The study of severe cutaneous drug hypersensitivity reactions from a systems biology perspective

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.

Genetic basis of hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

PURPOSE OF REVIEW

NSAIDs are the main triggers of hypersensitivity reactions to drugs. However, the full genetic and molecular basis of these reactions has yet to be uncovered. In this article, we have summarized research from recent years into the effects of genetic variants on the different clinical entities induced by NSAID hypersensitivity, focusing on prostaglandin and leukotriene-related genes as well as others beyond the arachidonic acid pathway.

RECENT FINDINGS

We introduce recent contributions of high-throughput approaches including genome-wide association studies as well as available information from epigenetics and next-generation sequencing. Finally, we give our thoughts on future directions in this field, including the scope for bioinformatics and systems biology and the need for clear patient phenotyping.

SUMMARY

The full genetic and molecular basis of clinical entities induced by NSAIDs hypersensitivity has yet to be uncovered, and despite commendable efforts over recent years, no clinically proven genetic markers currently exist for these disorders. It is clear that we will continue to find more about these reactions in the coming years, concurrently with improvements in technology and experimental techniques, and a precise definition of different phenotypes.

Clinical characteristics and treatment outcome of Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are erythematous skin lesions with blister formation accompanied by mucosal involvement. These conditions are considered to be life-threatening illnesses. Understanding the clinical presentation, risk factors, treatment options and results will be advantageous for physicians in the management of patients in the future. The aim of the present study was to review and analyze the clinical manifestations, drug implications, treatment and outcome of patients with SJS and/or TEN who had been hospitalized in a tertiary care center. All hospitalized patients with SJS and/or TEN during a 5-year period were retrospectively reviewed. The clinical severity was graded according to the score of toxic epidermal necrolysis (SCORTEN) scale. Clinical symptoms, diagnosis, possible precipitating factors, management and outcome data were collected for analysis. A total of 43 patients (mean age, 49.5 years) were hospitalized and classified into the SJS group (55.8%), SJS/TEN overlap group (20.9%) and TEN group (23.3%). The majority of the patients (90.7%) had mucocutaneous eruptions associated with oral drug administration. Allopurinol, anticonvulsants and antibiotics were the most common causative agents for the mucocutaneous eruption. Twenty-eight patients (65.1%) were treated with corticosteroids. The mortality rate was 6.9%. Comparison between the survival group and the non-survival group revealed that patient age >70 years (P=0.014) and body surface area involvement >20% (P<0.01) were the significant factors associated with mortality. The use of systemic steroids was higher in the survival group in comparison with the non-survival group (65.1 vs. 0%, respectively; P=0.014). The mucocutaneous eruptions in SJS and TEN are mostly caused by medication. With early recognition and treatment, the mortality rate in this study was lower than that in previous reports. Patient age and the area of mucocutaneous involvement were significant factors associated with mortality.

Hypersensitivity reactions to nonsteroidal anti-inflammatory drugs: from phenotyping to genotyping

PURPOSE OF REVIEW

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent drugs involved in hypersensitivity drugs reactions. Both immunological and nonimmunological mechanisms can be involved. We describe the different phenotypes as well as analyze the genetic basis for NSAIDs hypersensitivity.

RECENT FINDINGS

Five major clinical entities are currently accepted in the classification of hypersensitivity reactions to NSAIDs. Three are mediated by nonspecific immunological mechanisms: NSAIDs-exacerbated respiratory disease, NSAIDs-exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema. Two are mediated by specific immunological mechanisms: single-NSAID-induced urticaria/angioedema or anaphylaxis and single-NSAID-induced delayed hypersensitivity reactions. The classification becomes more complex if we consider that in an important number of cases skin and airway involvement can occur, as well as the participation of other organs.

SUMMARY

Hypersensitivity reactions to NSAIDs are more complex than for other drugs like betalactams in terms of the number and types of reactions elicited, and mechanisms involved. As NSAIDs are the most frequent cause of drug hypersensitivity, it is feasible to gather a sufficient number of cases for undertaking pharmacogenetic studies.