Factors involved in the remission of oral lichen planus treated with topical corticosteroids.

AIM: To determine the factors that affected the complete clinical remission of oral lichen planus (OLP) treated with topical corticosteroids. MATERIAL AND METHODS: We retrospectively evaluated the charts of patients diagnosed as OLP. Age, sex, current medical conditions, medications, type of OLP, Thongprasom score, pain level assessed by a numeric rating scale (NRS), Candida infection, topical steroid treatment preparation, duration of treatment until the first complete clinical remission, and follow-up duration were assessed as variables. RESULTS: In total 100 patients, after complete remission, 22 patients reported a relapse within 1.5-45 months, with a mean of 15.6 ± 13.2 months. Age, duration, gingiva and vestibule area, hypertension, dyslipidemia, Thongprasom score, preparation and topical corticosteroid potency were factors affecting the remission. Multivariate logistic regression analysis revealed that the patients' age and duration of treatment were significant factors after adjusted for age, sex, and independent factors with a P-value < 0.1 in the univariate analysis. The likelihood of having incomplete remission of the OLP lesion increased by 7.9% for every year increase in age and increased by 2.3% for every month of treatment. CONCLUSIONS: There are many different factors between the complete remission and incomplete remission groups. However, age and duration of treatment were significant factors affecting the remission of OLP.

Orodental health status of patients with inborn errors of immunity.

BACKGROUND: Various orodental problems affect patients with inborn errors of immunity (IEI), but there are limited studies on these issues. AIM: To study orodental status and its confounding factors in patients with IEI. DESIGN: Caries, enamel defects, gingival, and soft tissue conditions were examined. Data on patient characteristics, dental hygiene habits, dental attendance, and household income were collected. Statistical analysis and logistic regression were performed. RESULTS: Forty-five participants with a mean age of 9.20 ± 6.41 years were included. Almost all participants had gingivitis (42 of 45; 93.3%), whereas a small number had periodontitis (five of 45; 11.1%). Calculus was found in 33 (73.3%) and caries in 30 (66.7%). Mucosal ulcers, enamel defects, and candidiasis were observed in 23 of 45 (51.1%), 16 of 43 (37.2%), and six of 43 (14.0%), respectively. Chances of having caries, moderate-to-severe gingivitis, periodontitis, calculus, and ulcers increased with age. Taking antibiotics in the last two months increased the risk of caries by five times. Lower income increased the risk of calculus deposit by nine times. CONCLUSION: Gingivitis, calculus, caries, and mucosal ulcers were the most common orodental findings in patients with IEI. Antibiotics increased the risk of caries, and low-income children had higher calculus accumulation.

Cysts of the jaws: A multicentre study.

OBJECTIVES: To determine the relative frequency, demographic and pathologic profiles of patients diagnosed with cysts of the jaws. MATERIALS AND METHODS: Biopsy records of the participating institutions from 2000 to 2020 were reviewed for lesions diagnosed in the cyst category. Demographic data, the location of the cysts and pathologic diagnoses were collected. Data were analyzed by appropriate statistics using IBM SPSS software version 28.0. RESULTS: From 148,353 accessioned cases, 25,628 cases (17.28%) were diagnosed in the cyst category. Mean age of the patients ± SD = 42.62 ± 19.36 years. Paediatric patients (aged ≤ 16 years) accounted for 9.63%, while geriatric patients (aged ≥ 65) comprised 14.22% of all the patients. The male-to-female ratio was 1.27:1. The majority of the lesions were encountered in the mandible. The most prevalent cyst was radicular cyst followed by dentigerous cyst and odontogenic keratocyst. In the paediatric group, dentigerous cyst was the most prevalent, whereas in the geriatric group, radicular cyst was the most common. CONCLUSIONS: In general, the results of this study are in accordance with previous studies. This study provides an invaluable database for clinicians when formulating clinical differential diagnoses as well as for pathologists in rendering the final diagnosis.

Tooth agenesis patterns and variants in PAX9: A systematic review.

Mutations in PAX9 are the most common genetic cause of tooth agenesis (TA). The aim of this study was to systematically review the profiles of the TA and PAX9 variants and establish their genotype-phenotype correlation. Forty articles were eligible for 178 patients and 61 mutations (26 in frame and 32 null mutations). PAX9 mutations predominantly affected molars, mostly the second molar, and the mandibular first premolar was the least affected. More missing teeth were found in the maxilla than the mandible, and with null mutations than in-frame mutations. The number of missing teeth was correlated with the locations of the in-frame mutations with the C-terminus mutations demonstrating the fewest missing teeth. The null mutation location did not influence the number of missing teeth. Null mutations in all locations predominantly affected molars. For the in-frame mutations, a missing second molar was commonly associated with mutations in the highly conserved paired DNA-binding domain, particularly the linking peptide (100% prevalence). In contrast, C-terminus mutations were rarely associated with missing second molars and anterior teeth, but were commonly related to an absent second premolar. These finding indicate that the mutation type and position contribute to different degrees of loss of PAX9 function that further differentially influences the manifestations of TA. This study provides novel information on the correlation of the PAX9 genotype-phenotype, aiding in the genetic counseling for TA.

Effects of blue-light LED toothbrush on reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances: a crossover randomized controlled trial.

BACKGROUND: Patients with fixed orthodontic appliances have higher plaque accumulation and gingival inflammation. Our aim was to compare the effectiveness of a light emitting diode (LED) toothbrush with a manual toothbrush in reducing dental plaque and gingival inflammation in orthodontic patients with fixed appliances, and to investigate the effect of the LED toothbrush on Streptococcus mutans (S. mutans) biofilm in vitro. METHODS: Twenty-four orthodontic patients were recruited and randomly assigned into 2 groups: (1) started with manual and (2) started with LED toothbrushes. After a 28-day usage and 28-day wash-out period, the patients switched to the other intervention. The plaque and gingival indices were determined at baseline and 28 days after each intervention. The patients' compliance and satisfaction scores were collected using questionnaires. For the in vitro experiments, S. mutans biofilm was divided into 5 groups (n = 6) with 15-, 30-, 60-, or 120-sec LED exposure, and without LED exposure as a control group. RESULTS: There was no significant difference in the gingival index between the manual and LED toothbrush groups. The manual toothbrush was significantly more effective in reducing the plaque index in the proximal area on the bracket side (P = 0.031). However, no significant difference was found between the two groups in other areas around the brackets or on the non-bracket side. After LED exposure in vitro, the percentages of bacterial viability after LED exposure for 15-120 s were significantly lower compared with the control (P = 0.006). CONCLUSION: Clinically, the LED toothbrush was not more effective in reducing dental plaque or gingival inflammation than the manual toothbrush in orthodontic patients with fixed appliances. However, the blue light from the LED toothbrush significantly reduced the number of S. mutans in biofilm when it was exposed to the light for at least 15 s in vitro. CLINICAL TRIAL REGISTRATION: Thai Clinical Trials Registry (TCTR20210510004). Registered 10/05/2021.

Patterns of nonsyndromic tooth agenesis and sexual dimorphism.

BACKGROUND: Sex dimorphism has been implicated in oral health differences and the pathogenesis of oral diseases, such as tooth agenesis, periodontal disease, dental caries, and tooth loss. Tooth agenesis (TA) is one of the most common developmental anomalies in humans, and its prevalence and patterns are different across ethnic groups. The aim of this study was to investigate the phenotypes and sex-associated patterns of nonsyndromic tooth agenesis (TA) in Thai dental patients. METHODS: One thousand ninety panoramic radiographs were examined. One hundred and one subjects (37 males, 64 females, 15-20 years-old) with nonsyndromic TA were evaluated. Differences in TA prevalence between groups were analyzed using the chi-square or Fisher exact test. RESULTS: The TA prevalence, excluding third molars, was 9.3% and more frequently found in the mandible compared with the maxilla. The maxilla demonstrated a higher prevalence of first premolar agenesis than the mandible (P = 0.012), while the mandible had a higher prevalence of second premolar agenesis than the maxilla (P = 0.031). There were significantly more males missing one tooth than females, however, there were more females missing two or more teeth than males (P = 0.042). A missing maxillary left lateral incisor was significantly more frequent in males (P = 0.019), while a missing mandibular right lateral incisor was more frequent in females (P = 0.025). In females, the pattern of two mandibular lateral incisors agenesis was the most common and significantly present in females more than males (P = 0.015). In contrast, the pattern of one mandibular left lateral incisor agenesis was only observed in males and significantly found in males more than females (P = 0.047). CONCLUSIONS: We demonstrate sex-associated differences in nonsyndromic tooth agenesis. The prevalence of single tooth agenesis was higher in males, while that of two or more teeth agenesis was higher in females. We found different patterns of lateral incisor agenesis between males and females.

Intraosseous jaw lesions: A 25-year experience.

Context: Jaw bones can be afflicted by to a diverse group of lesions ranging from developmental, reactive/inflammatory, cystic lesions to tumors and tumor-like lesions. Objectives: The objective of this study is to determine the relative frequency, demographic and pathologic profiles of patients with intraosseous jaw lesions from Thailand. Subjects and Methods: Biopsy records from 1995 to 2019 were reviewed. Age, gender and location of the lesions were collected from the biopsy records. Data were analyzed by appropriate statistics using the IBM SPSS software version 22.0. Results: From 23,344 accessioned cases, 7382 cases (31.62%) were encountered within the jaw bones. Age of the participants ranged from 1 to 96 years with the mean ± standard deviation = 36.05 ± 17.80 years. Pediatric participants (aged ≤16 years) comprised 13.80% of all the participants, whereas the geriatric ones (aged ≥65 years) accounted for 7.55%. The male-to-female ratio was 0.89:1. The majority of lesions were observed in the mandible. The most prevalent intra-osseous jaw lesion was radicular cyst followed by dentigerous cyst and ameloblastoma. The most common malignant tumor was osteosarcoma followed by ameloblastic carcinoma and lymphoma. Among the pediatric participants, dentigerous cyst was the most prevalent jaw lesion, while that in the geriatric participants was radicular cyst. Conclusions: This is the largest study on intra-osseous jaw lesions encompassing several pathological entities ever conducted from Thailand. It thus provides an invaluable database for clinicians to formulate a differential diagnosis as well as for the pathologists to render the final diagnosis. The results of this study are in accordance with previous studies in general.

Procedures Used in Managing SARS-CoV-2 Infected Dental Personnel or Patients: A Case Study From a Thai Dental Hospital.

SARS-CoV-2 can transmit undetected from asymptomatic and pre-symptomatic patients in dental clinics. Triaging dental patients using temperature and questionnaire screening cannot completely exclude asymptomatic SARS-CoV-2 infected individuals. Hence, asymptomatic SARS-CoV-2 infected individuals might visit dental hospitals/clinics seeking dental treatment without knowing that they are infected and might infect others, especially in a pandemic area. Ideally, a nasopharyngeal swab for real-time polymerase chain reaction or rapid antigen screening for dental personnel and patients prior to their appointment should be done. However, the implementation of this approach is impractical in some situations. Here, we describe the procedures for dental hospitals/clinics in case of an asymptomatic SARS-CoV-2 infected individual involved in dental service/treatment and later after testing positive for SARS-CoV-2. Potential closely contacted individuals were traced and classified according to their exposure risk. The recommended course of action is to identify individuals based on their risk and take the risk-appropriate action. We also discuss the implementation of these procedures in a dental setting during the COVID-19 pandemic in our school as a case study.

Interplay between vitamin D receptor FokI polymorphism and smoking influences Porphyromonas gingivalis proportions in subgingival plaque.

AIM: This cross-sectional study investigated the effect of the vitamin D receptor (VDR) FokI polymorphism and its interactions with smoking/drinking on the proportions of periodontal pathogens and periodontitis severity. MATERIALS AND METHODS: FokI genotyping and bacterial quantification were performed using real-time polymerase chain reaction. Periodontitis severity was determined using mean clinical attachment level (CAL). Regression analyses examined the associations between the FokI polymorphism (rs2228570) and bacterial proportions or periodontitis severity. Effect modification by smoking or drinking was assessed. RESULTS: The study population comprised 1,460 individuals, aged 39-66 years. After multivariable adjustment, the FokI risk genotypes (CC + CT) were associated with elevated Porphyromonas gingivalis proportions (regression coefficient (ß) =0.294 ± 0.139; p = .034) and increased mean CAL (ß = 0.130 ± 0.048; p = .007). The effect of the FokI polymorphism on P. gingivalis proportions was greater in smokers (ß = 0.897 ± 0.328; p = .006) compared to non-smokers (ß = 0.164 ± 0.153; p = .282) and in drinkers (ß = 0.668 ± 0.242; p = .006) compared to non-drinkers (ß = 0.114 ± 0.169; p = .500). The genotype*smoking interaction for P. gingivalis proportions was significant (p = .043), whereas the genotype*drinking interaction was not (p = .061). Similar results were found for the effect of the genotype*smoking/drinking interaction on mean CAL. CONCLUSIONS: These findings suggest that the interplay between the host genotype and smoking is important in determining the subgingival microbial composition and periodontitis severity.

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.

Vitamin D Receptor Gene Polymorphism and Smoking in the Risk of Chronic Periodontitis.

BACKGROUND: Polymorphisms of the vitamin D receptor (VDR) gene have been implicated in susceptibility to infections and bone-related diseases. However, their relationship with periodontal disease remains unclear. This cross-sectional study investigates whether susceptibility to chronic periodontitis (CP) in a Thai population is associated with VDR polymorphisms. METHODS: Genomic DNA was obtained from 1,460 participants, aged 39 to 66 years. Genotyping of VDR polymorphisms (FokI, BsmI, ApaI, and TaqI) was performed using real-time polymerase chain reaction. Participants were categorized into three groups: 1) no/mild; 2) moderate; and 3) severe CP. Multinomial logistic regression was used to determine degree of association between VDR polymorphisms and periodontal status adjusted for known confounders. RESULTS: The CC+CT genotypes of FokI polymorphism were associated with severe CP with an odds ratio (OR) of 1.9 (95% confidence interval [CI]: 1.3 to 2.8). Compared with genotype-negative (TT) non-smokers, positivity for the risk genotypes (CC+CT) alone and current smoking alone were associated with severe CP with ORs of 1.8 (95% CI: 1.1 to 3.2) and 2.5 (95% CI: 1.0 to 6.2), respectively. The combination of being genotype positive and smoking further increased the OR to 9.6 (95% CI: 4.5 to 20.4). This combined effect was 3.7 times (95% CI: 1.2 to 11.1) greater than expected from the sum of their individual effects, indicating a synergistic interaction. No significant association was observed between other polymorphisms and CP. CONCLUSION: FokI CC+CT genotypes were associated with increased susceptibility to severe CP, which was aggravated further when combined with smoking.

Effect of daily drinking of Aloe vera gel extract on plasma total antioxidant capacity and oral pathogenic bacteria in healthy volunteer: a short-term study.

BACKGROUND: The aim of this study was to investigate the effect of Aloe vera gel extract on plasma total antioxidant capacity (TAC) and oral pathogenic bacteria in healthy volunteer. METHODS: Fifty-three healthy volunteers were participated and interviewed for history of allergy, current systemic diseases and medications. Participants were received 250 mL of A. vera gel extract daily for 14 consecutive days. At days 0 and 15 of the experiment, blood samples were collected and analyzed for biochemical markers. The plasma TAC was evaluated by ferric reducing ability of plasma technique. The biochemical markers, including aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total protein (TP), serum albumin (ALB), serum globulin (GLB), total bilirubin (TB), blood urea nitrogen (BUN), serum creatinine (Cr) and creatinine clearance (CrCl) were measured. The antibacterial effect of A. vera gel extract against Lactobacillus spp. and Streptococcus mutans was also investigated. Statistical analysis was performed using paired t-test to compare between baseline and 14 days post-intervention. RESULTS: Neither allergy nor side effects of A. vera gel extract was detected. After 14 days of A. vera gel extract consumption, plasma TAC was significantly greater than that of baseline (p = 0.001). ALP, TB, TP and GLB were significantly increased (p < 0.05) which were still within normal range. AST, ALT, ALB, BUN, Cr and CrCl were not significantly different. A. vera gel extract significantly reduced the number of Lactobacillus spp. (p < 0.05), not S. mutans. CONCLUSIONS: Our data revealed that A. vera gel extract significantly increased plasma TAC, and decreased the number of Lactobacillus spp. without any clinical side effects.

Ameloblastoma: a multicentric study.

OBJECTIVE: The objective of this study was to supplement the current ameloblastoma database by reporting the clinicopathologic features of ameloblastoma from Asia and North America. MATERIALS AND METHODS: Biopsy records of the participating institutes were reviewed for lesions diagnosed as ameloblastoma during the years 1993 to 2009. Slides were reclassified according to the World Health Organization Classification of Odontogenic Tumors in 2005. Clinical information and radiographic features were collected and analyzed. RESULTS: The mean age of the patients ± SD was 38.27 ± 17.78 years; 662 patients (51.36%) were men. Mandible (84.26%) outnumbered maxilla and other locations combined in all countries. The number of multilocular radiolucencies (43.40%) was comparable with that of unilocular radiolucencies (42.04%). Follicular pattern was the most common histopathologic pattern (27.70%), followed by plexiform (21.10%) and unicystic pattern (20.71%), respectively. CONCLUSIONS: The clinicopathologic features of ameloblastomas in the present study show some similarities with previous studies; however, minor differences exist.

Genome-wide association study identifies variations in 6p21.3 associated with nevirapine-induced rash.

BACKGROUND: We aimed to identify disease-predisposing variations with nevirapine-induced rash using genome-wide single-nucleotide polymorphisms (SNPs) as genetic markers. METHODS: A genome-wide association study (GWAS) was performed using ∼550000 markers in 72 human immunodeficiency virus (HIV)-infected Thai patients with nevirapine-induced rash and 77 nevirapine-tolerant patients, and then candidate SNPs were further evaluated in a replication set (88 patients with nevirapine-induced rash and 145 nevirapine-tolerant patients). RESULTS: The genome-wide association analysis and replication studies of candidate SNPs identified significant associations of nevirapine-induced rash with 2 SNPs (rs1265112 and rs746647) within CCHCR1 on chromosome 6p21.3 (P(GWAS) = 1.6 × 10(-4); P(replication) = 2.6 × 10(-5); P(combined) = 1.2 × 10(-8)). The odds ratio (OR) of the risk genotypes under a dominant model was 4.36 (95% confidence interval [CI], 2.58-7.36). The noncoding SNPs rs1265112 and rs746647 were in complete linkage disequilibrium with the nonsynonymous SNP rs1576 (r(2) = 1.00), which has been associated with psoriasis. The logistic regression analysis also indicated genetic variations in CCHCR1 to be significantly associated with rash, with an OR of 2.59 (95% CI, 1.82-3.68; P = .007). The receiver operating characteristic curve showed that the algorithm had an area under the curve of 76.4%, which was developed with 5 factors: rs1576*G status, HLA-B*3505 status, not receiving prescribed lead-in of nevirapine, history of drug allergy, and CD4 cell count prior to the nevirapine treatment. CONCLUSIONS: We demonstrated that genetic variations in CCHCR1 are strongly associated with nevirapine-induced rash. A predictive model that includes genetic and clinical risk factors for nevirapine-associated rash might be useful in lowering the incidence of rash associated with nevirapine initiation among HIV-infected patients.

Development of new HLA-B*3505 genotyping method using Invader assay.

Several pharmacogenetic studies have revealed strong associations between specific human leukocyte antigen (HLA) alleles and the susceptibility to drug hypersensitivity. Recently, we reported HLA-B*3505 as a strong genetic biomarker for the nevirapine-induced skin rash in Thai population. Here, we developed a new HLA-B*3505 genotyping method by a combination of the Universal Invader assay and sequence-specific primer PCR. From the sequence alignment of 68 HLA-B alleles in the Thai population, we selected the two most discriminative SNPs (rs1140412 and rs4997052) as target SNP sites. When we carried out the assay using 324 Thai individuals, fluorescence intensities of HLA-B*3505-positive and HLA-B*3505-negative samples were apparently discriminated at the endpoint of the reaction. Our results were 100% concordant with those obtained by a sequence-based typing method. As our assay is simple and rapid, we believe our method will be a useful tool for pharmacogenetic testing of the nevirapine-induced skin rash.

Association between HLA-B*4001 and lipodystrophy among HIV-infected patients from Thailand who received a stavudine-containing antiretroviral regimen.

BACKGROUND: Stavudine-containing antiretroviral regimens are widely used in developing countries. Stavudine-associated lipodystrophy commonly occurs, without a clear predictable pattern owing to the unknown interaction between stavudine and the host, among patients who received this regimen. The aim of this study was to determine the clinical risk factors and human leukocyte antigen (HLA) alleles associated with stavudine-associated lipodystrophy. METHODS: A case-control, cross-sectional study was conducted for HIV-infected patients receiving stavudine-containing antiretroviral regimens. Clinical assessments for lipodystrophy by physical examination, anthropometry, and dual-energy X-ray absorptiometry were obtained. On the basis of their clinical assessment, the patients were classified into 2 groups: the case group (moderated to severe lipodystrophy) and the control group (absent to mild lipodystrophy). The clinical characteristics and allelic distribution of HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQB1, and HLA-DPB1 were compared between the case group and the control group, to determine the possible association with stavudine-associated lipodystrophy. RESULTS: There were 103 patients; 55 patients were in the case group, and 48 patients were in the control group. By use of forward stepwise logistic regression, the presence of HLA-B*4001 (odds ratio [OR], 14.05; 95% confidence interval [CI], 2.57-76.59; P=.002) and a longer duration of stavudine treatment (OR, 1.02; 95% CI, 1.00-1.04; P=.02) were significantly associated with stavudine-associated lipodystrophy, whereas a higher body mass index during treatment (OR, 0.73; 95% CI, 0.61-0.86; P<.001) was associated with a lower risk for lipodystrophy. HLA-B*4001 has a high specificity (95.8%) and a positive predictive value (88.9%) for lipodystrophy. CONCLUSIONS: HLA-B*4001 is a strong genetic risk factor for stavudine-associated lipodystrophy in HIV-infected patients in Thailand. HLA-B*4001 may be used as a genetic marker to predict which patients will develop stavudine-associated lipodystrophy, to avoid or shorten the duration of stavudine use. This finding needs to be confirmed in further replication studies.

Influence of CYP2B6 polymorphisms on the persistence of plasma nevirapine concentrations following a single intra-partum dose for the prevention of mother to child transmission in HIV-infected Thai women.

OBJECTIVES: To investigate the association of single nucleotide polymorphisms (SNPs) with nevirapine concentrations following intra-partum single-dose nevirapine. METHODS: Plasma and DNA samples were obtained from 330 HIV-infected Thai women who received intra-partum single-dose nevirapine in the PHPT-2 clinical trial to prevent perinatal HIV transmission. Nine SNPs within CYP2B6, CYP3A4 and ABCB1 were genotyped by real-time PCR. Nevirapine plasma concentrations were determined by HPLC and used in a population pharmacokinetic analysis. RESULTS: Higher nevirapine exposure was observed in women carrying the CYP2B6 516G>T polymorphism, but this did not reach statistical significance (P = 0.054). The TGATC CYP2B6 haplotype (g.3003T, 516G, 785A, g.18492T and g.21563C) was associated with increased nevirapine clearance and lower exposure (P = 0.0029). The median time for nevirapine concentrations to reach 10 ng/mL post-partum (nevirapine IC(50) for HIV-1) was 14 days [interquartile range (IQR, 14-18)] for TGATC homozygotes, 16 days (14-20) for TGATC heterozygotes and 18 days (14-20) for non-TGATC homozygotes (P = 0.020). CONCLUSIONS: The CYP2B6 516G>T impact on nevirapine concentrations was less pronounced after intra-partum single-dose nevirapine than reported under steady-state conditions, perhaps due to lack of enzyme auto-induction at the time of dosing. Although the TGATC CYP2B6 haplotype may shorten the persistence of nevirapine post-partum, its practical implications for the prevention of HIV transmission or selection of resistance mutations are likely limited.

HLA-B*3505 allele is a strong predictor for nevirapine-induced skin adverse drug reactions in HIV-infected Thai patients.

OBJECTIVE: Investigation of a possible involvement of differences in human leukocyte antigens (HLA) in the risk of nevirapine (NVP)-induced skin rash among HIV-infected patients. METHODS: A step-wise case-control association study was conducted. The first set of samples consisted of 80 samples from patients with NVP-induced skin rash and 80 samples from NVP-tolerant patients. These patients were genotyped for the HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQB1, and HLA-DPB1 by a sequence-based HLA typing method. Subsequently, we verified HLA alleles that showed a possible association in the first screening using an additional set of samples consisting of 67 cases with NVP-induced skin rash and 105 controls. RESULTS: An HLA-B*3505 allele revealed a significant association with NVP-induced skin rash in the first and second screenings. In the combined data set, the HLA-B*3505 allele was observed in 17.5% of the patients with NVP-induced skin rash compared with only 1.1% observed in NVP-tolerant patients [odds ratio (OR)=18.96; 95% confidence interval (CI)=4.87-73.44, Pc=4.6x10] and 0.7% in general Thai population (OR=29.87; 95% CI=5.04-175.86, Pc=2.6x10). The logistic regression analysis also indicated HLA-B*3505 to be significantly associated with skin rash with OR of 49.15 (95% CI=6.45-374.41, P=0.00017). CONCLUSION: A strong association between the HLA-B*3505 and NVP-induced skin rash provides a novel insight into the pathogenesis of drug-induced rash in the HIV-infected population. On account of its high specificity (98.9%) in identifying NVP-induced rash, it is possible to utilize the HLA-B*3505 as a marker to avoid a subset of NVP-induced rash, at least in Thai population.

Comparison of the TaqMan and LightCycler systems in evaluation of CYP2B6 516G>T polymorphism.

Understanding genetically encoded inherited differences in drug metabolism and drug targets offers the promise of minimizing adverse drug reactions and improving therapies. We have compared two real-time PCR-based methods, the TaqMan and LightCycler for the pharmacogenetic evaluation of CYP2B6 516G>T polymorphism. Both methods were found to be suitable for pharmacogenetic testing of CYP2B6 516G>T in the meaning of time consumption, accurate genotype calling, flexible reaction format, simple data analysis, and low cost per assay. The genotype success rate was similar, but the LightCycler procedure was less expensive in terms of cost per sample and shorter running time.