HLA associations and clinical implications in T-cell mediated drug hypersensitivity reactions: an updated review

Clues of HLAs, metabolic SNPs, and epigenetic factors in T cell-mediated drug hypersensitivity reactions

Drug hypersensitivities are common reactions due to immunologic responses. They are of utmost importance because they may generate severe and fatal outcomes. Some drugs may cause Adverse Drug Reactions (ADRs), such as drug hypersensitivity reactions (DHRs), which can occur due to the interaction of intact drugs or their metabolites with Human Leukocyte Antigens (HLAs) and T cell receptors (TCRs). This type develops over a period of 24-72 h after exposure and is classified as type IV of DHRs. Acute generalized exanthematic pustulosis (AGEP), Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS) are types of Severe Cutaneous Adverse Reactions (SCARs). In this review, we aim to discuss the types of ADRs, the mechanisms involved in their development, and the role of immunogenetic factors, such as HLAs in type IV DHRs, single-nucleotide polymorphisms (SNPs), and some epigenetic modifications, e.g., DNA/histone methylation in a variety of genes and their promoters which may predispose subjects to DHRs. In conclusion, development of promising novel in vitro or in vivo diagnostic and prognostic markers is essential for identifying susceptible subjects or providing treatment protocols to work up patients with drug allergies as personalized medicine.

Systemic and skin-limited delayed-type drug hypersensitivity reactions associate with distinct resident and recruited T cell subsets

Delayed-type drug hypersensitivity reactions are major causes of morbidity and mortality. The origin, phenotype, and function of pathogenic T cells across the spectrum of severity require investigation. We leveraged recent technical advancements to study skin-resident memory T cells (TRMs) versus recruited T cell subsets in the pathogenesis of severe systemic forms of disease, Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS), and skin-limited disease, morbilliform drug eruption (MDE). Microscopy, bulk transcriptional profiling, and single-cell RNA-sequencing (scRNA-Seq) plus cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq) plus T cell receptor sequencing (TCR-Seq) supported clonal expansion and recruitment of cytotoxic CD8+ T cells from circulation into skin along with expanded and nonexpanded cytotoxic CD8+ skin TRM in SJS/TEN. Comparatively, MDE displayed a cytotoxic T cell profile in skin without appreciable expansion and recruitment of cytotoxic CD8+ T cells from circulation, implicating TRMs as potential protagonists in skin-limited disease. Mechanistic interrogation in patients unable to recruit T cells from circulation into skin and in a parallel mouse model supported that skin TRMs were sufficient to mediate MDE. Concomitantly, SJS/TEN displayed a reduced Treg signature compared with MDE. DRESS demonstrated recruitment of cytotoxic CD8+ T cells into skin as in SJS/TEN, yet a pro-Treg signature as in MDE. These findings have important implications for fundamental skin immunology and clinical care.

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.

Single locus HLA sequencing with the nanopore technology for HLA disease association diagnosis

Associations between HLA genotype and disease susceptibility encompass almost all the classic HLA loci. The level of typing resolution enabling a correct identification of an HLA disease susceptibility gene depends on the disease itself and/or on the accumulated knowledge about the molecular involvement of the HLA allele(s) engaged. Therefore, the application of Next Generation Sequencing technologies to HLA disease association, which would improve typing resolution, could prove useful to better understand disease severity. In the present study, we tested a nanopore sequencing approach developed by Omixon Biocomputing Ltd, dedicated to on-demand locus typing for HLA and disease, as an alternative to the conventional widely used sequence specific oligoprobe (SSO) approach. A total of 145 DNA samples used in routine diagnosis by SSO were retrospectively analyzed with nanopore technology, for HLA-A*02 immunotherapy decision for A*29, B*27, B*51, B*57 identification in class I, and DRB1, DQA1, and DQB1 for bullous dermatosis, rheumatoid arthritis, diabetes, and celiac disease requests in class II. Each locus was typed in a separate experiment, except for DQB1 and DQA1, which were analyzed together. Concordance between typings reached 100% for all the loci tested. Ambiguities by nanopore were only found for missing exon coverage. This approach was found to be very well adapted to the routine flow imposed by the SSO technique. This study illustrates the use of the new NanoTYPE MONO kit for single locus HLA sequencing for HLA and disease association diagnosis.

Untoward immune effects of modern medication

Immune-related adverse events (irAEs) represent an increasingly concerning challenge in the assessment of biopharmaceutical products. In contrast to historically rare allergic reactions associated with small chemical drugs, contemporary biotherapeutics exhibit a significantly higher morbidity of irAEs, because of their complex structure and comprehensive mechanisms of action. While the immunogenicity of protein-based compounds is associated with the induction of anti-drug antibodies, the pathogenesis of irAEs in advanced biologics, such as cell and gene therapy, remains to be further delineated. In the current study, I present an updated profile regarding the untoward immune effects of medications, covering various material categories systematically, with the underlying mechanisms to inspire risk mitigation in biopharmaceutical development and application.

Ophthalmic Aspects of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Narrative Review

The aim of our review article was to summarize the current literature on Stevens-Johnson syndrome (SJS) and its severe form, toxic epidermal necrolysis (TEN). SJS/TEN is a serious, rare multi-system, immune-mediated, mucocutaneous disease with a significant mortality rate that can lead to severe ocular surface sequelae and even to bilateral blindness. Restoration of the ocular surface in acute and chronic SJS/TEN is challenging. There are only limited local or systemic treatment options for SJS/TEN. Early diagnosis, timely amniotic membrane transplantation and aggressive topical management in acute SJS/TEN are necessary to prevent long-term, chronic ocular complications. Although the primary aim of acute care is to save the life of the patient, ophthalmologists should regularly examine patients already in the acute phase, which should also be followed by systematic ophthalmic examination in the chronic phase. Herein, we summarize actual knowledge on the epidemiology, aetiology, pathology, clinical appearance and treatment of SJS/TEN.

Association of Human Leukocyte Antigen Alleles with Carbamazepine- or Lamotrigine-Induced Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in an Iranian Population: A Case-control Study

Background

Genetic diversity in human leukocyte antigen (HLA) alleles across populations is a significant risk factor for drug-induced severe cutaneous adverse reactions (SCARs), e.g., carbamazepine (CBZ)- and lamotrigine (LTG)-induced Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). The present study aimed to investigate the frequency of different HLA alleles in Iranian patients with CBZ- and LTG-induced SJS/TEN.

Methods

A case-control study was conducted from 2011 to 2018 at various hospitals affiliated with Shiraz University of Medical Sciences (Shiraz, Iran). A total of 31 patients receiving anticonvulsant drugs (CZB or LTG) were recruited and divided into two groups. The drug-induced group (n=14) included hospitalized patients due to CBZ- or LTG-induced SJS/TEN. The drug-tolerant group (n=17) included individuals receiving CBZ or LTG for at least three months with no adverse effects. In addition, 46 healthy individuals (control group) were recruited. The frequency of HLA-A, -B, and -DRB1 alleles in patients with CZB- or LTG-induced SJS/TEN was investigated. HLA typing was performed using the allele-specific polymerase chain reaction method. The Chi square test and Fisher's exact test were used to determine a potential association between SJS/TEN and HLA alleles. P<0.05 was considered statistically significant.

Results

CBZ- or LTG-induced SJS/TEN was not significantly associated with HLA alleles. However, HLA-DRB1*01 showed a significantly higher frequency in patients with CBZ-induced SJS/TEN than the CBZ-tolerant patients (30% vs. 9%, P=0.07).

Conclusion

Overall, no significant association was found between CBZ- or LTG-induced SJS/TEN and HLA alleles. Further large-scale studies are required to substantiate our findings.

Drug hypersensitivity syndrome induced by sulfasalazine: A case report

INTRODUCTION

Drug hypersensitivity syndrome (DHS) induced by sulfasalazine is a serious systemic delayed adverse drug reaction, which is associated with significant morbidity and mortality.

PATIENT CONCERNS

A 52-year-old man was hospitalized for developing a rash after 3 weeks of sulfasalazine treatment for ulcerative colitis (UC).

DIAGNOSIS

The patient was diagnosed with DHS based on his drug history, clinical manifestations, and laboratory test results.

INTERVENTIONS

The patient was administered intravenous glucocorticoids. The patient's condition improved after treatment with human immunoglobulin and antihistamines.

OUTCOMES

Combination therapy of glucocorticoid and gamma globulin, the whole-body pruritus disappeared, and no new rash appeared. The whole-body rash subsided or turned dark red.

CONCLUSION

This article describes the diagnosis and treatment process of a case of sulfasalazine-induced DHS and reviews the relevant literature to improve clinician understanding and avoid misdiagnosis and missed diagnosis.

Drug-induced hypersensitivity syndrome induced by propylthiouracil: case report and literature review

Background

Drug-induced hypersensitivity syndrome (DIHS) is a rare, potentially life-threatening systemic drug reaction. Antithyroid drugs (ATDs) causing DIHS have seldom been reported before.

Case presentation

We present a case of propylthiouracil (PTU)-induced DIHS, which included fever, skin rash, lymphadenopathy, hepatosplenomegaly, serious liver and kidney dysfunction, peripheral blood eosinophilia, and atypical lymphocytosis. Following supportive therapy, intravenous immunoglobulin (IVIG), and systemic corticosteroid, the patient experienced a resolution of fever and rash combined with progressive normalization of hematological index and organ function. These clinical features, and the skin lesion biopsy confirmed DIHS diagnosis.

Conclusions

To our knowledge, this is the second reported case of PTU-induced DIHS worldwide and the first human leukocyte antigen (HLA) typing of PTU-induced DIHS. Clinicians should cautiously distinguish hyperthyroidism etiology and identify the indication of ATDs. Timely recognition and formal DIHS treatment are required in patients with ATDs.

Advances in Our Understanding of the Interaction of Drugs with T-cells: Implications for the Discovery of Biomarkers in Severe Cutaneous Drug Reactions

Drugs can activate different cells of the immune system and initiate an immune response that can lead to life-threatening diseases collectively known as severe cutaneous adverse reactions (SCARs). Antibiotics, anticonvulsants, and antiretrovirals are involved in the development of SCARs by the activation of αβ naïve T-cells. However, other subsets of lymphocytes known as nonconventional T-cells with a limited T-cell receptor repertoire and innate and adaptative functions also recognize drugs and drug-like molecules, but their role in the pathogenesis of SCARs has only just begun to be explored. Despite 30 years of advances in our understanding of the mechanisms in which drugs interact with T-cells and the pathways for tissue injury seen during T-cell activation, at present, the development of useful clinical biomarkers for SCARs or predictive preclinical in vitro assays that could identify immunogenic moieties during drug discovery is an unmet goal. Therefore, the present review focuses on (i) advances in the understanding of the pathogenesis of SCARs reactions, (ii) a description of the interaction of drugs with conventional and nonconventional T-cells, and (iii) the current state of soluble blood circulating biomarker candidates for SCARs.

Skin Resident Memory T Cells May Play Critical Role in Delayed-Type Drug Hypersensitivity Reactions

Delayed-type drug hypersensitivity reactions (dtDHR) are immune-mediated reactions with skin and visceral manifestations ranging from mild to severe. Clinical care is negatively impacted by a limited understanding of disease pathogenesis. Though T cells are believed to orchestrate disease, the type of T cell and the location and mechanism of T cell activation remain unknown. Resident memory T cells (T_RM) are a unique T cell population potentially well situated to act as key mediators in disease pathogenesis, but significant obstacles to defining, identifying, and testing T_RM in dtDHR preclude definitive conclusions at this time. Deeper mechanistic interrogation to address these unanswered questions is necessary, as involvement of T_RM in disease has significant implications for prediction, diagnosis, and treatment of disease.

Current Perspectives on Severe Drug Eruption

Adverse drug reactions involving the skin are commonly known as drug eruptions. Severe drug eruption may cause severe cutaneous adverse drug reactions (SCARs), which are considered to be fatal and life-threatening, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), acute generalized exanthematous pustulosis (AGEP), and drug reaction with eosinophilia and systemic symptoms (DRESS). Although cases are relatively rare, approximately 2% of hospitalized patients are affected by SCARs. There is an incidence of 2 to 7 cases/million per year of SJS/TEN and 1/1000 to 1/10,000 exposures to offending agents result in DRESS. However, the mortality rate of severe drug eruptions can reach up to 50%. SCARs represent a real medical emergency, and early identification and proper management are critical to survival. The common pathogenesis of severe drug eruptions includes genetic linkage with HLA- and non-HLA-genes, drug-specific T cell-mediated cytotoxicity, T cell receptor restriction, and cytotoxicity mechanisms. A multidisciplinary approach is required for acute management. Immediate withdrawal of potentially causative drugs and specific supportive treatment is of great importance. Immunoglobulins, systemic corticosteroids, and cyclosporine A are the most frequently used treatments for SCARs; additionally, new biologics and plasma exchange are reasonable strategies to reduce mortality. Although there are many treatment methods for severe drug eruption, controversies remain regarding the timing and dosage of drug eruption. Types, dosages, and indications of new biological agents, such as tumor necrosis factor antagonists, mepolizumab, and omalizumab, are still under exploration. This review summarizes the clinical characteristics, risk factors, pathogenesis, and treatment strategies of severe drug eruption to guide clinical management.

Stevens-Johnson syndrome and toxic epidermal necrolysis in a referral center in Taiwan

BACKGROUND

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are potentially fatal adverse drug reactions. The characteristics of these diseases are changing with the use of novel drugs, posing new challenges to doctors. We aimed to review recent SJS/TEN cases in order to assist general practitioners with timely diagnosis and correct management.

METHODS

We conducted a retrospective chart review of SJS/TEN patients in a referral center in Taiwan from 2009 to 2019. We included 24 patients' charts and analyzed demographic data, medication histories, clinical courses, human leukocyte antigen (HLA) alleles, and long-term complications.

RESULTS

The average age was 63.4 years, and the average toxic epidermal necrolysis-specific severity of illness score was 1.9. The most common culprit drug was carbamazepine (33.3%), followed by antibiotics (12.5%) and nonsteroidal anti-inflammatory drugs (8.3%). Two cases were caused by immune checkpoint inhibitors, and one of them had a long latency of 210 days. Three out of the four patients carrying HLA-B*15:02 had carbamazepine-induced SJS/TEN. All patients were treated with systemic corticosteroids in the acute stage of the diseases. The length of in-hospital stay did not correlate with the average daily dose of corticosteroids. The overall mortality rate was 4.2%, and the disease-specific mortality rate was 0%.

CONCLUSIONS

The most common culprit drug was carbamazepine, which had strong association with HLA-B*15:02. There was no statistically significant correlation between in-hospital stay and the average daily dose of corticosteroids. Immune checkpoint inhibitor-related SJS/TEN may have an extended latent period.

Nevirapine-induced Stevens-Johnson syndrome in children living with HIV in South Africa

Background

Although adverse drug reactions resulting from the use of nevirapine (NVP) are well described in adults (estimated frequency of 6% - 10%), it has previously been considered less common in children (0.3% - 1.4%). Stock-outs of antiretroviral agents occur frequently in South Africa and result in interruptions in therapy and drug substitutions.

Objectives

To report on a case series of paediatric patients who suffered cutaneous drug reactions to NVP at rates not previously described in children.

Method

We describe a retrospective observational case series of six children living with HIV who developed Stevens-Johnson Syndrome (SJS) following exposure to NVP because of a prolonged stock-out of efavirenz 200 mg tablets in South Africa.

Results

Of the 392 paediatric patients receiving antiretroviral therapy at the institution, 172 were affected by the efavirenz stock-out. Of these, 85 children were changed to NVP of which six developed NVP-induced SJS (7.1% incidence rate). The median time between initiating NVP and developing symptoms was 27 days (range 12-35 days). All patients responded well to NVP cessation and symptomatic treatment. One patient was referred for specialist care. Two patients were successfully rechallenged with efavirenz after developing SJS and three continued lopinavir/ritonavir.

Conclusions

This is the second largest case series of NVP-induced SJS in children to date and raises the possibility that the incidence of SJS in children may be higher than previously described. Further research is required to explore the risk factors associated with NVP-induced SJS in children. This case series highlights the negative impact of drug stock-outs on patient health outcomes.

Pharmacogenetic Testing for Prevention of Severe Cutaneous Adverse Drug Reactions

Severe cutaneous adverse reactions (SCAR), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS), are idiosyncratic and unpredictable drug-hypersensitivity reactions with a high-mortality rate ranging from 10% to over 30%, thus causing a major burden on the healthcare system. Recent pharmacogenomic studies have revealed strong associations between SCAR and the genes encoding human-leukocyte antigens (HLAs) or drug-metabolizing enzymes. Some of pharmacogenetic markers have been successfully applied in clinical practice to protect patients from SCAR, such as HLA-B*15:02 and HLA-A*31:01 for new users of carbamazepine, HLA-B*58:01 for allopurinol, and HLA-B*57:01 for abacavir. This article aims to update the current knowledge in the field of pharmacogenomics of drug hypersensitivities or SCAR, and its implementation in the clinical practice.

Current challenges and possible future developments in personalized psychiatry with an emphasis on psychotic disorders

A personalized medicine approach seems to be particularly applicable to psychiatry. Indeed, considering mental illness as deregulation, unique to each patient, of molecular pathways, governing the development and functioning of the brain, seems to be the most justified way to understand and treat disorders of this medical category. In order to extract correct information about the implicated molecular pathways, data can be drawn from sampling phenotypic and genetic biomarkers and then analyzed by a machine learning algorithm. This review describes current difficulties in the field of personalized psychiatry and gives several examples of possibly actionable biomarkers of psychotic and other psychiatric disorders, including several examples of genetic studies relevant to personalized psychiatry. Most of these biomarkers are not yet ready to be introduced in clinical practice. In a next step, a perspective on the path personalized psychiatry may take in the future is given, paying particular attention to machine learning algorithms that can be used with the goal of handling multidimensional datasets.

A high-resolution HLA imputation system for the Taiwanese population: a study of the Taiwan Biobank

An imputation algorithm for human leukocyte antigen (HLA) is helpful for exploring novel disease associations. However, population-specific HLA imputation references are essential for achieving high imputation accuracy. In this study, a subset of 1012 individuals from the Taiwan Biobank (TWB) who underwent both whole-genome SNP array and NGS-based HLA typing were used to establish Taiwanese HLA imputation references. The HIBAG package was used to generate the imputation references for eight HLA loci at a two- and three-field resolution. Internal validation was carried out to evaluate the call threshold and accuracy for each HLA gene. HLA class II genes found to be associated with rheumatoid arthritis (RA) were validated in this study by the imputed HLA alleles. Our Taiwanese population-specific references achieved average HLA imputation accuracies of 98.11% for two-field and 98.08% for three-field resolution. The frequency distribution of imputed HLA alleles among 23,972 TWB subjects were comparable with PCR-based HLA alleles in general Taiwanese reported in the allele frequency net database. We replicated four common HLA alleles (HLA-DRB1*03:01, DRB1*04:05, DQA1*03:03, and DQB1*04:01) significantly associated with RA. The population-specific references provide an informative tool to investigate the associations of HLA variants and human diseases in large-scale population-based studies.

Research advances in the association of drug-induced liver injury with polymorphisms in human leukocyte antigen

Drug-induced liver injury is an important adverse drug reaction. Due to the lack of specificity in clinical symptoms and pathological features, there are still no reliable diagnostic biomarkers, so drug-induced liver injury is a diagnosis of exclusion. The article reviews the relevant advances in the association between novel human leukocyte antigen gene polymorphisms and drug-induced liver injury in order to identify potential biomarkers and provide a new method for the prediction and diagnosis of drug-induced liver injury. Henceforth, while studying the association between them, it will also need that the large sample and prospective studies to gain supporting evidence to implement translational application, so as to improve the safety and effectiveness of medication and achieve individualized treatment.

Effectiveness of fecal microbiota transplantation for severe diarrhea after drug-induced hypersensitivity syndrome

The aim of this study was to assess effectiveness of fecal microbiota transplantation (FMT) in treating intestinal failure associated with drug-induced hypersensitivity syndrome (DIHS).A 32-year-old Chinese woman, who developed DIHS-associated multiple organ dysfunction syndrome (MODS) manifesting as combined dysfunction of the intestine, liver, and kidney, was treated with 4 times of FMT at a frequency of once every 6 days. The structure and composition of the patient's fecal microbiota were analyzed by 16S rRNA-based molecular techniques. The clinical outcomes after FMT treatment were assessed by abdominal contrast-enhanced computed tomography (CT), characterization of fecal microbiota, measurement of serum inflammatory markers, and other clinical examinations.After 4 rounds of FMT were administered, the patient showed dramatic improvement in MODS and severe diarrhea with these clinical conditions under control. We consistently observed significant alteration in her gut microbiota, mainly involving considerable enrichment in Firmicutes members and depletion of Proteobacteria opportunistic organisms. Moreover, this reconstituted bacterial community composition correlated with fecal output, T helper cells, and inflammatory markers. Abdominal contrast-enhanced CT scans before and after FMT indicated significant improvement in inflammation and edema within the small intestine and colon of the patient. Notably, after completion of the fourth FMT, the level of inflammation in the intestine and colon had returned to normal. Over 6 months of follow-up, the intestinal mucous remained normal.Our results represent a breakthrough in the clinical management of MODS and suggest new therapeutic avenues to pursue for microbiota-related indications.

[Cutaneous drug reactions]

Cutaneous drug reactions are a common reason for calls and visits. This term chiefly refers to hypersensitivity reactions ranging from benign rash without contraindication of treatment to severe life-threatening clinical pictures, such as anaphylactic shock and epidermal necrolysis. They should be carefully managed from the outset. Indeed, history taking and precise semiological description of the lesions are crucial to the formulation of recommendations for the patient. Allergological investigation of such reactions has developed greatly in recent decades and must now be carried out much more extensively. The arrival of new drug families such as biotherapies and the development of drug habituation protocols constitute the challenges of tomorrow for cutaneous drug reactions.

The rash that presents as a red swollen face

A red swollen face can be a skin sign of a potentially life-threatening condition. We present in detail the main clinical presentations, diagnostic tests, and management of some of the most severe conditions that can frequently present as a red and swollen face: acute or recurrent angioedema, mast cell-driven or bradykinin-mediated angioedema, nonhereditary and hereditary angioedema, allergic or photoallergic facial contact dermatitis, contact urticaria, severe adverse drug reactions (particularly drug reaction with eosinophilia and systemic symptoms [DRESS]), skin infections (erysipelas, cellulitis, necrotizing fasciitis), and autoimmune diseases (dermatomyositis). There are many other conditions that also have to be considered in the differential diagnosis of a red swollen face.

Shared Genetic Risk Factors Across Carbamazepine-Induced Hypersensitivity Reactions

Carbamazepine (CBZ) causes life‐threating T‐cell‐mediated hypersensitivity reactions, including serious cutaneous adverse reactions (SCARs) and drug‐induced liver injury (CBZ‐DILI). In order to evaluate shared or phenotype‐specific genetic predisposing factors for CBZ hypersensitivity reactions, we performed a meta‐analysis of two genomewide association studies (GWAS) on a total of 43 well‐phenotyped Northern and Southern European CBZ‐SCAR cases and 10,701 population controls and a GWAS on 12 CBZ‐DILI cases and 8,438 ethnically matched population controls. HLA‐A*31:01 was identified as the strongest genetic predisposing factor for both CBZ‐SCAR (odds ratio (OR) = 8.0; 95% CI 4.10–15.80; P = 1.2 × 10⁻⁹) and CBZ‐DILI (OR = 7.3; 95% CI 2.47–23.67; P = 0.0004) in European populations. The association with HLA‐A*31:01 in patients with SCAR was mainly driven by hypersensitivity syndrome (OR = 12.9; P = 2.1 × 10⁻⁹) rather than by Stevens‐Johnson syndrome/toxic epidermal necrolysis cases, which showed an association with HLA‐B*57:01. We also identified a novel risk locus mapping to ALK only for CBZ‐SCAR cases, which needs replication in additional cohorts and functional evaluation.

A retrospective investigation of HLA-B*5801 in hyperuricemia patients in a Han population of China

BACKGROUND

Hyperuricemia and gout have become increasingly prevalent in China. Allopurinol is an effective urate-lowering therapy, but it has severe side effects. HLA-B*5801 is highly associated with the allopurinol-induced toxic epidermal necrolysis and Stevens-Johnson syndrome.

PATIENTS AND METHODS

In this retrospective report, we had genotyped HLA-B*5801 in 253 cases of hyperuricemia and gout patients in a Han population in Shenzhen and analyzed the clinical management of medications.

RESULTS

We found 30 carriers of the HLA-B*5801 allele in 253 cases of hyperuricemia or gout patients in the population (11.9%). Allopurinol was prescribed in both HLA-B*5801-positive and HLA-B*5801-negative groups. The evaluation of four models with or without genetic screening and management of allopurinol or febuxostat indicated that the HLA-B*5801 screening had significant cost benefit for clinical management.

CONCLUSION

For appropriate management and cost-effectiveness, the HLA-B*5801 allele should be screened in all patients with hyperuricemia and gout in the Chinese population.

Drug-Induced Skin Adverse Reactions: The Role of Pharmacogenomics in Their Prevention

Adverse drug reactions (ADRs) affect many patients and remain a major public health problem, as they are a common cause of morbidity and mortality. It is estimated that ADRs are responsible for about 6% of hospital admissions and about 9% of hospitalization costs. Skin is the organ that is most frequently involved in ADRs. Drug-induced skin injuries vary from mild maculopapular eruptions (MPE) to severe cutaneous adverse reactions (SCARs) that are potentially life threatening. Genetic factors have been suggested to contribute to these SCARs, and most significant genetic associations have been identified in the major histocompatibility complex (MHC) genes. Common drugs associated with SCARs connected with strong genetic risk factors include antiepileptic drugs (AEDs), allopurinol, abacavir, nevirapine, sulfonamides, dapsone, non-steroidal anti-inflammatory drugs (NSAIDs), and analgesic drugs. However, genetic associations vary between different ethnic populations. Differences may in part be explained by the different prevalence of HLA (human leukocyte antigen) alleles among ethnic groups. In this review, we present and discuss the recent advances in genetic associations with ADRs in the skin. Many of these ADRs are now preventable with pharmacogenetic screening.

Stevens-Johnson Syndrome After Armodafinil Use

ABSTRACT

We present the case of a 21-year-old woman in whom Stevens-Johnson syndrome (SJS) developed after initiation of armodafinil. Although this rare and life-threatening reaction is listed on armodafinil's label, no cases have been reported in the literature. This case, in addition to an update of the drug's label after post-marketing research, both support the link between armodafinil and SJS. Providers should maintain a high clinical suspicion for SJS when starting therapy to minimize associated morbidity and mortality by discontinuing armodafinil at the onset of first symptoms.

HLA-A*02:07 Allele Associates with Clarithromycin-Induced Cutaneous Adverse Drug Reactions in Chinese Patients

Genetic risk factors could cause cutaneous adverse drug reactions (cADRs) in patients after treatment with clarithromycin. This study explored the association of HLA class I genes with clarithromycin-cADRs in Han Chinese patients. A total of 12 clarithromycin-cADR patients and 34 clarithromycin-tolerant controls were recruited for the high-resolution genotyping of HLA class I genes (HLA-A, HLA-B and HLA-C). The population controls consisted of 283 Han Chinese retrieved from the MHC database for validated comparison. A molecular docking analysis of HLA-A*02:07 protein and clarithromycin was conducted using glide module with Schrödinger Suite. Among all tested HLA alleles, the carrier frequencies of HLA-A*02:07 (58% versus 5.9%, OR = 22.40, 95% CI = 3.58-139.98, p = 8.20 × 10E-5, pc = 1.1 × 10E-3) and HLA-B*46:01 (50% versus 5.9%, OR = 16.00, 95% CI = 2.59-98.99, p = 0.002, pc = 0.03) were significantly higher in clarithromycin-cADRs than in clarithromycin-tolerant controls. However, when compared to population controls, only HLA-A*02:07, and not HLA-B*46:01, reached statistical significance (58% versus 15.5%, OR = 7.61, 95% CI = 2.31-25.04, p = 1.2 × 10E-4, pc = 1.7 × 10E-3). Furthermore, molecular docking data revealed that clarithromycin could bind to and interact with HLA-A*02:07 in two possible binding situations. These data suggest that HLA-A*02:07 might be a genetic risk factor for developing clarithromycin-cADRs in Han Chinese and serve as a useful biomarker for personalized medicine to prevent clarithromycin-cADRs.

Treatment of toxic epidermal necrolysis by a multidisciplinary team. A review of literature and treatment results

BACKGROUND

Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are mucocutaneous hypersensitivity reactions, usually to drugs or their metabolites. TEN is the most severe involving greater than 30% of the total body surface area (TBSA). Management of these patients usually benefits from a large multidisciplinary team for both wound and medical management. Treatment of these patients varies between centers and physicians and there is lack of a standardized treatment protocol in the medical literature.

OBJECTIVES

To review the literature and complete a retrospective review of patients treated at Vancouver General Hospital over a 11-year period.

METHODS

A retrospective chart review of all patients diagnosed with SJS/TEN and treated at Vancouver General Hospital from 2001 to 2011 was completed. Data collected include patient demographics, time to transfer to a burn center, SCORTEN calculation, suspected cause of TEN, %TBSA involved, length of stay in hospital and ICU, medications, dressings, infections/cultures, fluids, mucosal involvement, teams involved, associated complications, morbidity and mortality. Data is reported quantitatively.

RESULTS

A total of 67 patients were identified (28 SJS, 21 SJS/TEN overlap, 18 TEN). In SJS/TEN overlap and TEN patients, oral mucosa and trunk were the primary sites involved. SCORTEN calculations were highest in the TEN group. Plastic surgery was consulted in 53% of TEN cases, 52% of SJS/TEN cases and 25% of SJS cases. Patients were admitted to a burn unit in 74% of TEN cases, 57% of TEN/SJS cases and 21% of SJS cases. Time from symptoms to diagnosis and transfer to a burn unit was highest for TEN patients. Time from presentation to diagnosis was highest in SJS/TEN overlap. Triggers were identified in 67-82% of cases. Treatment varied widely. Patients were treated conservatively, with steroids, IVIg, and cyclosporine alone or in combination. Observed mortality was higher than predicted by SCORTEN for patients treated with IVIg and lower for those treated with Cyclosporin. Dressings varied greatly and were often changed throughout a patients stay. Total mortality was 20.9% being the highest in the TEN group (35%).

CONCLUSIONS

SJS and TEN are a spectrum of severe mucocutaneous reactions that have unclear treatment recommendations within the literature and within our Level 1 hospital. Information gleaned from this research will help educate physicians involved in the treatment and management of patients with these diagnoses and has resulted in development of treatment guidelines in our hospital.

Association between HLA gene polymorphism and cutaneous adverse reactions caused by antiepileptic drugs

The association between cutaneous adverse drug reactions (cADRs) caused by antiepileptic drugs (AEDs) and human leukocyte antigen-A (HLA-A) and HLA-B genes in Chinese Han population in Shanghai was investigated. Through the case-control study, 30 child patients with AED-induced cADRs (cADRs group), 60 AED-tolerant child patients (AED-tolerant group) and 60 normal children not taking AEDs (normal group) were collected. The HLA-B*15:02 and HLA-A*31:01 genotypes were detected using the polymerase chain reaction-sequence-specific oligonucleotide (PCR-SSO) probe method, and the correlation of HLA-B*15:02 and HLA-A*31:01 genes with the incidence of cADRs was analyzed. The positive rate of HLA-B*15:02 gene was 83.33% in the cADRs group, which was significantly increased compared with that in the AED-tolerant and normal groups (P<0.01). The positive rate of HLA-A*31:01 gene was 63.33% in the cADRs group, which was obviously increased compared with that in the AED-tolerant and normal groups (P<0.01). There were no significant differences in HLA-B*15:02 and HLA-A*31:01 genotypes between the AED-tolerant and normal groups (P>0.05). The results showed that HLA-B*15:02 and HLA-A*31:01 are significantly associated with cADRs in a Chinese Han population in Shanghai, suggesting that HLA-B*15:02 and HLA-A*31:01 genotypes should be detected in the application of AEDs.

Severe cutaneous adverse reactions to drugs

During the past decade, major advances have been made in the accurate diagnosis of severe cutaneous adverse reactions (SCARs) to drugs, management of their manifestations, and identification of their pathogenetic mechanisms and at-risk populations. Early recognition and diagnosis of SCARs are key in the identification of culprit drugs. SCARS are potentially life threatening, and associated with various clinical patterns and morbidity during the acute stage of Stevens-Johnson syndrome and toxic epidermal necrolysis, drug reactions with eosinophilia and systemic symptoms, and acute generalised exanthematous pustulosis. Early drug withdrawal is mandatory in all SCARs. Physicians' knowledge is essential to the improvement of diagnosis and management, and in the limitation and prevention of long-term sequelae. This Seminar provides the tools to help physicians in their clinical approach and investigations of SCARs.

HLA-associated drug hypersensitivity and the prediction of adverse drug reactions

Adverse drug reactions are an important cause of morbidity and mortality and constitute the leading reason of drug withdrawal from the market. Besides classical reactions that are related to pharmacologic activity of the drug, some reactions are unpredictable, not dose dependent, and seem to occur in genetically predisposed individuals. The majority of this reaction is immunologically driven and they are referred to as hypersensitivity reactions. A growing number of studies provided evidences that specific HLA alleles increase the risk of developing hypersensitivity drug reactions. In this context, drug hypersensitivities that have more robust pharmacogenetic data include abacavir hypersensitivity syndrome and severe cutaneous adverse reactions induced by allopurinol and carbamazepine.

DRESS Syndrome: Drug Reaction With Eosinophilia and Systemic Symptoms

DRESS syndrome is a cutaneous and systemic drug reaction with severe complications and a long course that can be fatal. Recognition may be difficult, and the condition is just rare enough that clinicians will eventually see it but may not be familiar with it. This review will focus on key elements to help clinicians with the challenges of recognition and differential diagnosis.

[Drug rash with eosinophilia and systemic symptoms syndrome induced by carbamazepine: Case report]

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is a hypersensitivity reaction associated with a variety of drugs, mainly anticonvulsants, which is characterized by systemic symptoms and erythematous lesions, common to other toxicodermas. It is an uncommon clinical entity that requires a high suspicion by clinical staff given its varied initial presentation, and the fact that symptoms can overlap with those of other adverse cutaneous reactions to drugs. Without early diagnosis and appropriate treatment, mortality increases.We report the case of a 22-year-old patient with impaired neurodevelopment who received treatment with carbamazepine. Two months later he presented with general symptoms and skin erythematous lesions that began on his trunk. The patient received outpatient care with antihistamines and antipyretics without an appropriate response. His case progressed with increased skin lesions and systemic symptoms that met the diagnostic criteria for DRESS syndrome. He was hospitalized and received medical treatment according to recommended guidelines. The patient's condition improved as his symptoms and associated complications resolved. He was discharged with gradual clearing of the steroid therapy.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Concise Review with a Comprehensive Summary of Therapeutic Interventions Emphasizing Supportive Measures

INTRODUCTION

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are two of the most severe dermatologic conditions occurring in the inpatient setting. There is a lack of consensus regarding appropriate management of SJS and TEN.

PURPOSE

The scientific literature pertaining to SJS and TEN (subsequently referred to as SJS/TEN) is summarized and assessed. In addition, an interventional approach for the clinician is provided.

METHODS

PubMed was searched with the key words: corticosteroids, cyclosporine, etanercept, intravenous immunoglobulin, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The papers generated by the search, and their references, were reviewed.

RESULTS

Supportive care is the most universally accepted intervention for SJS/TEN. Specific guidelines differ from the care required for patients with thermal burns. Adjuvant therapies are utilized in most severe cases, but the data are thus far underwhelming and underpowered. Using systemic corticosteroids as sole therapy is not supported. A consensus regarding combined corticosteroids and intravenous immunoglobulin (IVIG) has not been reached. Data regarding IVIG, currently the standard of care for most referral centers, is conflicting. Newer studies regarding cyclosporine and tumor necrosis factor inhibitors are promising, but not powered to provide definitive evidence of efficacy. Data regarding plasmapheresis is equivocal. Thalidomide increases mortality.

CONCLUSION

Clinicians who manage SJS/TEN should seek to employ interventions with the greatest impact on their patients' condition. While supportive care measures may seem an obvious aspect of SJS/TEN patient care, providers should understand that these interventions are imperative and that they differ from the care recommended for other critically ill or burn patients. While adjuvant therapies are frequently discussed and debated for hospitalized patients with SJS/TEN, a standardized management approach is not yet clear based on the current data. Therefore, until further data are available, decisions regarding such treatments should be made on a case-by-case basis.

HLA-B (*) 58:01 for Allopurinol-Induced Cutaneous Adverse Drug Reactions: Implication for Clinical Interpretation in Thailand

Background: The aim of this study was to investigate the predisposition to different types of allopurinol-induced cutaneous adverse drug reactions (CADR), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN; SJS-TEN, n = 13), drug reaction with eosinophilia and systemic symptoms (DRESS, n = 10) and Maculopapular eruption (MPE; n = 7), conferred by HLA-B^*58:01 in a Thai population.

Methods: This case-control association study compares 30 patients with allopurinol-induced CADR, allopurinol-tolerant control patients (n = 100), and a Thai general population (n = 1095). Patients' human leukocyte antigen type B (HLA-B) alleles were genotyped by using a two-stage sequence-specific oligonucleotide probe system.

Results: Of a total 30 patients with CADR due to allopurinol, 29 (96.7%) patients were found to be at least heterozygous for HLA-B^*58:01, compared to only 4.0% in allopurinol-tolerant patients (p < 0.001). Odds ratio (OR) for the association of HLA-B^*58:01 with allopurinol-induced CADR in this population was 696.0 (95% CI: 74.8–6475.0). The HLA-B^*58:01 allele was present in all patients with allopurinol-induced SJS-TEN (OR = 579.0, 95%CI: 29.5–11362.7, p < 0.001) and DRESS (OR 430.3, 95%CI: 22.6–8958.9, p < 0.001). Additionally, OR of HLA-B^*58:01 was highly significant in the allopurinol-induced MPE patients (OR 144.0, 95%CI: 13.9–1497.0, p < 0.001).

Conclusion: In this study we confirmed the association between HLAB^*58:01 and allopurinol-induced SJS-TEN in a Thai population. In addition, we identified an association between HLA-B^*58:01 and allopurinol-induced DRESS and MPE in this population. Therefore, HLA-B^*58:01 can be used as a pharmacogenetic marker for allopurinol-induced CADR including SJS-TEN, DRESS and MPE. These results suggest that screening for HLA-B^*58:01 alleles in patients who will be treated with allopurinol would be clinically helpful in preventing the risk of developing CARD in a Thai patients.

Summary

Regardless of phenotype, this is the first pharmacogenetic study of allopurinol-induced CADR in patients of Thai ancestry.

In this study we confirmed the association between HLA-B^*58:01 and allopurinol-induced SJS-TEN, DRESS, and MPE in Thai population.

Regarding to our findings, the pharmacogenetic interpretation could be generalized to drug hypersensitivity including DRESS, SJS-TEN, and MPE.

The HLA-B*15:02 allele in a Spanish Romani patient with carbamazepine-induced Stevens-Johnson syndrome

The HLA-B*15:02 allele is a risk factor for carbamazepine (CBZ)-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in populations where the allele is prevalent. Han Chinese and Thai patients are advised to take a genetic test before introducing CBZ. Such testing is not recommended for patients of European descent. We report the case of a Spanish Romani patient who developed Stevens-Johnson syndrome upon treatment with CBZ. In vitro assays confirmed CBZ as the culprit drug. HLA typing showed that the patient carried the HLA-B*15:02 allele. A public database search revealed that 2% of Spanish Romani people likely carry the risk variant HLA-B*15:02 and therefore may be included in the population to be tested prior to beginning treatment with CBZ.

The pharmacogenomics of epilepsy

Genetic factors contribute to the high interindividual variability in response to antiepileptic drugs. However, most genetic markers identified to date have limited sensitivity and specificity, and the value of genetic testing in guiding antiepileptic drug (AED) therapy is limited. The best defined indication for testing relates to HLA-B*15:02 genotyping to identify those individuals of South Asian ethnicity who are at high risk for developing serious adverse cutaneous reactions to carbamazepine. The indication for HLA-A*31:01 testing to identify individuals at risk for skin reactions from carbamazepine, or for CYP2C9 genotyping to identify individuals at risk for serious skin reactions from phenytoin is less compelling. The use of genetic testing to guide epilepsy treatment is likely to increase in the future, as better understanding of the function of epilepsy genes will permit the application of precision medicine targeting the biological mechanisms responsible for epilepsy in the specific individual.

Human leukocyte antigen genetic risk factors of drug-induced liver toxicology

INTRODUCTION

Drug-induced liver injury (DILI) is a rare adverse drug reaction, which impacts significantly on patients. Human leukocyte antigen (HLA) risk alleles have been found to be associated with DILI supporting an immunological basis to DILI pathogenesis.

AREAS COVERED

HLA alleles associated with risk of liver injury induced by specific therapeutic drugs are described. The evidence for a role of the adaptive immune system in DILI is presented; case-control studies showing an association between DILI and HLA alleles are reviewed. Clinical applications of pharmacogenomics are considered.

EXPERT OPINION

Increasing evidence points to a crucial role for the adaptive immune system in the pathogenesis of DILI. Identification of specific HLA alleles as risk factors through large genome-wide association studies has been instrumental in this and in vitro analyses have facilitated improved understanding of the molecular mechanisms. This provides the basis for developing clinical pharmacogenomic applications. Already, genotyping for hypersensitivity HLA risk alleles has been implemented and opportunities for pre-prescription testing in DILI identified. However, although associations are strong, the rarity of DILI means routine testing has not been formally evaluated. Nevertheless, enhanced understanding of how HLA alleles contribute to injury risk is valuable for drug development. Translation of this research into effective pre-emption and primary prevention remains the goal.