Drug-induced severe adverse reaction enhanced by human herpes virus-6 reactivation

Tools to improve the diagnosis and management of T-cell mediated adverse drug reactions

Delayed drug T-cell immune-mediated hypersensitivity reactions have a large clinical heterogeneity varying from mild maculopapular exanthema (MPE) to severe cutaneous adverse reactions (SCARs) such as acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS) and severe skin necrosis and blistering as seen in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Given the knowledge gaps related to the immunopathogenesis of these conditions, the absence of validated diagnostic tools and the significant associated morbidity and mortality, patients with SCARs often have limited drug choices. We performed a comprehensive review aiming to evaluate in vivo diagnostic tools such as delayed intradermal skin and patch testing and ex vivo/in vitro research assays such as the lymphocyte transformation test (LTT) and the enzyme-linked ImmunoSpot (ELISpot) assay. We searched through PubMed using the terms “drug allergy,” “in vivo” and “ex vivo” for original papers in the last 10 years. A detailed meticulous approach adapted to the various clinical phenotypes is recommended for the diagnostic and management of delayed drug hypersensitivity reactions. This review highlights the current diagnostic tools for the delayed drug hypersensitivity phenotypes.

Histopathologic Features of Maculopapular Drug Eruption

Background: Cutaneous adverse drug reaction (CADR) is common in both inpatient and outpatient clinical settings and has been associated with a large variety of medications. Drug reactions represent a significant burden to the healthcare system due to increased hospital stay durations and associated costs. Moreover, some of these reactions may be life-threatening. The most common clinical manifestation of a CADR is a maculopapular drug eruption (MDE). Due to its many clinical mimics and associations with a variety of histopathologic patterns, maculopapular drug eruption is difficult to definitively diagnose from both a clinical and histopathological perspective. Summary: We reviewed the clinical and histopathologic features of 327 cases of MDE from several studies in the literature and summarized characteristic histopathologic findings and their frequencies of occurrence. We found that the most common and suggestive histopathologic features of MDE were epidermal spongiosis, lymphocytic infiltrate, and occasional necrotic keratinocytes; interface change at the DEJ; superficial perivascular and interstitial lymphocytic infiltrate with or without eosinophils and neutrophils in the mid-to-deep dermis and mild papillary dermal edema; and dilation of superficial vessels. The presence of multiple histopathologic patterns within the same tissue specimen is also suggestive of MDE. This review and analysis suggest that a biopsy may improve the diagnostic accuracy by both establishing common and uncommon features associated with MDE and reviewing features that help to exclude other causes of maculopapular eruption. Key Message: Histopathologic criteria for the diagnosis of MDE, while not entirely specific, may aid in establishing a differential that includes a drug eruption. Thus, a biopsy can be a helpful diagnostic tool when MDE is suspected by demonstrating findings suggestive of MDE or by ruling out clinical mimics. However, biopsy results cannot be used in isolation as clinical-pathologic correlation is paramount in MDE.

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.

Síndrome de Stevens-Johnson con reactivación de herpes simple asociado a la ingestión de paracetamol. Reporte de caso

Introducción. El síndrome de Stevens-Johnson (SJS) es una enfermedad poco común que afecta la piel y las mucosas oral, ocular y urogenital; además, en más del 50% de los casos es producida por reacciones a medicamentos. Presentación del caso. Hombre de 20 años quien asistió al servicio de urgencias de hospital de tercer nivel de Popayán por un cuadro clínico de 10 días de evolución consistente en astenia, adinamia, fiebre no cuantificada, tos con escasa expectoración blanquecina y cefalea, sintomatología que mejoraba con el uso de paracetamol; sin embargo, la condición del paciente empeoró en los últimos dos días, presentando hiporexia, prurito en faringe, vesículas y ampollas en comisuras labiales, mucosa oral, tronco y extremidades, y dificultad respiratoria y odinofagia, razón por la cual acudió al servicio. En principio de sospechó de herpes simple diseminado, lupus eritematoso sistémico, y SJS; sin embargo, con base en los hallazgos clínicos y de laboratorio se confirmó el diagnóstico de SJS con reactivación de herpes simple asociado a la ingesta de paracetamol, por lo que se suspendió este medicamento y se inició manejo con aciclovir y metilprednisolona. El paciente tuvo una evolución satisfactoria y fue dado de alta a los 10 días del inicio del nuevo tratamiento y en las citas de control su condición general era óptima. Conclusión. El desarrollo de SJS puede estar asociado al consumo de paracetamol; sin embargo, su uso no se desaconseja gracias a sus grandes bondades y beneficios generales. En este sentido, dado que el paracetamol es un medicamento venta libre y uso extenso en Colombia, es indispensable reconocer las manifestaciones clínicas del SJS para poder dar un manejo adecuado y evitar complicaciones en casos como el aquí reportado.

Viral Infections and Cutaneous Drug-Related Eruptions

In the general population, up to 10% of children treated by antibiotics have cutaneous adverse drug reaction, but allergy is confirmed in less than 20% of patients. Most of the non-allergic reactions are probably due to virus, such as enterovirus acute infection or Ebstein-Barr Virus (EBV) acute infection or reactivation. Especially in children, viruses have the propensity to induce skin lesions (maculopapular rash, urticaria) due to their skin infiltration or immunologic response. In drug-related skin eruptions, a virus can participate by activating an immune predisposition. The culprit antibiotic is then the trigger for reacting. Even in severe drug-induced reactions, such as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, viruses take part in immune phenomena, especially herpes viruses. Understanding the mechanisms of both virus- and drug-induced skin reaction is important to develop our clinical reflection and give an adaptive care to the patient. Our aim is to review current knowledge on the different aspects and potential roles of viruses in the different type of drug hypersensitivity reactions (DHR). Although major advances have been made those past year, further studies are needed for a better understanding of the link between viruses and DHR, to improve management of those patients.

Reactive infectious mucocutaneous eruption: Mycoplasma pneumoniae-induced rash and mucositis and other parainfectious eruptions

Mycoplasma pneumoniae-induced rash and mucositis is the most accurate diagnosis for patients with blistering mucocutaneous disease provoked by an infection. Recent literature suggests expansion of the name is required, as other infections have caused a clinically similar presentation. This review provides a concise update on current understanding of M. pneumoniae-induced rash and mucositis and other reactive infectious mucocutaneous eruptions.

Biomarkers of Drug-Induced Liver Toxicity

Drug-induced liver injury (DILI) is a comprehensive phenomenon. The injury to the liver may occur as an unexpected and undesired reaction to a therapeutic dose of a drug (idiosyncratic reaction) or as an expected therapeutic effect of the direct (intrinsic) toxicity of a drug taken in a large enough dose to cause liver injury. The direct toxicity (type A) reactions represent an extension of the drug's therapeutic effect; they occur relatively frequently and are typically dose-related and frequency-of-exposure-related. By contrast, idiosyncratic reactions, or type B reactions, are unpredictable, occurring only in susceptible individuals, and are unrelated to the dose or frequency of exposure. DILI encompasses both acute and/or chronic hepatic lesions. The liver injury may be the only clinical manifestation of the adverse drug effect. Otherwise, it may be accompanied by injury to other organs, or by systemic manifestations. The liver injury may be observed in 1-8 days from taking the drug. DILI cases may result in the disapproval of a new drug or in the removal of a useful drug from the market by regulatory agencies. The purpose of this review is to provide guidance to facilitate the detection and assessment of hepatotoxicity induced by therapeutics that received market authorization. This review supports the safe and effective use of drugs by patients and guides laboratory medicine professional in determining the possible drug-induced liver damage.

Drug Metabolism, Drug Interactions, and Drug-Induced Liver Injury in Living Donor Liver Transplant Patients

Living donor liver transplant (LDLT) fills a critically needed gap in the number of livers available for transplant. However, little is known about the functional recovery of the liver in the donor and in the recipient after surgery. Given that both donor and recipients are treated with several drugs, it is important to characterize the time course of recovery of hepatic synthetic, metabolic, and excretory function in these patients. In the absence of data from LDLT, information on the effect of liver disease on the pharmacokinetics of medications can be used as guidance for drug dosing in LDLT patients.

Genome-Wide Association Study in Immunocompetent Patients with Delayed Hypersensitivity to Sulfonamide Antimicrobials

Background

Hypersensitivity (HS) reactions to sulfonamide antibiotics occur uncommonly, but with potentially severe clinical manifestations. A familial predisposition to sulfonamide HS is suspected, but robust predictive genetic risk factors have yet to be identified. Strongly linked genetic polymorphisms have been used clinically as screening tests for other HS reactions prior to administration of high-risk drugs.

Objective

The purpose of this study was to evaluate for genetic risk of sulfonamide HS in the immunocompetent population using genome-wide association.

Methods

Ninety-one patients with symptoms after trimethoprim-sulfamethoxazole (TMP-SMX) attributable to “probable” drug HS based on medical record review and the Naranjo Adverse Drug Reaction Probability Scale, and 184 age- and sex-matched patients who tolerated a therapeutic course of TMP-SMX, were included in a genome-wide association study using both common and rare variant techniques. Additionally, two subgroups of HS patients with a more refined clinical phenotype (fever and rash; or fever, rash and eosinophilia) were evaluated separately.

Results

For the full dataset, no single nucleotide polymorphisms were suggestive of or reached genome-wide significance in the common variant analysis, nor was any genetic locus significant in the rare variant analysis. A single, possible gene locus association (COL12A1) was identified in the rare variant analysis for patients with both fever and rash, but the sample size was very small in this subgroup (n = 16), and this may be a false positive finding. No other significant associations were found for the subgroups.

Conclusions

No convincing genetic risk factors for sulfonamide HS were identified in this population. These negative findings may be due to challenges in accurately confirming the phenotype in exanthematous drug eruptions, or to unidentified gene-environment interactions influencing sulfonamide HS.

Allopurinol induces innate immune responses through mitogen-activated protein kinase signaling pathways in HL-60 cells

Allopurinol, an inhibitor of xanthine oxidase, is a frequent cause of severe cutaneous adverse reactions (SCARs) in humans, including drug rash with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis. Although SCARs have been suspected to be immune-mediated, the mechanisms of allopurinol-induced SCARs remain unclear. In this study, we examined whether allopurinol has the ability to induce innate immune responses in vitro using human dendritic cell (DC)-like cell lines, including HL-60, THP-1 and K562, and a human keratinocyte cell line, HaCaT. In this study, we demonstrate that treatment of HL-60 cells with allopurinol significantly increased the mRNA expression levels of interleukin-8, monocyte chemotactic protein-1 and tumor necrosis factor α in a time- and concentration-dependent manner. Furthermore, allopurinol induced the phosphorylation of mitogen-activated protein kinases (MAPK), such as c-Jun N-terminal kinase and extracellular signal-regulated kinase, which regulate cytokine production in DC. In addition, allopurinol-induced increases in cytokine expression were inhibited by co-treatment with the MAPK inhibitors. Collectively, these results suggest that allopurinol has the ability to induce innate immune responses in a DC-like cell line through activation of the MAPK signaling pathways. These results indicate that innate immune responses induced by allopurinol might be involved in the development of allopurinol-induced SCARs. Copyright © 2015 John Wiley & Sons, Ltd.

Drug-drug interactions with oral anti-HCV agents and idiosyncratic hepatotoxicity in the liver transplant setting

Studies of boceprevir and telaprevir based antiviral therapy in liver transplant (LT) recipients with hepatitis C genotype 1 infection have demonstrated dramatic increases in tacrolimus, cyclosporine, and mTOR inhibitor exposure. In addition to empiric dose reductions, daily monitoring of immunosuppressant blood levels is required when initiating as well as discontinuing the protease inhibitors to maximize patient safety. Although improved suppression of HCV replication is anticipated, 20 to 40% of treated subjects have required early treatment discontinuation due to various adverse events including anemia (100%), infection (30%), nephrotoxicity (20%) and rejection (5 to 10%). Simeprevir and faldaprevir will likely have improved efficacy and safety profiles but potential drug interactions with other OATP1B1 substrates and unconjugated hyperbilirubinemia are expected. In contrast, sofosbuvir and daclatasvir based antiviral therapy are not expected to lead to clinically significant drug-drug interactions in LT recipients but confirmatory studies are needed. Liver transplant recipients may also be at increased risk of developing drug induced liver injury (DILI). Establishing a diagnosis of DILI in the transplant setting is very difficult with the variable latency, laboratory features and histopathological manifestations of hepatotoxicity associated with a given drug, the need to exclude competing causes of allograft injury, and the lack of an objective and verifiable confirmatory test. Nonetheless, a heightened awareness of the possibility of DILI is warranted in light of the large number of medications used in LT recipients and the potential adverse impact that DILI may have on patient outcomes.