The immunological and clinical spectrum of delayed drug-induced exanthems

Modulation of the Immune Response to Allergies Using Alternative Functional Foods

Modulation of the allergic immune response through alternative therapies is a field of study that aims to address allergic reactions differently from traditional approaches. These therapies encompass the utilization of natural functional foods, which have been observed to exert an influence on the immune response, thus mitigating the severity of allergies. Indeed, some studies suggest that the incorporation of these nutraceuticals can regulate immune function, leading to a reduction in histamine release and subsequent alleviation of allergic symptoms. Moreover, certain herbs and dietary supplements, such as curcumin, are believed to possess anti-inflammatory properties, which may serve to moderate allergic responses. Although the results remain somewhat mixed and require further research, these alternative therapies exhibit the potential to impact the allergic immune response, thereby providing complementary options to conventional treatments. Therefore, in this review, we aim to provide an updated account of functional foods capable of modulating the immune response to allergies. In that sense, the review delves into functional foods sourced from plants (phytochemicals), animals, and marine algae. Emphasis is placed on their potential application in the treatment of allergic disorders. It also provides an overview of how these foods can be effectively utilized as functional foods. Additionally, it explores the molecular mechanisms and scientific validity of various bioactive natural compounds in the management of allergies.

Compound-honeysuckle-induced drug eruption with special manifestations: A case report

BACKGROUND

The clinical manifestations of drug eruption are complex and diverse, which can lead to missed diagnosis or misdiagnosis. The clinical manifestations of drug eruption caused by compound honeysuckle have not been reported.

CASE SUMMARY

A 20-year-old man was admitted to our department of dermatology due to erythema and papules on the chest and abdomen with pruritus for 3 d. The next day after taking compound honeysuckle granules, the patient suddenly developed a rash and intense itching on his chest and abdomen. Physical examination revealed diffuse red needle-cap size macules and papules with well-defined borders on the chest and abdomen, and discoloration after finger pressure. No abnormality was observed in other areas of the skin. Back skin scratch was positive. White blood cells, eosinophil count and eosinophil ratio were higher than normal. Histopathological examination of the skin lesions on the left abdomen revealed intercellular edema, blurred focal basal cell layers, and focal lymphocyte infiltration in the superficial dermis and perivascular areas. Immunohistochemistry showed CD3⁺_, CD4⁺ and CD8⁺ T lymphocytes. The diagnosis was drug eruption with special manifestations induced by compound honeysuckle. The skin lesions completely subsided without pruritus after 2 wk of antihistamine and hormone therapy. Follow-up for > 1 mo showed no recurrence.

CONCLUSION

Chinese patent medicine compound honeysuckle granules can induce allergic reaction and rare skin damage.

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.

Advances in the Pathomechanisms of Delayed Drug Hypersensitivity

Delayed drug hypersensitivity continues to contribute to major clinical problems worldwide. The clinical presentations of delayed drug hypersensitivity are diverse, ranging from mild skin rashes to life-threatening systemic reactions. The pathomechanism of delayed drug hypersensitivity involves human leukocyte antigens (HLA) presentation of drugs/metabolites to T cell receptors (TCR), resulting in T-cell activation. The pathogenesis of delayed drug hypersensitivity also has reactivation of the virus, and activation of many immune mediators. In this review, we discuss the immune pathogenesis, molecular interactions of HLA/drugs/TCR, and downstream signaling of cytotoxic proteins/cytokines/chemokines, as well as disease prevention and management for delayed drug hypersensitivity.

A review of hypersensitivity methods to detect immune responses to SARS-CoV-2

The investigation of the immune response after SARS-CoV-2 infection has been the goal of many researchers worldwide. The study of humoral immune responses and in vitro T cell production after infection requires the obtaining of individualized blood samples to test the presence of antibodies or activated T cells specific for the virus. In vitro T cell studies are especially troublesome due to the need for more specialized resources often outside the daily routine of clinical laboratories. For this reason the development of a simple and objective method to achieve these T cell studies is needed. In this manuscript we reviewed the hypersensitivity reactions, the theoretical basis and the historical background of delayed type hypersensitivity (DTH) which uses the principles of use of this test in the clinical setting for the past century. In the second part of the review, we focus on COVID adaptive immune responses, to understand the differences and challenges offered by this new application of DTH to investigate immune responses elicited after infection. In the last part of the review a vision provided for the use of this test to investigate the immunogenicity elicited by the vaccines. In our opinion, the clinical guidelines of immune assessment of SARS-CoV-2-infected or vaccinated individuals should include this simple and low-cost test to measure T-cell immunity. Rationale and improved vaccination schemes could be obtained after its implementation in the routine assessment of immunity in this pandemic situation.

Current Perspective Regarding the Immunopathogenesis of Drug-Induced Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms (DIHS/DRESS)

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a severe type of adverse drug eruption associated with multiorgan involvement and the reactivation of human herpesvirus 6, which arises after prolonged exposure to certain drugs. Typically, two waves of disease activity occur during the course of DIHS/DRESS; however, some patients experience multiple waves of exacerbation and remission of the disease. Severe complications, some of which are related to cytomegalovirus reactivation, can be fatal. DIHS/DRESS is distinct from other drug reactions, as it involves herpes virus reactivation and can lead to the subsequent development of autoimmune diseases. The association between herpesviruses and DIHS/DRESS is now well established, and DIHS/DRESS is considered to arise as a result of complex interactions between several herpesviruses and comprehensive immune responses, including drug-specific immune responses and antiviral immune responses, each of which may be mediated by distinct types of immune cells. It appears that both CD4 and CD8 T cells are involved in the pathogenesis of DIHS/DRESS but play distinct roles. CD4 T cells mainly initiate drug allergies in response to drug antigens, and then herpesvirus-specific CD8 T cells that target virus-infected cells emerge, resulting in tissue damage. Regulatory T-cell dynamics are also suggested to contribute to the diverse symptoms of DIHS/DRESS. However, the pathomechanisms of this complex disease remain largely unknown. In particular, how viral infections contribute to the pathogenesis of DIHS/DRESS and why autoimmune sequelae arise in DIHS/DRESS are yet to be elucidated. This review describes the clinical features of DIHS/DRESS, including the associated complications and sequelae, and discusses recent advances in our understanding of the immunopathogenic mechanisms of DIHS/DRESS.

Serum soluble Fas ligand levels and peripheral blood lymphocyte subsets in patients with drug-induced maculopapular rashes, dress, and viral exanthemas

BACKGROUND

Fatty acid synthetase (Fas)/Fas ligand (FasL)-dependent apoptotic pathways have been reported as being involved in the pathogenesis of drug-induced maculopapular rashes.

OBJECTIVE

We investigated serum soluble FasL (sFasL) levels and peripheral blood lymphocyte subtypes to discriminate maculopapular drug eruptions (MPDE) from viral exanthema (VE).

PATIENTS/METHODS

Children with confirmed MPDE (group I), VE (group II), and drug rashes with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS) (group III) were included. Serum sFasL levels and peripheral blood lymphocyte subtypes were analyzed in groups I-III on admission, and repeated twice (only once for group IV - controls).

RESULTS

There were no significant serum soluble FasL level differences among the groups for all the samples. In the initial samples, CD19⁺ cell numbers in group II were significantly higher than in group IV, and the CD4⁺/CD8⁺ ratio was higher than groups I and IV. In the second samples, CD4⁺ and CD19⁺ cell numbers were significantly higher in group II than group I. In the final samples, CD4⁺ cell numbers in group II were significantly higher than group I and group III. CD19⁺ cells numbers in group III were significantly lower than the other groups for all samples.

CONCLUSION

Serum sFasL levels were not found to be useful in discriminating viral exanthemas from other drug rashes. The significant differences between MPDE, VE, and DRESS were high CD4⁺ and CD19⁺ cell-count numbers in VE but low B-cell numbers in DRESS. This might be important for discriminating VE from DRESS, and the low B-cell count in early symptoms might be a useful predictor of DRESS development.

Attenuation of Wnt/β-catenin signaling in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN) are rare but life-threatening severe cutaneous adverse reactions. Current studies have suggested that the pathobiology of drug-mediated SJS/TEN involves a dysregulation of cellular immunity with overwhelming activation of cytotoxic T lymphocytes. The canonical Wnt signaling pathway plays important roles in T cell development and activation, which may provide potential avenues for alleviating dysregulated immunity in SJS/TEN. In this study, we aimed to assess the implication of Wnt signaling in drug-reactive T cells in SJS/TEN. We showed downregulation of Wnt signaling components, including T cell factor 1 (TCF-1)/lymphoid enhancer binding factor 1 (LEF-1) transcription factors, in SJS/TEN patients, suggesting that canonical Wnt signaling is regulated during cytotoxic T cell responses in SJS/TEN. Further analyses demonstrated that engagement of the T cell receptor by antigen encounter and treatment of a prognostic marker of SJS/TEN, IL-15, in vitro led to the downregulation of LEF-1 and TCF-1 expression in CD8+ T cells. Enhancement of Wnt signaling by adding the Wnt activators attenuated ex vivo activation of drug-specific T cells from SJS/TEN patients, indicating a functional involvement of Wnt signaling in the pathomechanism of SJS/TEN. These findings provide additional insight into the immunopathogenesis and therapeutic intervention of this devastating condition.

Multistep Grading System for Evaluation of Chronic Ocular Sequelae in Patients With Stevens-Johnson Syndrome

PURPOSE

To propose a new scoring system for grading of chronic ocular sequelae in Stevens-Johnson syndrome (SJS).

DESIGN

Reliability and validity analysis.

METHODS

Participants: Four hundred eyes of 200 patients with chronic ocular SJS/toxic epidermal necrolysis (TEN) were included in the study.

SETTINGS

Single-center, tertiary eye care referral center.

PROCEDURE

All patients with SJS/TEN with chronic (more than 1 year) ocular sequelae were recruited for the study. Corneal, eyelid, and conjunctival signs were evaluated and given scores ranging from 0 to 5 depending on the increasing severity. Twelve signs (6 corneal, 3 conjunctival, and 3 eyelid) were evaluated to obtain the total severity score for each eye. Based on the corrected distance visual acuity (CDVA) and total score, each eye was graded using receiver operating characteristic (ROC) analysis.

MAIN OUTCOME MEASURES

Correlation of CDVA with the severity score determined on the basis of 12 corneal, eyelid, and conjunctival signs.

RESULTS

Mean age was 24.09 ± 10.9 years. The most common inciting agent for SJS was oral medications (85%). The scores of 12 ocular surface parameters correlated significantly with CDVA (P < .001). ROC analysis revealed 4 grades of total severity score of 0-11 (stage 0), 12-16 (stage 1), 17-22 (stage 2), and 23-53 (stage 3). The total severity score correlated significantly with logMAR visual acuity grades with an agreement of 60.7% using Cohen's kappa analysis (kappa coefficient = 0.420 ± 0.03). The most common stage of total severity score was stage 3 in 49% of eyes (196/400), followed by stage 0 (107/400, 26.7%).

CONCLUSIONS

The multistep scoring system of chronic ocular features in SJS/TEN sequelae is a useful tool to grade all levels of severity. This may help to evaluate the efficacy of the surgical intervention by comparing preoperative with postoperative ocular grades.

Delayed-Type Hypersensitivity Underlying Casein Allergy Is Suppressed by Extracellular Vesicles Carrying miRNA-150

In patients with non-IgE-mediated milk allergy, a cellular mechanism of delayed-type hypersensitivity (DTH) is considered. Recent findings prove that cell-mediated reactions can be antigen-specifically inhibited by extracellular vesicles (EVs) carrying miRNA-150. We sought to establish a new mouse model of DTH to casein and test the possibility of antigen-specific suppression of the inflammatory reaction. To produce soluble antigenic peptides, casein was subjected to alkaline hydrolysis. DTH reaction to casein was induced in CBA, C57BL/6, and BALB/c mice by intradermal (id) injection of the antigen. Cells collected from spleens and lymph nodes were positively or negatively selected and transferred to naive recipients intravenously (iv). CBA mice were tolerized by iv injection of mouse erythrocytes conjugated with casein antigen and following id immunization with the same antigen. Suppressive EVs were harvested from cell cultures and serum of tolerized donors by means of ultrafiltration and ultracentrifugation for further therapeutic utilization. The newly established mouse model of DTH to casein was mediated by CD4+ Th1 cells and macrophages, while EVs produced by casein-tolerized animals effectively suppressed effector cell response, in an miRNA-150-dependent manner. Altogether, our observations contribute to the current understanding of non-IgE-mediated allergy to casein and of the possibilities to downregulate this reaction.

NSAIDs hypersensitivity: questions not resolved

PURPOSE OF REVIEW

NSAIDs are the drugs most frequently involved in hypersensitivity reactions (HSR). These are frequently prescribed at all ages. HSR are of great concern and can affect people at any age. These drugs can induce reactions by stimulating the adaptive immune system (IgE or T cell), known as selective responders or more frequently by abnormalities in biochemical pathways related with prostaglandin metabolism. These are known as cross-intolerant. With some exceptions, skin testing and in-vitro studies are of little value in selective responders.

RECENT FINDINGS

In the last years, several classifications have been provided based on clinical symptoms, time interval between drug intake and appearance of symptoms, response to other nonchemically related NSAIDs and the underlying disease. Based on this classification, several well differentiated categories within each group of entities cross-intolerant and selective responders are now recognized. The most complex groups for evaluation are cross-intolerant in which three major groups exist: NSAIDs exacerbated respiratory disease, NSAIDs exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema in the absence of chronic spontaneous urticaria. Within the selective responders, there are two mechanisms involved: drug-specific IgE or T-cell effector responses. New entities have been added to this classification like mixed reactions within the cross-intolerant category, that must manifest as anaphylaxis and multiple immediate selective reactions.

SUMMARY

The precise evaluation of patients with NSAIDs hypersensitivity following established guidelines will improve not only our understanding but also the management of these entities. As the number of patients affected with NSAIDs is important, further studies are warranted.

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.

Adverse Medication Reactions

Cutaneous adverse drug reactions (ADRs) are among the most frequent adverse reactions in patients receiving drug therapy. They have a broad spectrum of clinical manifestations, are caused by various drugs, and result from different pathophysiological mechanisms. Hence, their diagnosis and management is challenging.

Severe cutaneous ADRs comprise a group of diseases with major morbidity and mortality, reaching 30 % mortality rate in cases of Toxic Epidermal Necrolysis.

This chapter covers the terminology, epidemiology, pathogenesis and classification of cutaneous ADR, describes the severe cutaneous ADRs and the clinical and laboratory approach to the patient with cutaneous ADR and presents the translation of laboratory-based discoveries on the genetic predisposition and pathogenesis of cutaneous ADRs to clinical management guidelines.

Severe delayed skin reactions related to drugs in the paediatric age group: A review of the subject by way of three cases (Stevens-Johnson syndrome, toxic epidermal necrolysis and DRESS)

Severe delayed drug-induced skin reactions in children are not common but potentially serious. This article describes aspects concerning the etiology, pathogenesis and clinical manifestations of these processes; it presents three paediatric cases, namely STS (Steven Johnson Syndrome), TEN (toxic epidermal necrolysis), probably related to amoxicillin/clavulanate and ibuprofen and DRESS (a drug reaction with eosinophilia and systemic symptoms) secondary to phenytoin; and in relation to them, the diagnosis and the treatment of these processes are discussed and reviewed. The AGEP (acute generalised exanthematous pustulosis) is also reviewed. The aetiological diagnosis of severe non-immediate reactions is difficult, and the value of current allergological testing is not well defined in these cases. Diagnosis is based on clinical history, the empirical risk of drugs to trigger SJS/TEN or DRESS, and the in vivo and in vitro testing of the suspect drug. Skin biopsy confirms that the clinical diagnosis and delayed hypersensitivity tests, especially the patch test and the lymphoblastic transformation test (LTT), may be important to confirm the aetiological diagnosis, in our cases emphasising the latter. These diseases can be life threatening (especially DRESS and TEN) and/or have a high rate of major complications or sequelae (SJS/TEN). The three cases described progressed well without sequelae. All were treated with corticosteroids, which is the most currently accepted treatment although the effect has not been clearly demonstrated.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: An Update

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening mucocutaneous reactions, predominantly drug induced. The mortality rates for SJS and TEN are as high as 30 %, and short- and long-term morbidities are very common. SJS/TEN is one of the few dermatological diseases that constitute a true medical emergency. Early recognition and prompt and appropriate management can be lifesaving. In recent years, our understanding of the pathogenesis, clinical presentation, and management of SJS/TEN has improved. Nevertheless, in 2015, there are still no internationally accepted management guidelines. This review summarizes up-to-date insights on SJS/TEN and describes a protocol for assessment and treatment. We hope these suggested guidelines serve as a practical clinical tool in the management of SJS/TEN. The classic manifestation of SJS/TEN consists of initial "flu-like" symptoms (malaise, fever, anorexia) in the prodromal phase, followed by cutaneous and mucous membrane (ocular, oral, and genital) inflammation and pain, and other systemic involvement. Symptoms usually begin 4-28 days after the onset of drug intake. Treatment is multidisciplinary and includes identification and withdrawal of the culprit drug, transfer to a specialist unit, supportive care, medical treatment, communication, and provision of appropriate information and emotional support.

Severe Cutaneous Drug Reactions: Do Overlapping Forms Exist?

Acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms are all severe hypersensitivity reactions to medications. While each of these reactions is a well-established entity with specific diagnostic criteria, clinicians see cases that fulfill criteria for more than one form, prompting discussion on the possibility of combined forms. Such overlapping clinical pictures meeting the criteria for 2 conditions have thus become a topic of debate in dermatology in recent years. We describe 2 patients with cutaneous drug reactions having the characteristics of both acute generalized exanthematous pustulosis and Stevens-Johnson syndrome -toxic epidermal necrolysis. We also review previously published cases and current thinking on such overlapping conditions.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Cutaneous drug reactions in the pediatric population

Cutaneous adverse drug reactions (ADRs) constitute a major pediatric health problem frequently encountered in clinical practice, and represent a diagnostic challenge. Children are more susceptible than adults to errors in drug dosage because of their smaller body size; moreover, ADRs can mimic other skin diseases of children, especially viral exanthems. Most ADRs with cutaneous involvement are mild and resolve on withdrawal of the causative drug. The most common forms of cutaneous ADRs, maculopapular exanthems and urticarial reactions, have excellent outcomes. Less frequent but more severe reactions may incur a risk of mortality.

Diphenylhydantoin Induced DRESS Syndrome: A Case Report

Drug Rash with Eosinophilia and Systemic Symptoms" (DRESS) syndrome is a severe adverse drug reaction. The drugs most often implicated are anti-convulsants, bupropion, sulfonamides, sulfasalazine, allopurinol, minocycline, abacavir and neviparine. There are also immune and infectious causes that can lead to DRESS syndrome. A 70-year-old female patient had undergone endovascular coil embolization for intracranial aneurysm and experienced a generalised seizure postoperatively. She had been given diphenylhidantoin (DPH). Six days after DPH therapy, the patient had complained of widespread skin rash. Although DPH was replaced with levetiracetam afterwards, the skin rash deteriorated, causing facial oedema and swelling of the tongue. She had severe facial oedema with swelling of the tongue, causing disturbance of breathing. On the second day in the critical care unit, the patient's breathing deteriorated, leading successively to intubation and mechanical ventilation. The patient's rash was still persistent and the results of a punch biopsy taken from the lesions revealed superficial perivascular dermatitis involving spongiotic eosinophils compatible with spongiotic drug eruption. As a result, it is important to realise that medications we use can be the cause of a range of reactions ranging from simple rash to life threatening syndromes.

HLA-A*3101 and carbamazepine-induced hypersensitivity reactions in Europeans

BACKGROUND

Carbamazepine causes various forms of hypersensitivity reactions, ranging from maculopapular exanthema to severe blistering reactions. The HLA-B*1502 allele has been shown to be strongly correlated with carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS-TEN) in the Han Chinese and other Asian populations but not in European populations.

METHODS

We performed a genomewide association study of samples obtained from 22 subjects with carbamazepine-induced hypersensitivity syndrome, 43 subjects with carbamazepine-induced maculopapular exanthema, and 3987 control subjects, all of European descent. We tested for an association between disease and HLA alleles through proxy single-nucleotide polymorphisms and imputation, confirming associations by high-resolution sequence-based HLA typing. We replicated the associations in samples from 145 subjects with carbamazepine-induced hypersensitivity reactions.

RESULTS

The HLA-A*3101 allele, which has a prevalence of 2 to 5% in Northern European populations, was significantly associated with the hypersensitivity syndrome (P=3.5×10(-8)). An independent genomewide association study of samples from subjects with maculopapular exanthema also showed an association with the HLA-A*3101 allele (P=1.1×10(-6)). Follow-up genotyping confirmed the variant as a risk factor for the hypersensitivity syndrome (odds ratio, 12.41; 95% confidence interval [CI], 1.27 to 121.03), maculopapular exanthema (odds ratio, 8.33; 95% CI, 3.59 to 19.36), and SJS-TEN (odds ratio, 25.93; 95% CI, 4.93 to 116.18).

CONCLUSIONS

The presence of the HLA-A*3101 allele was associated with carbamazepine-induced hypersensitivity reactions among subjects of Northern European ancestry. The presence of the allele increased the risk from 5.0% to 26.0%, whereas its absence reduced the risk from 5.0% to 3.8%. (Funded by the U.K. Department of Health and others.).

Clinical application of static fluorescence-based cytometry, Cellscan, in cutaneous adverse drug reaction

The aim of the present study was to evaluate the effectiveness of Cellscan in identifying culprit drugs causing cutaneous adverse drug reaction. It was a prospective study with 3 months follow up conducted at the Departments of Dermatology, Internal Medicine and Dermatology Outpatient Clinic, Chaim Sheba Medical Center, Tel Hashomer, Israel. The study included 36 patients with cutaneous reaction suspected to be secondary to drugs, treated with a total number of 148 drugs. All patients and drugs were classified to three probability groups according to accepted clinical criteria. The effectiveness of the Cellscan test in identifying the culprit drug was addressed according to the clinical probability for cutaneous drug reaction, the drug class and the type of rash. Data analysis according to the clinical probability for cutaneous drug reaction revealed that patients in the moderate and high probability groups had a high test sensitivity of 77.7% and 83.3% with specificity of 71% and 63%, respectively, in identifying the culprit drug. Classifying the data according to drug classes, revealed that for the antibiotic and cardiovascular drug classes the sensitivity of the test was 100% and 92% with specificity of 83.3% and 55.5%, respectively, in identifying the culprit drug. Finally, the classification of patients according to the type of rash revealed a high evaluating accuracy for culprit drugs in maculopapular rashes with sensitivity and specificity of 90% and 60.4%, respectively. The results of this study imply that the Cellscan test is it a good practical tool for identifying the culprit drug in cutaneous adverse drug reaction.

Cutaneous drug hypersensitivity: immunological and genetic perspective

Drug hypersensitivity is an unpredictable, immunologically mediated adverse reaction, clustered in a genetically predisposed individual. The role of "hapten concept" in immune sensitization has recently been contested by the "pharmacological interaction" hypothesis. After completion of the "human genome project" and with the availability of high-resolution genotyping, genetic susceptibility to hypersensitivity for certain drugs has been proved beyond doubt though the trend is ethnicity and phenotype dependent. Application of this newly acquired knowledge may reduce or abolish the morbidity and mortality associated with cutaneous drug hypersensitivity.

Reações tegumentares adversas relacionadas aos agentes antineoplásicos: parte II

Os eventos e reações envolvendo quimioterapia são frequentes na prática oncológica. Agentes quimioterápicos são uma modalidade de tratamento amplamente utilizada. Efeitos colaterais podem variar de frequência e também ser confundidos com outras manifestações tegumentares do tratamento oncológico. Este artigo objetiva expor as informações sobre reações cutâneas à quimioterapia, em especial, aqueles para os quais o dermatologista é requisitado a emitir parecer e a comentar sobre a segurança e a viabilidade da readministração de uma droga específica. Os autores descrevem os aspectos associados a esses eventos, fazendo uma análise detalhada de cada um deles.

A decade of infliximab: The Austrian evidence based consensus on the safe use of infliximab in inflammatory bowel disease

Infliximab (IFX) has tremendously enriched the therapy of inflammatory bowel diseases (IBD) and other immune mediated diseases. Although the efficacy of IFX was undoubtedly proven during the last decade numerous publications have also caused various safety concerns. To summarize the immense information concerning adverse events and safety issues the Austrian Society of Gastroenterology and Hepatology launched this evidence based consensus on the safe use of IFX which covers the following topics: infusion reactions and immunogenicity, skin reactions, opportunistic infections (including tuberculosis), non-opportunistic infections (bacterial and viral), vaccination, neurological complications, hepatotoxicity, congestive heart failure, haematological side effects, intestinal strictures, stenosis and bowel obstruction (SSO), concomitant medication, malignancy and lymphoma, IFX in the elderly and the young, mortality, fertility, pregnancy and breast feeding. To make the vast amount of information practicable for routine application the consensus was finally condensed into a checklist for a safe use of IFX which consists of two parts: issues to be addressed prior to anti-TNF therapy and issues to be addressed during maintenance. Both parts are further divided into obligatory and facultative items.

CD8+ T cells mediate skin allergy to amoxicillin in a mouse model

BACKGROUND

Delayed allergic skin reactions to drugs are common iatrogenic diseases mediated by activation of specific T cells in the skin.

METHODS

To better understand the role of T cells in these diseases, we developed a mouse model of drug allergy induced by skin sensitization to amoxicillin (amox), a penicillin antibiotic frequently involved in delayed drug allergy.

RESULTS

Whereas wild-type mice could not be sensitized to amox, CD4+ T-cell-deficient mice developed an amox-specific allergic skin response, mediated by IFN-gamma-producing CD8+ T cells. Amox-specific CD8+ T cells, induced in lymphoid organs at a high frequency during sensitization, were recruited in the skin upon challenge. CD8+ T cells were effectors of the allergic skin reaction to amox as in vivo treatment with depleting anti-CD8 mAbs abrogated the skin inflammatory reaction and as purified CD8+ T cells could adoptively transfer the allergic response to naive recipients.

CONCLUSION

CD8+ T cells mediate penicillin skin allergy.

Pharmacogenetics and human genetic polymorphisms

The term pharmacogenetics was first used in the late 1950s and can be defined as the study of genetic factors affecting drug response. Prior to formal use of this term, there was already clinical data available in relation to variable patient responses to the drugs isoniazid, primaquine and succinylcholine. The subject area developed rapidly, particularly with regard to genetic factors affecting drug disposition. There is now comprehensive understanding of the molecular basis for variable drug metabolism by the cytochromes P450 and also for variable glucuronidation, acetylation and methylation of certain drugs. Some of this knowledge has already been translated to the clinic. The molecular basis of variation in drug targets, such as receptors and enzymes, is generally less well understood, although there is consistent evidence that polymorphisms in the genes encoding the β-adrenergic receptors and the enzyme vitamin K epoxide reductase is of clinical importance. The genetic basis of rare idiosyncratic adverse drug reactions had also been examined. Susceptibility to reactions affecting skin and liver appears to be determined in part by the HLA (human leucocyte antigen) genotype, whereas reactions affecting the heart and muscle may be determined by polymorphisms in genes encoding ion channels and transporters respectively. Genome-wide association studies are increasingly being used to study drug response and susceptibility to adverse drug reactions, resulting in identification of some novel pharmacogenetic associations.

Two cases of pustular toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a life-threatening, immune-mediated reaction, characterized by severe cutaneous and mucosal blisters and erosions. It often presents with flu-like symptoms, followed by a maculopapular, urticarial, purpuric or erythema multiforme-like eruption, which then evolves into blisters and sheet-like erosions. Presentation with pustules, however, is not well described in the English literature, and may lead to delayed diagnosis. We present two unusual cases of TEN that initially presented with pustular lesions.

Epicutaneous patch testing in drug hypersensitivity syndrome (DRESS)

BACKGROUND

In some patterns of cutaneous adverse drug reactions, and depending on the culprit drug, patch testing has been helpful in confirming its cause. Its value in Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) has not been established in a large cohort of patients.

OBJECTIVE

The aim of the present study is to evaluate the safety and usefulness of patch testing in DRESS.

PATIENTS/METHODS

Between January 1998 and December 2008, we studied 56 patients with DRESS induced by antiepileptic agents in 33 patients (59%), allopurinol in 19 (34%) and sulfasalazine, cotrimoxazole, tenoxicam, and amoxicillin in 1 patient each (7%).

RESULTS

A positive patch test reaction was observed in 18 patients (32.1%), of which 17 were with antiepileptics and 1 with tenoxicam. In the antiepileptic group, carbamazepine alone was responsible for 13 of 17 positive reactions (76.5%). Patch tests with allopurinol and its metabolite were negative in all cases attributed to this drug.

CONCLUSIONS

In this study, patch testing was a safe and useful method in confirming the culprit drug in DRESS induced by antiepileptic drugs, whereas it had no value in DRESS induced by allopurinol. The pathogenesis of DRESS is not yet entirely clarified, but positive patch tests suggest a drug-dependent delayed hypersensitivity mechanism.

The molecular mechanism of etanercept, an anti-tumour necrosis factor-alpha receptor-fusion protein, in the treatment of acute generalized exanthematous pustulosis

INTRODUCTION

Acute generalized exanthematous pustulosis (AGEP) is one of the severe adverse cutaneous drug reactions. In its pathophysiology, releasing of tumour necrosis factor-alpha (TNF-alpha) is very important. Therefore, treatment with an anti-TNF-alpha receptor-fusion protein, such as etanercept, may be effective.

OBJECTIVE

To present a case and evaluate the molecular mechanism of etanercept in the treatment of AGEP.

CASE

A 53-year-old woman with multiple disseminated pustules and a rash on the upper part of her back, which was progressively worsening and spreading to approximately 60-70% of the skin on her back, and fever (38.7 degrees C), was admitted to our department. After etanercept treatment, all the symptoms were rapidly improved and the patient's skin practically cleared within 5 days. Biopsy samples taken from this patient with AGEP before and after etanercept treatment were stained immunohistochemically with p53 and bcl-2 antibodies and also an apoptosis detection kit.

RESULTS

In epidermis, increasing p53 expression-related apoptosis and decreasing bcl-2 expression was detected. However, after etanercept treatment, p53 expression-related apoptosis decreased and bcl-2 expression increased.

CONCLUSION

Because TNF-alpha stimulated inflammation and also p53-related apoptosis occurs in AGEP, a TNF-alpha blocking agent such as etanercept may be effective for quick treatment.

Immune-mediated adverse drug reactions

Many adverse drug reactions are mediated by the immune system. This can be because the therapeutic effect of the drug targets the immune system. For example, immunosuppressive drugs increase the risk of infections. It is paradoxical that some immunosuppressive drugs can lead to autoimmune reactions. Another mechanism by which drugs can cause an adverse reaction involves an idiosyncratic response to the drug such as an immune-mediated skin rash. These idiosyncratic drug reactions (IDRs) are difficult to study because of the paucity of valid animal models and their unpredictable nature. Therefore, much of our mechanistic knowledge of IDRs is based on inferences from the clinical characteristics of IDRs rather than on controlled mechanistic studies. In general, IDRs are associated with a delay between starting the drug and the onset of the adverse reaction, and the typical delay is different for different types of IDRs. In contrast, on rechallenge, there is usually a rapid onset of the adverse reaction, which is characteristic of an amnestic immune response. The absence of such a rapid response is usually considered evidence that an IDR is not immune-mediated; yet, there are immune-mediated IDRs that do not have an amnestic response. One possible reason for the lack of an amnestic response is if the IDR has a strong autoimmune component leading to deletion of autoimmune memory cells when the drug is withdrawn. Another interesting characteristic of IDRs is that there are many drugs that can cause different types of IDRs in different patients. A possible explanation is that although the immune response is induced by a drug, it is directed against an autoantigen, and interindividual differences in the immune repertoire determine which autoantigen and target organ are affected. Although testing these hypotheses represents a difficult challenge, the importance of these adverse reactions makes it a high priority.

Matrix metalloproteinase-7 (matrilysin) controls neutrophil egress by generating chemokine gradients

Matrilysin [matrix metalloproteinase 7 (MMP7)] is induced by mucosal injury of many tissues. To assess function of this proteinase, we subjected wild-type and Mmp7(-/-) mice to acute colon injury. When matrilysin expression was increasing, 73% of wild-type mice died, whereas only 32% of Mmp7(-/-) mice succumbed. Although re-epithelialization was delayed in Mmp7(-/-) mice, overall injury did not differ markedly between genotypes. We hypothesized that differences in acute inflammation caused increased mortality in wild-type mice. Indeed, whereas overall neutrophil influx into tissue was similar in wild-type and Mmp7(-/-) mice, their location and extent of migration differed between genotypes. Neutrophils were dispersed throughout the mucosa and within the lumen of wild-type mice, but these leukocytes were largely confined to the submucosa in Mmp7(-/-) mice. The levels of neutrophil chemokines, keratinocyte-derived chemokine and MIP-2, increased in the colon tissue of both genotypes, but these factors were detected only in lumenal lavages of wild-type mice. Our findings indicate that matrilysin mediates beneficial and deleterious effects in response to injury. On one hand, it promotes re-epithelialization, but it also controls the transepithelial influx of neutrophils, which if excessive, can lead to tissue damage.

Hydroxychloroquine-induced DRESS syndrome

The authors describe the first case of drug rash with eosinophilia and systemic symptoms syndrome caused by hydroxychloroquine treatment in a male patient affected by seronegative arthritis.

Allergen-specific T-cell response in patients with phenytoin hypersensitivity; simultaneous analysis of proliferation and cytokine production by carboxyfluorescein succinimidyl ester (CFSE) dilution assay

BACKGROUND

Phenytoin can induce diversified adverse reactions including generalized eruptions and the hypersensitivity syndrome. Delayed-type allergic mechanisms have been postulated to underlie these reactions. The tests most widely used to detect T-cell sensitization to drugs are the patch test and the lymphocyte transformation test (LTT), but their sensitivity is not sufficient. Simultaneous assessment of both the frequencies and the cytokine-producing phenotypes of allergen-specific T cells has become possible with the recently introduced carboxyfluorescein succinimidyl ester (CFSE) assay.

METHODS

Seven patients who presented with phenytoin-induced maculopapular exanthema with and without fever were included in this study. Peripheral blood mononuclear cells (PBMCs) were labeled with CFSE and cultured with phenytoin for seven days. The cells were stained with anti-CD4 and cytokine-specific monoclonal antibodies (MoAbs), and analyzed with FACSCalibur.

RESULTS

The phenytoin-specific proliferation of CD4+ cells in patients was significantly higher than in the four controls exposed to phenytoin, and in seven healthy children with no previous phenytoin intake. A significant difference in the percentages of CD4+ IFN-gamma+ cells between patients and the seven healthy children was observed. The sensitivity and specificity of proliferation were 100% and 90.9%, and those of IFN-gamma secretion were 71.4% and 100%, respectively.

CONCLUSIONS

Phenytoin-specific proliferation may be detected with greater sensitivity by the CFSE dilution assay than the conventional LTT. The assay revealed that both CD4+ and CD4- T cells proliferated and produced IFN-gamma and TNF-alpha after stimulation with phenytoin. The CFSE dilution assay might be useful for the diagnosis and understanding of drug hypersensitivity.

Drug rash with eosinophilia and systemic symptoms vs toxic epidermal necrolysis: the dilemma of classification

According to contemporary vernacular, when the cutaneous manifestations of drug rash with eosinophilia and systemic signs (DRESS) syndrome are those of Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), the condition is defined as "DRESS syndrome with severe cutaneous reactions". In this article, we have presented arguments for and against including patients with skin lesions of the SJS/TEN syndromes who also have fever (practically all of the patients) and internal organ involvement (most of the patients) under the definition of DRESS syndrome. After weighing the arguments for and against this alteration of definition, we conclude that it makes more sense for patients with SJS/TEN to be classified as such and not be lumped together under the misleading label of DRESS syndrome.

Histopathology of drug-induced exanthems: is there a role in diagnosis of drug allergy?

PURPOSE OF REVIEW

Cutaneous eruptions are among the most common adverse drug reactions and may often represent a challenging diagnostic problem. This review focuses on histopathological and immunohistochemical findings of drug-induced maculo-papular exanthems and discusses the value of skin biopsies and consequent histopathological examination in the diagnosis of these reactions.

RECENT FINDINGS

Data from immunohistological studies indicate that CD4+ T cells expressing cytotoxic granule proteins such as perforin and granzyme B are critically involved in the pathogenesis and contribute to the generation of typical histopathological features of drug-induced maculo-papular exanthems, i.e. an interface dermatitis with vacuolar alteration and some apoptotic basal keratinocytes. In addition, an upregulation of both type 1 (i.e. IFN-gamma, TNF-alpha) and type 2 (i.e. IL-5) cytokines has been reported. IL-5 together with other chemokines (i.e. eotaxin/CCL-11) provides an explanation for tissue eosinophilia, which may be suggestive of a drug eruption if present.

SUMMARY

There are no absolute histological or immunohistological criteria for the diagnosis of drug-induced maculo-papular exanthems and even if the observed histological changes are compatible with a drug-induced eruption, biopsy may not definitely exclude alternative causes since there is considerable overlap with features seen in other entities. In mild cases with no severe signs or symptoms and a clear temporal relationship, clinical information and the morphologic pattern of skin lesions are often sufficient for diagnosis. However, in complex and severe cases or when the precise morphology is unclear, histopathological findings may provide some clues and assist in reaching a correct diagnosis.

Bull�se Arzneimittelexantheme

Bullous drug exanthems are clinically characteristic, usually severe cutaneous and mucosal drug hypersensitivity reactions. Commonly, they appear 5-14 days after onset of drug treatment. Therapy of choice is to avoid the culprit drug and systemic administration of glucocorticoids. A key element in the immune pathogenesis of bullous drug exanthems is presumably the activation of cytotoxic CD8(+) T lymphocytes which recognize drug metabolites as nominal antigens. These compounds form spontaneously (e.g. penicillins) or are metabolized by cytochrome P450-dependent enzymes (sulfonamides). The diagnosis of bullous drug exanthems is primarily based on skin tests and in vitro-techniques. Among the skin tests, prick as well as patch tests are important. Patch tests can be also applied at the former skin lesion in fixed drug eruption. In vitro techniques include analysis of drug-specific IgE (only available for anti-penicillin, anti-sulfamethoxazole) and cellular tests with the patients' lymphocytes (lymphocyte transformation test-LTT).