Drug hypersensitivity: pharmacogenetics and clinical syndromes

Clinical Features of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Induced by Immune Checkpoint Inhibitor versus Non-Immune Checkpoint Inhibitor Drugs in China: A Cross-Sectional Study and Literature Review

Purpose

Immune checkpoint inhibitors (ICIs) can cause life-threatening Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Large-scale original research on ICI-induced SJS/TEN is limited. This study aimed to explore the unique clinical characteristics and potential pathophysiological mechanisms of SJS/TEN induced by ICIs.

Methods

This cross-sectional study compared the clinical features of SJS/TEN induced by ICIs and non-ICIs, and reviewed the case characteristics of ICI-induced SJS/TEN. Clinical features were analyzed using independent t-tests, Mann-Whitney U-tests, and multivariable regression models.

Results

This study enrolled 41 cases of ICI-induced SJS/TEN and 107 non-ICI-induced cases from January 22, 2015, to May 28, 2024. ICI-induced SJS/TEN patients exhibited a trend towards a longer latency period (β: 17, 95% CI: -1.49 to 35.48), a smaller affected body surface area (BSA) (β: -40.68, 95% CI: -71.59 to -9.77), and milder oral and ocular mucositis than non-ICI-induced cases. A literature review identified PD-1 inhibitors as the primary ICIs involved and systemic corticosteroids as the most frequent intervention. No statistically significant difference in mortality rate was observed between patients treated with systemic corticosteroids alone and those receiving combination therapies (P= 0.85). The mortality rate for ICI-induced SJS/TEN was 24.5%.

Conclusion

This study offered the largest comparative analysis to date, highlighting the unique clinical features of ICI-induced SJS/TEN, including a smaller affected BSA, a prolonged latency period trend, and milder oral and ocular mucositis. We described the epidemiology, clinical presentation, and therapeutic strategies for ICI-induced SJS/TEN. These findings not only contribute to a deeper understanding of the complex immune-inflammatory pathways in severe immune-related cutaneous adverse events (ircAEs) but also may inform the development of more targeted and effective treatments.

A Comprehensive Review on HIV-Associated Dermatologic Manifestations: From Epidemiology to Clinical Management

Dermatological disorders are among the most prevalent manifestations of HIV infection/acquired immunodeficiency syndrome (AIDS). In this review, we aimed to characterize the various dermatologic presentations among HIV-infected patients with a detailed categorization of the mucocutaneous signs and symptoms, their etiopathogenic factors, and clinical management. In fact, cutaneous manifestations of HIV are quite various, ranging from AIDS-specific skin eruptions (xerosis, pruritic papular eruptions, eosinophilic folliculitis, and acne), opportunistic infections (herpes simplex, molluscum contagiosum, cutaneous leishmaniasis, bacillary angiomatosis, disseminated histoplasmosis, disseminated cryptococcosis, and zoster) to AIDS-related malignancies (Kaposi's sarcoma, lymphoma, and nonmelanoma skin cancers) and antiretroviral therapy (ART)-associated drug eruptions. We tried to classify HIV-related cutaneous presentations which can help clinicians for a better understanding of the various specific and nonspecific features of AIDS-associated cutaneous manifestations and management of the condition.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Focus on the Pathophysiological and Diagnostic Role of Viruses

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a heterogeneous, multiorgan and potentially life-threatening drug-hypersensitivity reaction (DHR) that occurs several days or weeks after drug initiation or discontinuation. DHRs constitute an emerging issue for public health, due to population aging, growing multi-organ morbidity, and subsequent enhanced drug prescriptions. DRESS has more consistently been associated with anticonvulsants, allopurinol and antibiotics, such as sulphonamides and vancomycin, although new drugs are increasingly reported as culprit agents. Reactivation of latent infectious agents such as viruses (especially Herpesviridae) plays a key role in prompting and sustaining aberrant T-cell and eosinophil responses to drugs and pathogens, ultimately causing organ damage. However, the boundaries of the impact of viral agents in the pathophysiology of DRESS are still ill-defined. Along with growing awareness of the multifaceted aspects of immune perturbation caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the ongoing SARS-CoV-2-related disease (COVID-19) pandemic, novel interest has been sparked towards DRESS and the potential interactions among antiviral and anti-drug inflammatory responses. In this review, we summarised the most recent evidence on pathophysiological mechanisms, diagnostic approaches, and clinical management of DRESS with the aim of increasing awareness on this syndrome and possibly suggesting clues for future research in this field.

Pathology of T-cell-mediated drug hypersensitivity reactions and impact of tolerance mechanisms on patient susceptibility

PURPOSE OF REVIEW

T-cell-mediated drug hypersensitivity is responsible for significant morbidity and mortality, and represents a substantial clinical concern. The purpose of this article is to focus on T-cell reactions and discuss recent advances in disease pathogenesis by exploring the impact of tolerance mechanisms in determining susceptibility in genetically predisposed patients.

RECENT FINDINGS

Certain drugs preferentially activate pathogenic T cells that have defined pathways of effector function. Thus, a critical question is what extenuating factors influence the direction of immune activation. A large effort has been given towards identifying phenotypic (e.g., infection) or genotypic (e.g., human leukocyte antigen) associations which predispose individuals to drug hypersensitivity. However, many individuals expressing known risk factors safely tolerate drug administration. Thus, mechanistic insight is needed to determine what confers this tolerance. Herein, we discuss recent clinical/mechanistic findings which indicate that the direction in which the immune system is driven relies upon a complex interplay between co-stimulatory/co-regulatory pathways which themselves depend upon environmental inputs from the innate immune system.

SUMMARY

It is becoming increasingly apparent that tolerance mechanisms impact on susceptibility to drug hypersensitivity. As the field moves forward it will be interesting to discover whether active tolerance is the primary response to drug exposure, with genetic factors such as HLA acting as a sliding scale, influencing the degree of regulation required to prevent clinical reactions in patients.

An Updated Review of Genetic Associations With Severe Adverse Drug Reactions: Translation and Implementation of Pharmacogenomic Testing in Clinical Practice

Adverse drug reactions (ADR) remain the major problems in healthcare. Most severe ADR are unpredictable, dose-independent and termed as type B idiosyncratic reactions. Recent pharmacogenomic studies have demonstrated the strong associations between severe ADR and genetic markers, including specific HLA alleles (e.g., HLA-B*15:02/HLA-B*57:01/HLA-A*31:01 for carbamazepine-induced severe cutaneous adverse drug reactions [SCAR], HLA-B*58:01 for allopurinol-SCAR, HLA-B*57:01 for abacavir-hypersensitivity, HLA-B*13:01 for dapsone/co-trimoxazole-induced SCAR, and HLA-A*33:01 for terbinafine-induced liver injury), drug metabolism enzymes (such as CYP2C9*3 for phenytoin-induced SCAR and missense variant of TPMT/NUDT15 for thiopurine-induced leukopenia), drug transporters (e.g., SLCO1B1 polymorphism for statin-induced myopathy), and T cell receptors (Sulfanilamide binding into the CDR3/Vα of the TCR 1.3). This mini review article aims to summarize the current knowledge of pharmacogenomics of severe ADR, and the potentially clinical use of these genetic markers for avoidance of ADR.

Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far most reactions (n=145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions are anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%) and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin) and possibly iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS, but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is (far) higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing. This article is protected by copyright. All rights reserved.

Drug reaction with eosinophilia and systemic symptoms (DRESS) induced by phenytoin re-exposure: case report and systematic review

Introduction: Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an adverse and severe skin reaction due to patients' susceptibility to medications, including phenytoin. The objective was to explore the characteristics of patients with DRESS secondary to phenytoin through a systematic review.Methods: We describe a case of DRESS syndrome secondary to phenytoin in a patient with previous exposure to this drug. A systematic literature review of cases of phenytoin-induced DRESS syndrome was conducted in PubMed/Medline, Scopus and Web of Science until May 2019.Results: 37 articles describing 40 cases of DRESS syndrome were selected. Mean age of onset was 33 years, without gender difference. Symptoms started between two and 90 days (mean ± 23 days). Liver and respiratory tract were most frequently involved, and eosinophilia was a common feature, it was presented with an average value of 9.7%. A discussion of the case and qualitative synthesis of the evidence reported in the literature were made.Conclusion: Patients and presentation characteristics will mostly be presented according to the criteria used by RegiSCAR. It is recommended to consider adequate monitoring of adverse reactions to antiepileptic drugs such as DRESS syndrome, given its severity and high lethality.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome in liver transplantation

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare delayed-type hypersensitivity reaction that causes skin abnormalities and mucosal involvement of the entire body. This is a case report of DRESS occurring in a liver transplantation recipient after taking drugs. A 57-year-old female patient with hepatocellular carcinoma underwent living donor liver transplantation in April 2019. She had no previous medical histories relevant to allergic diseases. There were no adverse events during hospitalization. She was admitted to evaluate and treat a headache occurring at one month after transplantation. However, she suffered from adverse drug reactions after taking anticonvulsants, showing skin rash, itching sense, and fever with eosinophilia. Piperacillin/Tazoperan was administered for ten days as an empirical antibiotic. Skin biopsy was performed on postoperative day 106 for erythematous maculopapular rash in the arms, legs, and torso. Her symptoms improved after discontinuation of the suspected medication with conservative skin treatment and high-dose steroid treatment. This case suggests that suspicion of drug history is essential for early diagnosis and management of DRESS.

Genotyping HLA alleles to predict the development of Severe cutaneous adverse drug reactions (SCARs): state-of-the-art

Introduction: Pharmacogenomics has great potential in reducing drug-induced severe cutaneous adverse drug reactions (SCARs). Pharmacogenomic studies have revealed an association between HLA genes and SCARs including acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN).Areas covered: Pharmacogenomics-guided therapy could prevent severe drug hypersensitivity reactions. The US Food and Drug Administration (FDA), Clinical Pharmacogenetics Implementation Consortium (CPIC), and Dutch Pharmacogenetics Working Group (DPWG) provided guidelines in the translation of clinically relevant and evidence-based SCARs pharmacogenomics research into clinical practice. In this review, we intended to summarize the significant HLA alleles associated with SCARs induced by different drugs in different populations. We also summarize the SCARs associated with genetic and non-genetic factors and the cost-effectiveness of screening tests.Expert opinion: The effectiveness of HLA screening on a wider scale in clinical practice requires significant resources, including state-of-the-art laboratory; multidisciplinary team approach and health care provider education and engagement; clinical decision support alert system via electronic medical record (EMR); laboratory standards and quality assurance; evidence of cost-effectiveness; and cost of pharmacogenomics tests and reimbursement.

The Roles of Immunoregulatory Networks in Severe Drug Hypersensitivity

The immunomodulatory effects of regulatory T cells (Tregs) and co-signaling receptors have gained much attention, as they help balance immunogenic and immunotolerant responses that may be disrupted in autoimmune and infectious diseases. Drug hypersensitivity has a myriad of manifestations, which ranges from the mild maculopapular exanthema to the severe Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome (DRESS/DIHS). While studies have identified high-risk human leukocyte antigen (HLA) allotypes, the presence of the HLA allotype at risk is not sufficient to elicit drug hypersensitivity. Recent studies have suggested that insufficient regulation by Tregs may play a role in severe hypersensitivity reactions. Furthermore, immune checkpoint inhibitors, such as anti-CTLA-4 or anti-PD-1, in cancer treatment also induce hypersensitivity reactions including SJS/TEN and DRESS/DIHS. Taken together, mechanisms involving both Tregs as well as coinhibitory and costimulatory receptors may be crucial in the pathogenesis of drug hypersensitivity. In this review, we summarize the currently implicated roles of co-signaling receptors and Tregs in delayed-type drug hypersensitivity in the hope of identifying potential pharmacologic targets.

A retrospective, 5-year, clinicoepidemiological study of severe cutaneous adverse reactions (SCARs)

BACKGROUND

A severe cutaneous adverse reaction (SCAR) is a rare, clinically heterogeneous, life-threatening phenomenon that results in serious skin damage, systemic complications, and significant morbidity or mortality comprising of Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), or SJS-TEN overlap, acute generalized exanthematous pustulosis (AGEP), exfoliative dermatitis, and drug rash with eosinophilia and systemic symptoms (DRESS).

MATERIALS AND METHODS

A retrospective study was conducted on all cases of SCARs admitted in a tertiary care referral hospital from January 2015 to December 2019. Clinical and epidemiological details were retrieved from the records of patients as per predesigned proforma. The data collected were analyzed and statistically evaluated.

RESULTS AND ANALYSIS

A total of 142 patients (67 males, 75 females) with SCARs, constituting 0.08% of total hospital admission and 0.027% of total dermatology outpatient department (OPD), were studied. Age group ranged from 2 to 61 years, with the mean age of 33.6 years (SD = 17.43). Most patients belonged to SJS-TEN complex (75 cases; SJS 48, SJS-TEN 18, TEN nine) followed by exfoliative dermatitis (27 cases/19%), AGEP (26 cases/18.3%), and DRESS (14 cases/9.8%). Anticonvulsants were most commonly implicated (22%) followed by antibiotics (20%), nonsteroidal anti-inflammatory drugs (NSAIDs) (17%), and ayurvedic (7%). There was only single mortality in a DRESS patient.

CONCLUSION

SCAR has considerable disease burden with marginal female preponderance in SJS/TEN and exfoliative dermatitis and can involve even the pediatric population. Anticonvulsants followed by antibiotics, NSAIDs, and ayurvedic medicines are common groups known to cause SCARs. To date, there are no definitive recommendations regarding their optimal treatment regimen, hence early diagnosis, prompt withdrawal of culprit drug, high standard of nursing care, and interdisciplinary consultations are vital steps to avoid disease progression and restore health.

The risk of anti-osteoporotic agent-induced severe cutaneous adverse drug reactions and their association with HLA

BACKGROUND

There is increasing use of anti-osteoporotic agents (AOA) worldwide for prevention or management of patients with osteoporosis. However, there have been reports of severe cutaneous adverse reactions (SCAR) induced by AOA. A recent study showed weak association between HLA and strontium ranelate (SR)-SCAR.

OBJECTIVE

To characterize patients with AOA-SCAR and investigate the HLA association and utility of in vitro diagnostic methods.

METHODS

We enrolled 16 cases with AOA-cutaneous adverse drug reactions (cADR), including SCAR (n = 10: 8 with Stevens-Johnson syndrome [SJS] and 2 with drug rash with eosinophilia and systemic symptoms [DRESS]) and maculopapular exanthema (MPE) (n = 6) from Taiwan and Hong Kong. We analysed the clinical characteristics, outcomes, HLA alleles and in vitro testing of AOA-SCAR, and tolerability to alternative drugs. We further performed literature review and meta-analysis on the HLA association of AOA-SCAR.

RESULTS

Our data showed strontium ranelate is the most common causality of AOA-SCAR in Asian populations. There was no cross-hypersensitivity of SR-SCAR with other AOA. HLA genotyping showed that SR-SJS was most significantly associated with HLA-A*33:03 (Pc = 5.17 × 10^-3 , OR: 25.97, 95% CI: 3.08-219.33). Meta-analysis showed that HLA-A*33:03 was associated with SR-SJS (P = 5.01 × 10^-5 ; sensitivity: 85.7%) in Asians. The sensitivity of lymphocyte activation test (LAT) for identifying the culprit drug of SR-SJS was 83.3%.

CONCLUSIONS

Strontium ranelate is identified as the most notorious AOA associated with SCAR. The HLA-A*33:03 genetic allele and LAT testing may add benefits to the diagnosis of SR-SCAR in patients whose reaction developed while taking multiple drugs.

Maternal known drug allergy and long-term dermatological morbidity of the offspring

Drug allergy is associated with adverse short-term perinatal outcomes such as caesarian delivery and preterm delivery. The aim of the present study was to determine whether being born to a mother with known drug allergy increases the risk for long-term dermatological morbidity of the offspring. A population-based cohort study, comparing long-term dermatological morbidity of offspring to mothers with and without known drug allergy, was conducted. Dermatological morbidity was assessed up to the age of 18 years according to a predefined set of ICD-9 codes associated with hospitalization of the offspring. A Kaplan-Meier survival curve was used to compare cumulative incidence of long-term dermatological morbidity, and a Cox proportional hazards model was constructed to control of confounders. During the study period, 243,682 deliveries met the inclusion criteria, of them 4% (n = 9756) were of mothers with known drug allergy. Offspring born to mothers with known drug allergy had higher rates of long-term dermatological morbidity Likewise, the cumulative incidence of long-term dermatological morbidity was higher as compared with those without known drug allergy (Kaplan-Meier log-rank P = .021). Using a Cox proportional hazards model, controlling for confounders, being born to a mother with known drug allergy was found to be an independent risk factor for long-term dermatological morbidity of the offspring (adjusted HR 1.2, 95% CI 1.03-1.33, P = .016). Being born to a mother with known drug allergy is independently associated with higher risk for long-term dermatological morbidity of the offspring.

Role of in vivo and in vitro Tests in the Diagnosis of Severe Cutaneous Adverse Reactions (SCAR) to Drug

Severe cutaneous adverse reactions (SCAR) are life-threatening conditions including acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Diagnosis of causative underlying drug hypersensitivity (DH) is mandatory due to the high morbidity and mortality upon re-exposure with the incriminated drug. If an underlying DH is suspected, in vivo test, including patch tests (PTs), delayed-reading intradermal tests (IDTs) and in vitro tests can be performed in selected patients for which the suspected culprit drug is mandatory, or in order to find a safe alternative treatment. Positivity of in vivo and in vitro tests in SCAR to drug varies depending on the type of reaction and the incriminated drugs. Due to the severe nature of these reactions, drug provocation test (DPT) is highly contraindicated in patients who experienced SCAR. Thus, sensitivity is based on positive test results in patients with a suggestive clinical history. Patch tests still remain the first-line diagnostic tests in the majority of patients with SCAR, followed, in case of negative results, by delayed-reading IDTs, with the exception of patients with bullous diseases where IDTs are still contra-indicated. In vitro tests have shown promising results in the diagnosis of SCAR to drug. Positivity is particularly high when the lymphocyte transformation test (LTT) is combined with cytokines and cytotoxic markers measurement (cyto-LTT), but this still has to be confirmed with larger studies. Due to the rarity of SCAR, large multi-center collaborative studies are needed to better study the sensitivity and specificity of in vivo and in vitro tests.

Hypersensitivity Reactions to Monoclonal Antibodies in Children

Biologic drugs are widely used in pediatric medicine. Monoclonal antibodies (mAbs) in particular are a therapeutic option for rheumatic, autoinflammatory and oncologic diseases. Adverse drug reactions and hypersensitivity reactions (HSR) to mAbs may occur in children. Clinical presentation of HSRs to mAbs can be classified according to phenotypes in infusion-related reactions, cytokine release syndrome, both alpha type reactions and type I (IgE/non-IgE), type III, and type IV reactions, all beta-type reactions. The aim of this review is to focus on HSRs associated with the most frequent mAbs in childhood, with particular attention to beta-type reactions. When a reaction to mAbs is suspected a diagnostic work-up including in-vivo and in-vitro testing should be performed. A drug provocation test is recommended only when no alternative drugs are available. In selected patients with immediate IgE-mediated drug allergy a desensitization protocol is indicated. Despite the heavy use of mAbs in childhood, studies evaluating the reliability of diagnostic test are lacking. Although desensitization may be effective in reducing the risk of reactions in children, standardized pediatric protocols are still not available.

Severe cutaneous adverse drug reactions manifesting as Stevens-Johnson syndrome and toxic epidermal necrolysis reported to the national pharmacovigilance center in Nigeria: a database review from 2004 to 2017

Background:

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions (SCARs). There is scant literature on the characteristics and causes of these conditions among the Nigerian population. Here, we describe the epidemiology, associated morbidity and mortality, and culpable drugs in SJS and TEN cases using the National Pharmacovigilance (NPC) database in Nigeria.

Methods:

A retrospective review of the NPC database was done to analyze SJS and TEN cases reported over a period of 14 years. Annual reports, age and sex of patients, type of reporter, suspects and concomitant drugs, time to onset (TTO) of the reactions, and outcome of SJS and TEN were evaluated.

Results:

The NPC received a total of 24,015 adverse drug reaction (ADR) reports. SJS and TEN accounted for 284 (0.1%) of the total reports, of which 254 (89.4%) were SJS and the remainder were TEN. Females (n = 184, 64.8%) and individuals aged 19–40 years (n = 181, 63.7%) were the most affected by SJS and TEN. Antiretrovirals, followed by antibiotics, were the most common drug classes reported to cause SJS and TEN, with nevirapine (n = 174, 40.7%) and co-trimoxazole (n = 143, 33.5%) being the most widely implicated drugs. Among patients with reported outcomes, 73 (28.7%) SJS and 3 (10.0%) TEN cases recovered without sequelae, at the time of reporting. Severity of the SCAR was reported for only 171 (69.0%) cases, of which 12 (4.7%) and 8 (26.7%) resulted in death (Grade 5) among SJS and TEN cases, respectively.

Conclusions:

Antiretroviral and antibiotics were the commonly reported offending group of drugs for SJS and TEN cases. Nevirapine and co-trimoxazole were the commonly reported suspect drugs. SJS and TEN were reported most frequently in females and in patients aged 19–40 years, indicating that drug surveillance and counseling in these groups of patients may be beneficial.

DRESS syndrome in response to Denosumab: First documented case report

Denosumab is an antiresorptive drug targeting RANK ligand, currently licensed for postmenopausal and male osteoporosis, bone loss associated with hormone ablation in men with prostate cancer and with systemic glucocorticoid treatment, and also used in oncology for the treatment of bone metastases and unresectable giant cell tumour of bone. When used for the treatment of osteoporosis or bone loss the drug is usually well-tolerated with non-specific musculoskeletal pain being the most common side effect. However denosumab has been associated with some dermatological manifestations including dermatitis, eczema, pruritus and, less commonly, cellulitis. All these side effects are generally mild and self-limiting. We hereby report the first documented case of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome following denosumab administration. DRESS syndrome is an extremely rare but potentially life-threatening hypersensitivity reaction. The syndrome should be considered in patients who present with new rash, eosinophilia and systemic organ dysfunction, especially when associated with new medications. Notably it has been previously reported in patients with osteoporosis treated with strontium ranelate but it has never been linked to any other antiosteoporotic drugs. Since the clinical manifestations of DRESS syndrome can span over a period of several months the diagnosis can frequently be quite difficult and it can become even more challenging in people taking denosumab and other drugs given in period doses, as both clinicians and patients are less likely to link the symptoms to the medication. Better recognition of DRESS syndrome is therefore needed, as well as awareness of the possibility of this reaction to occur in patients taking denosumab.

Protocols for drug allergy desensitization in children

Introduction: When a drug hypersensitivity reaction is proven, desensitization protocols allow the reintroduction of the molecule in patients for whom such therapy is essential. Through drug desensitization (DDS), a temporary immune tolerance is maintained for the single course of a specific therapy. In pediatrics, indications for such a procedure include children with chronic diseases, severe infectious diseases and/or malignancies, who have a proven drug hypersensitivity.Areas covered: We ran a search on PubMed and Web of Science for papers on DDS and on DDS in children. Most protocols and recommendations on DDS focus on adults and have been adapted for children. The best candidates for desensitization are children with a history of immediate, IgE-mediated drug allergy, but this therapy may be applied also in nonallergic hypersensitivities and in non-immediate reactions. Most protocols in literature focus on antibiotics, especially beta-lactams, on chemotherapeutic agents, and on monoclonal antibodies.Expert opinion: Pediatric allergists should cooperate with specialists in infectious diseases and onco-hematology to provide DDS to children in need. Standardized protocols and international guidelines are still needed to optimize such treatment and to implement it in clinical daily practice.

Diagnostic Utility of Human Leukocyte Antigen B*15:02 Screening in Severe Carbamazepine Hypersensitivity Syndrome

Background

Despite many studies suggesting an association between human leukocyte antigen (HLA)-B*15:02 and carbamazepine (CBZ)-induced severe cutaneous adverse drug reactions essentially toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), the evidence of association in different populations and the degree of association remain uncertain.

Materials and Methods

The primary analysis was based on population control studies. Data were pooled by means of a random-effects model, and sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratios (DOR), and areas under the summary receiver operating characteristic curve (AUC) were calculated.

Results

In 23 population control studies, HLA-B*15:02 was measured in 373 patients with CBZ-induced TEN/SJS and 3452 patients without CBZ-induced TEN/SJS. The pooled sensitivity, specificity, LR+, LR-, DOR, and AUC were 0.67 (95% confidence interval [CI] = 0.63-0.72), 0.98 (95% CI = 0.98-0.99), 19.73 (95% CI = 10.54-36.92), 0.34 (95% CI = 0.23-0.49), 71.38 (95% CI = 34.89-146.05), and 0.96 (95% CI = 0.92-0.98), respectively. Subgroup analyses for Han Chinese, Thai, and Malaysian populations yielded similar findings. Specifically, racial/ethnic subgroup analyses revealed similar findings with respect to DOR for Han Chinese (99.28; 95% CI = 22.20-443.88), Thai (61.01; 95% CI = 23.05-161.44), and Malaysian (30; 95% CI = 7.08-126.68) populations, which are similar to the pooled DOR for the relationship between the HLA-B*15:02 allele and CBZ-induced TEN/SJS across all populations (71.38; 95% CI = 34.89-146.05).

Conclusions

The present study reveals that CBZ is the leading cause of TEN/SJS in many countries. Screening of HLA-B*15:02 may help patients to prevent the occurrence of CBZ-induced TEN/SJS, especially in populations with a higher (≥5%) risk allele frequency.

Acute kidney injury associated with febuxostat and allopurinol: a post-marketing study

BACKGROUND

For patients with recurrent flares of gout, tophi, urate crystal arthropathy, and renal stones, urate-lowering therapies (ULTs, including allopurinol and febuxostat) are the first-line treatment. Due to the widespread use of these ULTs (especially in patients with impaired renal function), assessment of the associated renal risk is essential. Accordingly, we performed a disproportionality analysis of reported cases of acute renal failure (ARF) associated with allopurinol and febuxostat.

METHODS

We carried out a case/non-case study of the World Health Organization's VigiBase® pharmacovigilance database between January 1, 2008, and December 31, 2018. The frequency of reports of ARF as a standardized Medical Dictionary for Regulatory Activities query for allopurinol and febuxostat was compared with that of all other reports for the two drugs and quoted as the reporting odds ratio (ROR) [95% confidence interval (CI)]. The results' stability was assessed in a series of sensitivity analyses (notably after the exclusion of putative competing drugs).

RESULTS

Among 3509 "suspected drug" notifications for febuxostat and 18,730 for allopurinol, we identified respectively 317 and 1008 cases of ARF. Acute renal failure was reported significantly more frequently for febuxostat and allopurinol than for other drugs (ROR [95%CI] 5.67 [5.05-6.36] and 3.25 [3.05-3.47], respectively). For both drugs, the ROR was higher in women than in men, respectively 11.60 [9.74-13.82] vs. 3.14 [2.69-3.67] for febuxostat and 4.45 [4.04-4.91] vs. 2.29 [2.11-2.50] for allopurinol. The sensitivity analyses confirmed the disproportionality for these two ULTs.

CONCLUSIONS

Acute renal failure was reported respectively 5.7 and 3.3 times more frequently for febuxostat and for allopurinol than for other drugs. Due to the potential consequences of ARF, physicians should take account of this disproportionality signal when prescribing the ULTs febuxostat and allopurinol.

Drug Hypersensitivity

BACKGROUND

Adverse drug reactions (ADRs) can be divided into pharmacological ADRs (type A) and hypersensitivity reactions (type B). Type B reactions can be further subdivided into immediate (<1 h, urticaria, anaphylaxis) and delayed reactions (>1 h, variable manifestation like exanthema, hepatitis, cytopenias). Prevention of hypersensitivity is often still a challenge.

METHODS

Selective literature search in Medline and Google Scholar as well as research in ADR databases like OpenVigil or SIDER.

RESULTS

Laboratory tests ([specific] IgE, lymphocyte transformation test), histological examination, dermatological tests (prick tests, epicutaneous testing) and-under certain circumstances-provocation tests can be used for diagnostics. There are only a few pharmacogenetic biomarkers to predict hypersensitivity reactions. Currently, testing for defined HLA genes is mandatory before prescription of abacavir and before the use of carbamazepine in Han Chinese or Thai patients. Immediate discontinuation of the trigger is essential in all allergic hypersensitivity reactions. Immediate reactions are treated with antihistamines, glucocorticoids and occasionally with epinephrine. Delayed reactions are usually treated with glucocorticoids.

CONCLUSION

Careful, structured diagnostics in case of suspected hypersensitivity together with adequate documentation (allergy passport) is necessary in order to avoid incidents in patients receiving subsequent treatment. Consistent use of existing resources (diagnostics and documentation) can help to avoid hypersensitivity reactions or to rapidly recognize and treat them, respectively.

Molecular docking predictions of fragrance binding to human leukocyte antigen molecules

BACKGROUND

Over 4000 small chemicals have been identified as allergens capable of inducing skin sensitization. Many sensitizers are hypothesized to act as haptens producing novel antigens, which can be presented to T cells by human leukocyte antigens (HLAs). Recent studies suggest that some chemical allergens use hapten-independent mechanisms.

OBJECTIVE

To determine whether molecular docking can identify HLA molecules that bind skin-sensitizing chemical allergens.

METHODS

Structural models of HLA molecules were used as the basis for molecular docking of 22 chemical allergens. Allergens predicted to bind HLA-B*57:01 were tested for their ability to stimulate T cells by the use of proliferation and interferon-gamma enzyme-linked immunospot assays.

RESULTS

Chemical allergens that did not satisfy the criteria for hapten activity in vitro were predicted to bind more strongly to common HLA isoforms than those with known hapten activity. HLA-B*57:01, which is an HLA allele required for drug hypersensitivity reactions, was predicted to bind several allergens, including benzyl benzoate, benzyl cinnamate, and benzyl salicylate. In in vitro T cell stimulation assays, benzyl salicylate and benzyl cinnamate were found to stimulate T cell responses from HLA-B*57:01 carriers.

CONCLUSIONS

These data suggest that small-molecule skin sensitizers have the potential to interact with HLA, and show that T cell-based in vitro assays may be used to evaluate the immunogenicity of skin-sensitizing chemicals.

Drug-induced liver injury with skin reactions: Drugs and host risk factors, clinical phenotypes and prognosis

While dermatologic manifestations of adverse drug reactions are frequent, drug-induced liver injury is rare. Numerous drugs are implicated in either Drug-Induced Liver Injury or Drug-Induced Skin Injury. However, concomitant Drug-Induced Liver Injury and Drug-Induced Skin Injury are uncommon, not well characterized and appear to be caused by a limited number of drugs. These are often associated with immuno-allergic or hypersensitivity features such as fever, skin rash, blisters or peeling of skin, eosinophilia, lymphadenopathy and mucositis. Liver injury can range from asymptomatic elevation of liver biochemical tests to severe hepatitis and acute liver failure needing liver transplantation. Severe cutaneous adverse reaction, particularly drug reaction with eosinophilia and systemic symptoms is commonly associated with internal organ involvement, the liver being the most frequently involved in approximately 90% of the cases. In Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis, abnormalities in liver biochemistry tests are common but severe liver disease is rare. There is a strong association of Human Leukocyte Antigen genotype with both drug reaction with eosinophilia and systemic symptoms and Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis. It is likely that the delayed immune-mediated reaction triggering skin reaction is also responsible for hepatitis. Drug-specific lymphocytes are found in the organs involved and also in circulating blood, which along with the cytokines and chemokines play a role in pathogenesis. Anti-epileptic drugs, allopurinol, sulfonamides, antibiotics and nevirapine are the top five causes of concomitant liver and skin injury. This review will focus on drug and host factors causing concomitant Drug-Induced Skin Injury and Drug-Induced Liver Injury and discuss the characteristics of liver involvement in patients with severe cutaneous adverse reaction.

Variation of clinical manifestations according to culprit drugs in DRESS syndrome

PURPOSE

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but serious condition that systematically damages various internal organs through T-cell-mediated immunological drug reactions. We aimed to investigate whether clinical manifestations of DRESS syndrome differ according to culprit drugs.

METHODS

We retrospectively analyzed data from 123 patients with probable/definite DRESS syndrome based on the RegiSCAR criteria (January 2011 to July 2016). The data were obtained from the Korean Severe Cutaneous Adverse Reaction Registry. Causality was assessed using the World Health Organization-Uppsala Monitoring Centre criteria. The culprit drugs were categorized as allopurinol, carbamazepine, anti-tuberculosis drug, vancomycin, cephalosporins, dapsone, and nonsteroidal anti-inflammatory drugs.

RESULTS

Differences were observed among culprit drugs regarding the frequencies of hepatitis (P < 0.01), renal dysfunction (P < 0.0001), lymphadenopathy (P < 0.01), and atypical lymphocyte (P < 0.01). Latency period differed among culprit drugs (P < 0.0001), being shorter in vancomycin and cephalosporin. In terms of clinical severity, admission duration (P < 0.01) and treatment duration (P < 0.05) differed among culprit drugs, being longer in vancomycin and anti-tuberculosis drugs, respectively.

CONCLUSIONS

Based on the findings, clinical manifestations, including latency period and clinical severity, may differ according to culprit drugs in DRESS syndrome.

Spontaneous cutaneous adverse drug reaction reports-An analysis of a 10-year dataset in Singapore

We analyzed the spontaneous adverse event database in Singapore to determine the types of cutaneous adverse drug reactions (CADRs) and causative drugs reported. We selected 10 CADRs-of-interest, and identified the suspected drugs and the characteristics of the at-risk population. ADR reports received from 2006 to 2015 of the system organ class "Skin and Appendages Disorders" were analyzed based on patient demographics, the types of CADRs, suspected drugs, outcome, and latency period. Of the 104 372 reports analyzed, 56.2% involved females and 72.5% involved Chinese patients. The mean age was 41.1 years old. The top CADRs reported were rash (including nonspecified rash, follicular rash, maculopapular rash, and vesicular rash) (67.2%) and angioedema (13.9%). The drugs frequently associated with the CADRs-of-interest include nonsteroidal antiinflammatory drugs and antibiotics with angioedema, iohexol with urticaria, and antiepileptics and allopurinol with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). A subgroup analysis based on age, sex, and race on the 10 CADRs-of-interest showed the following trends in reporting: Alopecia (reported more in females), drug hypersensitivity syndrome (more in males), angioedema (more in younger patients), and photosensitivity (more in older patients). In general, the racial distribution across each CADR-of-interest was consistent with that of Singapore's population, with slight deviations observed for SJS/TEN, photosensitivity and skin discoloration. We analyzed CADR reports from Singapore over 10 years, and identified the types of CADRs reported, and their associated drugs, latency periods and patient characteristics. Such information could add value to healthcare professionals as they assess CADR cases and evaluate suspected drugs.

Genetic markers of severe cutaneous adverse reactions

Adverse drug reactions can cause considerable discomfort. They can be life-threatening in severe cases, requiring or prolonging hospitalization, impeding proper treatment, and increasing treatment costs considerably. Although the incidence of severe cutaneous adverse reactions (SCARs) is low, they can be serious, have permanent sequelae, or lead to death. A recent pharmacogenomic study confirmed that genetic factors can predispose an individual to SCARs. Genetic markers enable not only elucidation of the pathogenesis of SCARs, but also screening of susceptible subjects. The human leukocyte antigen (HLA) genotypes associated with SCARs include HLA-B*57:01 for abacavir (Caucasians), HLA-B*58:01 for allopurinol (Asians), HLA-B*15:02 (Han Chinese) and HLA-A*31:01 (Europeans and Koreans) for carbamazepine, HLA-B*59:01 for methazolamide (Koreans and Japanese), and HLA-B*13:01 for dapsone (Asians). Therefore, prescreening genetic testing could prevent severe drug hypersensitivity reactions. Large-scale epidemiologic studies are required to demonstrate the usefulness and cost-effectiveness of screening tests because their efficacy is affected by the genetic differences among ethnicities.

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.

Single-tube multiplex real-time PCR assay for rapid and reliable detection of HLA-A*31:01 allele

AIM

HLA-A*31:01 has been associated with carbamazepine-induced hypersensitivity reactions. HLA-A*31:01 genetic testing is recommended before the initiation of carbamazepine therapy.

METHODS

A novel real-time PCR assay was designed for HLA-A*31:01 detection by allele-specific primers and TaqMan minor groove binding probes.

RESULTS

The genotyping results in 100 subjects by the established method who were in 100% agreement with the sequencing-based typing method. The assay presents a sensitivity of 1 (95% CI: 0.69-1.00), a specificity of 1 (95% CI: 0.96-1.00) and a positive and negative predictive value of 1. The carrier rates of HLA-A*31:01 in Tibetan (n = 45), Han Chinese (n = 100), Miaos (n = 48) and Khalkhas (n = 48) were 22.2, 10, 4.2 and 18.8%, respectively.

CONCLUSION

This assay is reliable to detect HLA-A*31:01 and would be useful to prevent carbamazepine-induced hypersensitivity reactions.

Severe cutaneous adverse reactions induced by targeted anticancer therapies and immunotherapies

With the increasing use of targeted anticancer drugs and immunotherapies, there have been a substantial number of reports concerning life-threatening severe cutaneous adverse reactions (SCARs), including Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome, and acute generalized exanthematous pustulosis. Although the potential risks and characteristics for targeted anticancer agent- and immunotherapy-induced SCAR were not well understood, these serious adverse reactions usually result in morbidity and sequela. As a treatment guideline for this devastating condition is still unavailable, prompt withdrawal of causative drugs is believed to be a priority of patient management. In this review, we outline distinct types of SCARs caused by targeted anticancer therapies and immunotherapies. Also, we discuss the clinical course, latency, concomitant medication, tolerability of rechallenge or alternatives, tumor response, and mortality associated with these devastating conditions. Imatinib, vemurafenib, and rituximab were the top three offending medications that most commonly caused SJS/TEN, while EGFR inhibitors were the group of drugs that most frequently induced SJS/TEN. For drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis, imatinib was also the most common offending drug. Additionally, we delineated 10 SCAR cases related to innovative immunotherapies, including PD1 and CTLA4 inhibitors. There was a wide range of latency periods: 5.5–91 days (median). Only eight of 16 reported patients with SCAR showed clinical responses. Targeted anticancer drugs and immunotherapies can lead to lethal SCAR (14 deceased patients were identified as suffering from SJS/TEN). The mortality rate of TEN was high: up to 52.4%. The information compiled herein will serve as a solid foundation to formulate ideas for early recognition of SCAR and to discontinue offending drugs for better management.

Drug-Induced Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Call for Optimum Patient Stratification and Theranostics via Pharmacogenomics

The Global Genomic Medicine Collaborative, a multinational coalition of genomic and policy experts working to implement genomics in clinical care, considers pharmacogenomics to be among the first areas in genomic medicine that can provide guidance in routine clinical practice, by linking genetic variation and drug response. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe life-threatening reactions to medications with a high incidence worldwide. Genomic screening prior to drug administration is a key opportunity and potential paradigm for using genomic medicine to reduce morbidity and mortality and ultimately eliminate one of the most devastating adverse drug reactions. This review focuses on the current understanding of the surveillance, pathogenesis, and treatment of SJS/TEN, including the role of genomics and pharmacogenomics in the etiology, treatment, and eradication of preventable causes of drug-induced SJS/TEN. Gaps, unmet needs, and priorities for future research have been identified for the optimal management of drug-induced SJS/TEN in various ethnic populations. Pharmacogenomics holds great promise for optimal patient stratification and theranostics, yet its clinical implementation needs to be cost-effective and sustainable.

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.

[Severe skin reactions due to new medications]

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and a specific form of hypersensitivity syndrome which is nowadays called "drug reaction with eosinophilia and systemic symptoms" (DRESS) are severe, mainly drug-induced skin reactions. Whereas SJS/TEN is considered one reaction entity of different severity, DRESS has to be distinguished from SJS/TEN but also from other severe exanthems due to multiorgan involvement. Although SJS/TEN is generally referred to as drug reaction, in total only about three quarters of the cases are actually caused by drugs. After the clinical diagnosis is made, identification of the potential inducing factor is most important. In case medications are considered as causal, their withdrawal plays a key role in management. In order to identify and withdraw the inducing agent, a detailed and thorough medication history must be obtained. Agents identified or confirmed as inducers of SJS/TEN by pharmacoepidemiological studies are allopurinol, antibacterial sulfonamides, various antiepileptics, nevirapine and nonsteroidal anti-inflammatory drugs of the oxicam-type. Among drugs inducing DRESS are also various antiepileptics, but in addition allopurinol, sulfonamides and minocycline. Some cases of SJS/TEN and DRESS associated with the use of new medication, including targeted therapies and biologicals, have been observed.

Randomized, controlled trial of TNF-α antagonist in CTL-mediated severe cutaneous adverse reactions

BACKGROUND

Cytotoxic T lymphocyte-mediated (CTL-mediated) severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), are rare but life-threatening adverse reactions commonly induced by drugs. Although high levels of CTL-associated cytokines, chemokines, or cytotoxic proteins, including TNF-α and granulysin, were observed in SJS-TEN patients in recent studies, the optimal treatment for these diseases remains controversial. We aimed to evaluate the efficacy, safety, and therapeutic mechanism of a TNF-α antagonist in CTL-mediated SCARs.

METHODS

We enrolled 96 patients with SJS-TEN in a randomized trial to compare the effects of the TNF-α antagonist etanercept versus traditional corticosteroids.

RESULTS

Etanercept improved clinical outcomes in patients with SJS-TEN. Etanercept decreased the SCORTEN-based predicted mortality rate (predicted and observed rates, 17.7% and 8.3%, respectively). Compared with corticosteroids, etanercept further reduced the skin-healing time in moderate-to-severe SJS-TEN patients (median time for skin healing was 14 and 19 days for etanercept and corticosteroids, respectively; P = 0.010), with a lower incidence of gastrointestinal hemorrhage in all SJS-TEN patients (2.6% for etanercept and 18.2% for corticosteroids; P = 0.03). In the therapeutic mechanism study, etanercept decreased the TNF-α and granulysin secretions in blister fluids and plasma (45.7%-62.5% decrease after treatment; all P < 0.05) and increased the Treg population (2-fold percentage increase after treatment; P = 0.002), which was related to mortality in severe SJS-TEN.

CONCLUSIONS

The anti-TNF-α biologic agent etanercept serves as an effective alternative for the treatment of CTL-mediated SCARs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01276314.

FUNDING

Ministry of Science and Technology of Taiwan.

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.

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.

Drug Hypersensitivity and Anaphylaxis in Cancer and Chronic Inflammatory Diseases: The Role of Desensitizations

Drug allergy is a rising problem in the twenty-first century which affects all populations and races, children, and adults, and for which the recognition, diagnosis, management, and treatment is still not well standardized. Classical and new chemotherapy drugs, monoclonal antibodies (MoAbs), and small molecules to treat cancer and chronic inflammatory diseases are aimed at improving quality of life and life expectancy of patients, but an increasing number of reactions including anaphylaxis precludes their use in targeted populations. Women are more affected by drug allergy and up to 27% of women with ovarian and breast cancer develop carboplatin allergy after multiple cycles of treatment. Carriers of BRCA genes develop drug allergy after fewer exposures and can present with severe reactions, including anaphylaxis. Atopic patients are at increased risk for chemotherapy and MoAbs drug allergy and the current patterns of treatment with recurrent and intermittent drug exposures may favor the development of drug allergies. To overcome drug allergy, desensitization has been developed, a novel approach which provides a unique opportunity to protect against anaphylaxis and to improve clinical outcomes. There is evidence that inhibitory mechanisms blocking IgE/antigen mast cell activation are active during desensitization, enhancing safety. Whether desensitization modulates drug allergic and anaphylactic responses facilitating tolerance is currently being investigated. This review provides insight into the current knowledge of drug allergy and anaphylaxis to cancer and chronic inflammatory diseases drugs, the mechanisms of drug desensitization and its applications to personalized medicine.

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.