Displaying publications 1 - 20 of 23 in total

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  1. DNA methylation of ITGB2 contributes to allopurinol hypersensitivity
    Liu Y, Wang CW, Chen CB, Yu KH, Wu YJ, Choon SE, et al.
    Clin Immunol, 2023 Mar;248:109250.
    PMID: 36738816 DOI: 10.1016/j.clim.2023.109250
    BACKGROUNDS: HLA-B*58:01 allele was strongly associated with allopurinol induced severe cutaneous adverse drug reaction (SCAR). However, HLA-B genotype is not sufficient to predict the occurrence of allopurinol-induced SCAR.

    OBJECTIVE: To discover DNA methylation markers for allopurinol-induced SCAR which may improve the prediction accuracy of genetic testing.

    STUDY DESIGN: The study was designed as a retrospective case-control clinical study in multicenter hospitals across Taiwan, Mainland China, Malaysia and Canada. 125 cases of allopurinol-induced SCAR patients and 139 cases of allopurinol tolerant controls were enrolled in this study during 2005 to 2021.

    RESULTS: The results of genome-wide DNA methylation assay of 62 patients revealed that ITGB2 showed strong discriminative ability of allopurinol-induced SCAR in both HLA-B*58:01 positive and negative patients with AUC value of 0.9364 (95% CI 0.8682-1.000). In validation study, significant hypermethylation of ITGB2 were further validated in allopurinol-induced SCAR patients compared to tolerant controls, especially in those without HLA-B*58:01(AUC value of 0.8814 (95% CI 0.7121-1.000)). Additionally, the methylation levels of 2 sites on ITGB2 were associated with SCAR phenotypes. Combination of HLA-B*58:01 genotyping and ITGB2 methylation status could improve the prediction accuracy of allopurinol-induced SCAR with the AUC value up to 0.9387 (95% CI 0.9089-0.9684), while the AUC value of HLA-B*58:01 genotyping alone was 0.8557 (95% CI 0.8030-0.9083).

    CONCLUSIONS: Our study uncovers differentially methylated genes between allopurinol-induced SCAR patients and tolerant controls with positive or negative HLA-B*58:01 allele and provides the novel epigenetic marker that improves the prediction accuracy of genetic testing for prevention of allopurinol-induced SCAR.

    Matched MeSH terms: HLA-B Antigens/genetics
  2. Fulltext Implementing HLA-B*58:01 testing prior to allopurinol initiation in Malaysian primary care setting: A qualitative study from doctors' and patients' perspective
    Ng WL, Hussein N, Ng CJ, Qureshi N, Lee YK, Kwan Z, et al.
    PLoS One, 2024;19(1):e0296498.
    PMID: 38206925 DOI: 10.1371/journal.pone.0296498
    INTRODUCTION: Allopurinol, the first-line treatment for chronic gout, is a common causative drug for severe cutaneous adverse reactions (SCAR). HLA-B*58:01 allele was strongly associated with allopurinol-induced SCAR in Asian countries such as Taiwan, Japan, Thailand and Malaysia. HLA-B*58:01 screening before allopurinol initiation is conditionally recommended in the Southeast-Asian population, but the uptake of this screening is slow in primary care settings, including Malaysia. This study aimed to explore the views and experiences of primary care doctors and patients with gout on implementing HLA-B*58:01 testing in Malaysia as part of a more extensive study exploring the feasibility of implementing it routinely.

    METHODS: This qualitative study used in-depth interviews and focus group discussions to obtain information from patients with gout under follow-up in primary care and doctors who cared for them. Patients and doctors shared their gout management experiences and views on implementing HLA-B*58:01 screening in primary care. Data were coded and analysed using thematic analysis.

    RESULTS: 18 patients and 18 doctors from three different healthcare settings (university hospital, public health clinics, private general practitioner clinics) participated. The acceptability to HLA-B*58:01 screening was good among the doctors and patients. We discovered inadequate disclosure of severe side effects of allopurinol by doctors due to concerns about medication refusal by patients, which could potentially be improved by introducing HLA-B*58:01 testing. Barriers to implementation included out-of-pocket costs for patients, the cost-effectiveness of this implementation, lack of established alternative treatment pathway besides allopurinol, counselling burden and concern about genetic data security. Our participants preferred targeted screening for high-risk populations instead of universal screening.

    CONCLUSION: Implementing HLA-B*58:01 testing in primary care is potentially feasible if a cost-effective, targeted screening policy on high-risk groups can be developed. A clear treatment pathway for patients who test positive should be made available.

    Matched MeSH terms: HLA-B Antigens/genetics
  3. A new HLA-B*35 allele, B*3589, detected in a Malaysian individual
    Phipps M, Jinam T
    Tissue Antigens, 2009 Mar;73(3):279-80.
    PMID: 19144089 DOI: 10.1111/j.1399-0039.2008.01195.x
    A novel human leukocyte antigen-B allele officially named B*3589, was found in an indigenous individual of Jehai ethnicity when sequencing was performed to investigate human genome variation in a research project. B*3589 differs form B*3505 in a point mutation at codon 169 (CGC to TGC) resulting in an amino acid change from Arg to Cys.
    Matched MeSH terms: HLA-B Antigens/genetics*
  4. HLA-A, -B and -DR allele and haplotype frequencies in Malays
    Dhaliwal JS, Shahnaz M, Too CL, Azrena A, Maiselamah L, Lee YY, et al.
    Asian Pac J Allergy Immunol, 2007 Mar;25(1):47-51.
    PMID: 17891921
    One thousand four hundreds and forty-five Malays registered with the Malaysian Marrow Donor Registry were typed for HLA-A, HLA-B and HLA-DR. Fifteen HLA-A, twenty nine HLA-B and fourteen HLA-DR alleles were detected. The most common HLA-A alleles and their frequencies were HLA-A24 (0.35), HLA-A11 (0.21) and HLA-A2 (0.15). The most common HLA-B alleles were HLA-B15 (0.26), HLA-B35 (0.11) and HLA-B18 (0.10) while the most common HLA-DR alleles were HLA-DR15 (0.28), HLA-DR12 (0.27) and HLA-DR7 (0.10). A24-B15-DR12 (0.047), A24-B15-DR15 (0.03) and the A24-B35-DR12 (0.03) were the most frequent haplotypes. This data may be useful in determining the probability of finding a matched donor and for estimating the incidence of HLA associated diseases.
    Matched MeSH terms: HLA-B Antigens/genetics*
  5. Distribution of HLA-A, -B and -DRB1 alleles in the Kensiu and Semai Orang Asli sub-groups in Peninsular Malaysia
    Tasnim AR, Allia S, Edinur HA, Panneerchelvam S, Zafarina Z, Norazmi MN
    Hum Immunol, 2016 Aug;77(8):618-619.
    PMID: 27296326 DOI: 10.1016/j.humimm.2016.06.009
    The earliest settlers in Peninsular Malaysia are the Orang Asli population, namely Semang, Senoi and Proto Malays. In the present study, we typed the HLA-A, -B and -DRB1 loci of the Kensiu and Semai Orang Asli sub-groups. Sequence-based HLA typing was performed on 59 individuals from two Orang Asli sub-groups. A total of 11, 18 and 14 HLA-A, -B and -DRB1 alleles were identified, respectively. These data are available in the Allele Frequencies Net Database under the population name "Malaysia Kedah Kensiu" and "Malaysia Pahang Semai".
    Matched MeSH terms: HLA-B Antigens/genetics*
  6. Molecular analysis of HLA-B in the Malaysian aborigines
    Hirayama K, Zaidi AS, Lokman Hakim S, Kimura A, Ong KJ, Kikuchi M, et al.
    Tissue Antigens, 1996 Dec;48(6):692-7.
    PMID: 9008312
    We have examined 56 unrelated individuals from Malaysian aborigines for their DNA polymorphism of the HLA-B gene by sequence specific oligonucleotide probe (SSO) method. Using the SSO hybridization, we found that one specific DNA allele with a B*1513 like pattern of epitope combination (ECB1513) was dominant among the Melayu Asli (Af = 41.9%) and the Senoi (Af = 24%). To determine the nucleotide sequences of ECB1513, a DNA fragment spanning from the beginning of exon 1 to the middle of exon 4 of the HLA-B gene was amplified by polymerase chain reaction (PCR) from two ECB1513 positive individuals, and the PCR products were cloned and sequenced. This sequencing analysis confirmed that ECB1513 was identical to HLA-B*1513 in exon 1, 2, 3, and 4. Amino acid sequence of this major allele, HLA-B*1513, in the aborigines especially around the peptide binding groove (B and F pockets), was compared with that of African B*5301 that had been suggested to confer resistance to malaria infection in Africa. The amino acid residues composing of the F pocket were completely identical in B*1513 and B*5301. These observations suggest that a common environmental factor, the malaria infection, might have independently enhanced the selection of functional change in the polymorphic portion of HLA-B gene in Africa and in South-East Asia.
    Matched MeSH terms: HLA-B Antigens/genetics*
  7. Integrating real-world data in cost-effectiveness analysis of universal HLA-B*15:02 screening in Malaysia
    Chong HY, Lim KS, Fong SL, Shabaruddin FH, Dahlui M, Mei Lai PS, et al.
    Br J Clin Pharmacol, 2023 Nov;89(11):3340-3351.
    PMID: 37294011 DOI: 10.1111/bcp.15818
    AIMS: Despite the availability of newer antiseizure medications, carbamazepine (CBZ) remains the gold standard. However, patients of Asian ancestry are susceptible to CBZ-related severe cutaneous adverse reactions. Universal HLA-B*15:02 screening is a promising intervention to address this. With the increasing recognition of integrating real-world evidence in economic evaluations, the cost-effectiveness of universal HLA-B*15:02 screening was assessed using available real-world data in Malaysia.

    METHODS: A hybrid model of a decision tree and Markov model was developed to evaluate 3 strategies for treating newly diagnosed epilepsy among adults: (i) CBZ initiation without HLA-B*15:02 screening (current practice); (ii) universal HLA-B*15:02 screening prior to CBZ initiation; and (iii) alternative prescribing without HLA-B*15:02 screening. The model was populated with real-world inputs derived from the Malaysian population. From a societal perspective, base-case analysis and sensitivity analyses estimated the costs and outcomes over a lifetime. Incremental cost-effectiveness ratios were calculated.

    RESULTS: In the base-cases analysis, universal HLA-B*15:02 screening yielded the lowest total costs and the highest total quality-adjusted life years (QALYs) gained. Compared with current practice, universal screening was less costly by USD100 and more effective by QALYs increase of 0.1306, while alternative prescribing resulted in 0.1383 QALYs loss at additional costs of USD332. The highest seizure remission rate (56%) was estimated for universal HLA-B*15:02 screening vs. current practice (54%) and alternative prescribing (48%).

    CONCLUSION: Our study suggests that universal HLA-B*15:02 screening is a cost-effective intervention in Malaysia. With the demonstrated value of real-world evidence in economic evaluations, more relevant standardization efforts should be emphasized to better inform decision-making.

    Matched MeSH terms: HLA-B Antigens/genetics
  8. Fulltext Divergent HLA variations and heterogeneous expression but recurrent HLA loss-of- heterozygosity and common HLA-B and TAP transcriptional silencing across advanced pediatric solid cancers
    Lim WC, Marques Da Costa ME, Godefroy K, Jacquet E, Gragert L, Rondof W, et al.
    Front Immunol, 2023;14:1265469.
    PMID: 38318504 DOI: 10.3389/fimmu.2023.1265469
    The human leukocyte antigen (HLA) system is a major factor controlling cancer immunosurveillance and response to immunotherapy, yet its status in pediatric cancers remains fragmentary. We determined high-confidence HLA genotypes in 576 children, adolescents and young adults with recurrent/refractory solid tumors from the MOSCATO-01 and MAPPYACTS trials, using normal and tumor whole exome and RNA sequencing data and benchmarked algorithms. There was no evidence for narrowed HLA allelic diversity but discordant homozygosity and allele frequencies across tumor types and subtypes, such as in embryonal and alveolar rhabdomyosarcoma, neuroblastoma MYCN and 11q subtypes, and high-grade glioma, and several alleles may represent protective or susceptibility factors to specific pediatric solid cancers. There was a paucity of somatic mutations in HLA and antigen processing and presentation (APP) genes in most tumors, except in cases with mismatch repair deficiency or genetic instability. The prevalence of loss-of-heterozygosity (LOH) ranged from 5.9 to 7.7% in HLA class I and 8.0 to 16.7% in HLA class II genes, but was widely increased in osteosarcoma and glioblastoma (~15-25%), and for DRB1-DQA1-DQB1 in Ewing sarcoma (~23-28%) and low-grade glioma (~33-50%). HLA class I and HLA-DR antigen expression was assessed in 194 tumors and 44 patient-derived xenografts (PDXs) by immunochemistry, and class I and APP transcript levels quantified in PDXs by RT-qPCR. We confirmed that HLA class I antigen expression is heterogeneous in advanced pediatric solid tumors, with class I loss commonly associated with the transcriptional downregulation of HLA-B and transporter associated with antigen processing (TAP) genes, whereas class II antigen expression is scarce on tumor cells and occurs on immune infiltrating cells. Patients with tumors expressing sufficient HLA class I and TAP levels such as some glioma, osteosarcoma, Ewing sarcoma and non-rhabdomyosarcoma soft-tissue sarcoma cases may more likely benefit from T cell-based approaches, whereas strategies to upregulate HLA expression, to expand the immunopeptidome, and to target TAP-independent epitopes or possibly LOH might provide novel therapeutic opportunities in others. The consequences of HLA class II expression by immune cells remain to be established. Immunogenetic profiling should be implemented in routine to inform immunotherapy trials for precision medicine of pediatric cancers.
    Matched MeSH terms: HLA-B Antigens/genetics
  9. Fulltext Cost-effectiveness analysis of HLA-B*5801 testing in preventing allopurinol-induced SJS/TEN in Thai population
    Saokaew S, Tassaneeyakul W, Maenthaisong R, Chaiyakunapruk N
    PLoS One, 2014;9(4):e94294.
    PMID: 24732692 DOI: 10.1371/journal.pone.0094294
    BACKGROUND: Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), caused by allopurinol therapy, are strongly associated with the human leukocyte antigen (HLA), HLA-B*5801. Identification of HLA-B*5801 genotype before prescribing allopurinol offers the possibility of avoiding allopurinol-induced SJS/TEN. As there is a paucity of evidence about economic value of such testing, this study aims to determine the cost-effectiveness of HLA-B*5801 testing compared with usual care (no genetic testing) before allopurinol administration in Thailand.
    METHODS AND FINDING: A decision analytical and Markov model was used to estimate life time costs and outcomes represented as quality adjusted life years (QALYs) gained. The model was populated with relevant information of the association between gene and allopurinol-induced SJS/TEN, test characteristics, costs, and epidemiologic data for Thailand from a societal perspective. Input data were obtained from the literature and a retrospective database analysis. The results were expressed as incremental cost per QALY gained. A base-case analysis was performed for patients at age 30. A series of sensitivity analyses including scenario, one-way, and probabilistic sensitivity analyses were constructed to explore the robustness of the findings. Based on a hypothetical cohort of 1,000 patients, the incremental total cost was 923,919 THB (USD 29,804) and incremental QALY was 5.89 with an ICER of 156,937.04 THB (USD 5,062) per QALY gained. The cost of gout management, incidence of SJS/TEN, case fatality rate of SJS/TEN, and cost of genetic testing are considered very influential parameters on the cost-effectiveness value of HLA-B*5801 testing.
    CONCLUSIONS: The genetic testing for HLA-B*5801 before allopurinol administration is considered a highly potential cost-effective intervention in Thailand. The findings are sensitive to a number of factors. In addition to cost-effectiveness findings, consideration of other factors including ethical, legal, and social implications is needed for an informed policy decision making.
    Matched MeSH terms: HLA-B Antigens/genetics*
  10. Association of HLA-B*1502 allele with carbamazepine-induced toxic epidermal necrolysis and Stevens-Johnson syndrome in the multi-ethnic Malaysian population
    Chang CC, Too CL, Murad S, Hussein SH
    Int J Dermatol, 2011 Feb;50(2):221-4.
    PMID: 21244392 DOI: 10.1111/j.1365-4632.2010.04745.x
    BACKGROUND: Carbamazepine (CBZ), a frequently used anticonvulsant drug, is one of the most common causes of life-threatening cutaneous adverse drug reactions such as toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS). Recent studies have revealed a strong association between HLA-B*1502 and CBZ-induced TEN/SJS in the Taiwan Han Chinese population.
    OBJECTIVES: This study is aimed to investigate the association between human leucocyte antigens (HLA) and CBZ-induced TEN/SJS in the multi-ethnic Malaysian population.
    METHODS: A sample of 21 unrelated patients with CBZ-induced TEN/SJS and 300 race-matched, healthy controls were genotyped for HLA-A, -B and -DR using polymerase chain reaction (PCR). Allele frequencies were compared.
    RESULTS: HLA-B*1502 was present in 75.0% (12/16) of Malay patients with CBZ-induced TEN/SJS but in only 15.7% (47/300) of normal controls (odds ratio 16.15, 95% confidence interval 4.57-62.4; corrected P-value  = 7.87 × 10(-6) ), which suggests a strong association between HLA and CBZ-induced TEN/SJS. Additionally, HLA-B*1502 was found in all three Chinese and two Indian patients. Existing data show that frequencies of the HLA-B*1502 allele are generally much higher in Asian populations than in White European populations, which explains the higher incidences of SJS and TEN in Asian countries.
    CONCLUSIONS: HLA-B*1502 is strongly associated with CBZ-induced TEN/SJS in the Malay population in Malaysia, as has been seen in Han Chinese in Taiwan. This indicates that the genetic association apparent in the incidence of CBZ-induced TEN/SJS is linked with the presence of HLA-B*1502, irrespective of racial origin. Screening of patients for this genetic marker can help to prevent the occurrence of TEN/SJS.
    Matched MeSH terms: HLA-B Antigens/genetics*
  11. HLA polymorphism in six Malay subethnic groups in Malaysia
    Edinur HA, Zafarina Z, Spínola H, Nurhaslindawaty AR, Panneerchelvam S, Norazmi MN
    Hum Immunol, 2009 Jul;70(7):518-26.
    PMID: 19364514 DOI: 10.1016/j.humimm.2009.04.003
    In this study, human leukocyte antigen (HLA) class I and II were examined through sequence-specific primer typing in 176 unrelated individuals from six Malay subethnic groups of Peninsular Malaysia: Kelantan (n = 25), Minangkabau (34), Jawa (30), Bugis (31), Banjar (33), and Rawa (23). The most common HLA alleles in all groups were A*24 (26-41%), Cw*07 (24-32%), B*15 (22-30%), DRB1*12 (15-36%), and DQB1*03 (25-51%). The Malay subethnic groups studied demonstrated a close relationship to each other and to other Asian populations, despite specific differences between them. Banjar, Bugis, and Jawa Malays demonstrated no significant difference from each other, which could be a result of their related origin from the islands around the Java Sea. These three Malay subethnic groups were then collapsed into one group, which also helped to increase the sample number and sharpen statistical results. Minangkabau and Rawa Malays exhibited high similarities in allele group and haplotype frequencies, which could be a consequence of their common origin from Sumatera. Kelantan Malays, in addition to their statistically significant differences compared with the other groups, also exhibited differences on the most frequent haplotypes, which are almost absent in the other subethnic groups studied.
    Matched MeSH terms: HLA-B Antigens/genetics
  12. Fulltext Coupling Genotyping and Computational Modeling in Prediction of Anti-epileptic Drugs that cause Stevens Johnson Syndrome and Toxic Epidermal Necrolysis for Carrier of HLA-B*15:02
    Teh LK, Selvaraj M, Bannur Z, Ismail MI, Rafia H, Law WC, et al.
    J Pharm Pharm Sci, 2016;19(1):147-60.
    PMID: 27096699 DOI: 10.18433/J38G7X
    PURPOSE: The importance of HLA-B*15:02 genotyping to avoid carbamazepine induced SJS/TEN and molecular modeling to predict the role of HLA-B*15:0 and AEDs induced SJS/TEN are investigated.

    METHODS: DNA was extracted from eighty-six patients. The patients were genotyped by AS-PCR. Computational modeling of the HLA-B*15:02 followed by docking studies were performed to screen 26 AEDs that may induce ADR among HLA-B*15:02 carriers.

    RESULTS: Odd ratio for CBZ induced SJS/TEN and HLA-B*15:02 was 609.0 (95% CI: 23-15873; p=0.0002). Molecular modeling studies showed that acetazolamide, ethosuxiamide, lamotrigine, oxcarbazepine, phenobarbital, phenytoin, primidone and sodium-valproate may induce ADR in HLA-B*15:02 carriers alike CBZ. Conclusion. We confirmed HLA-B*15:02 as a predictor of SJS/TEN and recommend pre-screening. Computational prediction of DIHR is useful in personalized medicine.

    Matched MeSH terms: HLA-B Antigens/genetics*
  13. HLA-A, -B, -C, -DRB1 and -DQB1 alleles and haplotypes in 194 Southeast Asia Chinese from Peninsular Malaysia
    Too CL, Tan LK, Heselynn H, Nor-Shuhaila S, Eashwary M, Wahinuddin S, et al.
    Hum Immunol, 2019 Nov;80(11):906-907.
    PMID: 31558331 DOI: 10.1016/j.humimm.2019.09.005
    A total of 194 Southeast Asia Chinese from Peninsular Malaysia were genotyped for HLA-A, -B, -C -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, the HLA-B, HLA-DRB1 and HLA-DQB1 were in Hardy-Weinberg proportions (HWEP) (p > 0.05). We observed significant deviation from HWEP in HLA-A (p HLA-C (p 
    Matched MeSH terms: HLA-B Antigens/genetics*
  14. HLA-B*58: 01 association in allopurinol-induced severe cutaneous adverse reactions: the implication of ethnicity and clinical phenotypes in multiethnic Malaysia
    Low DE, Nurul-Aain AF, Tan WC, Tang JJ, Bakhtiar MF, Murad S, et al.
    Pharmacogenet Genomics, 2020 09;30(7):153-160.
    PMID: 32433341 DOI: 10.1097/FPC.0000000000000408
    OBJECTIVE: The association between human leukocyte antigen (HLA)-B*58:01 and risk of allopurinol-induced severe cutaneous adverse reactions (AIS) was observed across different populations. We explore the association between HLA-B*58:01 and AIS risk in multiethnic Malaysian population. The HLA-B*58:01 risk for different AIS clinical phenotypes and ethnicity was determined.

    METHODS: We performed a case-control association study by genotyping the HLA-B alleles of 55 patients with AIS [11 toxic epidermal necrolysis (TEN), 21 Steven Johnson syndrome (SJS) 22 drug reaction wit eosinophilia and systemic symptoms (DRESS) and one acute generalized exanthematous pustulosis (AGEP)] and 42 allopurinol-tolerant controls (ATC).

    RESULTS: HLA-B*58:01 was positive in 89.1 and 14.3% of the AIS and ATC study groups [odds ratio (OR) = 49.0, 95% confidence interval (CI) = 14.6-164.4, P < 0.0001)], respectively. Our data showed that 93.8% of the AIS-SJS/TEN patients and 86.4% of the AIS-DRESS patients were HLA-B*58:01 positive (AIS-SJS/TEN, OR = 90, 95% CI = 16.9-470.1, P < 0.0001 and AIS-DRESS OR = 38, 95% CI = 8.5-169.2, P < 0.0001). Stratification by ethnicity and clinical phenotypes revealed a significant increased risk between HLA-B*58:01 and Chinese-AIS patients (OR = 137.5, 95% CI = 11.3-1680.2, P < 0.0001), in particular Chinese patients with AIS-SJS/TEN phenotype (100% HLA-B*58:01 positive). HLA-B*58:01 was positive in 90.9% Chinese AIS-DRESS (P < 0.0001). Highly significant associations of HLA-B*58:01 were observed in Malay AIS-SJS/TEN (OR = 78, 95% CI = 9.8-619.9, P < 0.0001) and Malay AIS-DRESS (OR = 54, 95% CI = 6.6-442.9, P < 0.0001). Although the number of Indian-AIS patients was relatively small (n = 2), both were HLA-B*58:01 positive.

    CONCLUSION: Our data suggest strong associations between HLA-B*58:01 and AIS in Malaysian population with Chinese and Malays ethnicity. The strong association was also observed in three different clinical phenotypes of AIS, mainly the AIS-SJS/TEN.

    Matched MeSH terms: HLA-B Antigens/genetics*
  15. The pattern of HLA-A, -B and -DRB1 alleles and haplotypes of four Malay sub-ethnic groups namely Kelantan, Champa, Patani and Mandailing Malays of Peninsular Malaysia
    Allia S, Norazmi MN, Panneerchelvam S, Zafarina Z
    Hum Immunol, 2019 Jul;80(7):423-424.
    PMID: 30836128 DOI: 10.1016/j.humimm.2019.02.015
    "Bumiputra" or "son of the soil" is a term used to represent the Malays and other indigenous populations of Malaysia. The Malays are Austronesian speaking population and originated from different parts of the Indo-Malay Archipelago. The migration of Malay population from different parts of Indo-Malay Archipelago were mainly due to trading purposes which shaped the current Malay sub-ethnic groups with unique culture and with distinctive dialects. In this study, HLA typing was carried out using Sequence-based Typing (SBT) method on 109 individuals comprising of four Malay sub-ethnic groups namely Kelantan (n = 28), Champa (n = 29), Patani (n = 25) and Mandailing (n = 27) Malays. The HLA data is available in the Allele Frequencies Net Database (AFND).
    Matched MeSH terms: HLA-B Antigens/genetics*
  16. Fulltext Human leukocyte class I antigen alleles A2 and A11 are not associated with nasopharyngeal carcinoma in West Malaysia
    Lee LK, Tan EL, Gopala K, Sam CK
    Singapore Med J, 2007 Jul;48(7):632-4.
    PMID: 17609824
    Nasopharyngeal carcinoma (NPC) is the second most common cancer among Malaysian Chinese males. We determined the frequencies of 17 human leukocyte antigens (HLA), HLA-A and HLA-B, alleles in 88 Malaysian Chinese with NPC.
    Matched MeSH terms: HLA-B Antigens/genetics*
  17. Molecular analysis of HLA Class I and Class II genes in four indigenous Malaysian populations
    Jinam TA, Saitou N, Edo J, Mahmood A, Phipps ME
    Tissue Antigens, 2010 Feb;75(2):151-8.
    PMID: 20003135 DOI: 10.1111/j.1399-0039.2009.01417.x
    This is the first report of high-resolution human leukocyte antigen (HLA) typing in four indigenous groups in Malaysia. A total of 99 normal, healthy participants representing the Negrito (Jehai and Kensiu), Proto-Malay (Temuan) and a native group of Borneo (Bidayuh) were typed for HLA-A, -B, -DRB1 and -DQB1 genes using sequence-based typing. Eleven HLA-A, 26 HLA-B, 16 HLA-DRB1 and 14 HLA-DQB1 alleles were detected, including a new allele, HLA-B*3589 in the Jehai. Highly frequent alleles were A*2407, B*1513, B*1801, DRB1*0901, DRB1*1202, DRB1*1502, DQB1*0303 and DQB1*0502. Principal component analysis based on high-resolution HLA-A, -B and -DRB1 allele frequencies showed close affinities among all four groups, including the Negritos, with other Southeast Asian populations. These results showed the scope of HLA diversity in these indigenous minority groups and may prove beneficial for future disease association, anthropological and forensic studies.
    Matched MeSH terms: HLA-B Antigens/genetics
  18. Strategies for evaluating B*18 allelic diversity by sequence-based typing applied to studies of a population from Singapore and African-Americans
    Hou L, Tu B, Ling G, Tang T, Cao K, Steiner NK, et al.
    Tissue Antigens, 2006 Jan;67(1):66-9.
    PMID: 16451205
    Strategies to resolve B*18 alleles which carry a deletion in intron 1 close to the 5' end of exon 2 relative to other HLA-B alleles or a null allele mutation in exon 1 and to resolve ambiguities among allele combinations including B*18 are described. B*18 allele frequencies from volunteer donors recruited for two hematopoietic stem cell registries show the presence of two alleles, B*180101 and B*1802, in a population from Singapore and only B*180101 in African-Americans.
    Matched MeSH terms: HLA-B Antigens/genetics*
  19. HLA-A*31: 01 and HLA-B*15:02 association with Stevens-Johnson syndrome and toxic epidermal necrolysis to carbamazepine in a multiethnic Malaysian population
    Khor AH, Lim KS, Tan CT, Kwan Z, Tan WC, Wu DB, et al.
    Pharmacogenet Genomics, 2017 07;27(7):275-278.
    PMID: 28570299 DOI: 10.1097/FPC.0000000000000287
    The majority of the carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis CBZ-SJS/TEN are associated with HLA-B*15:02 in Asian populations where this allele is common. In contrast, the association with HLA-A*31:01 is only reported in Japanese and Europeans. This study aimed to further investigate the association with HLA-A*31:01 besides HLA-B*15:02 in a multiethnic Malaysian population. Twenty-eight CBZ-SJS/TEN cases and 227 CBZ-tolerant controls were recruited. Association was tested by comparing carrier frequencies of the alleles between cases and controls. Significant associations were detected between HLA-B*15:02 and CBZ-SJS/TEN in independent ethnic groups: Malays [P=2.00×10; odds ratio (OR): 49.0; 95% confidence interval (CI): 9.36-256.81], Chinese (P=0.0047; OR: 14.3; 95% CI: 2.38-86.03) and Indians (P=0.04; OR: 13.8; 95% CI: 1.51-124.99). Combined analysis of all ethnic groups showed a significant association with OR Cochran-Mantel-Haenszel (ORCMH) of 26.6 (95% CI: 12.80-55.25; PCMH=2.31×10). In Indians, HLA-A*31:01 was found to be associated significantly with CBZ-SJS/TEN (P=0.023; OR: 10.4; 95% CI: 1.64-65.79) and combined analyses of both variants, HLA-A*31:01 and HLA-B*15:02, increased the strength of the association (P=0.0068; OR: 14.3; 95% CI: 2.20-92.9). Besides HLA-B*15:02, our study found a new association between HLA-A*31:01 and CBZ-SJS/TEN in Indians.
    Matched MeSH terms: HLA-B Antigens/genetics*
  20. Cost-effectiveness analysis of HLA-B*58: 01 genetic testing before initiation of allopurinol therapy to prevent allopurinol-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in a Malaysian population
    Chong HY, Lim YH, Prawjaeng J, Tassaneeyakul W, Mohamed Z, Chaiyakunapruk N
    Pharmacogenet Genomics, 2018 02;28(2):56-67.
    PMID: 29176400 DOI: 10.1097/FPC.0000000000000319
    OBJECTIVE: Studies found a strong association between allopurinol-induced Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and the HLA-B*58:01 allele. HLA-B*58:01 screening-guided therapy may mitigate the risk of allopurinol-induced SJS/TEN. This study aimed to evaluate the cost-effectiveness of HLA-B*58:01 screening before allopurinol therapy initiation compared with the current practice of no screening for Malaysian patients with chronic gout in whom a hypouricemic agent is indicated.

    METHODS: This cost-effectiveness analysis adopted a societal perspective with a lifetime horizon. A decision tree model coupled with Markov models were developed to estimate the costs and outcomes, represented by quality-adjusted life years (QALYs) gained, of three treatment strategies: (a) current practice (allopurinol initiation without HLA-B*58:01 screening); (b) HLA-B*58:01 screening before allopurinol initiation; and (c) alternative treatment (probenecid) without HLA-B*58:01 screening. The model was populated with data from literature review, meta-analysis, and published government documents. Cost values were adjusted for the year 2016, with costs and health outcomes discounted at 3% per annum. A series of sensitivity analysis including probabilistic sensitivity analysis were carried out to determine the robustness of the findings.

    RESULTS: Both HLA-B*58:01 screening and probenecid prescribing were dominated by current practice. Compared with current practice, HLA-B*58:01 screening resulted in 0.252 QALYs loss per patient at an additional cost of USD 322, whereas probenecid prescribing resulted in 1.928 QALYs loss per patient at an additional cost of USD 2203. One SJS/TEN case would be avoided for every 556 patients screened. At the cost-effectiveness threshold of USD 8695 per QALY, the probability of current practice being the best choice is 99.9%, in contrast with 0.1 and 0% in HLA-B*58:01 screening and probenecid prescribing, respectively. This is because of the low incidence of allopurinol-induced SJS/TEN in Malaysia and the lower efficacy of probenecid compared with allopurinol in gout control.

    CONCLUSION: This analysis showed that HLA-B*58:01 genetic testing before allopurinol initiation is unlikely to be a cost-effective intervention in Malaysia.
    Matched MeSH terms: HLA-B Antigens/genetics*
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