Immunogenetics of drug-induced skin blistering disorders. Part I: Perspective

Unveiling new genetic insights in rheumatoid arthritis for drug discovery through Taxonomy3 analysis

Genetic support for a drug target has been shown to increase the probability of success in drug development, with the potential to reduce attrition in the pharmaceutical industry alongside discovering novel therapeutic targets. It is therefore important to maximise the detection of genetic associations that affect disease susceptibility. Conventional statistical methods such as genome-wide association studies (GWAS) only identify some of the genetic contribution to disease, so novel analytical approaches are required to extract additional insights. C4X Discovery has developed Taxonomy3, a unique method for analysing genetic datasets based on mathematics that is novel in drug discovery. When applied to a previously published rheumatoid arthritis GWAS dataset, Taxonomy3 identified many additional novel genetic signals associated with this autoimmune disease. Follow-up studies using tool compounds support the utility of the method in identifying novel biology and tractable drug targets with genetic support for further investigation.

Cutaneous immune-related adverse events to immune checkpoint inhibitors: from underlying immunological mechanisms to multi-omics prediction

The development of immune checkpoint inhibitors (ICIs) has dramatically altered the landscape of therapy for multiple malignancies, including urothelial carcinoma, non-small cell lung cancer, melanoma and gastric cancer. As part of their anti-tumor properties, ICIs can enhance susceptibility to inflammatory side effects known as immune-related adverse events (irAEs), in which the skin is one of the most commonly and rapidly affected organs. Although numerous questions still remain unanswered, multi-omics technologies have shed light into immunological mechanisms, as well as the correlation between ICI-induced activation of immune systems and the incidence of cirAE (cutaneous irAEs). Therefore, we reviewed integrated biological layers of omics studies combined with clinical data for the prediction biomarkers of cirAEs based on skin pathogenesis. Here, we provide an overview of a spectrum of dermatological irAEs, discuss the pathogenesis of this "off-tumor toxicity" during ICI treatment, and summarize recently investigated biomarkers that may have predictive value for cirAEs via multi-omics approach. Finally, we demonstrate the prognostic significance of cirAEs for immune checkpoint blockades.

A Retrospective, Single-Institution Experience of Bullous Pemphigoid as an Adverse Effect of Immune Checkpoint Inhibitors

Immune checkpoint inhibitors are a class of cancer treatment drugs that stimulate the immune system's ability to fight tumor cells. These drugs are monoclonal antibodies targeting im-mune-inhibiting proteins on cancer cells, such as CTLA-4 and PD-1/PD-L1. Immune checkpoint inhibitors cause many immune-related adverse events. Cutaneous toxicities are of the most common adverse effects and occur with a range of severity. Bullous Pemphigoid is a rare adverse event with a high impact on quality of life that may occur after immune checkpoint inhibitor treatment. In this article, we investigate current research on immune checkpoint inhibitors, cutaneous adverse events, and common presentations and treatments, with a specific focus on Bullous Pemphigoid, its characteristics, onset timing, and treatment. Significant findings include a negative skew in the onset of presentation. Furthermore, we describe exclusive cases.

A Case of Lansoprazole-Induced Bullous Pemphigoid After Zantac Recall

Proton pump inhibitors (PPIs) are the mainstay of treatment for many gastric acid-related diseases with a relatively safe drug profile. One of the rare side effects is PPI-induced bullous pemphigoid. We describe a case of new-onset bullous pemphigoid on initiation of lansoprazole for esophagitis after a nationwide Zantac recall. This condition can improve with the cessation of PPI and the use of corticosteroids. However, it poses a significant challenge to the management of gastroesophageal reflux disease by limiting available pharmacologic options. In addition, this case highlights the negative effects of a drug recall.

Association Between Medication Use and Bullous Pemphigoid: A Systematic Review and Meta-analysis

Importance

The association between the use of medications and the development of bullous pemphigoid (BP) is unclear.

Objective

To assess the associations between previous exposure to certain medications and BP.

Data Sources

For this systematic review and meta-analysis, PubMed, the Cochrane Central Register of Controlled Trials, and Embase were searched for relevant studies from inception to February 20, 2020.

Study Selection

Case-control or cohort studies and randomized clinical trials that examined the odds or risk of BP in patients with previous medication use were included. No geographic or language limitations were imposed.

Data Extraction and Synthesis

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline was followed. The Newcastle-Ottawa Scale was used to evaluate the risk of bias of included observational studies; Cochrane Collaboration's tool was used for randomized clinical trials. Aggregate data were used to conduct a random-effects model meta-analysis if the included studies were sufficiently homogenous. Subgroup analyses were performed for use of various medications of the same category.

Main Outcomes and Measures

Odds ratio (OR), hazard ratio, and risk ratio of bullous pemphigoid in association with medication use.

Results

This meta-analysis included 13 case-control studies, 1 cohort study, and 1 randomized clinical trial with a total of 285 884 participants. The meta-analysis of case-control studies showed a significant association of BP with previous use of aldosterone antagonists (pooled OR, 1.75; 95% CI, 1.28-2.40), dipeptidyl peptidase 4 inhibitors (pooled OR, 1.92; 95% CI, 1.55-2.38), anticholinergics (pooled OR, 3.12; 95% CI, 1.54-6.33), and dopaminergic medications (pooled OR, 2.03; 95% CI, 1.34-3.05). One cohort study found an increased risk of BP among patients receiving dipeptidyl peptidase 4 inhibitors (hazard ratio, 2.38; 95% CI, 1.16-4.88; P = .02). One trial found a higher occurrence of BP in patients with diabetes receiving linagliptin (0.2% in diabetes group vs 0% in the placebo group).

Conclusions and Relevance

The findings of this systematic review and meta-analysis suggest that aldosterone antagonists, dipeptidyl peptidase 4 inhibitors, anticholinergics, and dopaminergic medications are associated with BP. These medications should be judiciously prescribed, particularly in high-risk patients who are elderly and have disabling neurologic disorders.

Adverse Immunologically Mediated Oral Mucosal Reactions to Systemic Medication: Lichenoid Tissue Reaction/Interface Dermatitis-Stomatitis, Autoimmune Vesiculobullous Disease, and IgE-Dependent and Immune Complex Reactions

Drug-induced hypersensitivity immune reactions are exaggerated immunoinflammatory responses to allergenic components of the medications that occur in genetically susceptible subjects. The type of hypersensitivity immune response generated, whether antibody mediated or T cell mediated, or an immune complex reaction is determined by multiple factors, including the molecular characteristics of the allergen, the route of administration of the medication, the manner of presentation of the allergen by antigen-presenting cells to naïve T cells, the repertoire of the T cell receptors, and the cytokine profile within the microenvironment. This review deals with the clinical and histopathological aspects of adverse immunologically mediated oral mucosal reactions to systemic medication. We elaborate on diseases showing features of lichenoid tissue reaction/interface dermatitis-stomatitis, autoimmune vesiculobullous oral lesions, and immunoglobulin E- (IgE-) and immune complex-mediated oral reactions to drugs.

Autoimmune Bullous Skin Disorders with Immune Checkpoint Inhibitors Targeting PD-1 and PD-L1

Monoclonal antibodies (mAb) targeting immune checkpoint pathways such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) may confer durable disease control in several malignancies. In some patients, immune checkpoint mAbs cause cutaneous immune-related adverse events. Although the most commonly reported cutaneous toxicities are mild, a subset may persist despite therapy and can lead to severe or life-threatening toxicity. Autoimmune blistering disorders are not commonly associated with immune checkpoint mAb therapy. We report a case series of patients who developed bullous pemphigoid (BP), an autoimmune process classically attributed to pathologic autoantibody formation and complement deposition. Three patients were identified. Two patients developed BP while receiving the anti-PD-1 mAb nivolumab, and one while receiving the anti-PD-L1 mAb durvalumab. The clinicopathologic features of each patient and rash, and corresponding radiologic findings at the development of the rash and after its treatment, are described. Patients receiving an anti-PD-1/PD-L1 mAb may develop immune-related BP. This may be related to both T-cell- and B-cell-mediated responses. Referral to a dermatologist for accurate diagnosis and management is recommended. Cancer Immunol Res; 4(5); 383-9. ©2016 AACR.

Rapid and reliable genotyping of HLA-B*58:01 in four Chinese populations using a single-tube duplex real-time PCR assay

AIM

HLA-B*58:01 is strongly associated with allopurinol-induced severe cutaneous adverse reactions. This study aimed to develop a new and convenient method for HLA-B*58:01 genotyping and to investigate HLA-B*58:01 distribution in different Chinese populations.

MATERIALS & METHODS

Combining of sequence-specific primers and TaqMan probe, a single-tube duplex real-time PCR assay for HLA-B*58:01 typing was established.

RESULTS

The HLA-B*58:01 genotyping result in Buyei (n = 100) by real-time PCR showed 100% concordance with those by sequence-based typing. The prevalence of HLA-B*58:01 carrier in Buyei (17%, n = 100) was significantly higher than those in Northern Han (4%, n = 100), Tibetan (5.1%, n = 99) and Uighur (2%, n = 50) populations (p < 0.05).

CONCLUSION

The newly developed reliable assay was appropriate for HLA-B*58:01 detection prior to allopurinol administration in clinical settings.

Drug-induced pemphigoid: a review of the literature

Bullous pemphigoid is an acquired autoimmune disease that is characterized by subepidermal blistering and affects mainly the elderly. The pathogenesis of the condition has not yet been fully elucidated, but it is widely accepted that a strong correlation with various medications may exist. In reality, more than 50 different drugs have been associated with the appearance of bullous pemphigoid and as new therapies emerge, this number is very likely to increase. A number of pathogenetic mechanisms have been proposed in the past. It is true that a delicate immunological balance is disturbed in all patients with the disease. The variable effects that may be exhibited by the use of biological drugs could shed some light in this complex immunological behaviour. At the same time, drug-induced bullous pemphigoid is difficult to differentially diagnose from its idiopathic counterpart, as the clinical picture and histopathological findings in both conditions may only have subtle differences. Patients who present with bullous pemphigoid and receive multiple regimens should always be suspected of suffering from the drug-induced variant of the condition. This possibility must be considered, as after the withdrawal of the suspect medication most patients respond rapidly to treatment and do not experience relapses.

A whole-genome association study of major determinants for allopurinol-related Stevens-Johnson syndrome and toxic epidermal necrolysis in Japanese patients

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are severe, cutaneous adverse drug reactions that are rare but life threatening. Genetic biomarkers for allopurinol-related SJS/TEN in Japanese were examined in a genome-wide association study in which Japanese patients (n=14) were compared with ethnically matched healthy controls (n=991). Associations between 890 321 single nucleotide polymorphisms and allopurinol-related SJS/TEN were analyzed by the Fisher's exact test (dominant genotype mode). A total of 21 polymorphisms on chromosome 6 were significantly associated with allopurinol-related SJS/TEN. The strongest association was found at rs2734583 in BAT1, rs3094011 in HCP5 and GA005234 in MICC (P=2.44 × 10(-8); odds ratio=66.8; 95% confidence interval, 19.8-225.0). rs9263726 in PSORS1C1, also significantly associated with allopurinol-related SJS/TEN, is in absolute linkage disequilibrium with human leukocyte antigen-B*5801, which is in strong association with allopurinol-induced SJS/TEN. The ease of typing rs9263726 makes it a useful biomarker for allopurinol-related SJS/TEN in Japanese.

[Pharmacogenetics]

Allergic reactions to drugs belong to the group of B-reactions, which are characterized not only by the pharmacologic profile of the drug but also by individual risk factors. Pharmacogenetic approaches facilitate identifying these risk factors. The most important example for Caucasian patients is NIDR (non-immediate drug reaction) to abacavir. Chinese patients possess risk factors for NIDR to allopurinol and anticonvulsants and the HLA locus on chromosome 6. Another potentially important area is assessing risk factors to prevent allergic reactions to antibiotics, especially with regard to the effective treatment of MRSA.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.