Association of HLA-B∗38:02 with Antithyroid Drug-Induced Agranulocytosis in Kinh Vietnamese Patients

Novel Association of KLRC4-KLRK1 Gene Polymorphisms with Susceptibility and Progression of Antithyroid Drug-Induced Agranulocytosis

OBJECTIVE

Antithyroid drug (ATD)-induced agranulocytosis (TIA) is the most serious adverse effect during ATD treatment of Graves' disease (GD). Previously, the MICA gene was reported to be associated with TIA. MICA protein is an important ligand for the NKG2D protein, which is encoded by the KLRK1 gene and KLRC4-KLRK1 read-through transcription. This study further investigated the association between KLRC4-KLRK1 gene polymorphisms and susceptibility to TIA.

METHODS

Twenty-eight candidate single nucleotide polymorphisms (SNPs) on KLRC4-KLRK1 read-through transcription were evaluated by the iPLEX MassARRAY system in 209 GD control patients and 38 TIA cases.

RESULTS

A significant association of rs2734565 polymorphism with TIA was found (p=0.02, OR=1.80, 95% CI=1.09-2.96). The haplotype C-A-A-C-G, including rs2734565-C, was associated with a significantly higher risk of TIA (p=4.79E-09, OR=8.361, 95% CI=3.737-18.707). In addition, the interval time from hyperthyroidism to agranulocytosis onset was shorter in patients carrying the rs2734565-C allele than in non-carrying groups (45.00 (14.00-6570.00) d vs. 1080.00 (30.00-3600.00) d, p=0.046), and the interval from ATD treatment to agranulocytosis onset was also shorter in patients carrying rs2734565-C allele (29.00 (13.00-75.00) d vs. 57.50 (21.00-240.00) d, p=0.023).

CONCLUSIONS

The findings suggest that the KLRC4-KLRK1 gene polymorphism is associated with susceptibility and progression of ATD-induced agranulocytosis. Patients carrying the rs2734565-C allele had a higher susceptibility and faster onset time of TIA.

A single-tube multiplex real-time PCR for HLA-B*38:02 genotype by detecting highly specific SNPs

Purpose: HLA-B*38:02 is closely related to carbimazole/methimazole-induced agranulocytosis. This study aimed to develop and validate a rapid and economical method for HLA-B*38:02 genotyping. Methods: A single-tube multiplex real-time PCR detection system comprising amplification refractory mutation system primers and TaqMan probes was established for HLA-B*38:02 genotyping. Sequence-based typing was applied to validate the accuracy of the assay. Results: The accuracy of the assay was 100% for HLA-B*38:02 genotyping. The detection limit of the new method was 0.05 ng DNA. The positive rate of HLA-B*38:02 in the Han (8%, n = 100), Bouyei (17.8%, n = 90) and Tibetan (12.7%, n = 110) populations was significantly higher than that in the Uighur population (1%, n = 100) (p < 0.05). Conclusion: The proposed method is rapid and reliable for HLA-B*38:02 screening in a clinical setting.

Association of KCNJ11 and ABCC8 single-nucleotide polymorphisms with type 2 diabetes mellitus in a Kinh Vietnamese population

Type 2 diabetes mellitus (T2DM) is a genetically influenced disease, but few studies have been performed to investigate the genetic basis of T2DM in Vietnamese subjects. Thus, the potential associations of KCNJ11 and ABCC8 single nucleotide polymorphisms (SNPs) with T2DM were investigated in a Kinh Vietnamese population. A cross-sectional study consisting of 404 subjects including 202 T2DM cases and 202 non-T2DM controls was designed to examine the potential associations of 4 KCNJ11 and ABCC8 SNPs (rs5219, rs2285676, rs1799859, and rs757110) with T2DM. Genotypes were identified based on restriction fragment length polymorphism and tetra-primer amplification refractory mutation system polymerase chain reaction. After statistically adjusting for age, sex, and BMI, rs5219 was found to be associated with an increased risk of T2DM under 2 inheritance models: codominant (OR = 2.15, 95% confidence intervals [CI] = 1.09-4.22) and recessive (OR = 2.08, 95%CI = 1.09-3.94). On the other hand, rs2285676, rs1799859, and rs757110 were not associated with an increased risk of T2DM. Haplotype analysis elucidated a strong linkage disequilibrium between the 3 SNPs, rs5219, rs2285676, and rs757110. The haplotype rs5219(A)/rs2285676(T)/rs757110(G) was associated with an increased risk of T2DM (OR = 1.42, 95%CI = 1.01-1.99). The results show that rs5219 is a lead candidate SNP associated with an increased risk of developing T2DM in the Kinh Vietnamese population. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.

Association of ADIPOQ Single-Nucleotide Polymorphisms with the Two Clinical Phenotypes Type 2 Diabetes Mellitus and Metabolic Syndrome in a Kinh Vietnamese Population

PURPOSE

Genetic factors play an important role in the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). However, few genetic association studies related to these disorders have been performed with Vietnamese subjects. In this study, the potential associations of ADIPOQ single nucleotide polymorphisms (SNPs) with T2DM and MetS in a Kinh Vietnamese population were investigated.

PATIENTS AND METHODS

A study with 768 subjects was conducted to examine the associations of four ADIPOQ SNPs (rs266729, rs1501299, rs3774261, and rs822393) primarily with T2DM and secondarily with MetS. The TaqMan SNP genotyping assay was used to determine genotypes from subjects' DNA samples.

RESULTS

After statistical adjustment for age, sex, and body mass index, the ADIPOQ SNP rs266729 was found to be associated with increased risk of T2DM under multiple inheritance models: codominant (OR = 2.30, 95% CI = 1.16-4.58), recessive (OR = 2.17, 95% CI = 1.11-4.26), and log-additive (OR = 1.32, 95% CI = 1.02-1.70). However, rs1501299, rs3774261, and rs822393 were not associated with risk for T2DM. Additionally, rs266729, rs3774261, and rs822393 were statistically associated with MetS, while rs1501299 was not. Haplotype analysis showed a strong linkage disequilibrium between the SNP pairs rs266729/rs822393 and rs1501299/rs3774261, and the haplotype rs266729(G)/rs822393(T) was not statistically associated with MetS.

CONCLUSION

The results show that rs266729 is a lead candidate SNP associated with increased risk of developing T2DM and MetS in a Kinh Vietnamese population, while rs3774261 is associated with MetS only. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.

Association of MICA gene polymorphisms with thionamide-induced agranulocytosis

BACKGROUND

Thionamide-induced agranulocytosis (TIA), namely antithyroid drug (ATD)-induced agranulocytosis, is one of the most feared adverse effect of ATDs. It is defined as a granulocyte count of less than 0.5 × 10⁹/L after ATD administration. Several studies reported that TIA is associated with human leukocyte antigen (HLA) and nearby genes. Our previous study found that the susceptibility genes of TIA are similar in north China and European populations.

METHODS

We evaluated the associations of 23 candidate single nucleotide polymorphisms (SNPs) in 37 patients with TIA and 254 patients with Graves' disease (GD) as controls by iPLEX MassARRAY system.

RESULTS

Five SNPs in the MHC class I polypeptide-related sequence A(MICA) genes [rs4349859 (p = 1.43E-7); rs145575084 (p = 5.79E-6); rs116135464 (p = 3.70E-5); rs148015908 (p = 3.79E-5) and rs189600525 (p = 2.15E-4)] were found to be significantly associated with TIA after Bonferroni correction. After combining with previous data of rs4349859 and HLA-B*27:05, the haplotype analysis showed that patients carrying P-A-C-A-T-T-A haplotype have a higher risk of TIA (p = 9.76E-7; OR = 14.85, 95% CI 3.63-60.77).

CONCLUSION

Our findings suggest that five high linked SNPs of MICA gene are significantly associated with susceptibility to TIA.

MICA polymorphisms associated with antithyroid drug-induced agranulocytosis in the Chinese Han population

Background

Graves' disease (GD) is a clinical autoimmune thyroid disease. During the treatment of GD, antithyroid drug‐induced agranulocytosis (TIA) is a common and even life‐threatening adverse drug reaction. Previous studies suggested that susceptibility to TIA is strongly associated with HLA‐B*27:05, HLA‐B*38:02, and HLA‐DRB1*08:03 genetic variation and six single nucleotide polymorphisms (SNPs) in MICA genes.

Aims

The purpose of this study is to further study the associations between TIA, HLA‐B and MICA.

Materials & Methods

We genotyped MICA‐STR and MICA‐129 variants in 41 TIA and 308 control patients with GD and investigated the linkage effect among SNPs and short tandem repeat (STR) of MICA and HLA‐B alleles.

Results

The results showed that MICA*A5.1 was significantly associated with TIA (p = .007, odd ratio = 1.958, 95% confidence interval, 1.192–3.214). In addition, high linkage among MICA‐129 and six SNPs MICA and HLA‐B was detected, and two haplotypes (AAAACAAAAACGGCCTA and AACAAAAAAAACATTAA (p = 5.14E−07 and p = 3.42E−08, respectively)) were significantly associated with TIA. Furthermore, when we analyzed only MICA‐129 and HLA‐B separately, the haplotypes (AAAACAAAAAA with p = 2.49E−07 and AACAAAAAAAA with p = 2.14E−09) were identified with more significant effects. MICA‐129 was completely linked to six SNPs with haplotypes ACATTACA (p = 2.05E−05) significantly associated with TIA.

Conclusion

These data indicated that there was a significant linkage effect between MICA‐129 and other alleles, suggesting that they exert interactive effects as risk factors for the development of TIA.

HLA-B*39:01:01 is a novel risk factor for antithyroid drug-induced agranulocytosis in Japanese population

Antithyroid drug (ATD) is a mainstay of Graves' disease (GD). About 0.1-0.5% of patients with GD treated with ATD exhibit ATD-induced agranulocytosis, which is characterized by severe reduction of circulating neutrophils. Immune-mediated responses have been proposed as a possible mechanism for the pathogenesis of ATD-induced agranulocytosis. Although it has been reported that the HLA class II allele (HLA-DRB1*08:03) was associated with ATD-induced agranulocytosis in multiple populations, the entire HLA region have not been explored in Japanese. Therefore, we performed HLA sequencing for 10 class I and 11 class II genes in 87 patients with ATD-induced agranulocytosis and 384 patients with GD who did not show ATD-induced agranulocytosis. By conducting case-control association studies at the HLA allele and haplotype levels, we replicated the association between HLA-DRB1*08:03:02 and ATD-induced agranulocytosis (P = 5.2 × 10^-7, odds ratio = 2.80), and identified HLA-B*39:01:01 as an independent risk factor (P = 1.4 × 10^-3, odds ratio = 3.35). To verify reproducibility of the novel association of HLA-B*39:01:01, we reanalyzed allele frequency data for HLA-B*39:01:01 from previous case-control association studies. The association of HLA-B*39:01:01 was significantly replicated in Chinese (P = 9.0 × 10^-3), Taiwanese (P = 1.1 × 10^-3), and European populations (P = 5.2 × 10^-4). A meta-analysis combining results from the previous and current studies reinforced evidence of the association between HLA-B*39:01:01 and ATD-induced agranulocytosis (P_meta = 1.2 × 10^-9, pooled OR = 3.66, 95% CI; 2.41-5.57). The results of this study will provide a better understanding of the pathogenesis of ATD-induced agranulocytosis in the context of HLA-mediated hypersensitivity reactions.

High-Throughput Sequencing to Investigate Associations Between HLA Genes and Metamizole-Induced Agranulocytosis

Background and Objective: Agranulocytosis is a rare and potentially life-threatening complication of metamizole (dipyrone) intake that is characterized by a loss of circulating neutrophil granulocytes. While the mechanism underlying this adverse drug reaction is not well understood, involvement of the immune system has been suggested. In addition, associations between genetic variants in the Human Leukocyte Antigen (HLA) region and agranulocytosis induced by other drugs have been reported. The aim of the present study was to assess whether genetic variants in classical HLA genes are associated with the susceptibility to metamizole-induced agranulocytosis (MIA) in a European population by targeted resequencing of eight HLA genes.

Design: A case-control cohort of Swiss patients with a history of neutropenia or agranulocytosis associated with metamizole exposure (n = 53), metamizole-tolerant (n = 39) and unexposed controls (n = 161) was recruited for this study. A high-throughput resequencing (HTS) and high-resolution typing method was used to sequence and analyze eight HLA loci in a discovery subset of this cohort (n = 31 cases, n = 38 controls). Identified candidate alleles were investigated in the full Swiss cohort as well as in two independent cohorts from Germany and Spain using HLA imputation from genome-wide SNP array data. In addition, variant calling based on HTS data was performed in the discovery subset for the class I genes HLA-A, -B, and -C using the HLA-specific mapper hla-mapper.

Results: Eight candidate alleles (p < 0.05) were identified in the discovery subset, of which HLA-C^∗04:01 was associated with MIA in the full Swiss cohort (p < 0.01) restricted to agranulocytosis (ANC < 0.5 × 10⁹/L) cases. However, no candidate allele showed a consistent association in the Swiss, German and Spanish cohorts. Analysis of individual sequence variants in class I genes produced consistent results with HLA typing but did not reveal additional small nucleotide variants associated with MIA.

Conclusion: Our results do not support an HLA-restricted T cell-mediated immune mechanism for MIA. However, we established an efficient high-resolution (three-field) eight-locus HTS HLA resequencing method to interrogate the HLA region and demonstrated the feasibility of its application to pharmacogenetic studies.

High-Resolution HLA Typing of HLA-A, -B, -C, -DRB1, and -DQB1 in Kinh Vietnamese by Using Next-Generation Sequencing

Human leukocyte antigen (HLA) genotyping displays the particular characteristics of HLA alleles and haplotype frequencies in each population. Although it is considered the current gold standard for HLA typing, high-resolution sequence-based HLA typing is currently unavailable in Kinh Vietnamese populations. In this study, high-resolution sequence-based HLA typing (3-field) was performed using an amplicon-based next-generation sequencing platform to identify the HLA-A, -B, -C, -DRB1, and -DQB1 alleles of 101 unrelated healthy Kinh Vietnamese individuals from southern Vietnam. A total of 28 HLA-A, 41 HLA-B, 21 HLA-C, 26 HLA-DRB1, and 25 HLA-DQB1 alleles were identified. The most frequently occurring HLA alleles were A^∗11:01:01, B^∗15:02:01, C^∗07:02:01, DRB1^∗12:02:01, and DQB1^∗03:01:01. Haplotype calculation showed that A^∗29:01:01∼B^∗07:05:01, DRB1^∗12:02:01∼DQB1^∗3:01:01, A^∗29:01:01∼C^∗15:05:02∼B^∗07:05:01, A^∗33:03:01∼B^∗58:01:01∼DRB1^∗03:01:01, and A^∗29:01:01∼C^∗15:05:02∼B^∗07:05:01∼DRB1^∗10:01:01∼DQB1^∗05:01:01 were the most common haplotypes in the southern Kinh Vietnamese population. Allele distribution and haplotype analyses demonstrated that the Vietnamese population shares HLA features with South-East Asians but retains unique characteristics. Data from this study will be potentially applicable in medicine and anthropology.

Informatics investigations into anti-thyroid drug induced agranulocytosis associated with multiple HLA-B alleles

INTRODUCTION

Adverse drug reactions have been linked with HLA alleles in different studies. These HLA proteins play an essential role in the adaptive immune response for the presentation of self and non-self peptides. Anti-thyroid drugs methimazole and propylthiouracil have been associated with drug induced agranulocytosis (severe lower white blood cell count) in patients with B*27:05, B*38:02 and DRB1*08:03 alleles in different populations: Taiwanese, Vietnamese, Han Chinese and Caucasian.

METHODS

In this study, informatics methods were used to investigate if any sequence or structural similarities exist between the two associated HLA-B alleles, compared with a set of "control" alleles assumed not be associated, which could help explain the molecular basis of the adverse drug reaction. We demonstrated using MHC Motif Viewer and MHCcluster that the two alleles do not have a propensity to bind similar peptides, and thus at a gross level the structure of the antigen presentation region of the two alleles are not similar. We also performed multiple sequence alignment to identify polymorphisms shared by the risk but not by the control alleles and molecular docking to compare the predicted binding poses of the drug-allele combinations.

RESULTS

Two residues, Cys67 and Thr80, were identified from the multiple sequence alignments to be unique to these risk alleles alone. The molecular docking showed the poses of the risk alleles to favour the F-pocket of the peptide binding groove, close to the Thr80 residue, with the control alleles generally favouring a different pocket. The data are thus suggestive that Thr80 may be a critical residue in HLA-mediated anti-thyroid drug induced agranulocytosis, and thus can guide future research and risk assessment.

Association of HLA-C*03:02 with methimazole-induced liver injury in Graves' disease patients

Methimazole (MMI) has been used for the treatment of Graves' Disease (GD) for more than half a century. The MMI treatment has been reported to be associated with hepatotoxicity. Previous studies have demonstrated that human leukocyte antigen (HLA) genetic polymorphisms were associated with many drugs-induced liver injuries. To investigate HLA genetic susceptibility to MMI-induced liver injury (MMI-DILI), we characterized both HLA class I and class Ⅱ in a well-characterized phenotypic cohort with 40 MMI-DILI cases and 118 MMI-tolerant controls. Among the 40 MMI-DILI cases, 57.5% were women and 50% were cholestatic liver damage with occurring time from days to months after MMI dosing. The frequency of HLA-C*03:02 was 6.7% (5/75) in the MMI-DILI case patients and 6.4% (4/62) in MMI-induced cholestatic/mixed liver damage, which were significantly different from the percentage of 0.4% (1/231) in the MMI-tolerant patients (odds ratio (OR) = 15.4, 95% confidence interval (CI) = 1.77-133.9, adjusted P = 0.0292; OR=14.9, 95% CI=2.38-182.9, adjusted P = 0.0323; respectively). HLA-A*02:01 was also found to be associated with MMI-induced cholestatic/mixed liver injury (OR = 3.13, 95%CI=1.45-6.91, adjusted P = 0.0464). The present study demonstrated that individuals carrying HLA-C*03:02 allele are at increased risk of developing MMI-induced DILI. These results may assist doctors to prevent the occurrence of hepatotoxicity in GD patients receiving MMI.

Methimazole-Induced Aplastic Anemia with Concomitant Hepatitis in a Young Filipina with Graves' Disease

A 34-year-old female Filipino with Graves' disease on methimazole came in due to fever, sore throat and jaundice. She was initially diagnosed with methimazole-induced agranulocytosis and drug-induced liver injury. She was treated with intravenous broad-spectrum antibiotic and granulocyte colony stimulating factor. On day 4 of admission, she developed pancytopenia and was managed as methimazole-induced aplastic anemia. She was started on steroid therapy and received 1 unit of packed red blood cell. The jaundice also increased, hence, she was given ursodeoxycholic acid. On day 9 of admission, with the consideration of "lineage steal phenomenon," biopsy was done and eltrombopag was started. Patient was discharged stable at 12th hospital day. This case presents 3 rare life-threatening complications of methimazole namely: agranulocytosis, aplastic anemia and hepatitis.