European or Asian descent; as well as to compare the annual frequency of new cases with that observed in the previous decades.

PATIENTS AND METHODS

All patients with diagnosis of definite MS seen at the National Institute of Neurology and Neurosurgery of Mexico from January 1993 to December 2003 were studied (n=312). Sociodemographic and clinical characteristics were compared with reports of patients from either Western or Asian origin; the long-term disability score was analyzed according to gender, age of onset of MS and the initial symptom.

RESULTS

The clinical expression of MS in Mexican Mestizos shares some characteristics with both, Asian and Western forms of MS indicating that the genetic composition of Mexican Mestizos participates in the clinical expression of the disease. Also, at the prevalence date, the mean age of patients and the duration of the disease were lower in our patients than in MS patients from endemic countries suggesting a true increasing incidence in recent times, rather than only improved case ascertainment.

CONCLUSIONS

Clinical expression of MS in Mexican Mestizos shows the coexistence of some features common in European and in Asian cases.