Association of cutaneous adverse drug reactions due to antiepileptic drugs with HLA alleles in a North Indian population

Unraveling the genetic link: an umbrella review on HLA-B*15:02 and antiepileptic drug-induced Stevens-Johnson syndrome/toxic epidermal necrolysis

PURPOSE

This umbrella review was conducted to summarize the association between HLA*1502 allele with antiepileptic induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

METHODS

Pubmed, Scopus and EMBASE were searched for eligible reviews in May 2023. Two authors independently screened titles and abstracts and assessed full-text reviews for eligibility. The quality of meta-analyses and case-control studies was appraised with Assessing the Methodological Quality of Systematic Reviews 2 and Newcastle-Ottawa Scale, respectively. Narrative summaries of each antiepileptic drug were analyzed. Preestablished protocol was registered on the International Prospective Register of Systematic Reviews Registry(ID: CRD42023403957).

RESULTS

Included studies are systematic reviews, meta-analyses and case-control studies evaluating the association of HLA-B*1502 allele with the following antiepileptics. Seven meta-analyses for carbamazepine, three meta-analyses for lamotrigine (LTG), three case-control studies for oxcarbazepine, nine case-control studies for phenytoin and four case-control studies for phenobarbitone were included. The findings of this umbrella review suggest that there is a strong association between HLA-B-1502 with SJS/TEN for carbamazepine and oxcarbazepine and a milder association for lamotrigine and phenytoin.

CONCLUSION

In summary, although HLA-B*1502 is less likely to be associated with phenytoin or lamotrigine-induced SJS/TEN compared to carbamazepine-induced SJS/TEN, it is a significant risk factor that if carefully screened, could potentially reduce the development of SJS/TEN. In view of potential morbidity and mortality, HLA-B*1502 testing may be beneficial in patients who are initiating lamotrigine/phenytoin therapy. However, further studies are required to examine the association of other alleles with the development of SJS/TEN and to explore the possibility of genome-wide association studies before initiation of treatment.

HLA alleles and antiseizure medication-induced cutaneous reactions in Brazil: A case-control study

In this observational case-control study, 107 cutaneous adverse reaction (CAR) cases (CAR+) manifesting up to 12 weeks after the start of treatment with antiseizure medication (ASM) were identified. Control groups consisted of 98 epilepsy patients without a history of CAR (CAR-) and 3965 healthy individuals in the Brazilian National Registry of Bone Marrow Donors. All participants were HLA typed by high-resolution Next Generation Sequencing for HLA-A, B, C, DQB1 and DRB1; HLA-DPA1, DPB1, DQA1, DRB3, DRB4 and DRB5 were also sequenced in samples from CAR+ and CAR- individuals. The relationship between the carrier frequency of each allele, CAR type and ASM for all participants was investigated. The ASMs most frequently associated with CAR were carbamazepine (48% of CAR+ subjects), lamotrigine (23%), phenytoin (18%), phenobarbital (13%) and oxcarbazepine (5%). The main alleles associated with a risk of CAR were HLA-A*02:05 (OR = 6.28; p = 0.019, carbamazepine or oxcarbazepine); HLA-DPA1*02:02 (OR = 4.16, p = 0.003, carbamazepine); HLA-B*53:01 (OR = 47.9, p = 0.014, oxcarbazepine), HLA-DPA1*03:01/DPB1*105:01 (OR = 25.7, p = 0.005, phenobarbital); HLA-C*02:10 (OR = 25.7, p = 0.005, phenobarbital) and HLA-DRB1*04:02 (OR = 17.22, p = 0.007, phenytoin). HLA-A*03:01 increased the risk for phenytoin-induced maculopapular exanthema 4.71-fold (p = 0.009), and HLA-B*35:02 was associated with a 25.6-fold increase in the risk of carbamazepine-induced Stevens-Johnson syndrome (p = 0.005). None of the 4170 subjects carried the HLA-B*15:02 allele, and HLA-A*31:01 was not associated with CAR. Hence, HLA-A*31:01 and HLA-B*15:02 were not associated with CAR in this population. Although other HLA class I and II alleles tested were associated with a risk of CAR, none of these associations were strong enough to warrant HLA testing before prescribing ASM.

Clocking Epilepsies: A Chronomodulated Strategy-Based Therapy for Rhythmic Seizures

Epilepsy is a neurological disorder characterized by hypersynchronous recurrent neuronal activities and seizures, as well as loss of muscular control and sometimes awareness. Clinically, seizures have been reported to display daily variations. Conversely, circadian misalignment and circadian clock gene variants contribute to epileptic pathogenesis. Elucidation of the genetic bases of epilepsy is of great importance because the genetic variability of the patients affects the efficacies of antiepileptic drugs (AEDs). For this narrative review, we compiled 661 epilepsy-related genes from the PHGKB and OMIM databases and classified them into 3 groups: driver genes, passenger genes, and undetermined genes. We discuss the potential roles of some epilepsy driver genes based on GO and KEGG analyses, the circadian rhythmicity of human and animal epilepsies, and the mutual effects between epilepsy and sleep. We review the advantages and challenges of rodents and zebrafish as animal models for epileptic studies. Finally, we posit chronomodulated strategy-based chronotherapy for rhythmic epilepsies, integrating several lines of investigation for unraveling circadian mechanisms underpinning epileptogenesis, chronopharmacokinetic and chronopharmacodynamic examinations of AEDs, as well as mathematical/computational modeling to help develop time-of-day-specific AED dosing schedules for rhythmic epilepsy patients.

Genotyping for HLA risk alleles versus patch tests to diagnose anti-seizure medication induced cutaneous adverse drug reactions

Aim: To provide a comparison of genotyping for HLA risk alleles versus patch testing to determine which of these two tests is a better diagnostic tool for cutaneous hypersensitivity reactions caused by anti-seizure medication. Methods: A literature study was performed in PubMed to assess the sensitivity and specificity of HLA genotyping and patch tests for identifying anti-seizure medication induced cutaneous hypersensitivity reactions. Results: This study shows that HLA-B*15:02 genotyping shows high sensitivity for carbamazepine-induced SJS/TEN, especially in Han Chinese and Southeast Asian patients (66.7-100.0%) whereas the sensitivity of patch tests (0.0-62,5%), HLA-A*31:01 (0-50%) and HLA-B*15:11 (18.2-42.9%) are lower. On the contrary, for carbamazepine and phenytoin induced DRESS, patch tests (respectively 70.0-88.9% and 14.3-70.0%) show higher sensitivity than HLA tests (0-66.7% and 0-12.7%). Also for lamotrigine-induced DRESS patch tests perform better than HLA-B*15:02 (33.3-40.0 versus 0%). For anti-seizure medication induced MPE and for oxcarbazepine-induced SCARs more studies are needed. Conclusion: Use of HLA-B genotyping may aid clinicians in the diagnosis of carbamazepine, phenytoin, lamotrigine and oxcarbazepine induced SJS/TEN, particularly in Han Chinese and Southeast Asian patients. On the other hand, patch tests seem to perform better in the diagnosis of carbamazepine and phenytoin induced DRESS.

Role of human leukocyte antigen in anti-epileptic drugs-induced Stevens-Johnson Syndrome/toxic epidermal necrolysis: A meta-analysis

PURPOSE

Antiepileptic drugs (AEDs) are extensively used to manage epilepsy and other comorbidities associated with seizures. Human Leukocyte Antigen (HLA) has a strong association with AED-induced severe cutaneous adverse drug reactions.

OBJECTIVE

We aimed to perform a systematic review and meta-analysis to identify, critically evaluate, and synthesize the best possible evidence on HLA-associated AED-induced Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN).

METHODS

MEDLINE/PubMed, Scopus, and the Cochrane Library were searched for literature from inception up to July 2022. We included case control studies analyzing association between HLA and AED-induced SJS/TEN. We assessed the studies' risk of bias in using Quality of genetic studies (Q-genie) tool. Outcomes focused on association (risk) between HLA and AED-induced SJS/TEN. The estimated risk was presented in the form of odds ratio (OR).

RESULTS

We included 37 studies (51,422 participants; 7027 cases and 44,395 controls). There was a significantly higher risk of Carbamazepine-induced SJS/TEN with HLA-A (OR: 1.50; 95% CI: 1.03 to 2.17), HLA-B (OR: 1.94; 95% CI: 1.45 to 2.58), HLA-C (OR: 7.83; 95% CI: 4.72 to 12.98), and HLA-DRB1 (OR: 2.82; 95% CI: 1.94 to 4.12). Lamotrigine-induced SJS/TEN posed a higher risk with HLA-A (OR: 2.38; 95% CI: 1.26 to 4.46) and HLA-B (OR: 2.79; 95% CI: 1.75 to 4.46). Phenytoin-induced SJS/TEN showed a higher risk with HLA-A (OR: 3.47; 95% CI: 2.17 to 5.56), HLA-B (OR: 1.72; 95% CI: 1.38 to 2.15), and HLA-C (OR: 2.92; 95% CI: 1.77 to 4.83). Phenobarbital-induced SJS/TEN had a higher risk with HLA-A (OR: 6.98; 95% CI: 1.81 to 26.84), HLA-B (OR: 2.40; 95% CI: 1.39 to 4.17), and HLA-C (OR: 3.37; 95% CI: 1.03 to 11.01). Zonisamide-induced SJS/TEN was significantly associated with HLA-A*02:07 (OR: 9.77; 95% CI: 3.07 to 31.1), HLA-B*46:01 (OR: 6.73; 95% CI: 2.12 to 21.36), and HLA-DRB1×08:03 (OR: 3.78; 95% CI: 1.20 to 11.97). All other alleles of HLA were observed to have a non-significant association with AED-induced SJS/TEN. All included studies were of good quality, with a score of >50 and a mean score of 54.96 out of 77.

CONCLUSION

Our study showed a significant association between few variants of HLA alleles and AED-induced SJS/TEN. Evidences from our study could help in population-based studies and in implementation of individualized treatment regimens. These findings could be part of translational research helping in precision therapy.

Associations of HLA genetic variants with carbamazepine-induced cutaneous adverse drug reactions: An updated meta-analysis

Aggregated risk of carbamazepine (CBZ)-induced cutaneous adverse drug reactions (cADRs) with different HLA variants are unclear and limited in terms of the power of studies. This study aimed to assess the aggregated risk of CBZ-induced cADRs associated with carrying the following HLA variants: HLA-B*15:02, HLA-B*15:11, HLA-B*15:21, HLA-B*38:02, HLA-B*40:01, HLA-B*46:01, HLA-B*58:01, HLA-A*24:02, and HLA-A*31:01. Literature was searched in different databases following PRISMA guidelines. The outcomes were measured as odds ratio (OR) using RevMan software by a random/fixed effects model, where p < 0.05 was set as statistical significance. In total, 46 case-control studies met the inclusion criteria and were included in this analysis consisting of 1817 cases and 6614 controls. It was found that case-patients who carried the HLA-B*15:02 allele were associated with a significantly increased risk of CBZ-induced Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) compared to controls (OR 26.01; 95% CI 15.88-42.60; p < 0.00001). The aggregated risk of cADRs was slightly higher in Asian compared to Caucasian patients (Asians: OR 14.84; 95% CI 8.95-24.61; p < 0.00001; Caucasians: OR 11.65; 95% CI 1.68-80.70; p = 0.01). Further, HLA-B*15:11, HLA-B*15:21, or HLA-A*31:01 allele was also associated with significantly increased risk of CBZ-induced cADRs (HLA-B*15:11: OR 6.08; 95% CI 2.28-16.23; p = 0.0003; HLA-B*15:21: OR 5.37; 95% CI 2.02-14.28; p = 0.0008; HLA-A*31:01: OR 5.92; 95% CI 4.35-8.05; p < 0.00001). Other HLA variants were not found to have any significant associations with CBZ-induced cADRs. Strong associations between the HLA-B*15:02, HLA-B*15:11, HLA-B*15:21, or HLA-A*31:01 allele with CBZ-induced cADRs have been established in this analysis. Pharmacogenetic testing of particular HLA alleles before initiation of CBZ therapy may be beneficial to patients and may help to eradicate cADRs substantially.

Evolution of HLA-B Pharmacogenomics and the Importance of PGx Data Integration in Health Care System: A 10 Years Retrospective Study in Thailand

Background: The HLA-B is the most polymorphic gene, play a crucial role in drug-induced hypersensitivity reactions. There is a lot of evidence associating several risk alleles to life-threatening adverse drug reactions, and a few of them have been approved as valid biomarkers for predicting life-threatening hypersensitivity reactions.

Objectives: The objective of this present study is to present the progression of HLA-B pharmacogenomics (PGx) testing in the Thai population during a 10‐year period, from 2011 to 2020.

Methods: This was a retrospective observational cohort study conducted at the Faculty of Medicine Ramathibodi Hospital. Overall, 13,985 eligible patients who were tested for HLA-B risk alleles between periods of 2011–2020 at the study site were included in this study.

Results: The HLA PGx testing has been increasing year by year tremendously, 94 HLA-B testing was done in 2011; this has been raised to 2,880 in 2020. Carbamazepine (n = 4,069, 33%), allopurinol (n = 4,675, 38%), and abacavir (n = 3,246, 26%) were the most common drugs for which the HLA-B genotyping was performed. HLA-B*13:01, HLA-B*15:02 and HLA-B*58:01 are highly frequent, HLA-B*51:01 and HLA-B*57:01 are moderately frequent alleles that are being associated with drug induced hypersensitivity. HLA-B*59:01 and HLA-B*38:01 theses alleles are rare but has been reported with drug induced toxicity. Most of the samples were from state hospital (50%), 36% from private clinical laboratories and 14% from private hospitals.

Conclusion: According to this study, HLA-B PGx testing is increasing substantially in Thailand year after year. The advancement of research in this field, increased physician awareness of PGx, and government and insurance scheme reimbursement assistance could all be factors. Incorporating PGx data, along with other clinical and non-clinical data, into clinical decision support systems (CDS) and national formularies, on the other hand, would assist prescribers in prioritizing therapy for their patients. This will also aid in the prediction and prevention of serious adverse drug reactions.

Incidence of Anti-Seizure Medication-Induced Severe Cutaneous Adverse Reactions in Malaysia

Anti-seizure medication (ASM) can potentially cause severe cutaneous adverse reactions (SCAR), and certain ASM-induced SCAR is associated with specific HLA alleles. This caused a change in ASM prescribing pattern, which may influence the incidence of ASM-induced SCAR. Thus, we aimed to determine the incidence of ASM-induced SCAR and its change over 15 years (2006-2019) in Malaysia. This retrospective analysis combined ASM-induced SCAR cases from the national Adverse Drug Reaction (ADR) database in the National Pharmaceutical Regulatory Agency (NPRA), ASM-drug utilisation data from the Malaysian Statistics of Medicine, and prescribing data from UMMC, a national level tertiary hospital to calculate ASM-induced SCAR incidence in Malaysia. We observed an upward trend in reported ASM-induced SCAR cases from 28 cases in 2006 to 92 in 2016. The incidence of carbamazepine (CBZ)-induced SCAR increased from 7.5 per 1,000 person-year (2006) to 17.8 per 1,000 person-year (2016) but dropped to 7.2 per 1,000 person-year (2019) subsequently. Concurrently, there was an increase in the incidence of SCAR secondary to phenytoin and lamotrigine. The prevalent users of CBZ had reduced from 22.8% (2006) to 14.1% (2016), whereas the levetiracetam and sodium valproate users increased by 5.5% and 4.8%, respectively. The incidence of CBZ-induced SCAR had reduced since 2016, probably related to the implementation of HLA-B*1502 screening in Malaysia or substitution of CBZ with other ASM. However, this was accompanied with an increase of SCAR incidence related to phenytoin and lamotrigine. This article is protected by copyright. All rights reserved.

Clinical Aspects of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis With Severe Ocular Complications in India

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a spectrum of rare, severe immunological blistering skin reactions which are triggered by medication intake or infections. The acute phase is characterized by necrolysis of the skin and desquamation of mucosa, primarily oral and ocular, with significant mortality rates. The chronic phase is characterized by multi-organ sequelae with increased rates of morbidity and reduced quality of life for patients who have survived the acute phase. Since the primary goal in the acute phase is saving the life of the patient, ocular involvement is often missed and a significant proportion of patients present to an ophthalmologist with the chronic ocular sequelae. In India, chronic ocular sequelae and low vision are observed in two-thirds of patients who present in the chronic phase of SJS/TEN. In the chronic phase of ocular involvement, there are definite windows of opportunity which if targeted with specific interventions such as scleral lenses and mucous membrane grafts can help reduce the incidence of corneal blindness and improve the quality of life for patients with SJS/TEN. Over the last decade, several studies from India have advanced the understanding of the natural course of ocular involvement in SJS/TEN and the outcomes of timely interventions in the chronic phase of the disease. We present an overview of the epidemiology of ocular complications of SJS/TEN in India, the specific challenges faced in the management of ocular complications in the acute stage and recent advances in management of the chronic ocular complications of the disease.

HLA Allele-Restricted Immune-Mediated Adverse Drug Reactions: Framework for Genetic Prediction

Human leukocyte antigen (HLA) is a hallmark genetic marker for the prediction of certain immune-mediated adverse drug reactions (ADRs). Numerous basic and clinical research studies have provided the evidence base to push forward the clinical implementation of HLA testing for the prevention of such ADRs in susceptible patients. This review explores current translational progress in using HLA as a key susceptibility factor for immune ADRs and highlights gaps in our knowledge. Furthermore, relevant findings of HLA-mediated drug-specific T cell activation are covered, focusing on cellular approaches to link genetic associations to drug-HLA binding as a complementary approach to understand disease pathogenesis. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Genetics and antiepileptic mood stabilizer treatment response in bipolar disorder: what do we know?

Antiepileptic mood stabilizers (AED-MS) are often used to treat bipolar disorder (BD). Similar to other mood disorder medications, AED-MS treatment response varies between patients. Identification of biomarkers associated with treatment response may ultimately help with the delivery of individualized treatment and lead to improved treatment efficacy. Here, we conducted a narrative review of the current knowledge of the pharmacogenomics of AED-MS (valproic acid, lamotrigine and carbamazepine) treatment response in BD, including genetic contributions to AED-MS pharmacokinetics. Genes involved in neurotransmitter systems and drug transport have been shown to be associated with AED-MS treatment response. As more studies are conducted, and experimental and analytical methods advance, knowledge of AED-MS pharmacogenomics is expected to grow and contribute to precision medicine in BD.

Association of HLA-B*51:01, HLA-B*55:01, CYP2C9*3, and Phenytoin-Induced Cutaneous Adverse Drug Reactions in the South Indian Tamil Population

Phenytoin (PHT) is one of the most commonly reported aromatic anti-epileptic drugs (AEDs) to cause cutaneous adverse reactions (CADRs), particularly severe cutaneous adverse reactions (SCARs). Although human leukocyte antigen (HLA)-B*15:02 is associated with PHT-induced Steven Johnson syndrome/toxic epidermal necrosis (SJS/TEN) in East Asians, the association is much weaker than it is reported for carbamazepine (CBZ). In this study, we investigated the association of pharmacogenetic variants of the HLA B gene and CYP2C9*3 with PHT-CADRs in South Indian epileptic patients. This prospective case-controlled study included 25 PHT-induced CADRs, 30 phenytoin-tolerant patients, and 463 (HLA-B) and 82 (CYP2C9*3) normal-controls from previous studies included for the case and normal-control comparison. Six SCARs cases and 19 mild-moderate reactions were observed among the 25 cases. Pooled data analysis was performed for the HLA B*51:01 and PHT-CADRs associations. The Fisher exact test and multivariate binary logistic regression analysis were used to identify the susceptible alleles associated with PHT-CADRs. Multivariate analysis showed that CYP2C9*3 was significantly associated with overall PHT-CADRs (OR = 12.00, 95% CI 2.759–84.87, p = 003). In subgroup analysis, CYP2C9*3 and HLA B*55:01 were found to be associated with PHT-SCARs (OR = 12.45, 95% CI 1.138–136.2, p = 0.003) and PHT-maculopapular exanthema (MPE) (OR = 4.041, 95% CI 1.125–15.67, p = 0.035), respectively. Pooled data analysis has confirmed the association between HLA B*51:01/PHT-SCARs (OR = 6.273, 95% CI 2.24–16.69, p = <0.001) and HLA B*51:01/PHT-overall CADRs (OR = 2.323, 95% CI 1.22–5.899, p = 0.037). In this study, neither the case nor the control groups had any patients with HLA B*15:02. The risk variables for PHT-SCARs, PHT-overall CADRs, and PHT-MPE were found to be HLA B*51:01, CYP2C9*3, and HLA B*55:01, respectively. These alleles were identified as the risk factors for the first time in the South Indian Tamil population for PHT-CADRs. Further investigation is warranted to establish the clinical relevance of these alleles in this population with larger sample size.

Safety, efficacy, and tolerability of lacosamide for the treatment of epilepsy in pediatric patients in Uygur, China

PURPOSE

Lacosamide (LCM) was approved in China in 2018. However, the safety of LCM has not been established in pediatric patients. Therefore, the objective of this study was to investigate its safety, efficacy, and tolerability in pediatric patients living in Uygur, Northwest China.

METHODS

This is a retrospective analysis of pediatric patients diagnosed with epilepsy and on LCM therapy at a medical center. The seizure frequencies at 3, 6, and 12 months after starting LCM therapy were recorded and compared with the baseline monthly frequency. The primary outcome variables were the 50% responder and seizure-free rates. The secondary outcome variables included the terminal 6-month seizure remission and percentages of discontinuation due to a lack of efficacy and tolerability. Safety variables included the incidence and type of adverse reactions.

RESULTS

Seventy-two pediatric patients with epilepsy living in Uygur, China and receiving LCM treatment were included in the present study. Fifty (69%) children responded to LCM therapy with a more than 50% reduction in the frequency of seizures. Seizure-free rates increased over time, at 14%, 19%, and 20% at 3, 6, and 12 months, respectively. The number of baseline anti-seizure medications (ASMs) and order of LCM introduction significantly impacted the likelihood of seizure remission during the 12-month follow-up period (p < 0.05). During the entire period of LCM treatment, twenty-two children (30.5%) experienced at least one adverse reaction.

CONCLUSION

This retrospective study of 72 pediatric patients with epilepsy in Uygur, China, showed that LCM therapy is safe and effective for epilepsy in children, resulting in a reduction in the seizure rate.

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2C9 and HLA-B Genotypes and Phenytoin Dosing: 2020 Update

Phenytoin is an antiepileptic drug with a narrow therapeutic index and large interpatient pharmacokinetic variability, partly due to genetic variation in CYP2C9. Furthermore, the variant allele HLA-B*15:02 is associated with an increased risk of Stevens-Johnson syndrome and toxic epidermal necrolysis in response to phenytoin treatment. We summarize evidence from the published literature supporting these associations and provide therapeutic recommendations for the use of phenytoin based on CYP2C9 and/or HLA-B genotypes (updates on cpicpgx.org).

Genetic Markers for Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis in the Asian Indian Population: Implications on Prevention

This review attempts to collate all the studies performed in India or comprising a population originating from India and to find out if there is an association between the HLA (human leucocyte antigen) type of individual and development of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) subsequent to medication use. The authors performed a PubMed search of all articles published in English from 2009 to 2019 for articles that studied HLA type in patients who developed SJS/TEN after intake of a specific drug in the Asian Indian population or in individuals of Asian Indian origin. The selection criteria were satisfied by a total of 11 studies that reported HLA associations with specific drugs, which induced SJS/TEN, mainly anti-epileptic drugs, and cold medicine/non-steroidal anti-inflammatory drugs. These studies involved a small number of patients, and hence, there is limited evidence to conclude if these associations can be extrapolated to a larger population of the same ethnicity. Similar multi-center studies need to be conducted with a larger sample size to confirm these associations. This would have implications in policy making and for understanding the potential of using genetic markers as a screening tool before prescribing a drug to a patient, which might make them susceptible to developing a potentially life-threatening disease such as SJS/TEN. This is possibly the only mode of primary prevention for this potentially fatal severe cutaneous adverse drug reaction.

HLA-A∗24:02 associated with lamotrigine-induced cutaneous adverse drug reactions: A systematic review and meta-analysis

BACKGROUND

Several studies demonstrated a connection between human leukocyte antigen (HLA)-B∗1502 and lamotrigine (LTG)-induced cutaneous adverse drug reactions (cADRs). The correlation between the HLA-A∗24:02 and LTG-cADRs remains controversial. To examine the associations between HLA-A∗24:02 and LTG-cADRs, we conducted a systematic review and meta-analysis.

METHODS

We performed a comprehensive search of the literature in several electronic database systems including Cochrane Library, EMBASE and PubMed from inception to January 2020. Review Manager was used to compare the frequencies of HLA-A∗24:02 carriers between the subgroups.

RESULTS

A total of 5 studies were eligible, including 197 LTD-cADRs, 396 LTD-tolerant controls, and 2068 population controls. Compared with the LTG-tolerant controls, there was a statistically significant association between the HLA-A∗24:02 allele and LTG-induced cADRs (odds ratios: 1.94, 95% confidence intervals 1.06-3.54; P = .03). Compared with the general population, the relationship between the HLA-A∗24:02 genotype and LTG-induced cADRs was statistically significant (summary odds ratios: 2.12, 95% confidence intervals 1.04-4.30; P = .04).

CONCLUSIONS

HLA-A∗24:02 may be a risk factor for LTG-cADRs.

Development and validation of an innovative UPLC method to quantify lacosamide, oxcarbazepine, and lamotrigine in the serum of children with epilepsy in China

This study has developed and validated a novel UPLC method to quantify lacosamide (LCM), oxcarbazepine (OXC), and lamotrigine (LTG) in children with epilepsy in Xinjiang, China. Phenytoin sodium was used as the internal standard. The mobile phase contained ammonium dihydrogen phosphate solution (10 mmol/L, pH = 4.0) and methanol (55:45, v/v). The flow rate, injection volume, column temperature, and detection wavelength were 0.2 mL/min, 2 μL, 30°C, and 240 nm, respectively. The method was linear within 0.5-40, 2.5-80, and 2.5-40 μg/mL for LCM, 10-hydroxycarbazepine (MHD), and LTG, respectively (r²  ≥ 0.998). The intra- and inter-day precision as measured by the relative standard deviation values was between 1.36 and 4.50, 0.54 and 1.91, and 0.58 and 1.56%. Recovery ranged from 96.58 to 106.22%. All serum samples could be maintained for up to 3 h at ambient temperature, 24 h at 4°C, 30 days at -30°C, and after successive freeze-thaw cycles (24 h per cycle) in the absence of significant degradation.

Genetic Landscape of Common Epilepsies: Advancing towards Precision in Treatment

Epilepsy, a neurological disease characterized by recurrent seizures, is highly heterogeneous in nature. Based on the prevalence, epilepsy is classified into two types: common and rare epilepsies. Common epilepsies affecting nearly 95% people with epilepsy, comprise generalized epilepsy which encompass idiopathic generalized epilepsy like childhood absence epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy and epilepsy with generalized tonic-clonic seizure on awakening and focal epilepsy like temporal lobe epilepsy and cryptogenic focal epilepsy. In 70% of the epilepsy cases, genetic factors are responsible either as single genetic variant in rare epilepsies or multiple genetic variants acting along with different environmental factors as in common epilepsies. Genetic testing and precision treatment have been developed for a few rare epilepsies and is lacking for common epilepsies due to their complex nature of inheritance. Precision medicine for common epilepsies require a panoramic approach that incorporates polygenic background and other non-genetic factors like microbiome, diet, age at disease onset, optimal time for treatment and other lifestyle factors which influence seizure threshold. This review aims to comprehensively present a state-of-art review of all the genes and their genetic variants that are associated with all common epilepsy subtypes. It also encompasses the basis of these genes in the epileptogenesis. Here, we discussed the current status of the common epilepsy genetics and address the clinical application so far on evidence-based markers in prognosis, diagnosis, and treatment management. In addition, we assessed the diagnostic predictability of a few genetic markers used for disease risk prediction in individuals. A combination of deeper endo-phenotyping including pharmaco-response data, electro-clinical imaging, and other clinical measurements along with genetics may be used to diagnose common epilepsies and this marks a step ahead in precision medicine in common epilepsies management.

Diagnostic Test Criteria for HLA Genotyping to Prevent Drug Hypersensitivity Reactions: A Systematic Review of Actionable HLA Recommendations in CPIC and DPWG Guidelines

Introduction

Certain HLA variants are associated with an increased risk of hypersensitivity reactions to specific drugs. Both the Clinical Pharmacogenetics Implementation Consortium (CPIC) and the Dutch Pharmacogenetics Working Group (DPWG) have issued actionable HLA gene - drug interaction guidelines but diagnostic test criteria remain largely unknown. We present an overview of the diagnostic test criteria of the actionable HLA - drug pairs.

Methods

A systematic literature search was conducted in PubMed, Embase, Web of Science and Cochrane Library. Original case-control and cohort studies were selected and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and number needed to genotype (NNG) were calculated for the actionable HLA-drug pairs.

Results

In general, the HLA tests show high specificity and NPV for predicting hypersensitivity reactions. The sensitivity of HLA tests shows a wide range, from 0-33% for HLA-B*1502 testing to predict lamotrigine induced SJS/TEN up to 100% for HLA-B*5701 to predict immunologically confirmed abacavir hypersensitivity syndrome (ABC-HSR). PPV is low for all tests except for HLA-B*5701 and ABC-HSR which is approximately 50%. HLA-B*5701 to predict ABC-HSR shows the lowest NNG followed by HLA-B*5801 for allopurinol induced severe cutaneous adverse drug reactions and HLA-B*1502 for carbamazepine induced SJS/TEN.

Discussion

This is the first overview of diagnostic test criteria for actionable HLA-drug pairs. Studies researching HLA genes and hypersensitivity are scarce for some of the HLA-drug pairs in some populations and patient numbers in studies are small. Therefore, more research is necessary to calculate the diagnostic test criteria more accurately.

Impact of ABCB1 Polymorphism on Levetiracetam Serum Concentrations in Epileptic Uygur Children in China

BACKGROUND

Interindividual variations in the efficacy of antiseizure medications make epilepsy treatment challenging. This is due to genetic factors such as gene polymorphisms in Adenosine-triphosphate (ATP)-binding cassette sub-family B member 1 (ABCB1). In this article, the impact of polymorphisms in the P-glycoprotein-encoding gene, ABCB1 (C1236T, G2677T/A, and C3435T), on levetiracetam disposition was evaluated in Uygur Chinese children with epilepsy.

METHODS

MDR1 C3435T polymorphism was analyzed by polymerase chain reaction-fluorescence staining in situ hybridization. The χ test and Fisher exact test were used to analyze the allelic and genotypic distribution of ABCB1, C1236T, G2677T, and C3435T between the drug-resistant and drug-responsive groups. Differences in steady-state and dose-corrected levetiracetam serum concentrations between the different genotypes were analyzed using 1-way analysis of variance and Mann-Whitney test.

RESULTS

Total 245 Uygur children with epilepsy were analyzed [drug-resistant, n = 117 (males:females = 53:64) and drug-responsive, n = 128 (males:females = 76:52)]. The frequency of ABCB1 C1236T, G2677T/A, and ABCB1 C3435T genotypes, alleles, haplotypes, or diplotypes did not differ significantly between the 2 groups (P > 0.05). Significantly higher levetiracetam concentrations and serum concentration/body mass dose were seen in ABCB1 2677-GT, TT, GA, and AT genotypes and 3435-TT carriers compared with GG and CC carriers (P = 0.021 and P = 0.002 versus P = 0.001 and P = 0.000, respectively).

CONCLUSIONS

ABCB1 G2677T/A and C3435T may affect levetiracetam disposition and therapeutic efficacy in Uygur children with epilepsy. Genetic analysis could be a valuable tool for predicting the response to antiseizure medications before the start of treatment and could contribute to personalized medicine for Uygur children with epilepsy.

Association between HLA genotype and antiseizure medications (ASMs)-induced maculopapular eruption among epilepsy patients in Xinjiang, China

PURPOSE

To determine genetic associations between antiseizure medications (ASMs)-induced maculopapular eruption (MPE) and human leukocyte antigen (HLA) variants in Xinjiang, China.

METHODS

A total of 409 patients were enrolled in this study, including 36 subjects with ASMs-induced MPE (case group) and 373 ASMs-tolerant patients (control group). We detected the whole sequence of the HLA alleles in the 409 Uighur patients using next-generation sequencing (NGS). The carried rate of HLA alleles were compared between the case group, the control group, and the general Chinese population.

RESULTS

The carried rate of HLA-A*03:01, HLA-B*07:02, HLA-C*01:02, and HLA-DRB1 *06:09 allele was significantly higher in the ASMs-MPE group when compared with both the ASMs-tolerant group (p = 0.000, odds ratio (OR) = 23.92, 95 % confidence interval (CI) = 3.96-74.84; p = 0.000, OR = 21.40, 95 % CI = 3.55-67.52; p = 0.030, OR = 4.69, 95 % CI = 0.90-61.73 and p = 0.000, OR = 18.94, 95 % CI = 3.15-60.58; respectively), and the general Chinese population (p = 0.000, OR = 21.34, 95 % CI = 3.31-38.98; p = 0.000, OR = 23.92, 95 % CI = 3.96-74.84; p = 0.019, OR = 5.53, 95 % CI = 0.14-19.86 and p = 0.000, OR = 21.67, 95 % CI = 3.68-11.73; respectively). Moreover, the carried rate of the HLA-B*4001 allele was significantly higher in the ASMs-tolerant group when compared with the ASMs-MPE group (p = 0.024, OR = 5.13, 95 % CI = 1.01-9.99).

CONCLUSIONS

In this study, we identified for the first time that the carried rate of HLA-A*03:01, HLA-B*07:02, HLA-C*01:02, and HLA-DRB1 *06:09 allele was significantly higher in the ASMs-MPE group when compared with the ASMs-tolerant group.

Association of HLA genotypes with phenytoin induced severe cutaneous adverse drug reactions in Thai children

PURPOSE

Phenytoin (PHT) is a common causative drug for severe cutaneous adverse drug reactions (SCARs) in children. SCARs, including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), are associated with a variation in HLA genotypes. Blood screening for specific HLA allele before PHT prescription would help in the reduction of the incidence of PHT induced SCARs. This study was to investigate the association between variations of HLA genotypes and PHT induced SCARs in Thai children.

METHODS

Cases were Thai children aged between 0-18 years diagnosed with SCARs from PHT. Control groups were Thai children of corresponding age who had taken PHT for a least 12 weeks without any hypersensitivity reaction and healthy population controls. Blood samples from both groups were collected for HLA genotyping using a reverse-sequence specific oligonucleotide (SSO) probes method. Carrier rates of HLA alleles were compared between 22 cases (17 DRESS and 5 SJS-TEN), 60 tolerant controls and 649 population controls.

RESULTS

Two HLA alleles includingHLA-B*51:01 and HLA-C*14:02 were significantly associated with PHT induced DRESS (OR 5.83; 95 % CI 1.36-25.00, p = 0.022 and OR 5.85; 95 % CI 1.16-29.35, p = 0.039). HLA-B*38:02 was significantly associated with PHT induced SJS-TEN (OR12.67; 95 % CI 1.50-106.89, p = 0.044). Haplotype analysis demonstrated the association of HLA haplotype A*11:01-B*51:01-C*14:02 and PHT induced DRESS compared to tolerant controls and the healthy population control group (OR 8.92; 95 % CI 1.47-54.02, p = 0.019, and OR 10.2; 95 % CI 3.04-34.21, p = 0.002). HLA haplotype B*38:02-C*07:01 in PHT induced SJS-TEN was significantly higher than those in tolerant controls and the healthy population control group (40 % vs 3.3 % vs 0.3 %; OR 19.33; 95 % CI 1.98-188.59, p = 0.027 and OR 215.67; 95 % CI 22.40-2076.04, p = 0.0003. HLA-B*15:02 was not associated with PHT induced SCARs.

SIGNIFICANCE

An association betweenHLA-B*51:01 and HLA-C*14:02 and PHT induced DRESS and HLA-B*38:02 and PHT induced SJS-TEN has been demonstrated in Thai children.