Drug-induced liver injury (DILI) is the most common adverse drug reaction in the treatment of tuberculosis (TB). Several studies showed that patients with TB and the slow-acetylator phenotype caused by NAT2 variants are highly susceptible to DILI caused by anti-TB drugs, hereafter designated AT-DILI. However, the role of NAT2 variants in AT-DILI has never been assessed for an Indonesian population. We recruited 50 patients with TB and AT-DILI and 191 patients with TB but without AT-DILI; we then used direct DNA sequencing to assess single-nucleotide polymorphisms in the coding region of NAT2. NAT2*6A was significantly associated with susceptibility to AT-DILI (P=7.7 × 10(-4), odds ratio (OR)=4.75 (1.8-12.55)). Moreover, patients with TB and the NAT2-associated slow-acetylator phenotype showed higher risk of AT-DILI than patients with the rapid- or intermediate-acetylator phenotypes (P=1.7 × 10(-4), OR=3.45 (1.79-6.67)). In conclusion, this study confirms the significance of the association between slow-acetylator NAT2 variants and susceptibility to AT-DILI in an Indonesian population.

Carbamazepine (CBZ) is a common cause of life-threatening cutaneous adverse drug reactions such as Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Previous studies have reported a strong association between the HLA genotype and CBZ-induced SJS/TEN. We investigated the association between the HLA genotype and CBZ-induced SJS/TEN in Javanese and Sundanese patients in Indonesia. Nine unrelated patients with CBZ-induced SJS/TEN and 236 healthy Javanese and Sundanese controls were genotyped for HLA-B and their allele frequencies were compared. The HLA-B*15:02 allele was found in 66.7% of the patients with CBZ-induced SJS/TEN, but only in 29.4% of tolerant control (p = 0.029; odds ratio [OR]: 6.5; 95% CI: 1.2–33.57) and 22.9% of healthy controls (p = 0.0021; OR: 6.78; 95% CI: 1.96–23.38). These findings support the involvement of HLA-B*15:02 in CBZ-induced SJS/TEN reported in other Asian populations. Interestingly, we also observed the presence of the HLA-B*15:21 allele. HLA-B*15:02 and HLA-B*15:21 are members of the HLA-B75 serotype, for which a greater frequency was observed in CBZ-induced SJS/TEN (vs tolerant control [p = 0.0078; OR: 12; 95% CI: 1.90–75.72] and vs normal control [p = 0.0018; OR: 8.56; 95% CI: 1.83–40]). Our findings suggest that screening for the HLA-B75 serotype can predict the risk of CBZ-induced SJS/TEN more accurately than screening for a specific allele.

Aim: We investigated the contribution of NAT2 variants and acetylator status to anti-tuberculosis drug-induced liver injury (AT-DILI) severity. Materials & methods: 100 patients with clinically severe AT-DILI and 210 non-AT-DILI controls were subjected to NAT2 genotyping by direct DNA sequencing. Results: NAT2 slow acetylator was significantly associated with AT-DILI risk (p = 2.7 × 10-7; odds ratio [95% CI] = 3.64 [2.21–6.00]). Subgroup analysis of NAT2 ultra-slow acetylator revealed a stronger association with AT-DILI risk (p = 4.3 × 10-6; odds ratio [95% CI] = 3.37 [2.00–5.68]). Subset analysis of NAT2 acetylator status and severity grade confirmed these results in AT-DILI patients with more severe disease whereas fast and intermediate acetylator phenotypes were associated with a decreased AT-DILI risk. Conclusion: We elucidated the role of NAT2 phenotypes in AT-DILI in Indonesian population, suggesting that NAT2 genotype and phenotype determination are important to reduce AT-DILI risk.

ABSTRAK ABSTRACTBackground: Arylamine N-acetyltransferase 2 (NAT2) polymorphism was previously reported to have association with the risk of drug toxicities and the development of various diseases. Previous research on the Indonesian population, especially Javanese and Sundanese, showed that there were 33% NAT2 slow acetylator phenotype. The aim of this study was to map the NAT2 variation in the Malay ethnic to gain a deeper insight into NAT2 haplotypic composition in this ethnic.

Pharmacogenomics can enhance the outcome of treatment by adopting pharmacogenomic testing to maximize drug efficacy and lower the risk of serious adverse events. Next-generation sequencing (NGS) is a cost-effective technology for genotyping several pharmacogenomic loci at once, thereby increasing publicly available data. A panel of 100 pharmacogenes among Southeast Asian (SEA) populations was resequenced using the NGS platform under the collaboration of the Southeast Asian Pharmacogenomics Research Network (SEAPharm). Here, we present the frequencies of pharmacogenomic variants and the comparison of these pharmacogenomic variants among different SEA populations and other populations used as controls. We investigated the different types of pharmacogenomic variants, especially those that may have a functional impact. Our results provide substantial genetic variations at 100 pharmacogenomic loci among SEA populations that may contribute to interpopulation variability in drug response phenotypes. Correspondingly, this study provides basic information for further pharmacogenomic investigations in SEA populations.

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Tuberculosis (TB) is still a major public health problem in Indonesia. Anti-tuberculosis drug-induced hepatotoxicity (DIH) is common side effect leading to changes in treatment regimens, and the less effective second-line treatments. Several risk factors such as age, sex, body mass index (BMI) and acetylization status for hepatotoxicity were suggested in previous studies but in the fact, those are often not related to DIH incidence after receiving standard TB treatment regimen. The aim of this study was to asses the role of risk factors in the DIH incidence in pulmonary TB patients receiving standard TB treatment regimen in Dr. Soetomo Hospital, Surabaya. Study design was analytic observational with case control. The subjects were 30 TB DIH patients and 31 TB non-DIH patients receiving standard national TB program therapy. DIH severity was divided based on International DIH Expert Working Group. Demographic data and BMI status were taken from medical records. The age classification are ≥35 years old and <35 years old as one of the risk factors studied. DNA sequencing was used to assess single-nucleotide polymorphisms in NAT2 coding region to evaluate acetylator status from blood samples. The risk factors were evaluated using chi-square test and Mantel-Haenszel test. Significant association between low BMI and DIH in general was identified (OR=3.017; 95% CI=1.029-8.845) and more significant association between low BMI and moderate DIH (OR=15.833; 95% CI=1.792-139.922). Age, sex, and acetylization status has no significant correlation with DIH incidence in general. Significant association between slow acetylator phenotype and incidence of moderate DIH was identified (OR=7.125; 95% CI= 1.309-38.711). In conclusion, some risk factors were correlated to DIH incidence in pulmonary TB patientsreceiving standart TB treatment regimen.

Background N‐acetyltransferase 2 (NAT2) is a key enzyme involved in the phase II metabolism of aromatic amines and heterocyclic aromatic amines present in a wide range of xenobiotics. The aim of this study was to investigate the NAT2 polymorphism in the Buginese ethnic group of Indonesia to determine the frequency of NAT2 alleles in this population. Results We found six haplotypes consisting of six single‐nucleotide polymorphisms and 12 NAT2 genotype variations. NAT2*6A haplotype (42%) showed the highest frequency, followed by NAT2*4 (33%), NAT2*7B (15%), NAT2*5B (5%), NAT2*12A (3%), and NAT2*13 (2%). In terms of phenotypes, the Buginese population comprised 18% rapid acetylators, 40% intermediate acetylators, and 42% slow acetylators. Conclusion We confirmed the high‐frequency slow acetylator phenotype in the Buginese population. The NAT2*6A/*6A genotype was the most frequent slow acetylator genotype, followed by NAT2*6A/*7B. The pattern of NAT2 alleles of Buginese is similar to Southeast Asian populations but not Northeast Asian populations. However, the slow acetylator frequencies in the Buginese population were higher than those in Northeast Asian populations and lower than those in Caucasians and some American populations.