Risk and association of HLA with oxcarbazepine-induced cutaneous adverse reactions in Asians

Recent advances in managing and understanding Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening diseases characterized by detachment of the epidermis and mucous membrane. SJS/TEN are considered to be on the same spectrum of diseases with different severities. They are classified by the percentage of skin detachment area. SJS/TEN can also cause several complications in the liver, kidneys, and respiratory tract. The pathogenesis of SJS/TEN is still unclear. Although it is difficult to diagnose early stage SJS/TEN, biomarkers for diagnosis or severity prediction have not been well established. Furthermore, optimal therapeutic options for SJS/TEN are still controversial.

Several drugs, such as carbamazepine and allopurinol, are reported to have a strong relationship with a specific human leukocyte antigen (HLA) type. This relationship differs between different ethnicities. Recently, the usefulness of HLA screening before administering specific drugs to decrease the incidence of SJS/TEN has been investigated.

Skin detachment in SJS/TEN skin lesions is caused by extensive epidermal cell death, which has been considered to be apoptosis via the Fas-FasL pathway or perforin/granzyme pathway. We reported that necroptosis, i.e. programmed necrosis, also contributes to epidermal cell death. Annexin A1, released from monocytes, and its interaction with the formyl peptide receptor 1 induce necroptosis. Several diagnostic or prognostic biomarkers for SJS/TEN have been reported, such as CCL-27, IL-15, galectin-7, and RIP3.

Supportive care is recommended for the treatment of SJS/TEN. However, optimal therapeutic options such as systemic corticosteroids, intravenous immunoglobulin, cyclosporine, and TNF-α antagonists are still controversial. Recently, the beneficial effects of cyclosporine and TNF-α antagonists have been explored. In this review, we discuss recent advances in the pathophysiology and management of SJS/TEN.

The Association Between HLA-A*03:01 and HLA-B*07:02 Alleles and Oxcarbazepine-induced Maculopapular Eruption in the Uighur Chinese Population

PURPOSE

To determine genetic associations between oxcarbazepine (OXC)-induced maculopapular eruption (MPE) and human leukocyte antigen (HLA) variants in the Uighur Chinese population.

METHODS

A total of 208 patients were enrolled in this study, including 20 subjects with OXC-induced MPE (case group) and 188 OXC-tolerant patients (control group). We detected the whole sequence of the HLA alleles in the 208 Uighur patients using next-generation sequencing (NGS).

RESULTS

The carried rate of HLA-A*03:01 was significantly different between the OXC-induced MPE group and the tolerant group (7/20, 35% versus 4/188, 2.13%; P = 0.000, odds ratio [OR] = 24.77, 95% confidence interval [CI] = 6.41-95.65). Additionally, the carried rate of HLA-B*07:02 was significantly different between the OXC-induced MPE group and the tolerant group (3/20, 15% versus 2/188, 0.011%; P = 0.000, odds ratio [OR] = 16.41, 95% confidence interval (CI) = 2.56-105.09).

CONCLUSIONS

HLA-A*03:01 and HLA-B*07:02 may be the risk alleles for MPE in the Uighur Chinese population.

Genetic variants associated with T cell-mediated cutaneous adverse drug reactions: A PRISMA-compliant systematic review-An EAACI position paper

Drug hypersensitivity reactions (DHRs) are associated with high global morbidity and mortality. Cutaneous T cell-mediated reactions classically occur more than 6 hours after drug administration and include life-threatening conditions such as toxic epidermal necrolysis, Stevens-Johnson syndrome, and hypersensitivity syndrome. Over the last 20 years, significant advances have been made in our understanding of the pathogenesis of DHRs with the identification of human leukocyte antigens as predisposing factors. This has led to the development of pharmacogenetic screening tests, such as HLA-B*57:01 in abacavir therapy, which has successfully reduced the incidence of abacavir hypersensitivity reactions. We have completed a PRISMA-compliant systematic review to identify genetic associations that have been reported in DHRs. In total, 105 studies (5554 cases and 123 548 controls) have been included in the review reporting genetic associations with carbamazepine (n = 31), other aromatic antiepileptic drugs (n = 24), abacavir (n = 11), nevirapine (n = 14), trimethoprim-sulfamethoxazole (n = 11), dapsone (n = 4), allopurinol (n = 10), and other drugs (n = 5). The most commonly reported genetic variants associated with DHRs are located in human leukocyte antigen genes and genes involved in drug metabolism pathways. Increasing our understanding of genetic variants that contribute to DHRs will allow us to improve diagnosis, develop new treatments, and predict and prevent DHRs in the future.

Cytokines/Chemokines: Novel Biomarkers Associated with Severe Cutaneous Adverse Reactions

Although the incidence of severe cutaneous adverse reactions (SCARs) is very low, if it is not diagnosed and treated in time, it can not only cause skin and mucous membrane involvement, but can also cause multiple organ failure and even death. The diagnostic criteria and treatment guidelines for severe drug eruptions have not been unified. Many medical centers have used human leukocyte antigen alleles to diagnose SCARs. Some prospective studies have shown that susceptibility gene testing can prevent SCARs as early as possible, but the widespread implementation of its technology is limited by being ethnically specific. With the unique advantages of cytokine detection technology, cytokines are increasingly important for the diagnosis and treatment of SCARs. Related cytokines/chemokines involved in the pathogenesis, adjuvant diagnosis, and treatment of SCARs are discussed.

SJS/TEN 2019: From science to translation

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are potentially life-threatening, immune-mediated adverse reactions characterized by widespread erythema, epidermal necrosis, and detachment of skin and mucosa. Efforts to grow and develop functional international collaborations and a multidisciplinary interactive network focusing on SJS/TEN as an uncommon but high burden disease will be necessary to improve efforts in prevention, early diagnosis and improved acute and long-term management. SJS/TEN 2019: From Science to Translation was a 1.5-day scientific program held April 26-27, 2019, in Vancouver, Canada. The meeting successfully engaged clinicians, researchers, and patients and conducted many productive discussions on research and patient care needs.

Trigeminal Neuralgia: Basic and Clinical Aspects

The trigeminal nerve is the largest of all cranial nerves. It has three branches that provide the main sensory innervation of the anterior two-thirds of the head and face. Trigeminal neuralgia (TN) is characterized by sudden, severe, brief, and stabbing recurrent episodes of facial pain in one or more branches of the trigeminal nerve. Pain attacks can occur spontaneously or can be triggered by non-noxious stimuli, such as talking, eating, washing the face, brushing teeth, shaving, a light touch or even a cool breeze. In addition to pain attacks, a proportion of the patients also experience persistent background pain, which along with autonomic signs and prolonged disease duration, represent predictors of worse treatment outcomes. It is now widely accepted that the presence of a neurovascular compression at the trigeminal root entry zone is an anatomic abnormality with a high correlation with classical TN. However, TN may be related to other etiologies, thus presenting different and/or additional features. Since the 1960s, the anticonvulsant carbamazepine is the drug of choice for TN treatment. Although anti-epileptic drugs are commonly used to treat neuropathic pain in general, the efficacy of carbamazepine has been largely limited to TN. Carbamazepine, however, is associated with dose-limiting side-effects, particularly with prolonged usage. Thus, a better understanding and new treatment options are urgently warranted for this rare, but excruciating disease.

Pharmacogenomics of Antidepressant and Antipsychotic Treatment: How Far Have We Got and Where Are We Going?

In recent decades, very few new psychiatric drugs have entered the market. Thus, improvement in the use of antidepressant and antipsychotic therapy has to focus mainly on enhanced and more personalized treatment with the currently available drugs. One important aspect of such individualization is emphasizing interindividual differences in genes relevant to treatment, an area that can be termed neuropsychopharmacogenomics. Here, we review previous efforts to identify such critical genetic variants and summarize the results obtained to date. We conclude that most clinically relevant genetic variation is connected to phase I drug metabolism, in particular to genetic polymorphism of CYP2C19 and CYP2D6. To further improve individualized pharmacotherapy, there is a need to take both common and rare relevant mutations into consideration; we discuss the present and future possibilities of using whole genome sequencing to identify patient-specific genetic variation relevant to treatment in psychiatry. Translation of pharmacogenomic knowledge into clinical practice can be considered for specific drugs, but this requires education of clinicians, instructive guidelines, as well as full attention to polypharmacy and other clinically relevant factors. Recent large patient studies (n > 1,000) have replicated previous findings and produced robust evidence warranting the clinical utility of relevant genetic biomarkers. To further judge the clinical and financial benefits of preemptive genotyping in psychiatry, large prospective randomized trials are needed to quantify the value of genetic-based patient stratification in neuropsychopharmacotherapy and to demonstrate the cost-effectiveness of such interventions.

Drug hypersensitivity reactions in Asia: regional issues and challenges

There are geographical, regional, and ethnic differences in the phenotypes and endotypes of patients with drug hypersensitivity reactions (DHRs) in different parts of the world. In Asia, aspects of drug hypersensitivity of regional importance include IgE-mediated allergies and T-cell-mediated reactions, including severe cutaneous adverse reactions (SCARs), to beta-lactam antibiotics, antituberculous drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and radiocontrast agents. Delabeling of low-risk penicillin allergy using direct oral provocation tests without skin tests have been found to be useful where the drug plausibility of the index reaction is low. Genetic risk associations of relevance to Asia include human leucocyte antigen (HLA)-B*1502 with carbamazepine SCAR, and HLA-B*5801 with allopurinol SCAR in some Asian ethnic groups. There remains a lack of safe and accurate diagnostic tests for antituberculous drug allergy, other than relatively high-risk desensitization regimes to first-line antituberculous therapy. NSAID hypersensitivity is common among both adults and children in Asia, with regional differences in phenotype especially among adults. Low dose aspirin desensitization is an important therapeutic modality in individuals with cross-reactive NSAID hypersensitivity and coronary artery disease following percutaneous coronary intervention. Skin testing allows patients with radiocontrast media hypersensitivity to confirm the suspected agent and test for alternatives, especially when contrasted scans are needed for future monitoring of disease relapse or progression, especially cancers.

Attenuation of Wnt/β-catenin signaling in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN) are rare but life-threatening severe cutaneous adverse reactions. Current studies have suggested that the pathobiology of drug-mediated SJS/TEN involves a dysregulation of cellular immunity with overwhelming activation of cytotoxic T lymphocytes. The canonical Wnt signaling pathway plays important roles in T cell development and activation, which may provide potential avenues for alleviating dysregulated immunity in SJS/TEN. In this study, we aimed to assess the implication of Wnt signaling in drug-reactive T cells in SJS/TEN. We showed downregulation of Wnt signaling components, including T cell factor 1 (TCF-1)/lymphoid enhancer binding factor 1 (LEF-1) transcription factors, in SJS/TEN patients, suggesting that canonical Wnt signaling is regulated during cytotoxic T cell responses in SJS/TEN. Further analyses demonstrated that engagement of the T cell receptor by antigen encounter and treatment of a prognostic marker of SJS/TEN, IL-15, in vitro led to the downregulation of LEF-1 and TCF-1 expression in CD8+ T cells. Enhancement of Wnt signaling by adding the Wnt activators attenuated ex vivo activation of drug-specific T cells from SJS/TEN patients, indicating a functional involvement of Wnt signaling in the pathomechanism of SJS/TEN. These findings provide additional insight into the immunopathogenesis and therapeutic intervention of this devastating condition.

Five Hundred Patients with Memory Loss in One Clinic in India: Does the Prevalence Vary Between Communities?

This observational study reports on the cause of memory loss in 500 consecutive patients. It confirms the previously reported finding in a smaller sample of 100 patients. There have been several publications suggesting that the prevalence of dementia is lower in certain communities but the reason is not known. This study was conducted to see if it could explain the variation between communities. Also, the observation that dementia with Lewy bodies (24.4%) outnumbers cases of Alzheimer’s disease (5.8%) has not been reported by any other investigators and needs to be verified. This finding could open a new topic of research and also help in the management of patients.

The 2-Hydroxyiminostilbene Metabolite of Carbamazepine or the Supernatant from Incubation of Hepatocytes with Carbamazepine Activates Inflammasomes: Implications for Carbamazepine-Induced Hypersensitivity Reactions

Although the pathophysiology of carbamazepine-induced idiosyncratic or hypersensitivity reactions is unclear, they are presumed to be immune mediated, involving a complex interaction between drug metabolism and activation of the immune system. Cell stress can be caused by reactive metabolites, and this has the potential to release damage-associated molecular patterns (DAMPs), which are responsible for activation of the immune system. Idiosyncratic drug reactions occur mainly in the liver because of its role in drug metabolism and reactive metabolite formation. DAMPs can activate inflammasomes, which may be a common mechanism by which DAMPs lead to an immune response. In the present study, we investigated whether carbamazepine induces the release of DAMPs by using human hepatocarcinoma functional liver cell-4 (FLC-4) cells for bioactivation of carbamazepine. THP-1 cells, a human macrophage cell line, were used for detecting inflammasome activation. We found that increased caspase-1 activity and production of interleukin-1β by THP-1 cells were caused by the supernatant from the incubation of carbamazepine with FLC-4 cells. In the supernatant, heat shock protein 60 was significantly increased. In addition, 2-hydroxyiminostilbene, which is a metabolite of carbamazepine, activated inflammasomes. These results suggest that the reactive iminoquinone metabolite can directly activate inflammasomes or that stressed hepatocytes cause the release of DAMPs, which are responsible for inflammasome activation. The activation of inflammasomes may be an important step in the immune system activation by carbamazepine, which can lead to hypersensitivity reactions in some patients. SIGNIFICANCE STATEMENT: A metabolite of carbamazepine, 2-hydroxyiminostilbene itself, and the damage-associated molecular patterns released from hepatocytes incubated with carbamazepine activated inflammasomes. The activation of inflammasomes may be an important step in the immune system activation by carbamazepine, which can lead to hypersensitivity reactions in some patients.

Identification of drug-specific public TCR driving severe cutaneous adverse reactions

Drug hypersensitivity such as severe cutaneous adverse reactions (SCAR), including Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), could be life-threatening. Here, we enroll SCAR patients to investigate the T cell receptor (TCR) repertoire by next-generation sequencing. A public αβTCR is identified from the cytotoxic T lymphocytes of patients with carbamazepine-SJS/TEN, with its expression showing drug/phenotype-specificity and an bias for HLA-B*15:02. This public αβTCR has binding affinity for carbamazepine and its structural analogs, thereby mediating the immune response. Adoptive transfer of T cell expressing this public αβTCR to HLA-B*15:02 transgenic mice receiving oral administration of carbamazepine induces multi-organ injuries and symptoms mimicking SCAR, including hair loss, erythema, increase of inflammatory lymphocytes in the skin and blood, and liver and kidney dysfunction. Our results not only demonstrate an essential role of TCR in the immune synapse mediating SCAR, but also implicate potential clinical applications and development of therapeutics.

Severe cutaneous adverse reactions (SCAR) is a T cell-mediated, potentially lethal drug hypersensitivity (DH). Here, the authors identify a carbamazepine-specific TCR common among patients with carbamazepine-induced SCAR that confers SCAR-like pathology in mice upon carbamazepine exposure, thereby implicating specific TCRs in DH etiology.

Pharmacogenomics in chronic pain therapy: from disease to treatment and challenges for clinical practice

Pharmacogenomics (PGx) has emerged as an encouraging tool in chronic pain therapy. Genetic variations associated with drug effectiveness or adverse reactions (amitriptyline/nortriptyline/codeine/oxycodone/tramadol-CYP2D6, amitriptyline-CYP2C19, carbamazepine-HLA-A, carbamazepine/oxcarbazepine-HLA-B) can be used to guide chronic pain management. Despite this evidence, many obstacles still need to be overcome for the effective clinical implementation of PGx. To translate the pharmacogenetic testing into actionable clinical decisions, the Clinical Pharmacogenetics Implementation Consortium has been developing guidelines for several drug–gene pairs. This review will show the applicability of PGx in chronic pain from disease to treatment; report the drug–gene pairs with strongest evidences in the clinic; and the challenges for the clinical implementation of PGx.

Association Between HLA-B*1301 and Dapsone-Induced Cutaneous Adverse Drug Reactions: A Systematic Review and Meta-analysis

Importance

Dapsone-induced hypersensitivity syndrome (DHS) is a life-threatening adverse drug reaction. Based on available epidemiologic studies, HLA genotypes may play an important role in DHS.

Objective

To assess the association between HLA-B*1301 and dapsone-induced cutaneous adverse drug reactions (cADRs).

Data Sources

Human studies investigating associations between HLA-B*1301 and dapsone-induced cADRs were systematically searched without language restriction from the inception of each database until September 12, 2017, in PubMed, the Human Genome Epidemiology Network), and the Cochrane Library. Combinations of HLA genotypes, dapsone, and synonymous terms were used; reference lists were searched in selected articles.

Study Selection

Two reviewers identified studies investigating the associations between HLA-B*1301 and dapsone-induced cADRs that reported sufficient data for calculating the frequency of HLA-B*1301 carriers among case and control patients, in which all patients received dapsone before HLA-B*1301 screening. An initial search of the databases identified 391 articles, of which 3 studies (2 in Chinese populations and 1 in a Thai population) met the inclusion criteria.

Data Extraction and Synthesis

Overall odds ratios (ORs) with 95% CIs were calculated using a random-effects model to determine the association between HLA-B*1301 and dapsone-induced cADRs. Subgroup analyses by type of cADR were also performed. PRISMA guidelines were used to abstract and assess data.

Main Outcomes and Measures

Primary outcomes were associations between HLA-B*1301 and dapsone-induced cADRs in dapsone-tolerant controls. The outcomes are reported as overall OR. Statistical heterogeneity was assessed using the Q statistic and I2 tests.

Results

From the 3 included studies, there were 111 unique patients with dapsone-induced cADRs (subsequently used in the meta-analysis), 1165 dapsone-tolerant patients, and 3026 healthy controls. The cases included 64 men and 49 women (2 patients were missing from the meta-analysis; 1 each from 2 of the 3 studies); mean age was 39.7 years. An association between HLA-B*1301 and dapsone-induced cADRs was identified (summary OR, 43.0; 95% CI, 24.0-77.2). Subgroup analyses among types of cADRs produced similar findings in DHS (OR, 51.7; 95% CI, 16.9-158.5), dapsone-induced severe cADRs (Stevens-Johnson syndrome and toxic epidermal necrolysis [SJS/TEN] plus drug rash [adverse skin reaction to a drug] along with eosinophilia and systemic symptoms [DRESS]) (OR, 54.0; 95% Cl, 8.0-366.2), dapsone-induced SJS/TEN (OR, 40.5; 95% CI, 2.8-591.0), and dapsone-induced DRESS (OR, 60.8; 95% CI, 7.4-496.2). There was no heterogeneity (I2 = 0%, P = .38).

Conclusions and Relevance

Associations between HLA-B*1301 and dapsone-induced cADRs were found in dapsone-tolerant and healthy control groups. For patient safety, genetic screening for HLA-B*1301 in Asian populations before dapsone therapy is warranted.

Oseltamivir induced Stevens-Johnson syndrome/toxic epidermal necrolysis-case report

RATIONALE

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are 2 rare but life-threatening diseases characterized by detachment of epidermis, bullous skin lesions, and mucous membrane erosions. Drugs are highly suspected to be the causative agents. We report a case of SJS/TEN induced by oseltamivir, which is a very rare event.

PATIENT CONCERNS

A 9-year-old girl with upper respiratory tract infections presented with generalized maculopapular rash the second day after taking oseltamivir.

DIAGNOSIS

The diagnosis of SJS/TEN was made based on cytotoxic skin lesions and mucous membrane involvement.

INTERVENTIONS

After discontinuing of the drug and combination therapy of corticosteroid and human immunoglobulin initiation, the lesions were improved. Human leukocyte antigen (HLA) gene sequencing was done.

OUTCOMES

The girl was followed-up for 1 year. The skin and mucous membranes symptoms were relieved.

LESSONS

We report this case to attract attention to the rare but serious side effect of this antiviral drug.

Novel genetic and epigenetic factors of importance for inter-individual differences in drug disposition, response and toxicity

Individuals differ substantially in their response to pharmacological treatment. Personalized medicine aspires to embrace these inter-individual differences and customize therapy by taking a wealth of patient-specific data into account. Pharmacogenomic constitutes a cornerstone of personalized medicine that provides therapeutic guidance based on the genomic profile of a given patient. Pharmacogenomics already has applications in the clinics, particularly in oncology, whereas future development in this area is needed in order to establish pharmacogenomic biomarkers as useful clinical tools. In this review we present an updated overview of current and emerging pharmacogenomic biomarkers in different therapeutic areas and critically discuss their potential to transform clinical care. Furthermore, we discuss opportunities of technological, methodological and institutional advances to improve biomarker discovery. We also summarize recent progress in our understanding of epigenetic effects on drug disposition and response, including a discussion of the only few pharmacogenomic biomarkers implemented into routine care. We anticipate, in part due to exciting rapid developments in Next Generation Sequencing technologies, machine learning methods and national biobanks, that the field will make great advances in the upcoming years towards unlocking the full potential of genomic data.

HLA-associated antiepileptic drug-induced cutaneous adverse reactions

Adverse drug reactions (ADRs) are a common cause of hospital admissions (up to 19%), with the majority of cases due to off-target predictable drug effects (type A reactions). However, idiosyncratic drug-induced immune activated (type B) reactions contribute to a range of hypersensitivity reactions, with T-cell-mediated type IV hypersensitivity reactions mainly manifesting as cutaneous ADRs (cADRs). Aromatic antiepileptic drugs (AEDs), used in the treatment of epilepsy as well as bipolar disorder or neuropathic pain, have been implicated as culprit drugs in a spectrum of pathologies ranging from mild maculopapular exanthema (MPE) to severe and life-threatening conditions including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). These AED-induced cADRs are unpredictable based on pharmacological and clinical factors alone, thereby prompting investigations into genomic contributors mediating risk of pathology. The most strongly associated risk genes identified are from the human leukocyte antigen (HLA) class I alleles, which play a critical role in adaptive immunity by flagging either infected or aberrant cells for recognition by surveying T-cells. In the setting of drug hypersensitivity, the immunogenicity of HLA molecules and their peptide cargo can be modulated by interactions with small drug molecules that drive inappropriate T-cell responses. This review discusses the current understanding of HLA class I molecules in modifying risk of AED-induced cADRs.

Adverse drug reactions associated with six commonly used antiepileptic drugs in southern China from 2003 to 2015

BACKGROUND

This active, open observational study aimed to investigate adverse drug reactions (ADRs) associated with six commonly used antiepileptic drugs (AEDs) in southern Chinese outpatients with epilepsy from 2003 to 2015.

METHODS

The Wenzhou Epilepsy Follow-Up Registry Database (WEFURD) was established by a single epilepsy center in China in January 2003 to record AED efficacy and the associated ADRs by registered outpatients diagnosed with epilepsy. We reviewed the data of outpatients who had only taken one or more of six commonly used AEDs, namely, carbamazepine (CBZ), valproate (VPA), lamotrigine (LTG), oxcarbazepine (OXC), topiramate (TPM) and levetiracetam (LEV), and were registered in the WEFURD between 2003 and 2015. We evaluated the ADRs caused by the single or combined use of the above six specific AEDs based on the WHO-UMC scale. The data of the ADRs were categorized by age, sex, number of AEDs related to ADRs, medications, seriousness of ADRs, causality levels of the WHO-UMC scale and system organ class (SOC). The unit of analysis was one ADR.

RESULTS

A total of 3069 epilepsy outpatients (1807 outpatients with 5049 eligible ADRs and 1262 outpatients without ADRs) were included. The overall ADR rate was 58.88% (1807/3069). An average of 2.79 ADRs (5049/1807) occurred per patient with an ADR; 53.8% of the 5049 ADRs were recorded in females, and 50.4% were caused by monotherapy. Of the ADRs, 10.6% (537/5049) were severe adverse reactions (SARs), including 34 serious adverse effects (SAEs). The SAR rates caused by one, two and three or more AEDs were 9.9, 10.0 and 19.6%, respectively (p <  0.001). Eighteen SOC categories were identified, and the top three were psychiatric disorders (1633/5049, 32.3%), neurological disorders (1222/5049, 24.2%) and gastrointestinal disorders (564/5049, 11.2%). Of the 537 SARs, skin and appendage disorders accounted for 24.4% (131/537). Among the 34 SAEs, serious allergies, fetal malformations, renal calculus and pancreatitis accounted for the majority.

CONCLUSIONS

Our findings suggest that clinicians should pay attention to psychiatric ADRs and be alert for SARs, especially when three or more AEDs are used together. Moreover, active surveillance might provide another method of pharmacovigilance in China.

Association between HLA-A*3201 allele and oxcarbazepine-induced cutaneous adverse reactions in Eastern Han Chinese population

PURPOSE

To determine genetic associations between oxcarbazepine (OXC)-induced cutaneous adverse drug reactions (cADRs) and human leukocyte antigen (HLA) variants in the Eastern Han Chinese population.

METHODS

A total of 120 patients were enrolled in this study, including 30 subjects with OXC-induced cADRs (case group) and 90 OXC-tolerant patients (control group). High-resolution HLA genotyping was conducted for HLA-A, HLA-B, HLA-C, and HLA-DRB1, and allele frequencies were compared.

RESULTS

No patient carried the HLA-B *1502 allele in the case group, the frequency of HLA-B *1502 allele in the control group was 6.1%. HLA-A*3201 allele was detected in 13.3% of 30 patients with OXC-induced cADRs (4/30) and 0% of 90 OXC-tolerant patients (0/90). The difference in HLA-A*3201 frequency between the two groups was statistically significant [P = 0.004, odds ratio (OR) = 15.877, 95% confidence interval (CI) = 1.817-138.720].

CONCLUSIONS

Eastern Han Chinese patients with the HLA-A*3201 allele may be more susceptible to OXC-induced cADRs, while the HLA-B*1502 allele is not correlated with it. The precise association between HLA alleles and OXC-induced cADRs warrants further study.

Temporal trends and patterns in carbamazepine use, related severe cutaneous adverse reactions, and HLA-B*15:02 screening: A nationwide study

OBJECTIVE

After discovering the association between the HLA-B*15:02 allele and carbamazepine-related severe cutaneous adverse reactions (SCARs), particularly in Southeastern Asian populations, clinical strategies to prevent carbamazepine-related SCARs have changed. We aimed to investigate 10-year trends in carbamazepine use and carbamazepine-related SCARs and to examine the patterns and determinants of HLA-B*15:02 screening in Taiwan.

METHODS

A nationwide study was performed using Taiwan's National Health Insurance Research Database. In the first part of the study, new users of carbamazepine were included, and those who experienced SCAR-related admissions were further identified. In the second part of the study, recipients of HLA-B*15:02 screening (reimbursed by Taiwan's National Health Insurance since June 2010) were included and multivariate logistic regression was used to explore factors associated with the use of screening.

RESULTS

The numbers of new users of carbamazepine and SCAR cases decreased remarkably during the 10-year period (-82.6% and -87.1%, respectively), and the incidence rates of SCARs showed a downward trend after 2011. The screening rate of the HLA-B*15:02 allele increased to 24.9% in 2014. Neurologists (odds ratio 12.33, 95% confidence interval 9.30-16.35), psychiatrists (9.97, 7.31-13.61), and neurosurgeons (3.23, 2.42-4.32) were more likely to perform screening tests than other specialties were. Physicians practicing in medical centers (6.00, 5.51-6.54) were more likely to perform screening tests than those practicing in other hospitals, whereas the screening rates in clinics remained at 0.0% throughout the study period.

SIGNIFICANCE

In recent years, the number of carbamazepine-related SCAR cases has decreased substantially in Taiwan. However, only one-fourth of new users of carbamazepine received HLA-B*15:02 screening, and there were considerable disparities in the screening rates across different physician groups. Policymakers should consider solutions to barriers to implementing screening tests in clinical practice and should not neglect the value of other safety communications and regulations to complement the limitations of pharmacogenomic testing.

The skin as a metabolic and immune-competent organ: Implications for drug-induced skin rash

Current advances in the study of cutaneous adverse drug reactions can be attributed to the recent understanding that the skin is both a metabolically and immunologically competent organ. The ability of the skin to serve as a protective barrier with limited drug biotransformation ability, yet highly active immune function, has provided insights into its biological capability. While the immune response of the skin to drugs is vastly different from that of the liver due to evolutionary conditioning, it frequently occurs in response to various drug classes and manifests as a spectrum of hypersensitivity reactions. The skin is a common site of adverse and idiosyncratic drug reactions; drug-specific T-cells, as well as involvement of an innate immune response, appear to be key mechanistic drivers in such scenarios. Association of other factors such as human leukocyte antigen (HLA) polymorphisms may play a significant role for particular drugs. This review aims to integrate emerging findings into proposed mechanisms of drug metabolism and immunity in the skin that are likely responsible for rashes and other local allergic responses. These unique biological aspects of the skin, and their translation into implications for drug development and the use of animal models, will be discussed.

Association between HLA-B*5901 and methazolamide-induced Stevens-Johnson syndrome/toxic epidermal necrolysis: a systematic review and meta-analysis

Methazolamide-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are life-threatening adverse drug reactions. Based on previous studies, HLA genotypes may play an important role in methazolamide-induced SJS/TEN. Therefore, to identify the associations between HLA genotypes and methazolamide-induced cutaneous adverse drug reactions (cADRs) (i.e., SJS/TEN and hypersensitivity syndrome), a systematic review and meta-analysis were performed. Two studies (one study in Korean and another in Han Chinese) met the inclusion criteria. The studies included 13 patients with methazolamide-induced SJS/TEN, 30 methazolamide-tolerant, and 768 population controls. Associations between HLA-B*5901, HLA-B*5901-Cw*0102 haplotype, and methazolamide-induced SJS/TEN were identified in methazolamide-tolerant and population controls. Overall ORs were 305.0 (95% CI = 11.3-8, 259.4) in methazolamide-tolerant and 715.3 (95% CI = 83.1-6,158.5) in population control. In addition, statistically significant associations between the HLA-Cw*0102 and methazolamide-induced SJS/TEN were found in methazolamide-tolerant (OR = 12.1; 95% CI = 1.3-111.7) and population control (OR = 17.5; 95% CI = 3.2-96.6). Since HLA-B*5901 and HLA-B*5901-Cw*0102 haplotype are associated with methazolamide-induced SJS/TEN, genetic screening prior to methazolamide therapy in Asian populations is warranted.

Current and Innovative Pharmacological Options to Treat Typical and Atypical Trigeminal Neuralgia

Trigeminal neuralgia is a representative neuropathic facial pain condition, characterised by unilateral paroxysmal pain in the distribution territory of one or more divisions of the trigeminal nerve, triggered by innocuous stimuli. A subgroup of patients with trigeminal neuralgia [TN (previously defined as atypical TN)] also suffer from concomitant continuous pain, i.e. a background pain between the paroxysmal attacks. The aim of this review is to provide current, evidence-based, knowledge about the pharmacological treatment of typical and atypical TN, with a specific focus on drugs in development. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews and the Clinical Trials database (ClinicalTrials.gov), taking into account publications up to February 2018. Two authors independently selected studies for inclusions, data extraction, and bias assessment. Carbamazepine and oxcarbazepine are the first-choice drugs for paroxysmal pain. When sodium channel blockers cannot reach full dosage because of side effects, an add-on treatment with lamotrigine or baclofen should be considered. In patients with atypical TN, both gabapentin and antidepressants are expected to be efficacious and should be tried as an add-on to oxcarbazepine or carbamazepine. Although carbamazepine and oxcarbazepine are effective in virtually the totality of patients, they are responsible for side effects causing withdrawal from treatment in an important percentage of cases. A new, better tolerated, Nav1.7 selective state-dependent, sodium channel blocker (vixotrigine) is under development. Future trials testing the effect of combination therapy in patients with TN are needed, especially in patients with concomitant continuous pain and in TN secondary to multiple sclerosis.

Applications of Immunopharmacogenomics: Predicting, Preventing, and Understanding Immune-Mediated Adverse Drug Reactions

Adverse drug reactions (ADRs) are a significant health care burden. Immune-mediated adverse drug reactions (IM-ADRs) are responsible for one-fifth of ADRs but contribute a disproportionately high amount of that burden due to their severity. Variation in human leukocyte antigen ( HLA) genes has emerged as a potential preprescription screening strategy for the prevention of previously unpredictable IM-ADRs. Immunopharmacogenomics combines the disciplines of immunogenomics and pharmacogenomics and focuses on the effects of immune-specific variation on drug disposition and IM-ADRs. In this review, we present the latest evidence for HLA associations with IM-ADRs, ongoing research into biological mechanisms of IM-ADRs, and the translation of clinical actionable biomarkers for IM-ADRs, with a focus on T cell-mediated ADRs.

Current Perspectives on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are considered a delayed-type hypersensitivity reaction to drugs. They represent true medical emergencies and an early recognition and appropriate management is decisive for the survival. SJS/TEN manifest with an "influenza-like" prodromal phase (malaise, fever), followed by painful cutaneous and mucous membrane (ocular, oral, and genital) lesions, and other systemic symptoms. The difference between SJS, SJS/TEN overlap, and TEN is defined by the degree of skin detachment: SJS is defined as skin involvement of < 10%, TEN is defined as skin involvement of > 30%, and SJS/TEN overlap as 10-30% skin involvement. The diagnosis of different degrees of epidermal necrolysis is based on the clinical assessment in conjunction with the corresponding histopathology. The mortality rates for SJS and TEN have decreased in the last decades. Today, the severity-of-illness score for toxic epidermal necrolysis (SCORTEN) is available for SJS/TEN severity assessment. Drugs with a high risk of causing SJS/TEN are anti-infective sulfonamides, anti-epileptic drugs, non-steroidal anti-inflammatory drugs of the oxicam type, allopurinol, nevirapine, and chlormezanone. Besides conventional drugs, herbal remedies and new biologicals should be considered as causative agents. The increased risk of hypersensitivity reactions to certain drugs may be linked to specific HLA antigens. Our understanding of the pathogenesis of SJS/TEN has improved: drug-specific T cell-mediated cytotoxicity, genetic linkage with HLA- and non-HLA-genes, TCR restriction, and cytotoxicity mechanisms were clarified. However, many factors contributing to epidermal necrolysis still have to be identified, especially in virus-induced and autoimmune forms of epidermal necrolysis not related to drugs. In SJS/TEN, the most common complications are ocular, cutaneous, or renal. Nasopharyngeal, esophageal, and genital mucosal involvement with blisters, erosions as well as secondary development of strictures also play a role. However, in the acute phase, septicemia is a leading cause of morbidity and fatality. Pulmonary and hepatic involvement is frequent. The acute management of SJS/TEN requires a multidisciplinary approach. Immediate withdrawal of potentially causative drugs is mandatory. Prompt referral to an appropriate medical center for specific supportive treatment is of utmost importance. The most frequently used treatments for SJS/TEN are systemic corticosteroids, immunoglobulins, and cyclosporine A.

The Medication Risk of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in Asians: The Major Drug Causality and Comparison With the US FDA Label

Specific ethnic genetic backgrounds are associated with the risk of Stevens-Johnson syndrome / toxic epidermal necrolysis (SJS/TEN) especially in Asians. However, there have been no large cohort, multiple-country epidemiological studies of medication risk related to SJS/TEN in Asian populations. Thus, we analyzed the registration databases from multiple Asian countries who were treated during 1998-2017. A total 1,028 SJS/TEN cases were identified with the algorithm of drug causality for epidermal necrolysis. Furthermore, those medications labeled by the US Food and Drug Administration (FDA) as carrying a risk of SJS/TEN were also compared with the common causes of SJS/TEN in Asian countries. Oxcarbazepine, sulfasalazine, COX-II inhibitors, and strontium ranelate were identified as new potential causes. In addition to sulfa drugs and beta-lactam antibiotics, quinolones were also a common cause. Only one acetaminophen-induced SJS was identified, while several medications (e.g., oseltamivir, terbinafine, isotretinoin, and sorafenib) labeled as carrying a risk of SJS/TEN by the FDA were not found to have caused any of the cases in the Asian countries investigated in this study.

HLA Pharmacogenetic Markers of Drug Hypersensitivity in a Thai Population

Severe cutaneous adverse drug reactions (SCARs) including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reactions with eosinophilia and systemic symptoms (DRESS) are potentially life-threatening cutaneous reactions caused by several drugs. Recently, a number of genes encoding for human antigen presenting proteins, HLA alleles, have been discovered as valid pharmacogenetic markers for prediction of these life-threatening reactions. This study was aimed to determine the distribution of HLA alleles including the HLA class I and class II genes in 183 unrelated individuals of a Thai population using high resolution HLA genotyping in order to obtain 2-field data (4-digit resolution) and compare the frequencies of the HLA alleles that have been proposed as markers of SCARs with other ethnics. Results revealed a high prevalence of pharmacogenetic markers of drug-induced SCARs e.g., B^*13:01 for dapsone; B^*15:02 for carbamazepine and oxcarbazepine; B^*58:01, A^*33:03 and C^*03:02 for allopurinol; C^*08:01, C^*14:02 and DRB1^*12:02 for co-trimoxazole. Whereas, low prevalence of pharmacogenetic markers of SCARs induced by abacavir, B^*57:01 and phenytoin, B^*56:02/B^*56:04 were noticed. The allele frequencies of B^*13:01, B^*15:02, and B^*58:01 observed in a Thai population were significantly higher than those reported in Japanese and Caucasian populations. Similar to those observed in other Southeast Asian populations, low frequencies of A^*31:01 and B^*57:01 alleles were noted in the study population. Based on the frequencies of HLA pharmacogenetic markers, Thai and other Southeast Asian populations may at higher risk of drug-induced SCARs compared with Caucasian population.

Association between HLA-B*15:02 and oxcarbazepine-induced cutaneous adverse reaction: a meta-analysis

Aim: HLA-B*15:02 has been demonstrated as a key risk factor for carbamazepine-induced severe cutaneous adverse reaction (sCAR), especially in Asian population. Oxcarbazepine (OXC) is a drug that has a similar structure of carbamazepine. However, the relationship between HLA-B*15:02 and induced cutaneous adverse reaction (cADR) remains unknown. This study aims to analyze this association in the published literature. Method: After filtering studies, eight studies were finally included for meta-analysis, including 32 sCAR cases, 112 mild cutaneous adverse reaction (mcADR) cases, 281 OXC tolerant control and 946 population control cases. Result: In the tolerant control group, an association was found between HLA-B*15:02 genotype and OXC-induced sCAR (odds ratio [OR]: 18.13; 95% CI: 6.77–48.56), but not in mcADR (OR: 1.43; 95% CI: 0.56–3.64). In population control group, an association was found between HLA-B*15:02 genotype and OXC-induced sCAR, (OR: 8.22; 95% CI: 3.03–22.34), but not in mcADR (OR: 2.06; 95% CI: 0.91–4.67). Discussion: Our study demonstrates that the genetic risk factor HLA-B*15:02 may be a factor in OXC-induced sCAR.

HLA-A*31:01 and Oxcarbazepine-Induced DRESS in a Patient With Seizures and Complete DCX Deletion

Oxcarbazepine is an antiepileptic drug (AED) commonly used as a first-line treatment option for focal epilepsy. Several AEDs, including carbamazepine, oxcarbazepine, and phenytoin are associated with various delayed-hypersensitivity reactions such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, or toxic epidermal necrolysis. The Food and Drug Administration-approved label for oxcarbazepine currently presents information regarding a pharmacogenomic association with the HLA antigen allele HLA-B*15:02 and hypersensitivity reactions in certain ancestry groups with a high incidence of this allele. However, unlike carbamazepine, screening for the presence of this allele is not routinely recommended before administration of oxcarbazepine. In practice, even with carbamazepine, HLA antigen testing is not always performed before initiating treatment because of lack of physician awareness of the recommendations and because of the desire to initiate treatment without delay. We present the clinical course of a pediatric patient with focal epilepsy refractory to several AEDs who developed drug reaction with eosinophilia and systemic symptoms after oxcarbazepine administration. The pharmacogenomic testing for various HLA antigen alleles was performed post hoc, and results were evaluated for structural similarities between AEDs and their molecular associations with HLA antigen proteins. In addition, we review the population-wide prevalence of various hypersensitivity reactions to AEDs and associated HLA antigen alleles. Finally, we discuss the potential utility of preemptive pharmacogenomic screening of patients before pharmacological treatment of epilepsy to assess the risk of developing hypersensitivity reactions.

An Updated Review of the Molecular Mechanisms in Drug Hypersensitivity

Drug hypersensitivity may manifest ranging from milder skin reactions (e.g., maculopapular exanthema and urticaria) to severe systemic reactions, such as anaphylaxis, drug reactions with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS), or Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). Current pharmacogenomic studies have made important strides in the prevention of some drug hypersensitivity through the identification of relevant genetic variants, particularly for genes encoding drug-metabolizing enzymes and human leukocyte antigens (HLAs). The associations identified by these studies are usually drug, phenotype, and ethnic specific. The drug presentation models that explain how small drug antigens might interact with HLA and T cell receptor (TCR) molecules in drug hypersensitivity include the hapten theory, the p-i concept, the altered peptide repertoire model, and the altered TCR repertoire model. The broad spectrum of clinical manifestations of drug hypersensitivity involving different drugs, as well as the various pathomechanisms involved, makes the diagnosis and management of it more challenging. This review highlights recent advances in our understanding of the predisposing factors, immune mechanisms, pathogenesis, diagnostic tools, and therapeutic approaches for drug hypersensitivity.

The Epidemiology of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in China

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are life-threatening disease. However, there are only few epidemiologic studies of SJS/TEN from China. To analyze the clinical characteristics, causality, and outcome of treatment for SJS/TEN in China, we reviewed case reports of patients with SJS/TEN from the China National Knowledge Infrastructure (CNKI) and Wanfang database from 2006 to 2016 and patients with SJS/TEN who were admitted to the First Affiliated Hospital of Fujian Medical University during the same period. There were 166 patients enrolled, including 70 SJS, 2 SJS/TEN overlap, and 94 TEN. The most common offending drugs were antibiotics (29.5%) and anticonvulsants (24.1%). Carbamazepine, allopurinol, and penicillins were the most common single offending drugs (17.5%, 9.6%, and 7.2%). Chinese patent medicines accounted for 5.4%. There were 76 (45.8%) patients receiving systemic steroid and intravenous immunoglobulin (IVIG) in combination therapy, especially for TEN (80.3%), and others were treated with systemic steroids alone. Mortality rate of combination treatment comparing with steroid alone in TEN patients had no statistical significance. In conclusion, carbamazepine and allopurinol were the leading causative drugs for SJS/TEN in China. Combination of IVIG and steroids is a common treatment for TEN, but its efficacy in improving mortality needs further investigation.

Clinical Pharmacogenetics Implementation Consortium Guideline for HLA Genotype and Use of Carbamazepine and Oxcarbazepine: 2017 Update

The variant allele HLA-B*15:02 is strongly associated with greater risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in patients treated with carbamazepine or oxcarbazepine. The variant allele HLA-A*31:01 is associated with greater risk of maculopapular exanthema, drug reaction with eosinophilia and systemic symptoms, and SJS/TEN in patients treated with carbamazepine. We summarize evidence from the published literature supporting these associations and provide recommendations for carbamazepine and oxcarbazepine use based on HLA genotypes.

HLAs: Key regulators of T-cell-mediated drug hypersensitivity

Adverse drug reactions (ADR) can be broadly categorised as either on-target or off-target. On-target ADRs arise as a direct consequence of the pharmacological properties of the drug and are therefore predictable and dose-dependent. On-target ADRs comprise the majority (>80%) of ADRs, relate to the drug's interaction with its known pharmacological target and are a result of a complex interplay of genetic and ecologic factors. In contrast, off-target ADRs, including immune-mediated ADRs (IM-ADRs), are due to unintended pharmacological interactions such as inadvertent ligation of host cell receptors or non-pharmacological interactions mediated through an adaptive immune response. IM-ADRs can be classified according to the primary immune cell involved and include B-cell-mediated (Gell-Coombs type I-III reactions) and T-cell-mediated (Gell-Coombs type IV or delayed hypersensitivity) reactions. IM-ADRs mediated by T cells are associated with phenotypically distinct clinical diagnoses and can vary from a mild delayed rash to a life-threatening cutaneous, systemic or organ disease, such as Stephen Johnson syndrome/toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms and drug-induced liver disease. T-cell-mediated ADRs are strongly linked to the carriage of particular HLA risk alleles which are in the case of abacavir hypersensitivity and HLA-B*57:01 has led to translation into the clinic as a routine screening test. In this review, we will discuss the immunogenetics and pathogenesis of IM-ADRs and how HLA associations inform both pre-drug screening strategies and mechanistic understanding.

SJS/TEN 2017: Building Multidisciplinary Networks to Drive Science and Translation

Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a life-threatening, immunologically mediated, and usually drug-induced disease with a high burden to individuals, their families, and society with an annual incidence of 1 to 5 per 1,000,000. To effect significant reduction in short- and long-term morbidity and mortality, and advance clinical care and research, coordination of multiple medical, surgical, behavioral, and basic scientific disciplines is required. On March 2, 2017, an investigator-driven meeting was held immediately before the American Academy of Dermatology Annual meeting for the central purpose of assembling, for the first time in the United States, clinicians and scientists from multiple disciplines involved in SJS/TEN clinical care and basic science research. As a product of this meeting, this article summarizes the current state of knowledge and expert opinion related to SJS/TEN covering a broad spectrum of topics including epidemiology and pharmacogenomic networks; clinical management and complications; special populations such as pediatrics, the elderly, and pregnant women; regulatory issues and the electronic health record; new agents that cause SJS/TEN; pharmacogenomics and immunopathogenesis; and the patient perspective. Goals include the maintenance of a durable and productive multidisciplinary network that will significantly further scientific progress and translation into prevention, early diagnosis, and management of SJS/TEN.

Association of HLA-A and HLA-B Alleles with Lamotrigine-Induced Cutaneous Adverse Drug Reactions in the Thai Population

Background: Lamotrigine (LTG) is commonly used for treatment of epilepsy and bipolar disorder. It is one of the common cause of cutaneous adverse drug reactions (CADR). Clinical symptoms of LTG-induced CADR range from maculopapular exanthema (MPE) to severe cutaneous adverse reactions (SCAR). This study aimed to determine the association of the LTG-induced CADR with human leukocyte antigen (HLA) alleles in Thai patients.

Methods: Fifteen patients with LTG-induced CADR [10 MPE; 4 Stevens–Johnson syndrome; and 1 drug reaction with eosinophilia and systemic symptoms] and 50 LTG-tolerant controls were included in the study. HLA-A and HLA-B genotyping was performed using polymerase chain reaction-sequence-specific oligonucleotides probes.

Results: The proportion of HLA-A^∗02:07 and HLA-B^∗15:02 allele carriers were significantly higher in the LTG-induced CADR group than in the tolerant controls [odds ratio (OR): 7.83; 95% confidence interval (CI): 1.60–38.25; P = 0.013, and OR: 4.89; 95% CI: 1.28–18.67; P = 0.014]. In addition, subjects with HLA-A^∗33:03, HLA-B^∗15:02, and HLA-B^∗44:03 were significantly higher in the LTG-induced MPE group than in the tolerant controls (OR: 8.27; 95% CI: 1.83–37.41; P = 0.005, OR: 7.33; 95% CI: 1.63–33.02; P = 0.005; and OR: 10.29; 95% CI: 1.45–72.81; P = 0.029). In contrast to the LTG-induced MPE group, there were no significant differences between HLA alleles and LTG-induced SCAR group.

Conclusion:HLA-A^∗02:07 and HLA-B^∗15:02 were associated with LTG-induced CADR in Thai patients. We also identified an association between HLA-A^∗33:03, HLA-B^∗15:02, and HLA-B^∗44:03 and LTG-induced MPE in this population. These results suggest that these alleles could be useful screening markers for preventing CADR before LTG treatment in Thai patients, but further replication studies with larger sample sizes are needed.

HLA Association with Drug-Induced Adverse Reactions

Adverse drug reactions (ADRs) remain a common and major problem in healthcare. Severe cutaneous adverse drug reactions (SCARs), such as Stevens–Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) with mortality rate ranges from 10% to more than 30%, can be life threatening. A number of recent studies demonstrated that ADRs possess strong genetic predisposition. ADRs induced by several drugs have been shown to have significant associations with specific alleles of human leukocyte antigen (HLA) genes. For example, hypersensitivity to abacavir, a drug used for treating of human immunodeficiency virus (HIV) infection, has been proposed to be associated with allele 57:01 of HLA-B gene (terms HLA-B^∗57:01). The incidences of abacavir hypersensitivity are much higher in Caucasians compared to other populations due to various allele frequencies in different ethnic populations. The antithyroid drug- (ATDs- ) induced agranulocytosis are strongly associated with two alleles: HLA-B^∗38:02 and HLA-DRB1^∗08:03. In addition, HLA-B^∗15:02 allele was reported to be related to carbamazepine-induced SJS/TEN, and HLA-B^∗57:01 in abacavir hypersensitivity and flucloxacillin induced drug-induced liver injury (DILI). In this review, we summarized the alleles of HLA genes which have been proposed to have association with ADRs caused by different drugs.

Severe Delayed Drug Reactions: Role of Genetics and Viral Infections

Adverse drug reactions (ADRs) are a significant source of patient morbidity and mortality and represent a major burden to health care systems and drug development. Up to 50% of such reactions are preventable. Although many ADRs can be predicted based on the on-target pharmacologic activity, ADRs arising from drug interactions with off-target receptors are recognized. Off-target ADRs include the immune-mediated ADRs (IM-ADRs) and pharmacologic drug effects. In this review, we discuss what is known about the immunogenetics and pathogenesis of IM-ADRs and the hypothesized role of heterologous immunity in the development of IM-ADRs.

Anti-epileptic drug utilisation in paediatrics: a systematic review

OBJECTIVES

This study aims to determine global anti-epileptic drug (AED) utilisation prevalence and describe utilisation trends in different countries.

METHODS

Databases Embase (1980-May 2017), Medline (1946-May 2017) and PubMed were searched for original research on AED utilisation. All paediatric national or regional database studies and surveys were included.

RESULTS

Twenty-one studies were identified. Five were excluded from the analysis as the data were collected before 2005, leaving 16 studies. Monotherapy regimen varied between 58% and 94% in different countries. In several of the studies, sodium valproate was the most frequently prescribed AED. However, there is a trend towards increasing utilisation of new-generation AEDs, particularly levetiracetam, in some countries.

CONCLUSION

Monotherapy was used in 58%-94%of patients. There is increasing utilisation of the new-generation AEDs, in particular lamotrigine, levetiracetam and topiramate. Old-generation AEDs are still used in the majority of patients. There is a need for up-to-date studies to determine the prevalence of AEDs in children.

Distribution of Types of Dementia in the First 100 Patients Seen at a Dementia Clinic in India

The aim of our study was to determine if the distribution of types of dementia could explain the reported lower prevalence of dementia in India. The study is an observational study of the first 100 cases of dementia. All patients were evaluated clinically and with blood tests and MRI of the brain. The causes of dementia were: Lewy body dementia (22%), depression (20%), Alzheimer's disease (13%), and mild cognitive impairment (18%). Other dementias were less common. The distribution of dementia types in this series is different from that reported globally. The observation of Lewy body dementia being the most common cause of dementia needs to be verified.

Tolerability and Safety of Commonly Used Antiepileptic Drugs in Adolescents and Adults: A Clinician's Overview

This paper discusses the issues surrounding the tolerability and safety of the commonly used antiepileptic drugs (AEDs) in adolescents and adults. The content includes dose-related adverse effects, idiosyncratic reactions, behavioural and psychiatric comorbidities, chronic problems, enzyme induction and teratogenesis. Twenty-one AEDs are discussed in chronological order of their introduction into the UK, starting with phenobarbital and ending with brivaracetam. Wherever possible, advice is given on anticipating, recognising and managing these issues and thereby improving the lives of people with epilepsy, most of whom will need to take one or more of these agents for life. Avoidance of side effects will increase the possibility of achieving and maintaining long-term seizure freedom. Alternatively, adverse events from AEDs will substantially reduce quality of life and often result in higher healthcare costs.