Cost-effectiveness analysis of genotyping for HLA-B*15:02 in Indonesian patients with epilepsy using a generic model.

Carbamazepine (CBZ)-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are strongly associated with the HLA-B*15:02 allele. Screening HLA-B*15:02 before CBZ administration might prevent CBZ-induced SJS/TEN by enabling clinicians to prescribe alternative therapy for positive patients. Similar to other Southeastern Asian countries, HLA-B*15:02 is highly prevalent in Indonesia. Therefore, we assessed the economic value of HLA-B*15:02 screening before CBZ prescription to patients with epilepsy in Indonesia. A generic cost-effectiveness model and decision support tool, developed to enable users to perform an initial cost-effectiveness analysis from a healthcare provider/payer perspective, were used to assess the value of HLA-B*15:02 genotyping. The incremental cost-effectiveness ratio of adopting universal HLA-B*15:02 screening was 656,444,671 Indonesian Rupiah (IDR)/quality-adjusted life year (QALY) gained for patients compared with 2,634,975,574 IDR/QALY gained for providing valproic acid (alternative drug) without screening. Thus, neither HLA-B*15:02 screening nor substitution with VPA meets the Indonesian threshold for cost effectiveness. However, the improved outcomes with this test in other Asian countries may inform the desirability of implementation in Indonesia even with suboptimal cost-effectiveness.

N-acetyltransferase 2 polymorphism and acetylation profiles in Buginese ethnics of Indonesia.

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.

NAT2 ultra-slow acetylator and risk of anti-tuberculosis drug-induced liver injury: a genotype-based meta-analysis.

BACKGROUND: NAT2 slow acetylator is a confirmed risk of anti-tuberculosis drug-induced liver injury (ATDILI). However, NAT2 ultra-slow acetylators, a new refinement among NAT2 slow acetylators, have been recently proposed. The patients with NAT2 genotypes of *6A/*6A, *6A/*7B and *7B/*7B are referred to in this group. OBJECTIVE: We aim to prove an association of the NAT2 ultra-slow acetylators with the risk of ATDILI. MATERIALS AND METHODS: Systematic review and meta-analysis were performed based on each NAT2 genotype and risk of ATDILI cases and also new classification of the ultra-slow acetylators up to 31 October 2016. Meta-analysis of 18 studies with 822 ATDILI cases and 4630 controls was carried out in the RevMan software, version 5.3 with fixed-effect (low heterogeneity) and random effect (moderate to high heterogeneity) methods. RESULTS: The strong associations between each NAT2 slow acetylator genotypes and ATDILI were confirmed in meta-analysis except for NAT2*5B/*5B [odds ratio (OR): 1.69; 95% confidence interval (CI): 0.96-2.95; P=0.0679]. The NAT2 ultra-slow acetylators contribute to higher risk of ATDILI (OR: 3.60; 95% CI: 2.30-5.63; P=1.76E-08) than all NAT2 slow acetylators (OR: 2.80; 95% CI: 2.20-3.57; P=5.73E-18) as well as fast acetylators. Additional in-vitro study using isoniazid as a substrate supports the existence of ultra-slow acetylator alleles (NAT2*6A and NAT2*7B). CONCLUSION: This is the first meta-analysis of NAT2 and the risk of ATDILI at the genotypic level. The result demonstrated that NAT2 ultra-slow acetylator genotypes will have the most effect on the increased risk of ATDILI.

NAT2 variants are associated with drug-induced liver injury caused by anti-tuberculosis drugs in Indonesian patients with tuberculosis.

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.

Frequencies of HLA-B alleles in Indonesian Malay Ethnic.

Background: The HLA-B alleles have been used as a marker to predict drug-induced adverse reactions and as a major contributor to hypersensitivity reactions. We examined the feasibility of HLA-B alleles as pharmacogenomic markers of drug-induced hypersensitivity in an Indonesian Malay Ethnic. Methods: Fifty-eight Indonesian individuals of Malay ethnicity were enrolled in this study. HLA-B alleles were determined using reverse sequence-specific oligonucleotide probe coupled with xMAP technology. Results: HLA-B*15:02 (15.52%), HLA-B*35:05 (9.48%), and HLA-B*07:05 (7.76%) were frequent alleles in the Indonesian Malay ethnic populations. We discovered at least eight pharmacogenomics markers of drug-induced hypersensitivity: HLA-B*15:02, HLA-B*15:21, HLA-B*13:01, HLA-B*35:05, HLA-B*38:02, HLA-B*51:01, HLA-B*57:01, and HLA-B*58:01. HLA-B*15:02 was in the same serotype group with HLA-B*15:21, which is a B-75 serotype associated with genetic predisposition for carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis. The Indonesian population, represented by Malay, Javanese, and Sundanese ethnicities, was similar to South East Asian, Han Chinese, and Taiwanese populations based on HLA-B*15:02 frequency as the most common allele found in Malay ethnics. Conclusion: We provided valuable information on the frequency of drug hypersensitivity-associated HLA-B alleles in Indonesian Malay ethnic population, which can improve treatment safety.

Development of population pharmacokinetics model and Bayesian estimation of rifampicin exposure in Indonesian patients with tuberculosis.

BACKGROUND: Interindividual variability in the pharmacokinetics (PK) of anti-tuberculosis (TB) drugs is the leading cause of treatment failure. Herein, we evaluated the influence of demographic, clinical, and genetic factors that cause variability in RIF PK parameters in Indonesian TB patients. METHODS: In total, 210 Indonesian patients with TB (300 plasma samples) were enrolled in this study. Clinical data, solute carrier organic anion transporter family member-1B1 (SLCO1B1) haplotypes *1a, *1b, and *15, and RIF concentrations were analyzed. The population PK model was developed using a non-linear mixed effect method. RESULTS: A one-compartment model with allometric scaling adequately described the PK of RIF. Age and SLCO1B1 haplotype *15 were significantly associated with variability in apparent clearance (CL/F). For patients in their 40s, each 10-year increase in age was associated with a 10% decrease in CL/F (7.85 L/h). Patients with the SLCO1B1 haplotype *15 had a 24% lower CL/F compared to those with the wild-type. Visual predictive checks and non-parametric bootstrap analysis indicated good model performance. CONCLUSION: Age and SLCO1B1 haplotype *15 were significant covariates of RIF CL/F. Geriatric patients with haplotype *15 had significantly greater exposure to RIF. The model could optimize TB pharmacotherapy through its application in therapeutic drug monitoring (clinical trial no. NCT05280886).

Genome-wide association studies of tuberculosis in Asians identify distinct at-risk locus for young tuberculosis.

Tuberculosis (TB) is one of the most devastating chronic infectious diseases, but the role of host genetics in disease development after infection in this disease remains unidentified. Genome-wide association studies (GWASs) in Thais and Japanese were carried out and separately analyzed, attempted replication, then, combined by meta-analysis were not yielding any convincing association evidences; these results suggested that moderate to high effect-size genetic risks are not existed for TB per se. Because of failure in replication attempt of the top 50 single-nucleotide polymorphisms (SNPs) identified form meta-analysis data, we empirically split TB cases into young TB case/control data sets (GWAS-T(young)=137/295 and GWAS-J(young)=60/249) and old TB case/control data sets (GWAS-T(old)=300/295 and GWAS-J(old)=123/685), re-analyzed GWAS based on age-stratified data and replicated the significant findings in two independent replication samples (young TB; Rep-T(young)=155/249, Rep-J(young)=41/462 and old TB; Rep-T(old)=212/187, Rep-J(old)=71/619). GWAS and replication studies conducted in young TB identified at-risk locus in 20q12. Although the locus is located in inter-genic region, the nearest genes (HSPEP1-MAFB) from this locus are promising candidates for TB susceptibility. This locus was also associated with anti-TNF responsiveness, drug with increased susceptibility for TB. Moreover, eight SNPs in an old TB meta-analysis and six SNPs in young TB meta-analysis provided replication evidences but did not survive genome-wide significance.These findings suggest that host genetic risks for TB are affected by age at onset of TB, and this approach may accelerate the identification of the major host factors that affect TB in human populations.

The influence of metformin transporter gene SLC22A1 and SLC47A1 variants on steady-state pharmacokinetics and glycemic response.

Interindividual variation is important in the response to metformin as the first-line therapy for type-2 diabetes mellitus (T2DM). Considering that OCT1 and MATE1 transporters determine the metformin pharmacokinetics, this study aimed to investigate the influence of SLC22A1 and SLC47A1 variants on the steady-state pharmacokinetics of metformin and the glycemic response. This research used the prospective-cohort study design for 81 patients with T2DM who received 500 mg metformin twice a day from six primary healthcare centers. SLC22A1 rs628031 A>G (Met408Val) and Met420del genetic variants in OCT1 as well as SLC47A1 rs2289669 G>A genetic variant in MATE1 were examined through the PCR-RFLP method. The bioanalysis of plasma metformin was performed in the validated reversed-phase HPLC-UV detector. The metformin steady-state concentration was measured for the trough concentration (Cssmin) and peak concentration (Cssmax). The pharmacodynamic parameters of metformin use were the fasting blood glucose (FBG) and glycated albumin (GA). Only SLC22A1 Met420del alongside estimated-glomerular filtration rate (eGFR) affected both Cssmax and Cssmin with an extremely weak correlation. Meanwhile, SLC47A1 rs2289669 and FBG were correlated. This study also found that there was no correlation between the three SNPs studied and GA, so only eGFR and Cssmax influenced GA. The average Cssmax in patients with the G allele of SLC22A1 Met408Val, reaching 1.35-fold higher than those with the A allele, requires further studies with regard to metformin safe dose in order to avoid exceeding the recommended therapeutic range.

Development of population pharmacokinetics model of isoniazid in Indonesian patients with tuberculosis.

OBJECTIVES: No population pharmacokinetics (PK) model of isoniazid (INH) has been reported for the Indonesian population with tuberculosis (TB). Therefore, we aimed to develop a population PK model to optimize pharmacotherapy of INH on the basis of therapeutic drug monitoring (TDM) implementation in Indonesian patients with TB. MATERIALS AND METHODS: INH concentrations, N-acetyltransferase 2 (NAT2) genotypes, and clinical data were collected from Dr. Soetomo General Academic Hospital, Indonesia. A nonlinear mixed-effect model was used to develop and validate the population PK model. RESULTS: A total of 107 patients with TB (with 153 samples) were involved in this study. A one-compartment model with allometric scaling for bodyweight effect described well the PK of INH. The NAT2 acetylator phenotype significantly affected INH clearance. The mean clearance rates for the rapid, intermediate, and slow NAT2 acetylator phenotypes were 55.9, 37.8, and 17.7 L/h, respectively. Our model was well-validated through visual predictive checks and bootstrapping. CONCLUSIONS: We established the population PK model for INH in Indonesian patients with TB using the NAT2 acetylator phenotype as a significant covariate. Our Bayesian forecasting model should enable optimization of TB treatment for INH in Indonesian patients with TB.

Genetic characterization of N-acetyltransferase 2 variants in acquired multidrug-resistant tuberculosis in Indonesia.

Background: Owing to the high resistance rate of tuberculosis (TB) to isoniazid, which is metabolized by N-acetyltransferase 2 (NAT2), we investigated the associations between NAT2 variants and multidrug-resistant (MDR)-TB. Materials & methods: The acetylator status based on NAT2 haplotypes of 128 patients with MDR-TB in Indonesia were compared with our published data from patients with anti-TB drug-induced liver injury (AT-DILI), TB and the general population. Results:NAT2*4 was more frequent in the MDR-TB group than in the AT-DILI group, TB controls and general controls. NAT2*4/*4 was significantly more frequent in patients with MDR-TB than in those with AT-DILI. NAT2*5B/7B, *6A/6A and *7B/*7B were detected at lower frequencies in patients with AT-DILI. Rapid acetylators were significantly more frequent in patients with MDR-TB than in those with AT-DILI. Conclusion: These results provide an initial data for optimizing TB treatment in the Indonesian population, and suggest that NAT2 genotyping may help to select appropriate treatment by predicting TB-treatment effect.

Prevalence of pharmacogenomic variants in 100 pharmacogenes among Southeast Asian populations under the collaboration of the Southeast Asian Pharmacogenomics Research Network (SEAPharm).

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.

A scan for genetic determinants of human hair morphology: EDAR is associated with Asian hair thickness.

Hair morphology is one of the most differentiated traits among human populations. However, genetic backgrounds of hair morphological differences among populations have not been clarified yet. In addition, little is known about the evolutionary forces that have acted on hair morphology. To identify hair morphology-determining genes, the levels of local genetic differentiation in 170 genes that are related to hair morphogenesis were evaluated by using data from the International HapMap project. Among highly differentiated genes, ectodysplasin A receptor (EDAR) harboring an Asian-specific non-synonymous single nucleotide polymorphism (1540T/C, 370Val/Ala) was identified as a strong candidate. Association studies between genotypes and hair morphology revealed that the Asian-specific 1540C allele is associated with increase in hair thickness. Reporter gene assays suggested that 1540T/C affects the activity of the downstream transcription factor NF-kappaB. It was inferred from geographic distribution of 1540T/C and the long-range haplotype test that 1540C arose after the divergence of Asians from Europeans and its frequency has rapidly increased in East Asian populations. These findings lead us to conclude that EDAR is a major genetic determinant of Asian hair thickness and the 1540C allele spread through Asian populations due to recent positive selection.

Association of disease severity with toll-like receptor polymorphisms in multidrug-resistant tuberculosis patients.

Background: The disease severity in pulmonary Multidrug-resistant tuberculosis (MDR-TB) varies from mild to severe, which is determined by host and pathogen virulence factors. The difference of symptoms felt by TB patients were interesting to investigate in discovering whether its the human immune response or bacteria's virulence gene that plays the role. The aim of this research was to analyze association between disease severity degree of pulmonary MDR-TB patients with Single nucleotide polymorphisms (SNPs) found in toll-like receptors (TLRs) gene. Method: Blood samples were obtained from pulmonary MDR-TB patients in Dr. Soetomo Hospital, Surabaya, Indonesia. Polymerase chain reaction (PCR) multiplex and target SNPs were analyze using DigiTag2 assay. The variant of esxA gene was determined using PCR and sequencing. Severity degree was determined by chest X-ray, the lesions were scored according to their severity, score of =2.5 ranking as mild, 2.5-6 as moderate and =6 as severe. Association level between SNP in TLRs gene degree of pulmonary MDR-TB was analyzed using Chi-square test. Bonferroni correction for multiple comparison was used to anticipate genotyping error. Results: A total of 22 MDR-TB patients were classified into severe degree group, while 16 patients were moderate/mild degree. SNPs in encoding gene of TLRs were mostly found in intron, specifically in TLR-1, TLR-2, and TLR-6. HWE P value in rs5743572 was 0.841; in rs3804100 was 0.0176; and in rs5743808 was 0.562. Association analysis between SNP in TLRs genes and degree of disease revealed significant association in rs5743572, SNP of TLR-1, with P < 0.05; odds ratio [OR] = 11.67 (95% confidence interval [CI]: 3.94-34.52); rs3804100, SNP of TLR-2 had P < 0.05; OR = 37.59 (95% CI: 9.30-151.88); and rs5743808, the SNP of TLR-6 had P < 0.05; OR = 31.5 (95% CI: 8.60-115.34). Conclusions: We concluded that SNPs in TLR-1, TLR-2, and TLR-6 of pulmonary MDR-TB patients was found to have an association with disease severity. TLRs polymorphism had significant association was present in TLR-1 rs5743572 in intron, TLR-2 rs3804100 in exon, and TLR-6 rs5743808 in exon and among MDR-TB isolates from patients with pulmonary MDR-TB of severe and moderate/mild degree.

FGFR2 is associated with hair thickness in Asian populations.

Hair morphology is one of the most differentiated traits among human populations. A previous study has shown that a nonsynonymous single nucleotide polymorphism (SNP) in the EDAR gene, EDAR 1540T/C, is strongly associated with hair thickness in Asian populations. However, the contributions of other genes remain to be elucidated. In this study, 12 SNPs on 10 hair formation-related genes with high differentiation between Asian and other populations were examined to further identify genes associated with hair morphology. A multiple regression analysis adjusted for age, sex, population and the effect of EDAR 1540T/C revealed an SNP in intron 9 of FGFR2, rs4752566, to be significantly associated with hair thickness (cross-sectional area; P-value=0.0052, small diameter; P-value=0.029 and large diameter; P-value=0.0015). In the genomic region containing the FGFR2 gene, rs4752566 was not in strong linkage disequilibrium (LD) with the surrounding SNPs, indicating that the significant association of rs4752566 with the hair thickness is not due to LD with polymorphisms of the other genes. The rs4752566-T allele of FGFR2, associated with thicker hair, was also shown to be associated with higher mRNA level of FGFR2 (P-value=0.0270). These results suggest that the FGFR2 polymorphism affects the variation in hair thickness in Asia through alteration in the expression level of FGFR2.

Glutathione S-transferase M1 and T1 null allele frequencies among Indonesian ethnics toward improved disease risk assessment.

Genetic variations in the glutathione S-transferase genes GSTT1 and GSTM1 have been widely studied, and homozygous deletions or null genotypes have been reported in different populations. Previous studies suggest that individuals who are homozygous-null at the GSTM1 or GSTT1 locus may have an increased risk of environmentally related cancers and drug-induced hepatotoxicity. The aim of the present study was to determine the GSTM1 and GSTT1 polymorphisms in 154 healthy, unrelated individuals from the Javanese-Sundanese and Malay ethnic populations of Indonesia to provide a resource for improving the prognosis of possible susceptibilities in specific populations. The subjects were genotyped for the presence of GSTM1 and GSTT1 using the multiplex polymerase chain reaction technique. The GSTM1-null genotype was more frequent among Javanese-Sundanese ethnics (99%) than among the Indonesian Malay (67.2%). Similarly, Javanese-Sundanese ethnics showed a higher frequency of the GSTT1-null genotype (66.7%) than the Indonesian Malay (36.2%). Analysis of the combined distribution of the GSTM1 and GSTT1 genes revealed that 66.7% of the individuals from the Javanese-Sundanese population lack both the genes, whereas only 21.1% of the Indonesian Malay is GSTM1-null and GSTT1-null. This study contributes significant information on the variability of GSTT1 and GSTM1 gene polymorphisms worldwide, which can provide new knowledge about the relationship between ethnicity and the prevalence of certain diseases.

NAT2 slow acetylator is associated with anti-tuberculosis drug-induced liver injury severity in indonesian population.

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.

Southeast Asian Pharmacogenomics Research Network (SEAPharm): Current Status and Perspectives.

Pharmacogenomics (PGx) is increasingly being recognized as a potential tool for improving the efficacy and safety of drug therapy. Therefore, several efforts have been undertaken globally to facilitate the implementation process of PGx into routine clinical practice. Part of these efforts include the formation of PGx working groups working on PGx research, synthesis, and dissemination of PGx data and creation of PGx implementation strategies. In Asia, the Southeast Asian Pharmacogenomics Research Network (SEAPharm) is established to enable and strengthen PGx research among the various PGx communities within but not limited to countries in SEA; with the ultimate goal to support PGx implementation in the region. From the perspective of SEAPharm member countries, there are several key elements essential for PGx implementation at the national level. They include pharmacovigilance database, PGx research, health economics research, dedicated laboratory to support PGx testing for both research and clinical use, structured PGx education, and supportive national health policy. The status of these essential elements is presented here to provide a broad picture of the readiness for PGx implementation among the SEAPharm member countries, and to strengthen the PGx research network and practice in this region.

Research Directions in Genetic Predispositions to Stevens-Johnson Syndrome / Toxic Epidermal Necrolysis.

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is one of the most devastating of adverse drug reactions (ADRs) and was, until recently, essentially unpredictable. With the discovery of several risk alleles for drug-induced SJS/TEN and the demonstration of effectiveness of screening in reducing incidence, the stage is set for implementation of preventive strategies in populations at risk. Yet much remains to be learned about this potentially fatal complication of commonly used drugs.

Association of the HLA-B alleles with carbamazepine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in the Javanese and Sundanese population of Indonesia: the important role of the HLA-B75 serotype.

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.

A human PSMB11 variant affects thymoproteasome processing and CD8+ T cell production.

The Psmb11-encoded ß5t subunit of the thymoproteasome, which is specifically expressed in cortical thymic epithelial cells (cTECs), is essential for the optimal positive selection of functionally competent CD8+ T cells in mice. Here, we report that a human genomic PSMB11 variation, which is detectable at an appreciable allele frequency in human populations, alters the ß5t amino acid sequence that affects the processing of catalytically active ß5t proteins. The introduction of this variation in the mouse genome revealed that the heterozygotes showed reduced ß5t expression in cTECs and the homozygotes further exhibited reduction in the cellularity of CD8+ T cells. No severe health problems were noticed in many heterozygous and 5 homozygous human individuals. Long-term analysis of health status, particularly in the homozygotes, is expected to improve our understanding of the role of the thymoproteasome-dependent positive selection of CD8+ T cells in humans.