The lymphocyte transformation test for the diagnosis of drug allergy: sensitivity and specificity

In vitro diagnostics of drug allergies

In vitro diagnostics for drug hypersensitivity reactions distinguish between serological and cellular-based tests. A serological test used for the diagnosis of immediate type reactions is the detection of specific IgE antibodies. The cellular tests include the basophil activation test for immediate type reactions and the lymphocyte transformation test, which is mainly used to detect delayed type hypersensitivity reactions. Further cellular-based tests are the CAST-ELISA and the mast cell activation test. None of the above-mentioned tests can definitively exclude an allergy if the result is negative. In addition, it is important to note that even a positive test result is not necessarily associated with an allergy but has to be interpreted in the clinical context.

Severe Acute Interstitial Nephritis Induced by α-glucosidase Inhibitor Miglitol in an Elderly Patient with Type 2 Diabetic Nephropathy

A 79-year-old male patient with type 2 diabetic nephropathy and hypertension was admitted to our hospital because of acute kidney injury with significantly elevated serum creatinine (8.12 mg/dL) and urinary β2-microglobulin (β2MG, 31,748 μg/L) levels. α-glucosidase inhibitor (α-GI) miglitol, started two weeks prior to presentation, was discontinued because drug-induced acute interstitial nephritis (AIN) was suspected. Renal biopsy revealed AIN and diabetic nephropathy. The drug-induced lymphocyte stimulation test for miglitol was also positive. After the discontinuation of miglitol, the urinary β2MG levels decreased to the normal range. This case raises the possibility that α-GI miglitol can worsen the renal function in patients with underlying renal dysfunction.

Tools for Etiologic Diagnosis of Drug-Induced Allergic Conditions

Drug hypersensitivity reactions are a serious concern in clinical practice because they can be severe and result in lifelong sequelae. An accurate diagnosis and identification of the culprit drug is essential to prevent future reactions as well as for the identification of safe treatment alternatives. Nonetheless, the diagnosis can be challenging. In vivo and in vitro tests can be helpful, although none are conclusive; therefore, the tests are not usually performed in isolation but as part of a diagnostic algorithm. In addition, some in vitro tests are only available in research laboratories, and standardization has not been fully accomplished. Collaborating research is needed to improve drug hypersensitivity reaction diagnosis. In this review, we update the current available in vivo and in vitro tools with their pros and cons and propose an algorithm to integrate them into clinical practice.

Accurate integration of multiple heterogeneous single-cell RNA-seq data sets by learning contrastive biological variation

For most biological and medical applications of single-cell transcriptomics, an integrative study of multiple heterogeneous single-cell RNA sequencing (scRNA-seq) data sets is crucial. However, present approaches are unable to integrate diverse data sets from various biological conditions effectively because of the confounding effects of biological and technical differences. We introduce single-cell integration (scInt), an integration method based on accurate, robust cell-cell similarity construction and unified contrastive biological variation learning from multiple scRNA-seq data sets. scInt provides a flexible and effective approach to transfer knowledge from the already integrated reference to the query. We show that scInt outperforms 10 other cutting-edge approaches using both simulated and real data sets, particularly in the case of complex experimental designs. Application of scInt to mouse developing tracheal epithelial data shows its ability to integrate development trajectories from different developmental stages. Furthermore, scInt successfully identifies functionally distinct condition-specific cell subpopulations in single-cell heterogeneous samples from a variety of biological conditions.

Reconstruction of the mandibular condyle due to degenerative disease

Degenerative joint disease (DJD), also known as osteoarthritis is the most common form of arthritis and can affect the temporomandibular joint (TMJ). TMJ DJD is characterized by degradation of the articular cartilage and synovial tissues resulting in characteristic morphologic changes in the underlying bone. DJD can occur at any age, but it is more common in older age groups. TMJ DJD may be unilateral or bilateral. The American Academy of Orofacial Pain categorizes TMJ DJD into primary and secondary types. Primary DJD is seen in the absence of any local or systemic factors and secondary DJD is associated with a prior traumatic event or disease process. Frequently, these patients present with pain and limited residual mandibular function resulting in significantly diminished quality of life. Classic radiographic features on orthopantogram and CT imaging include loss of joint space, osteophytes (bird-beak appearance of the condyle), subchondral cysts, erosions, flattening of the condylar head, bony resorption and/or heterotopic bone (Figure 1). Conservative and medical management is successful in the majority of patients until the active degenerative phase burns out, but some will progress to end stage joint disease and require reconstruction of the TMJ. Reconstruction of the mandibular condyle should be considered to restore mandibular function and form to patients who have lost it secondary to degenerative joint disease affecting the glenoid fossa/mandibular condyle unit.

Skin testing as a biomarker in drug allergy

Despite the significant negative impact drug allergies can have on patient care, the diagnosis is largely based on clinical history, and there are limited diagnostic tests that can be done at the time of a reaction. Biomarkers are needed to improve the diagnosis and the identification of the culprit medication. Skin testing is the most useful biomarker for immediate- and delayed-type reactions available, but it is limited by its low sensitivity. To improve its accuracy and reproducibility, a standardized procedure must be used. For immediate-type reactions, penicillin skin testing is the most widely studied, and it can be used in patients with history of anaphylaxis or recent immunoglobulin E-mediated reaction or for whom there is a significant risk if a reaction were to occur, such as pregnancy. Skin testing is also important in allergy to platinum agents allowing for continued first-line therapy. For delayed-type reactions, patch testing and delayed intradermal testing, used in conjunction with clinical history, can help to improve identification of the culprit medication depending on the type of reaction. Other biomarkers including in vitro testing for specific immunoglobulin E, basophil activation test, lymphocyte transformation test, ELISpot, and genetic factors that increase the likelihood of reaction are under investigation, and they may be most helpful when used in combination with the clinical history and skin testing results.

In Vitro Assays for Diagnosis of Drug-Induced Nonsevere Exanthemas: A Systematic Review and Meta-Analysis

Frequent mislabelled causal relationship between drug hypersensitivity reactions and culprit drugs reinforces the need for an accurate diagnosis. The systematic reviews and meta-analyses of in vitro assays published so far focused on immediate reactions and the most severe delayed reactions, while the most frequent drug-induced delayed reactions-nonsevere exanthemas-have been underestimated. We aim to fill this gap. A systematic review of studies on in vitro assays used in the diagnosis of nonsevere drug-induced delayed reactions was conducted following the methodology of Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies Statement. The EMBASE and PubMed databases were searched. We have included 33 studies from which we extracted the data, then performed meta-analysis where possible, or synthesised the evidence narratively. The quality of the analysed studies was assessed with the QUADAS-2 tool. The tests identified the most frequently were lymphocyte transformation test (LTT), ELISpot, and ELISA. In the meta-analysis carried out for LTT in reactions induce by beta-lactams, the pool estimate of sensitivity and specificity amounted to 49.1% (95% CI: 14.0%, 85.0%) and 94.6% (95% CI: 81.7%, 98.6%), respectively. The studies showed heterogeneity in study design and laboratory settings, which resulted in a wide range of specificity and sensitivity of testing.

Identification of a binding site on soluble RANKL that can be targeted to inhibit soluble RANK-RANKL interactions and treat osteoporosis

One of the major challenges for discovering protein-protein interaction inhibitors is identifying selective and druggable binding sites at the protein surface. Here, we report an approach to identify a small molecular binding site to selectively inhibit the interaction of soluble RANKL and RANK for designing anti-osteoporosis drugs without undesirable immunosuppressive effects. Through molecular dynamic simulations, we discovered a binding site that allows a small molecule to selectively interrupt soluble RANKL-RANK interaction and without interfering with the membrane RANKL-RANK interaction. We describe a highly potent inhibitor, S3-15, and demonstrate its specificity to inhibit the soluble RANKL-RANK interaction with in vitro and in vivo studies. S3-15 exhibits anti-osteoporotic effects without causing immunosuppression. Through in silico and in vitro experiments we further confirm the binding model of S3-15 and soluble RANKL. This work might inspire structure-based drug discovery for targeting protein-protein interactions.

Clozapine-specific proliferative response of peripheral blood-derived mononuclear cells in Japanese patients with clozapine-induced agranulocytosis

BACKGROUND

Although clozapine-induced granulocytopenia (CIG) is less severe than clozapine-induced agranulocytosis (CIA), and some patients with CIG may not go on to develop serious complications, clozapine is discontinued in cases of both CIA and CIG. Understanding the pathogenic mechanisms of CIA/CIG could provide better management of clozapine therapy. Recently, as a mechanistic insight into adaptive immune systems, European groups reported clozapine-specific proliferative responses and clozapine-specific T cells using blood taken from patients with CIA and/or CIG.

AIMS

The aims of our study are to support this mechanistic evidence and to investigate the difference in the lymphocyte response to clozapine between patients with CIG and those with CIA.

METHODS

Lymphocyte stimulation tests (LSTs) were conducted using CD25-positive cell-depleted peripheral blood-derived mononuclear cells (PBMCs) isolated from blood of four Japanese patients with CIA, four patients with CIG, and nine clozapine-tolerant subjects.

RESULTS

Three of four patients with CIA and one of four patients with CIG showed proliferative responses to clozapine with a stimulation index of greater than 2. In contrast, none of the nine clozapine-tolerant subjects showed any response to clozapine. Olanzapine did not stimulate PBMCs of patients with CIA, patients with CIG, or clozapine-tolerant subjects.

CONCLUSIONS

Clozapine- and CIA-specific lymphocyte reactions in a Japanese population provided supportive evidence that the pathogenesis of CIA is based on adaptive immune reactions. In addition, patients with CIG who show a positive response to an LST may at the very least not be chosen for clozapine-rechallenge and further prospective studies are desirable to verify this hypothesis.

Antibiotic Allergy De-Labeling: A Pathway against Antibiotic Resistance

Antibiotics are one of the most frequently prescribed drugs. Unfortunately, they also are the most common cause for self-reported drug allergy, limiting the use of effective therapies. However, evidence shows that more than 90% of patients labeled as allergic to antibiotics are not allergic. Importantly, the label of antibiotic allergy, whether real or not, constitutes a major public health problem as it directly impacts antimicrobial stewardship: it has been associated with broad-spectrum antibiotic use, often resulting in the emergence of bacterial resistance. Therefore, an accurate diagnosis is crucial for de-labeling patients who claim to be allergic but are not really allergic. This review presents allergy methods for achieving successful antibiotic allergy de-labeling. Patient clinical history is often inaccurately reported, thus not being able to de-label most patients. In vitro testing offers a complementary approach but it shows limitations. Immunoassay for quantifying specific IgE is the most used one, although it gives low sensitivity and is limited to few betalactams. Basophil activation test is not validated and not available in all centers. Therefore, true de-labeling still relies on in vivo tests including drug provocation and/or skin tests, which are not risk-exempt and require specialized healthcare professionals for results interpretation and patient management. Moreover, differences on the pattern of antibiotic consumption cause differences in the diagnostic approach among different countries. A multidisciplinary approach is recommended to reduce the risks associated with the reported penicillin allergy label.

Screening of immune-enhancing Lactobacillus in mice by using a cell-line

In this study, we found that it is possible to screen Lactobacillus strains that enhance the immune function of mice using HCT-8 cells. Lactobacillus were co-incubated with intestinal epithelial HCT-8 cells to detect and screen the strains that induced more interleukin-6 (IL-6) in the culture supernatant. Simultaneously, a mouse model of low immunity was established to administer the screened lactobacilli by gavage. After 4 weeks of continuous gavage, related cytokines in blood and immune cell indexes in organs were detected to comprehensively evaluate the feasibility of in vitro cell culture model for screening immune-enhancing strains. The content of IL-6 in the culture supernatant of HCT-8 cells induced by the three tested strains increased approximately 5, 8 and 15 fold compared with that of the control group. IL-6 content in serum of mice was significantly higher than that of the control group provided with cyclophosphamide (CTX). Lactobacillus paracasei ZLPC01 presented a higher ability to protect against the immune damage of CTX by decreasing the serum IgG level, increasing the transformation of mouse splenocytes, and the activity of NK cells. Furthermore, L. paracasei ZLPC01 increased cytokine content in serum (IL-6, IL-2, TNF-α and IFN-γ) and colon (IL-6 and TNF-α) in CTX-treated mice. Screening strains that enhance immunity via an in vitro cell-line is simple in operation, and the results are well correlated with those of animal experiments, which is feasible and effective in practice. In addition, L. paracasei ZLPC01 could have the potential to enhance the immunity of mice effectively through inducing intestinal cells to produce IL-6, TNF-α and other cytokines.

Successful treatment of a patient with adult food allergy and severe asthma using omalizumab

Food allergy is a typical immediate-onset allergic disease in which symptoms are provoked by exposure to the sensitized antigens. Although previous reports have shown that omalizumab has helped children with egg or milk allergy achieve oral immunotherapy safely, there is still no established method for induction of remission in adult food allergy. A 51-year-old woman with oral steroid-dependent severe asthma was treated with omalizumab for 6 years. She had shellfish and wheat food allergy and oral allergy syndrome induced by kiwi and other foods associated with latex-fruit syndrome. Since omalizumab treatment, her food allergy symptoms had disappeared. After 7 years of this treatment, disseminated erythema suddenly appeared; omalizumab was discontinued because of suspected drug-induced eruption. After omalizumab interruption, she felt an itching sensation in her throat with worsened asthma control immediately after wheat ingestion. Readministration of omalizumab improved these symptoms. Thus, we raised the possibility that omalizumab not only improved asthma control but also induced pharmacological remission of the patient's food allergy. Omalizumab may be considered as a treatment option for adult patients with food allergies and severe asthma.

Dendritic cells inclusion and cell-subset assessment improve flow-cytometry-based proliferation test in non-immediate drug hypersensitivity reactions

BACKGROUND

Lymphocyte transformation test (LTT) has been widely used to evaluate non-immediate drug hypersensitivity reactions (NIDHRs). However, the lack of standardization and the low sensitivity have limited its routine diagnostic use. The drug presentation by dendritic cells (DCs) and the assessment of proliferation on effector cells have shown promising results. Flow-cytometry-based methods can help apply these improvements. We aimed to assess the added value of using drug-primed-DCs and the determination of the proliferative response of different lymphocyte subpopulations in NIDHRs.

METHODS

Patients with confirmed NIDHR were evaluated by both conventional (C-LTT) and with drug-primed-DCs LTT (dDC-LTT)analysing the proliferative response in T cells and other effector cell subpopulations by using the fluorescent molecule, carboxyfluorescein diacetate succinimidyl ester (CFSE).

RESULTS

The C-LTT showed a significantly lower sensitivity (29.4%) compared with dDC-LTT (61.8%), which was confirmed analysing each particular clinical entity: SJS-TEN (62.5% vs 87.5%), MPE (15% vs 47.4%) and AGEP (33% vs 80%). When including the effector cell subpopulations involved in each clinical entity, CD3⁺ +CD4⁺ T_h 1 or CD3⁺ +NK cells in SJS-TEN, CD3⁺ +CD4⁺ T_h 1+NK cells in MPE and CD3⁺ +NK cells in AGEP, we could significantly increase the sensitivity of the in vitro test to 100%, 68.4% and 100%, respectively, with an overall sensitivity of 87% and 85% of specificity in NIDHR.

CONCLUSIONS

The use of a flow-cytometry-based test, DCs as drug presenting cells, and focusing on effector cell subpopulations for each clinical entity significantly improved the drug-specific proliferative response in NIDHRs with a unique cellular in vitro test.

Lymphocyte transformation test and cytokine detection assays: Determination of read out parameters for delayed-type drug hypersensitivity reactions

Drug hypersensitivity reactions (DHRs) occur in certain people and are often not predictable. DHRs can be classified as immediate and delayed reactions regarding to onset of clinical manifestations. Both reactions are considered to be an important public health problem because they can lead to life-threatening conditions; however, this review article will focus on delayed DHRs. The most important points for diagnosis of delayed DHRs are the recognition of drug hypersensitivity characteristics and culprit drug identification. While it is usually difficult to identify a culprit drug; clinical evaluation using the causality assessment method, a non-invasive process, can identify the culprit drug without the need for intensive investigation. Delayed DHRs can cause life-threatening conditions; therefore, in vivo skin tests, as well as drug provocation tests, have to be cautiously performed by a drug allergist and have not been recommended in uncontrolled conditions. ENDA/EAACI has recommended that in vitro tests (if available) be performed prior to any in vivo tests. Therefore, in vitro diagnostic tests can be alternative methods to identify a culprit drug for delayed DHR diagnosis as there is no or very low risk for patients under investigation. There are many testing approaches to identify causative agents for delayed DHRs such as: the lymphocyte transformation test (LTT), cytokine/mediator detection assays (i.e. ELISA and flow cytometry-based bead assays), multiplex bead-based immunoassay and ELISpot. The LTT is the most standardized method whereas it has been available in medical schools affiliated with university hospitals. Other in vitro tests, like cytokine detection assays, have also been used, even though they are still being evaluated. They could supplement LTT results that would provide drug allergist's with documentary evidence and prevent risk to patients by avoiding in vivo or drug provocation testing. Hence, the in vitro tests have been promising tests contributing to the management of the delayed DHR work-up process in clinical practice.

Delabeling Delayed Drug Hypersensitivity: How Far Can You Safely Go?

Delayed immune-mediated adverse drug reactions (IM-ADRs) are defined as reactions occurring more than 6 hours after dosing. They include heterogeneous clinical phenotypes that are typically T-cell-mediated reactions with distinct mechanisms across a wide spectrum of severity from benign exanthems through to life-threatening cutaneous or organ-specific diseases. For mild reactions such as benign exanthem, considerations for delabeling are similar to immediate reactions and may include a graded or single-dose drug challenge with or without preceding skin or patch testing. Evaluation of challenging cases such as the patient who is on multiple drugs at the time a severe delayed IM-ADR occurs should prioritize clinical ascertainment of the most likely phenotype and implicated drug(s). Although not widely available and validated, procedures such as patch testing, delayed intradermal skin testing, and laboratory-based functional drug assays or genetic (human leukocyte antigen) testing may provide valuable information to further help risk stratify patients and identify the likely implicated and/or cross-reactive drug(s). The decision to use a drug challenge as a diagnostic or delabeling tool in a patient with a severe delayed IM-ADR should weigh the risk-benefit ratio, balancing the severity and priority for the treatment of the underlying, and the availability of alternative efficacious and safe treatments.

ELISpot assay as a diagnostic tool in drug hypersensitivity reactions

In patients with drug hypersensitivity reactions, confirmation of causality frequently facilitates decision on a continuation or withdrawal of a given treatment. Unfortunately, identification of the culprit drug often proves difficult. In vivo methods possess well-known disadvantages like low sensitivity of skin tests or the risk of relapse during drug provocation tests. Therefore, laboratory assays are of great interest as they may improve causal diagnosis without putting patients at risk. In this article, the mechanistic principles and methodological issues of the enzyme-linked immunospot (ELISpot) assay were recapped the context of drug hypersensitivity reactions. A review of ELISpot application in causal diagnosis of drug hypersensitivity was based on literature search. The main findings are: (i) ELISpot assay has a good performance in the detection of drug-specific response. (ii) ELISpot results seem to be not substantially impacted by the type of drug or phenotype of the reaction. (iii) Testing within 30 days since the episode of drug hypersensitivity reaction shows a better performance than in later recovery phase. (iv) Data from pediatric population are too scarce to draw any conclusions. (v) Differences in laboratory protocols and in criteria used in the assessment of ELISpot plates along with the issue of the technical feasibility and reproducibility may limit the use of this assay in the routine diagnostic of drug hypersensitivity reactions.

Model Based Evaluation of Hypersensitivity Adverse Drug Reactions to Antimicrobial Agents in Children

Drug use in children is-in most cases-supported by extrapolation of data generated from clinical trials in adult populations. This puts children at higher risk of developing adverse drug reactions (ADRs) due to "off-label" use of drugs and dosing issues. Major types of ADRs are drug hypersensitivity reactions, an idiosyncratic type of ADRs that are largely unpredictable and can cause high morbidity and mortality in a hard-to-identify specific population of patients. Lack of a complete understanding of the pathophysiology of DHRs and their unpredictive nature make them problematic in clinical practice and in drug development. In addition, ethical and legal obstacles hinder conducting large clinical trials in children, which in turn make children a "therapeutic orphan" where clear clinical guidelines are lacking, and practice is based largely on the personal experience of the clinician, hence making modeling desirable. This brief review summarizes the current knowledge of model-based evaluation of diagnosis and management of drug hypersensitivity reactions (DHRs) to antimicrobial drugs in the pediatric population. Ethical and legal aspects of drug research in children and the effect of different stages of child development and other factors on the risk of DHRs are discussed. The role of animal models, in vitro models and oral provocation test in management of DHRs are examined in the context of the current understanding of the pathophysiology of DHRs. Finally, recent changes in drug development legislations have been put forward to encourage drug developers to conduct trials in children clearly indicate the urgent need for evidence to support drug safety in children and for modeling to guide these clinical trials.

Lymphocyte transformation test: History and current approaches

Drug-induced hypersensitivity reactions encompass a variety of different clinical phenotypes ranging from harmless rashes to fatal reactions. They can be classified into allergic (i.e. drug allergy) and non-allergic reactions (i.e. non-allergic hypersensitivity). Drug allergies in turn can either be antibody (e.g. IgE) or T cell-mediated. One of the diagnostic tools for the in vitro detection of drug allergy is the lymphocyte transformation test (LTT) which is based on the activation and expansion of the drug-specific memory T cells following co-incubation of the patient's peripheral mononuclear cells (PMBC) with the suspected drug in vitro. The read-out parameter in the classical LTT is T cell proliferation which can be measured as counts per minute following the addition of radiolabeled thymidine to the cell culture. However, in the course of time different modifications of the classical LTT with regard to the read-out parameters and methods have been proposed. Likewise, variations of the LTT platform itself have been described in the literature. This review article describes the development of the classical LTT and its use in the context of drug allergy detection and summarizes the modifications which have been published over time.

An Updated Review of the Diagnostic Methods in Delayed Drug Hypersensitivity

Delayed drug hypersensitivity reactions are clinically diverse reactions that vary from isolated benign skin conditions that remit quickly with no or symptomatic treatment, drug discontinuation or even continued drug treatment, to the other extreme of severe cutaneous adverse reactions (SCARs) that are associated with presumed life-long memory T-cell responses, significant acute and long-term morbidity and mortality. Diagnostic "in clinic" approaches to delayed hypersensitivity reactions have included patch testing (PT), delayed intradermal testing (IDT) and drug challenges for milder reactions. Patch and IDT are, in general, performed no sooner than 4-6 weeks after resolution of the acute reaction at the maximum non-irritating concentrations. Functional in vitro and ex vivo assays have largely remained the province of research laboratories and include lymphocyte transformation test (LTT) and cytokine release enzyme linked ImmunoSpot (ELISpot) assay, an emerging diagnostic tool which uses cytokine release, typically IFN-γ, after the patient's peripheral blood mononuclear cells are stimulated with the suspected drug(s). Genetic markers such as human leukocyte antigen have shown recent promise for both pre-prescription screening as well as pre-emptive and diagnostic testing strategies.

Comparison of Sensitivities of Skin Prick and Intradermal Tests with Oral Rechallenge Test: A Prospective Interventional Hospital-Based Study

Background:

Identification of culprit drug causing adverse cutaneous drug reactions may not be possible clinically due to the intake of more than one drug.

Aim:

To compare the sensitivity of skin tests with gold standard oral rechallenge test to detect adverse cutaneous drug reactions.

Materials and Methods:

This is a prospective interventional hospital-based study of patients with adverse cutaneous drug reactions attending the outpatient department of dermatology and venereology at a tertiary care center over a 12-month period. Skin prick tests, intradermal tests, and oral rechallenge tests were performed in these patients and their sensitivities were compared. The data of quantitative nature is presented in mean and standard deviation, and categorical variables are presented in number and percentage. The sensitivity of skin tests is compared with the gold standard oral rechallenge test.

Results:

A total of 49 patients with adverse cutaneous drug reactions were evaluated. Clinical spectrum of adverse cutaneous drug reactions ranged from mild to severe, with fixed drug eruption being the commonest (55.1%) followed by maculopapular exanthem (32.7%). The highest incidence was with fluoroquinolones (43.8%) followed by nonsteroidal anti-inflammatory drugs. Fluoroquinolones were the major cause of fixed drug eruption followed by nonsteroidal anti-inflammatory drugs. The sensitivity of skin prick test and intradermal tests were 49% and 73%, respectively and the difference was highly significant (P < 0.001). The difference in sensitivity in skin prick test versus oral rechallenge test and intradermal test versus oral rechallenge test was also highly significant (P < 0.001).

Limitations:

Small sample size was a major limitation. Histopathological examinations and human leukocyte antigen associations could not be done.

Conclusion:

Predominant causative drugs were fluoroquinolones followed by nonsteroidal anti-inflammatory drugs. Sensitivities of skin prick test and intradermal test were quite good and these skin tests should be performed before oral rechallenge test in cases of adverse cutaneous drug reactions.

Reliability assessment on intravascular photoacoustic imaging of lipid: ex vivo animal and human sample validation

Although the lipid-detecting IVPA imaging system has been developed in resolution, speed, and catheter size, there is no parameterization study of the reliability on the IVPA imaging for lipid diagnosis. Here, the sensitivity, specificity, and accuracy were calculated to assess the reliability of the IVPA imaging of lipid. Abdominal aortas from six rabbits with atherosclerosis, were subjected to the IVPA imaging and Oil Red O staining, and 75 groups of IVPA as well as corresponding histological images were obtained. Similarly, 125 groups of IVPA and histological results were obtained from five human carotid plaque samples. The sensitivity, specificity, and accuracy, calculated from the statistical data, were 96.8%, 83.3%, 94.6% and 97.3%, 72.7%, 95.2%, respectively. The numerical values of sensitivity, specificity, and accuracy demonstrated the reliability of IVPA imaging on distinguishing the lesions vessel with lipid-rich plaque, which provided the foundation for IVPA translation to clinical application.

Clinical value of in vitro tests for the management of severe drug hypersensitivity reactions

Drug hypersensitivity reactions (DHRs) occasionally present with severe cutaneous adverse reactions (SCARs) which result in a high risk of morbidity and mortality. Although SCARs are rare, the occurrence could lead to a significant increase in healthcare and economic burden, especially when more than one possible culprit drug is implicated. Therefore, the accurate identification of the culprit drug(s) is important for correct labeling and subsequent patient education and avoidance. To date, clinical evaluation using causality assessment has limitations because the assessment may be inaccurate due to the overlapping timelines when multiple drugs are initiated/continued. Moreover, drug provocation tests (DPTs) which is the gold standard in diagnosis, are contraindicated, and in vivo skin tests may also be associated with risks of triggering SCAR. The European Network for Drug Allergy recommended that in vitro tests, if available, should be performed before any in vivo tests. Basophil activation tests and lymphocyte transformation tests, could serve as reliable in vitro tests for both immediate and delayed-type DHR. Many academic medical centers with affiliated laboratory services offer these tests in the diagnostic evaluation of SCARs in clinical practice. This not only complements identification of the culprit drug(s), but may also be used to test for potentially non cross-reactive alternatives, hence avoiding DPTs. In this review, we summarize the roles of in vitro tests in identifying the culprit drug(s) in SCARs, issues with utilization and interpretation of test results, and our experience in clinical practice.

Anaphylaxis to three humanized antibodies for severe asthma: a case study

Background

Omalizumab, mepolizumab, benralizumab, and dupilumab are the currently available biologics used to treat asthma in Japan. Anaphylaxis following treatment with mepolizumab or benralizumab is considered rare.

Case presentation

We report the case of a 35-year-old woman with severe asthma, who experienced anaphylaxis following the administration of benralizumab, mepolizumab, and omalizumab, separately. The therapy with biologics was chosen to avoid the repeated use of systemic corticosteroids for asthma exacerbations. The mechanisms underlying anaphylaxis caused by these three biologics remain unclear. The patient’s asthma symptoms and lung function improved after treatment with bronchial thermoplasty.

Conclusions

To our knowledge, this is the first report of an asthmatic patient developing anaphylaxis after commencement of benralizumab, mepolizumab, and omalizumab therapy. These three biologics should be administered carefully, and patients should be monitored for anaphylaxis.

Multidisciplinary care in Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are potentially fatal mucocutaneous diseases that can involve many organ systems. Manifestations of SJS/TEN outside of the skin, eyes, and oral mucosa are not well defined or well recognized, and, therefore, are often not addressed clinically. As supportive care improves and mortality from SJS/TEN decreases, chronic complications in affected organ systems are becoming more prevalent. Recognition of the manifestations of SJS/TEN in the acute phase is critical to optimal care. In this review, we review the organ systems that may be involved in SJS/TEN, provide an overview of their management, and propose a list of items that should be communicated to the patient and family upon discharge. The organ systems discussed include the pulmonary, gastrointestinal/hepatic, oral, otorhinolaryngologic, gynecologic, genitourinary, and renal systems. In addition, the significant psychosocial, nutritional, and pain consequences and management of SJS/TEN are discussed.

Do Battlefield Injury-acquired Indwelling Metal Fragments Induce Metal Immunogenicity?

BACKGROUND

A battlefield-related injury results in increased local and systemic innate immune inflammatory responses, resulting in wound-specific complications and an increased incidence of osteoarthritis. However, little is known about whether severe injuries affect long-term systemic homeostasis, for example, immune function. Moreover, it also remains unknown whether battlefield-acquired metal fragments retained over the long term result in residual systemic effects such as altered immune reactivity to metals.

QUESTIONS/PURPOSES

Does a retained metal fragment from a battlefield injury contribute to increased (1) adaptive metal-specific immune responses, (2) systemically elevated metal ion serum levels, and (3) serum immunoglobulin levels compared with combat injuries that did not result in a retained metal fragment?

METHODS

In this pilot study, we analyzed metal-immunogenicity in injured military personnel and noninjured control participants using lymphocyte transformation testing (LTT, lymphocyte proliferation responses to cobalt, chromium and nickel challenge at 0.001, 0.01 and 0.1-mM concentrations in triplicate for each participant), serum metal ion analysis (ICP-mass spectroscopy), and serum immunoglobulin analysis (IgE, IgG, IgA, and IgM ). Military personnel with a battlefield-sustained injury self-recruited without any exclusion for sex, age, degree of injury. Those with battlefield injury resulting in retained metal fragments (INJ-FRAG, n = 20 male, mean time since injury ± SD was 12 ± 10 years) were compared with those with a battlefield injury but without retained metal fragments (INJ-NO-FRAG, n = 12 male, mean time since injury ± SD was 13 ± 12 years). A control group comprised of male noninjured participants was used to compare measured immunogenicity metrics (n = 11, males were selected to match battlefield injury group demographics).

RESULTS

Military participants with sustained metal fragments had increased levels of metal-induced lymphocyte responses. The lymphocyte stimulation index among military participants with metal fragments was higher than in those with nonretained metal fragments (stimulation index = 4.2 ± 6.0 versus stimulation index = 2.1 ± 1.2 (mean difference 2.1 ± 1.4 [95% confidence interval 5.1 to 0.8]; p = 0.07) and an average stimulation index = 2 ± 1 in noninjured controls. Four of 20 participants injured with retained fragments had a lymphocyte proliferation index greater than 2 to cobalt compared with 0 in the group without a retained metal fragment or 0 in the control participants. However, with the numbers available, military personnel with retained metal fragments did not have higher serum metal ion levels than military participants without retained metal fragment-related injuries or control participants. Military personnel with retained metal fragments had lower serum immunoglobulin levels (IgG, IgA, and IgM) than military personnel without retained metal fragments and noninjured controls, except for IgE. Individuals who were metal-reactive positive (that is, a stimulation index > 2) with retained metal fragments had higher median IgE serum levels than participants who metal-reactive with nonmetal injuries (1198 ± 383 IU/mL versus 171 ± 67 IU/mL, mean difference 1027 ± 477 IU/mL [95% CI 2029 to 25]; p = 0.02).

CONCLUSIONS

We found that males with retained metal fragments after a battlefield-related injury had altered adaptive immune responses compared with battlefield-injured military personnel without indwelling metal fragments. Military participants with a retained metal fragment had an increased proportion of group members and increased average lymphocyte reactivity to common implant metals such as nickel and cobalt. Further studies are needed to determine a causal association between exposure to amounts of retained metal fragments, type of injury, personnel demographics and general immune function/reactivity that may affect personal health or future metal implant performance.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Bullous pemphigoid-like skin rash associated with Rivaroxaban use in a very elderly patient with multimorbidity and chronic kidney disease: A case report

Direct oral anticoagulants (DOACs) are increasingly being used in the elderly population in view of its ease of use, efficacy, and favorable side-effect profile compared with the vitamin K antagonists. However, there is a need for increase awareness of well-characterized cases, albeit a small number, of bullous pemphigoid-like skin reactions associated with rivaroxaban.

Immune dysregulation increases the incidence of delayed-type drug hypersensitivity reactions

Delayed-type, T cell-mediated, drug hypersensitivity reactions are a serious unwanted manifestation of drug exposure that develops in a small percentage of the human population. Drugs and drug metabolites are known to interact directly and indirectly (through irreversible protein binding and processing to the derived adducts) with HLA proteins that present the drug-peptide complex to T cells. Multiple forms of drug hypersensitivity are strongly linked to expression of a single HLA allele, and there is increasing evidence that drugs and peptides interact selectively with the protein encoded by the HLA allele. Despite this, many individuals expressing HLA risk alleles do not develop hypersensitivity when exposed to culprit drugs suggesting a nonlinear, multifactorial relationship in which HLA risk alleles are one factor. This has prompted a search for additional susceptibility factors. Herein, we argue that immune regulatory pathways are one key determinant of susceptibility. As expression and activity of these pathways are influenced by disease, environmental and patient factors, it is currently impossible to predict whether drug exposure will result in a health benefit, hypersensitivity or both. Thus, a concerted effort is required to investigate how immune dysregulation influences susceptibility towards drug hypersensitivity.

Evaluation of Cellular Responses for the Diagnosis of Allergic Bronchopulmonary Mycosis: A Preliminary Study in Cystic Fibrosis Patients

Background: Allergic bronchopulmonary mycosis (ABPM) is an underestimated allergic disease due to fungi. Most reported cases are caused by Aspergillus fumigatus (Af) and are referred to as allergic bronchopulmonary aspergillosis (ABPA). The main risk factor of ABPA is a history of lung disease, such as cystic fibrosis, asthma, or chronic obstructive pulmonary disease. The main diagnostic criteria for ABPA rely on the evaluation of humoral IgE and IgG responses to Af extracts, although these cannot discriminate Af sensitization and ABPA. Moreover, fungi other than Af have been incriminated. Flow cytometric evaluation of functional responses of basophils and lymphocytes in the context of allergic diseases is gaining momentum. Objectives: We hypothesized that the detection of functional responses through basophil and lymphocyte activation tests might be useful for ABPM diagnosis. We present here the results of a pilot study comparing the performance of these cellular assays vs. usual diagnostic criteria in a cystic fibrosis (CF) cohort. Methods: Ex vivo basophil activation test (BAT) is a diagnostic tool highlighting an immediate hypersensitivity mechanism against an allergen, e.g., through CD63 upregulation as an indirect measure of degranulation. Lymphocyte stimulation test (LST) relies on the upregulation of activation markers, such as CD69, after incubation with allergen(s), to explain delayed hypersensitivity. These assays were performed with Af, Penicillium, and Alternaria extracts in 29 adult CF patients. Results: BAT responses of ABPA patients were higher than those of sensitized or control CF patients. The highest LST result was for a woman who developed ABPA 3 months after the tests, despite the absence of specific IgG and IgE to Af at the time of the initial investigation. Conclusion: We conclude that basophil and lymphocyte activation tests could enhance the diagnosis of allergic mycosis, compared to usual humoral markers. Further studies with larger cohorts and addressing both mold extracts and mold relevant molecules are needed in order to confirm and extend the application of this personalized medicine approach.

Targeted therapy guided by single-cell transcriptomic analysis in drug-induced hypersensitivity syndrome: a case report

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DiHS/DRESS) is a potentially fatal multiorgan inflammatory disease associated with herpesvirus reactivation and subsequent onset of autoimmune diseases1-4. Pathophysiology remains elusive and therapeutic options are limited. Cases refractory to corticosteroid therapy pose a clinical challenge1,5 and approximately 30% of patients with DiHS/DRESS develop complications, including infections and inflammatory and autoimmune diseases1,2,5. Progress in single-cell RNA sequencing (scRNA-seq) provides an opportunity to dissect human disease pathophysiology at unprecedented resolutions6, particularly in diseases lacking animal models, such as DiHS/DRESS. We performed scRNA-seq on skin and blood from a patient with refractory DiHS/DRESS, identifying the JAK-STAT signaling pathway as a potential target. We further showed that central memory CD4+ T cells were enriched with DNA from human herpesvirus 6b. Intervention via tofacitinib enabled disease control and tapering of other immunosuppressive agents. Tofacitinib, as well as antiviral agents, suppressed culprit-induced T cell proliferation in vitro, further supporting the roles of the JAK-STAT pathway and herpesviruses in mediating the adverse drug reaction. Thus, scRNA-seq analyses guided successful therapeutic intervention in the patient with refractory DiHS/DRESS. scRNA-seq may improve our understanding of complicated human disease pathophysiology and provide an alternative approach in personalized medicine.

Oral lichen planus: A disease or a spectrum of tissue reactions? Types, causes, diagnostic algorhythms, prognosis, management strategies

Oral lichen planus and lichenoid lesions comprise a group of disorders of the oral mucosa that likely represent a common reaction pattern to 1 or more unknown antigens. The coexistence of hyperkeratotic striation/reticulation, varying degrees of mucosal inflammation from mild erythema to severe widespread ulceration, and a band-like infiltrate of mononuclear inflammatory cells including activated T lymphocytes, macrophages, and dendritic cells, are considered suggestive of oral lichen planus and lichenoid lesions. Several classification systems of oral lichen planus and lichenoid lesions have been attempted, although none seem to be comprehensive. In this paper, we present a classification of oral lichen planus and lichenoid lesions that includes oral lichen planus, oral lichenoid contact lesions, oral lichenoid drug reactions, oral lichenoid lesions of graft vs. host disease, discoid lupus erythematosus, and systemic lupus erythematosus, lichen planus-like variant of paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome, chronic ulcerative stomatitis, lichen planus pemphigoides, solitary fixed drug eruptions, and lichen sclerosus. We present the clinical and diagnostic aspects of oral lichen planus and lichenoid lesions, and discuss related treatment options.

Fever as a predictor of positive lymphocyte transformation test

BACKGROUND

Few studies have characterized the clinical manifestations of delayed antibiotic hypersensitivity (AH) diagnosed using objective methods. The lymphocyte transformation test (LTT) is a reproducible method to diagnose type IV hypersensitivity. The purpose of the study was to evaluate the characteristics of delayed AH diagnosed on LTT in children.

METHODS

We performed a retrospective analysis of patients who were evaluated for AH using LTT at National Center for Child Health and Development, Tokyo, from 2002 to 2014. We extracted patient demographics, type and duration of antibiotics, and clinical characteristics from the medical records. Clinical manifestations were compared between LTT-positive and LTT-negative cases.

RESULTS

Seventy-five cases for which 101 drugs were tested were included in this study. LTT was positive against 34 drugs in 26 cases. Median age was 5 years (IQR, 1-9 years), and 49% of patients had underlying disease. LTT was performed at a median of 18 days (IQR, 4-59 days) after the suspected episode. The median number of days from the initiation of therapy to the onset of symptoms was 4. Rash was the most common manifestation (89%). Fever (>38°C) was observed in 20 cases (27%). Onset of fever preceded the rash in nine cases (45%), appeared simultaneously in five (25%), appeared afterwards in four (20%), and was unknown in two (10%). Fever was an independent factor associated with AH when comparing LTT-positive and LTT-negative cases (OR, 3.61; 95%CI: 1.03-12.64).

CONCLUSIONS

Fever was a common presenting symptom of delayed AH in children aged ≤18 years.

Vancomycin induced DRESS syndrome (drug reaction with eosinophilia and systemic symptoms) in a patient with tricuspid endocarditis

A 57-year-old man presented for an elective pacemaker upgrade, complicated by the discovery of device infection. He had a background of complex congenital heart disease, including replacement of heart valves, and was treated for presumed infective endocarditis that was later confirmed by echocardiography. Antibiotic treatment, with intravenous vancomycin, was given as per the tissue sample sensitivities. On day 24 of treatment he deteriorated clinically, with the evolution of recurrent fever, epigastric pain, diarrhoea, widespread pruritic rash, lymphadenopathy and severe hypoxia over the subsequent 7-10 days. Blood tests revealed development of a marked eosinophilia, transaminitis and rising inflammatory markers. Further radiological imaging was non-diagnostic. On the basis of these clinical and biochemical features a diagnosis of drug reaction with eosinophilia and systemic symptoms syndrome was made. This led to the cessation of vancomycin, the offending agent and the referral for specialist immunology advice. He was subsequently treated with oral prednisolone and made a full recovery.

Association between metal hypersensitivity and implant failure in patients who underwent titanium cranioplasty

OBJECTIVE

Digitally designed titanium plates are commonly used for the reconstruction of craniofacial defects, although implant exposure (referred to as failure) is one of the major complications. Metal hypersensitivities have been suggested as possible causes of implant failure of orthopedic, intravascular, gynecological, and dental devices, yet there has been no consensus on the requirement for allergy screening before cranioplasty.

METHODS

In this study, the authors prospectively investigated the prevalence of metal hypersensitivity in patients for whom cranioplasty is planned and assess its relationship with titanium implant failure (exposure).

RESULTS

Based on records from 207 included patients, 39.61% of patients showed hypersensitivity to at least one kind of metal. Approximately one-quarter (25.12%) of patients had multiple metal allergies. Co, Cd, and Zn were the 3 most frequently identified metal hypersensitivities. No allergy to titanium was detected in this study. The overall incidence of cranioplasty implant failure was 5.31% (11 of 207). Patients showing hypersensitivities to more than 3 kinds of metal had higher risks of titanium plate exposure.

CONCLUSIONS

Based on their findings, the authors suggest that routine allergy screening be performed before titanium plate cranioplasty. For patients with hypersensitivities to more than 3 metals, alternative materials, such as polyetheretherketone, should be considered for cranioplasty.

Evaluation of the drug-induced lymphocyte stimulation test for diagnosing mesalazine allergy

Background/Aims

Mesalazine is an effective drug for treating ulcerative colitis (UC), but causes allergic symptoms in a few cases. Therefore, the objective of this study was to evaluate the usefulness of the drug-induced lymphocyte stimulation test (DLST) for the diagnosis of mesalazine allergy.

Methods

Patients with UC treated with mesalazine with or without a history of associated adverse events (AEs) were enrolled at Kyorin University Hospital from July 2016 to April 2017.

Results

The DLST was performed in 104 patients with UC, of which 24 had a history of AEs due to mesalazine treatment. The control value of DLST was 337.4±296.3 counts per minute (cpm) in the AE⁺ group and 408.0±371.9 cpm in the AE⁻ group. The measured value of DLST was 578.8±424.7 cpm in the AE⁺ group and 476.5±471.8 cpm in the AE⁻ group. The stimulation index (SI) was 243.9%±291.1% in the AE⁺ group and 119.8%±53.0% in the AE⁻ group. The SI value and DLST positivity were significantly higher in the AE⁺ group than in the AE⁻ group (P=0.030 and P=0.029, respectively). The test sensitivity and specificity were 0.240 and 0.805, respectively, and the false-positive and false-negative rate was 0.195 and 0.760, respectively.

Conclusions

The DLST for mesalazine showed low sensitivity and high specificity, suggesting that it may be useful for the definitive diagnosis of allergy to mesalazine.

Tools to investigate and avoid drug-hypersensitivity in drug development

INTRODUCTION

Drug hypersensitivity reactions (DHRs) are common adverse effects of pharmaceuticals that clinically resemble allergies, and which are becoming an important burden to healthcare systems. Alongside accurate diagnostic techniques, tools which can predict potential drug-inducing hypersensitivity reactions in the pre-clinical phase are critical. Despite the important adverse reactions linked to immune-mediated hypersensitivity, at present, there are no validated or required in vivo or in vitro methods to screen the sensitizing potential of drugs and their metabolites in the pre-clinical phase. Areas covered: Enhanced prediction in preclinical safety evaluation is extremely important. The purpose of this review is to assess the state of the art of tools available to assess the allergenic potential of drugs and to highlight our current understanding of the molecular mechanisms underlying inappropriate immune activation. Expert opinion: The knowledge that allergenic drugs share common mechanisms of immune cell activation with chemical allergens, and of the definition of the mechanistic pathway to adverse outcomes, can enhance targeting toxicity testing in drug development and hazard assessment of hypersensitivity. Additional efforts and extensive resources are necessary to improve preclinical testing methodologies, including optimization, better design and interpretation of data.

In Vitro Assays in Severe Cutaneous Adverse Drug Reactions: Are They Still Research Tools or Diagnostic Tests Already?

Severe cutaneous adverse drug reactions (SCARs) represent life-threatening medical conditions and an appropriate causative diagnosis of these conditions is of the highest importance. Existing in vivo diagnostic methods are risky or are just contraindicated in these patients. Therefore, in vitro tests take on greater significance. In this survey, the studies on in vitro assays in SCARs were identified with a defined searching strategy and strict eligibility criteria. Different methods in the particular clinical manifestations and the groups of drugs were compared in respect to the diagnostic parameters obtained. The lymphocyte transformation test and IFNg-ELISpot (Interferon γ-Enzyme-linked immunospot assay) appeared to have the best evidence currently available. Further diagnostic assays, which are based mostly on distinct mechanisms of SCARs, may outdo previous assays but they still need confirmation in a larger group of patients and in more research centers. Data from pediatric populations and acute generalized exanthematous pustulosis (AGEP) patients are scarce. Some technical issues, limitations, and modifications of routine laboratory methods are also discussed.

The Value of In Vitro Tests to DiminishDrug Challenges

Drug hypersensitivity reactions have multiple implications for patient safety and health system costs, thus it is important to perform an accurate diagnosis. The diagnostic procedure includes a detailed clinical history, often unreliable; followed by skin tests, sometimes with low sensitivity or unavailable; and drug provocation testing, which is not risk-free for the patient, especially in severe reactions. In vitro tests could help to identify correctly the responsible agent, thus improving the diagnosis of these reactions, helping the physician to find safe alternatives, and reducing the need to perform drug provocation testing. However, it is necessary to confirm the sensitivity, specificity, negative and positive predictive values for these in vitro tests to enable their implementation in clinical practice. In this review, we have analyzed these parameters from different studies that have used in vitro test for evaluating drug hypersensitivity reactions and estimated the added value of these tests to the in vivo diagnosis.