Comprehensive human leukocyte antigen genotyping of patients with type 1 diabetes mellitus in Taiwan

Fifty years of HLA-associated type 1 diabetes risk: history, current knowledge, and future directions

More than 50 years have elapsed since the association of human leukocyte antigens (HLA) with type 1 diabetes (T1D) was first reported. Since then, methods for identification of HLA have progressed from cell based to DNA based, and the number of recognized HLA variants has grown from a few to tens of thousands. Current genotyping methodology allows for exact identification of all HLA-encoding genes in an individual's genome, with statistical analysis methods evolving to digest the enormous amount of data that can be produced at an astonishing rate. The HLA region of the genome has been repeatedly shown to be the most important genetic risk factor for T1D, and the original reported associations have been replicated, refined, and expanded. Even with the remarkable progress through 50 years and over 5,000 reports, a comprehensive understanding of all effects of HLA on T1D remains elusive. This report represents a summary of the field as it evolved and as it stands now, enumerating many past and present challenges, and suggests possible paradigm shifts for moving forward with future studies in hopes of finally understanding all the ways in which HLA influences the pathophysiology of T1D.

Association Between HLA Polymorphisms and Sympathetic Ophthalmia in Han Chinese

PURPOSE

Sympathetic ophthalmia (SO) is considered as an autoimmune disease with unclear mechanisms. This study investigated the relationship between HLA polymorphisms and SO.

METHODS

HLA typing was performed using the LABType reverse SSO DNA typing method. The allele and haplotype frequencies were assessed using the PyPop software. Statistical significance of genotype distributions between 116 patients and 84 healthy individuals (control) was determined using Fisher's exact test or Pearson's chi-squared test.

RESULTS

The SO group had a higher frequency of HLA-DRB1 * 04:05, HLA-DQB1 * 04:01, DRB1 * 04:05-DQB1 * 04:01 haplotype   as compared to the control group (Pc < 0.001 for all).

CONCLUSION

This study revealed that DRB1 * 04:05 and DQB1 * 04:01 alleles, as well as DRB1 * 04:05-DQB1 * 04:01 haplotye could be potential risk factors for SO.

Combining polygenic risk scores and human leukocyte antigen variants for personalized risk assessment of type 1 diabetes in the Taiwanese population

AIMS

To analyse the genome-wide association study (GWAS) data of patients with type 1 diabetes mellitus (T1D) in order to develop a risk score for the genetic effects on T1D risk and age at diagnosis in the Taiwanese population.

MATERIALS AND METHODS

We selected 610 patients with T1D and 2511 healthy individuals from an electronic medical record database of more than 300 000 individuals with genetic information, analysed their GWAS data, and developed a polygenic risk score (PRS).

RESULTS

The PRS, based on 149 selected single-nucleotide polymorphisms, could effectively predict T1D risk. A PRS increase was associated with increased T1D risk (odds ratio [OR] 2.09, 95% confidence interval [CI] 1.72-2.55). Moreover, a 1-unit increase in standardized T1D PRS decreased the age at diagnosis by 0.74 years. Combined PRS and human leukocyte antigen (HLA) DQA1*03:02-DQA1*05:01 genotypes could accurately predict T1D risk. In multivariable models, HLA variants and PRS were independent risk factors for T1D risk (OR 3.76 [95% CI 1.54-9.16] and 1.71 [95% CI 1.37-2.13] for HLA DQA1*03:02-DQA1*05:01 and PRS, respectively). In a limited study population of those aged ≤18 years, PRS remained significantly associated with T1D risk. The association between T1D PRS and age at diagnosis was more obvious among males and patients aged ≤18 years.

CONCLUSIONS

Polygenic risk score and HLA variations enable personalized risk estimates, enhance newborn screening efficiency for ketoacidosis prevention, and addresses the gap in data on T1D prediction in isolated Asian populations.

Human leukocyte antigen association in systemic sclerosis patients: our experience at a tertiary care center in North India

Introduction

Systemic sclerosis (SSc) is a chronic multisystem autoimmune rheumatic disease of unknown etiology. Several studies have established that SSc is triggered by a dynamic interplay between genetic factors and environmental stimuli. In the present study, we aimed to study the association of human leukocyte antigen (HLA) with familial and non-familial SSc patients [limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc)] from North India.

Methods

The HLA-A, B, DRB1, and DQB1 genotyping of 150 (70 lcSSc and 80 dcSSc) adult-onset SSc patients and 150 age-gender-matched healthy controls were performed with sequence-specific oligonucleotide (SSO) typing kits using the luminex platform. HLA typing for HLA class I (A, B, and C) and II (DRB1, DQB1, and DPB1) in five North Indian families consisting of parent-child/sibling pairs affected with SSc or overlap syndrome was performed by Next Generation Sequencing (NGS) with Illumina MiniSeq.

Rseults

Among the non-familial SSc patients, HLA- DRB1*11 (P = 0.001, OR: 2.38, P c = 0.01) was identified as a risk allele, and DRB1*12 (P = .0001, OR: 0.00, P c = 0.001) as a protective allele. There was no statistical association found with HLA-DQB1*. Also, no significant association was observed between HLA antigens and different clinical subsets (lcSSc and dcSSc) of SSc. Two cases of familial SSc patients had the DRB1*11 allele. The DRB1*12 allele was absent in all the familial SSc patients.

Discussion

HLA DRB1*11 (risk allele) and DRB1*12 (protective allele) were found to be strongly associated with non-familial SSc patients and partially explain the disease's familial clustering, supporting the susceptible genetic background theory for SSc development. The study also indicates the HLA allele as a common genetic risk factor in distinct autoimmune diseases contributing to overlap syndrome or polyautoimmunity.

HLA Class I Association With Autoimmune Diabetes in Chinese People: Distinct Implications in Classic Type 1 Diabetes and LADA

CONTEXT

We aimed to investigate whether human leukocyte antigen (HLA) Class I loci differentially modulated the risk for and clinical features of Chinese people with classic type 1 diabetes (T1D) and latent autoimmune diabetes in adults (LADA).

METHODS

In this case-control study, genotypes of HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 loci were obtained from 1067 cases with classic T1D, 1062 cases with LADA, and 1107 normal controls using next-generation sequencing.

RESULTS

Despite 4 alleles shared between classic T1D and LADA (protective: A*02:07 and B*46:01; susceptible: B*54:01 and C*08:01), 7 Class I alleles conferred risk exclusively for classic T1D (A*24:02, B*15:02, B*15:18, B*39:01, B*40:06, B*48:01, and C*07:02) whereas only A*02:01 was an additional risk factor for LADA. Class I alleles affected a wide spectrum of T1D clinical features, including positive rate of protein tyrosine phosphatase autoantibody and zinc transporter 8 autoantibody (A*24:02), C-peptide levels (A*24:02), and age at diagnosis (B*46:01, C*01:02, B*15:02, C*07:02, and C*08:01). By contrast, except for the detrimental effect of C*08:01 on C-peptide concentrations in LADA, no other Class I associations with clinical characteristics of LADA could be reported. The addition of Class I alleles refined the risk model consisting only of DR-DQ data in classic T1D while the overall predictive value of the LADA risk model comprising both Class I and II information was relatively low.

CONCLUSION

The attenuated HLA Class I susceptibility to LADA was indicative of a less deleterious immunogenetic nature compared with classic T1D. These autoimmune diabetes-related Class I variants might serve as additional markers in future screening among Chinese people.

Epidemiology and phenotypes of diabetes in children and adolescents in non-European-origin populations in or from Western Pacific region

BACKGROUND

Type 1 diabetes (T1D) incidence varies substantially between countries/ territories, with most studies indicating increasing incidence. In Western Pacific region (WPR), reported rates are much lower than European-origin populations. In contrast, there are reports of substantial numbers of young people with type 2 diabetes (T2D). A deeper understanding of T1D and T2D in the WPR may illuminate factors important in pathogenesis of these conditions. Furthermore, with varying resources and funding for diabetes treatment in this region, there is a need to more clearly determine the current burden of disease and also any gaps in knowledge.

AIM

To compile and summarise published epidemiologic and phenotypic data on childhood diabetes in non-European populations in and from WPR.

METHODS

Research articles were systematically searched from PubMed (MEDLINE), Embase, Cochrane library, and gray literature. Primary outcome measures were incidence and prevalence, with secondary measures including phenotypic descriptions of diabetes, including diabetes type categorization, presence of diabetic ketoacidosis (DKA) at onset, autoantibody positivity, C-peptide levels, and human leucocyte antigen phenotype. Extracted data were collected using a customized template. Three hundred and thirty relevant records were identified from 16 countries/territories, with analysis conducted on 265 (80.3%) records published from the year 2000.

RESULTS

T1D incidence ranged from < 1-7.3/100000 individuals/year, rates were highest in emigrant/ mixed populations and lowest in South-East Asia, with most countries/territories (71.4%) having no data since 1999. Incidence was increasing in all six countries/territories with data (annual increases 0.5%-14.2%, highest in China). Peak age-of-onset was 10-14 years, with a female case excess. Rate of DKA at onset varied from 19.3%-70%. Pancreatic autoantibodies at diagnosis were similar to European-origin populations, with glutamic acid decarboxylase-65 autoantibody frequency of 44.1%-64.5%, insulinoma-associated 2 autoantibody 43.5%-70.7%, and zinc transporter-8 autoantibody frequency 54.3% (one study). Fulminant T1D also occurs. T2D was not uncommon, with incidence in Japan and one Chinese study exceeding T1D rates. Monogenic forms also occurred in a number of countries.

CONCLUSION

T1D is less common, but generally has a classic phenotype. Some countries/ territories have rapidly increasing incidence. T2D is relatively common. Registries and studies are needed to fill many information gaps.

Increased Incidence of Pediatric Type 1 Diabetes With Novel Association With Coxsackievirus A Species in Young Children but Declined Incidence in Adolescents in Taiwan

OBJECTIVE

Type 1 diabetes (T1D) has been linked to enterovirus infection in small population-based epidemiological studies. We investigated the secular relationship of T1D incidence with enterovirus infection and enterovirus species using nationwide population-based analysis.

RESEARCH DESIGN AND METHODS

We accessed the National Health Insurance Research Database of Taiwan to identify T1D and enterovirus infection cases from 2001 to 2015. Enterovirus serotype isolation rates were obtained from the nationwide laboratory surveillance systems. Negative binomial regression models assessed the incidence trend, and extended Cox proportional hazards models analyzed the association of enterovirus infection with T1D incidence. Spearman correlation coefficients evaluated the correlation between T1D incidence and circulating enterovirus species.

RESULTS

T1D incidence rates in youth younger than 20 years were 6.30 and 5.02 per 100,000 person-years in 2001 and 2015 (P = 0.287), respectively. T1D incidence increased significantly in children aged 0-6 years (P < 0.001) but decreased in adolescents aged 13-19 years (P = 0.011). The T1D risk in children aged 0-6 years with enterovirus infection was significantly higher than that in noninfected subjects (hazard ratio 1.46; 95% CI 1.35-1.58; P < 0.001). Additionally, TID incidence in children aged 0-6 years was significantly correlated with the isolation rates of coxsackievirus A species (r = 0.60; P = 0.017), but no association was found beyond the age of 7.

CONCLUSIONS

We demonstrated that T1D incidence increased in children aged 0-6 years but decreased in adolescents aged 13-19 years in Taiwan. Enterovirus-infected subjects younger than 7 years had a higher risk of T1D than noninfected subjects.

The association of HLA-DP loci with autoimmune diabetes in Chinese

AIMS

To determine if HLA-DP loci independently contribute to classic type 1 diabetes (T1D) of all ages, childhood-onset T1D and latent autoimmune diabetes in adults (LADA) among Chinese Han population.

METHODS

A total of 518 patients with classic T1D (Among them 180 participants manifested T1D between 1 and 14 years), 519 patients with LADA and 527 normal controls were genotyped for both HLA-DPA1 and -DPB1 loci. The frequencies of DP alleles and haplotypes in patients were directly compared to those in controls, followed by adjustment for linkage disequilibrium (LD) with DR-DQ haplotypes.

RESULTS

In the direct comparison, DPA1*01:03, DPB1*04:01 and DPA1*01:03-DPB1*04:01 showed disease-predisposing effects in both the overall T1D group and the childhood-onset T1D group mainly due to their conjunction with the known susceptible DR3 haplotype. Conditioning on DR-DQ haplotypes, only DPA1*02:02-DPB1*02:02 significantly increased T1D risk among those diagnosed during childhood (OR = 2.02, 95% CI = 1.35-3.01). Whether or not adjusted for LD, no statistically significant HLA-DP association could be observed for LADA.

CONCLUSION

HLA-DP is implicated in the pathogenesis of childhood-onset T1D in Chinese, independent of the predominant DR-DQ loci and might serve as additional markers in genetic models for the recognition of those genetically at-risk individuals.