Predictive value of allergy tests for neuromuscular blocking agents: tackling an unmet need

Mast cell versus basophil activation test in allergy: Current status

In the past two decades, we witnessed the evolution of the basophil activation test (BAT) from mainly research applications to a potential complementary diagnostic tool to document IgE-dependent allergies. However, BAT presents some technical weaknesses. Around 10%-15% of tested patients are non-responders, BAT can be negative immediately post-reaction and the use of fresh basophils, ideally analysed within 4 h of collection, restricts the number of tests that can be performed per sample. The need for fresh basophils is especially limiting when conducting batch analyses and interlaboratory comparisons to harmonize BAT methodology. These limitations significantly hinder the wider application of BAT and urge the development of alternative testing, such as the mast cell activation test (MAT). The essential difference between BAT and MAT is the heterogeneity of the starting material used to perform the assays. Mast cells are tissue-resident, so cannot be easily accessed. Current alternative sources for functional studies are generating primary human mast cells, differentiated from donor progenitor cells, or using immortalized mast cell lines. Hence, the methodological approaches for MAT are not only vastly different from BAT, but also different among MAT protocols. This review summarizes the advantages and disadvantages of BAT and MAT assays, dedicating special attention to elucidating the key differences between the cellular sources used and provides an overview of studies hitherto performed comparing BAT and MAT in the diagnosis of IgE-mediated food and drug allergies.

Flow-based basophil activation test in immediate drug hypersensitivity. An EAACI task force position paper

Diagnosing immediate drug hypersensitivity reactions (IDHRs) can pose a significant challenge and there is an urgent need for safe and reliable tests. Evidence has emerged that the basophil activation test (BAT), an in vitro assay that mirrors the in vivo response, can be a complementary test for many drugs. In this position paper, members of Task Force (TF) "Basophil activation test in the evaluation of Drug Hypersensitivity Reactions" from the European Academy of Allergy and Clinical Immunology (EAACI) present the data from a survey about the use and utility of BAT in IDHRs in Europe. The survey results indicate that there is a great interest for using BAT especially for diagnosing IDHRs. However, there are still main needs, mainly in the standardization of the protocols. Subsequently consensus-based recommendations were formulated for: (i) Technical aspects of BAT in IDHRs including type of sample, management of drugs, flow cytometry protocols, interpretation of the results; and (ii) Drug-specific aspects that should be taken into account when performing BAT in relation to betalactams, neuromuscular blocking agents, fluoroquinolones, chlorhexidine, opioids, radio contrast media, chemotherapeutics, biological agents, nonsteroidal anti-inflammatory drugs, COVID vaccine, and excipients. Moreover, aspects in the evaluation of pediatric population have also been considered. All this indicates that BAT offers the clinician and laboratory a complementary tool for a safe diagnostic for IDHRs, although its place in the diagnostic algorithm depends on the drug class and patient population (phenotype, geography, and age). The standardization of BAT is important for generalizing this method beyond the individual laboratory.

Comparison of the passive mast cell activation test with the basophil activation test for diagnosis of perioperative rocuronium hypersensitivity

BACKGROUND

Rocuronium is a major cause of perioperative hypersensitivity (POH). Skin tests (STs) and quantification of specific immunoglobulin E antibodies (sIgEs) can yield incongruent results. In such difficult cases, the basophil activation test (BAT) can be helpful. Here, we evaluated the passive mast cell activation test (pMAT) as a substitute of BAT as part of the diagnostic tests for rocuronium allergy.

METHODS

Sera from patients with a suspected POH reaction potentially related to rocuronium were included. All patients had a complete diagnostic investigation, including STs, quantification of sIgEs to morphine and rocuronium, and BAT. For execution of pMAT, human mast cells were generated from healthy donor peripheral blood CD34+ progenitor cells and sensitised overnight with patient sera.

RESULTS

In total, 90 sera were studied: 41 from ST+sIgE+ patients, 13 from ST-sIgE- patients, 20 from ST+sIgE- patients, and 16 from ST-sIgE+ patients. According to BAT results, patients were further allocated into subgroups. Of the 38 BAT+ patients, 25 (66%) showed a positive pMAT as well. Of the 44 BAT- patients, 43 (98%) also showed a negative pMAT. Mast cells that were not passively sensitised did not respond to rocuronium.

CONCLUSIONS

We show that the pMAT, in many cases, can substitute for BAT in the diagnosis of rocuronium hypersensitivity and advance diagnosis in difficult cases with uncertain ST or sIgE results when BAT is not locally available.

A quarter of a century fundamental and translational research in perioperative hypersensitivity and anaphylaxis at the Antwerp university hospital, a Belgian Centre of Excellence of the World Allergy Organization

Perioperative hypersensitivity constitutes an important health issue, with potential dramatic consequences of diagnostic mistakes. However, safe and correct diagnosis is not always straightforward, mainly because of the application of incorrect nomenclature, absence of easy accessible in-vitro/ex-vivo tests and uncertainties associated with the non-irritating skin test concentrations. In this editorial we summarize the time line, seminal findings, and major realizations of 25 years of research on the mechanisms, diagnosis, and management of perioperative hypersensitivity.

Diagnostic value of a medical algorithm for investigation of perioperative hypersensitivity reactions

BACKGROUND

Evaluation of perioperative hypersensitivity (POH) is challenging, and accurate screening tools are needed to optimize the diagnostic process. We aimed to assess and validate the diagnostic value of a published algorithm (using tryptase and clinical presentation) to identify appropriate individuals for further testing for IgE-mediated POH.

METHODS

We analysed the clinical presentation (tryptase elevation, cardiovascular, respiratory, skin involvement) of patients proceeding to testing for possible IgE-mediated POH at a single tertiary referral centre, relative to subsequent skin testing and specific IgE results. Clinical presentations by drug class were also determined.

RESULTS

In 293 consecutive patients, the use of a published algorithm based on one or more of; (i) defined increase in serum tryptase, (ii) involvement of at least two-organ systems, or (iii) presentation with new urticaria and/or angioedema; was highly sensitive [98.8% (CI95: 95.7-99.9%)] but less specific [34.6% (CI95: 25.7-44.4%)] in identifying patients testing positive on skin testing and/or specific IgE. Presentation with cardiovascular symptoms was also sensitive [89.8%(CI95: 84.2-94.0%)], while the combination of respiratory symptoms and increased tryptase was most specific [85.9%(CI95:76.6-92.5%)]. Respiratory involvement was more common in neuromuscular blocking agent allergy, while urticaria/angioedema was more common in antibiotic allergy.

CONCLUSION

The published algorithm (of tryptase rise, two-organ involvement or new urticaria/angioedema) is highly sensitive, and appropriate as a screening tool to identify patients suitable for testing for IgE-mediated POH.

Reliability of Early and Late Testing for Suspected Perioperative Hypersensitivity

BACKGROUND

The optimal timing of diagnostic testing for perioperative hypersensitivity (POH) remains unknown. It has been recommended that investigation is best carried out at least 4 to 6 weeks after the event. On the other hand, guidelines discourage the use of in vitro tests later than 3 years after the index reaction.

OBJECTIVE

This retrospective study aimed to assess the reliability of early and late skin tests (STs). It also attempted to verify whether discouraging late ex vivo and in vitro tests is substantiated.

METHODS

For the first aim, patients were stratified over three epochs: an early timing group, with investigations performed within 6 weeks; a recommended timing group, with tests performed between 6 weeks and 6 months; and a late timing group, tested later than 6 months after the event. For the second study purpose, we studied the reliability of specific IgE quantification and basophil activation test rocuronium within 6 weeks and after 3 years in patients who experienced an ST-proven POH to rocuronium.

RESULTS

A total of 677 patients were included. Based on a positive ST result, a causative agent was found in 74.2% of the early timing group, 62.6% of the recommended timing group, and 50% of the late timing group. A positive specific IgE for rocuronium or morphine was found in 80% of patients tested within 6 weeks, 63% of patients tested between 6 weeks and 3 years, and 50% of patients tested more than 3 years after the event. A positive basophil activation test was found in 83.3%, 51%, and 20%, respectively, of patients.

CONCLUSIONS

Our data confirm that evaluation of drug allergy for suspected POH can be performed before 6 weeks after the event, and there is no maximal upper time limit disclosing ex vivo and in vitro testing.

Prevention of Drug Hypersensitivity Reactions: Prescreening and Premedication

Drug hypersensitivity reactions (DHR) are heterogeneous in their pathomechanisms, clinical presentation, severity, and outcomes. Novel DHR mechanisms, phenotypes, and endotypes have been described. The key to prevention from further exposure to the culprit drugs involves correct identification of the putative drug through a combination of in vitro and/or in vivo tests, accurate drug allergy labeling and reporting, and electronic decision support systems within electronic medical records to prevent future accidental prescribing. Prescreening and premedication, the focus of this review, may be a useful adjunct to preventive measures in certain situations. After an index immediate drug hypersensitivity reaction, prescreening may be useful in perioperative anaphylaxis, and iodinated (ICM) and gadolinium-based contrast media (GCM) where the culprit and potential alternative agents are skin tested. In certain nonimmediate DHR, pharmacogenomic prescreening may be used before prescribing high-risk drugs (eg, carbamazepine and allopurinol) where specific human-leukocyte antigen genotypes are associated with severe cutaneous adverse reactions. Premedication with antihistamine and systemic corticosteroids is another therapeutic strategy to prevent infusion reactions for certain biologicals and chemotherapeutic agents, in cases of perioperative anaphylaxis, ICM and GCM DHR, and clonal mast cell disorders. Rapid drug desensitization may also be used to induce temporary tolerance in situations where there are limited alternative drugs.

Severe Bronchoconstriction Caused by Administration of Rocuronium in a 3-Month-Old Infant: Case Report

We present the case of a 3-month-old infant with severe, persistent bronchoconstriction following administration of rocuronium. This observation raises awareness of a rare but potentially life-threatening reaction to neuromuscular blocking agents.

Early Skin Test after Anaphylaxis during Induction of Anesthesia: A Case Report

Background: It is recommended that a skin test be performed 4–6 weeks after anaphylaxis. However, there is little evidence about the timing of the skin test when there is a need to identify the cause within 4–6 weeks. Case report: A 57-year-old woman was scheduled to undergo surgery via a sphenoidal approach to remove a pituitary macroadenoma. Immediately after the administration of rocuronium, pulse rate increased to 120 beats/min and blood pressure dropped to 77/36 mmHg. At the same time, generalized urticaria and tongue edema were observed. Epinephrine was administered and the surgery was postponed. Reoperation was planned two weeks after the event. Four days after the anaphylactic episode, rocuronium was confirmed to be the cause by the skin prick test. Cisatracurium, which showed a negative reaction, was selected as an alternative agent for future procedures. Two weeks later, the patient underwent reoperation without any adverse events. Conclusions: The early skin test can be performed if there is a need even earlier than 4–6 weeks after anaphylaxis.

Interpreting the results of early skin tests after perioperative anaphylaxis requires special attention: a case report and review of literature

Skin tests are the gold standard for detecting the culprit drug of anaphylaxis, and should ideally be performed after an interval of 4-6 weeks after the reaction to avoid false-negative results. However, when re-operation cannot be delayed and early allergy tests are necessary, special attention is required during subsequent anesthesia, because early skin tests tend to produce false-negative results. This report presents a case of rocuronium-induced anaphylaxis in which early skin tests showed negative results for all the drugs tested. The second anesthesia was safely performed by avoiding all the drugs used for the first anesthesia. Ultimately, skin tests and basophil activation tests (BATs) performed after re-operation demonstrated rocuronium as the drug responsible for anaphylaxis. We recommend performing BATs in addition to skin tests to improve the accuracy of diagnosis of anaphylaxis. In this report, we also discuss interpretation of the results of early skin tests and subsequent selection of drugs for anesthesia. After postponement of surgery due to anaphylaxis, we are often required to perform allergy tests at an early stage if re-operation cannot be delayed. In such cases, skin test results alone should not be used to guide subsequent anesthesia management to avoid recurrent anaphylaxis.

Pediatric Patients with Previous Anaphylactic Reactions to General Anesthesia: a Review of Literature, Case Report, and Anesthetic Considerations

PURPOSE OF REVIEW

It is rare to see pediatric patients with previous perioperative anaphylaxis receiving future anesthesia, but it is critical to understand how to choose assessments, interpret the results, and develop a future anesthetic plan.

RECENT FINDINGS

Analysis of the results revealed that patients, at any age, regardless of sex and nationality, and the number of surgeries, have the risk of perioperative anaphylaxis while the risk of allergy increases as patients present multiple surgical events or have a previous history of atopy. 94.7% of pediatric patients with allergy testing after perioperative anaphylaxis tolerated subsequent general anesthesia without complications. Specific IgE tests, basophil activation tests, and skin tests are not available and suitable for all culprits. The early skin test could be considered a supplement for later testing. Drug challenge test is the golden standard but can only be used as the last resort. If general anesthesia is inevitable, avoidance of the culprit and use of alternative agents can help the patients prevent another potential recurrence. Full use of inhalation anesthesia without unnecessary neuromuscular blockade agents and avoidance of latex is recommended when the surgery is urgent or skin tests for children cannot be performed in time. This review summarizes characteristics of perioperative pediatric anaphylaxis, main tests for various drugs, and their sensitivities and specificities as well as recommendations as to how to implement safe anesthesia in the future.

Skin Testing to Identify Safe Drugs for Patients with Rocuronium-Induced Anaphylaxis

Among patients who develop anaphylaxis during anesthesia, anaphylaxis caused by a neuromuscular blocking agent has the highest incidence. In patients who developed IgE-mediated anaphylaxis, and cross-reactivity among NMBAs is a concern in subsequent anesthetic procedures. We present a patient who developed rocuronium-induced anaphylaxis in whom the skin prick test (SPT) and intradermal test (IDT) could identify a safe drug to use in the subsequent anesthetic procedure. A 32-year-old female developed anaphylactic shock at the induction of general anesthesia. She recovered by administration of hydrocortisone and epinephrine. Skin tests including the SPT followed by the IDT revealed rocuronium as the drug that caused anaphylaxis and vecuronium as a safe drug to use for the subsequent general anesthesia. She safely underwent surgery with general anesthesia using vecuronium one month after the skin testing. There are not many reports on the effectiveness of the SPT followed by IDT in identifying the causative drug as well as a safe drug to use in the subsequent anesthetic procedure following anaphylaxis during anesthesia. The usefulness of the SPT should be re-evaluated.

An EAACI position paper on the investigation of perioperative immediate hypersensitivity reactions

Perioperative immediate hypersensitivity reactions are rare. Subsequent allergy investigation is complicated by multiple simultaneous drug exposures, the use of drugs with potent effects and the many differential diagnoses to hypersensitivity in the perioperative setting. The approach to the investigation of these complex reactions is not standardized, and it is becoming increasingly apparent that collaboration between experts in the field of allergy/immunology/dermatology and anaesthesiology is needed to provide the best possible care for these patients. The EAACI task force behind this position paper has therefore combined the expertise of allergists, immunologists and anaesthesiologists. The aims of this position paper were to provide recommendations for the investigation of immediate-type perioperative hypersensitivity reactions and to provide practical information that can assist clinicians in planning and carrying out investigations.

Peri-Operative Anaphylaxis-An Investigational Challenge

Patients with suspected peri-operative anaphylaxis (POP) require thorough investigation to identify underlying trigger(s) and enable safe anesthesia for subsequent surgery. The changing epidemiology of POP has been striking. Previous estimates of the incidence of POP have ranged between 1:6,000 and1:20,000 anesthetics, but more recent data from France and the United Kingdom suggest an estimated incidence of 1:10,000. Other important changes include a change in the hierarchy of well-recognized triggers, with antibiotics (beta-lactams) supplanting neuromuscular blockers (NMB) as the leading cause of POP. The emergence of chlorhexidine, patent blue dye, and teicoplanin as important triggers have also been noteworthy findings. The mainstay of investigation revolves around critical analysis of the time-line of events leading up to anaphylaxis coupled with judicious skin testing. Skin tests have limitations with respect to unknown predictive values for most drugs/agents and therefore, knowledge of background positivity in healthy controls, test characteristics of individual drugs and the use of non-irritant concentrations is essential to avoid both false-positive and false-negative results. Specific IgE assays for individual drugs are available only for a limited number of agents and are not a substitute for skin testing. Acute serum total tryptase has a high specificity and positive predictive value in IgE-mediated POP anaphylaxis but is limited by its moderate sensitivity and negative predictive value. Planning for safe anesthesia in this group of patients is particularly challenging and consequently anesthetists need to be alert to the possibility of repeat episodes of anaphylaxis. Because of the limitations of current investigations for POP, collecting systematic data on the outcome of repeat anesthesia is valuable in validating current investigatory approaches. This paper reviews the changing epidemiology of POP with reference to the main triggers, and the investigation and outcome of subsequent anesthesia.

Assessing cross-reactivity to neuromuscular blocking agents by skin and basophil activation tests in patients with neuromuscular blocking agent anaphylaxis

BACKGROUND

Following diagnosis of neuromuscular blocking agent (NMBA) anaphylaxis, identifying safe alternatives for subsequent anaesthesia is critical. A patient with anaphylaxis to one NMBA can also have an allergic reaction to other NMBAs (cross-reactivity). Whilst drug provocation testing is standard for identifying or excluding allergy, there is significant risk. In vitro, after an allergen activates basophils, basophils express surface activation markers that can be measured by basophil activation testing (BAT). We compared cross-reactivity between NMBAs assessed by BAT against that by skin testing.

METHODS

All patients attending an anaesthetic allergy clinic in Sydney, Australia between May 2017 and July 2018 diagnosed with NMBA anaphylaxis qualified for this study comparing intradermal skin tests and BAT with a panel of NMBAs (rocuronium, vecuronium, pancuronium, suxamethonium, cisatracurium).

RESULTS

Of the 61 patients participating, sensitisation on skin testing and on BAT completely matched in only nine patients (15%). Sensitisation was not in agreement for pancuronium, cisatracurium and rocuronium, but was in agreement for vecuronium and suxamethonium. Nine patients with negative skin tests subsequently tolerated cisatracurium, and one false positive on BAT to cisatracurium was detected.

CONCLUSIONS

The utility of BAT in identifying safe NMBAs for subsequent anaesthesia needs further evaluation. BAT detects a different cross-reactivity profile to skin tests. Negative skin testing and BAT might increase confidence in performing drug provocation testing, but this and follow-up of subsequent anaesthesia in our cohort is necessary to determine the clinical significance of BAT sensitisation.

Rocuronium anaphylaxis in a 7-year-old boy during the induction of anesthesia

We report a case of rocuronium-induced anaphylaxis in a previously healthy 7-year-old boy. The first presenting sign of anaphylaxis was bronchospasm, appearing 11 min after he received intravenous doses of rocuronium (1 mg/kg) (Eslax^®, MSD Co. Ltd., Tokyo, Japan), propofol (2 mg/kg), and cefazolin sodium (25 mg/kg). After the administration of adrenalin and ephedrine hydrochloride, bronchospasm resolved, and the vital signs became stable. Percutaneous pinning of his left humeral supracondylar fracture was performed without problems. The next day, he was successfully liberated from the ventilator support and discharged on the fifth hospital day. On the 76th postoperative day, we performed intradermal tests of rocuronium, propofol, and cefazolin. It showed that diluted rocuronium alone induced 14 mm of flare and 8 mm of wheal within 5 min, both of which disappeared within 15 min after the intradermal injection. The reaction was too quick to mention the possible contribution of rocuronium-specific IgE. His rapid reaction at the rocuronium skin test and anaphylactic reaction upon the first exposure to this drug may highlight the association of rocuronium anaphylaxis with IgE independent mast cell stimulation through mas-related G-protein coupled receptor X2 (MRGPRX2 receptor).

Anaesthetic management of patients with pre-existing allergic conditions: a narrative review

This narrative review seeks to distinguish the clinical patterns of pre-existing allergic conditions from other confounding non-allergic clinical entities, and to identify the potential related risks and facilitate their perioperative management. Follow-up investigation should be performed after a perioperative immediate hypersensitivity to establish a diagnosis and provide advice for subsequent anaesthetics, the main risk factor for perioperative immunoglobulin E (IgE)-mediated anaphylaxis being a previous uninvestigated perioperative immediate hypersensitivity reaction. The concept of cross-reactivity between drugs used in the perioperative setting and food is often quoted, but usually not supported by evidence. There is no reason to avoid propofol in egg, soy, or peanut allergy. The allergenic determinants have been characterised for fish, shellfish, and povidone iodine, but remain unknown for iodinated contrast agents. Iodinated drugs may be used in seafood allergy. Evidence supporting the risk for protamine allergy in fish allergy and in neutral protamine Hagedorn insulin use is lacking. Conversely, cross-reactivity to gelatin-based colloid may occur in α-gal syndrome. Atopy and allergic asthma along with other non-allergic conditions, such as NSAID-exacerbated respiratory disease, chronic urticaria, mastocytosis, and hereditary or acquired angioedema, are not risk factors for IgE-mediated drug allergy, but there is a perioperative risk associated with the potential for exacerbation of the various conditions.

BAT in the Diagnosis of Drug Allergy: a Novel Tool in Clinical Daily Practice?

PURPOSE OF REVIEW

The aim of this study is to critically review the relevant literature published on basophil activation test, presenting the current knowledge and future perspectives.

RECENT FINDINGS

Basophil activation test (BAT) results varied accordingly to the class of the drug studied, and have promising results in immediate hypersensitivity reactions to pyrazolone (selective reactors), neuromuscular blockers, beta-lactams, and platinum compounds, all examples of classical IgE-mediated hypersensitivity drug reactions. Currently, BAT is applied in research settings, but based in the results of our review, the test can be considered as a diagnostic tool for daily practice for selected patients and selected drugs, when the test is available, particularly for patients who experienced severe reactions and when diagnosis cannot be stablished by serum-specific IgE and skin testing, in order to avoid unnecessary drug provocations tests.

Treatment of Anaphylaxis to Rocuronium with Sugammadex: A Case Report with Bronchospasm as the Only Symptom

Anaphylaxis during anaesthesia is a rare event occurring in up to 1:20,000 anaesthetics and in 33%-63% neuromuscular blocking agents are involved. Several case reports suggested the effectiveness of sugammadex in the treatment of rocuronium-induced anaphylactic shock refractory to conventional treatment. We report a case of anaphylactic reaction to rocuronium that caused isolated respiratory symptoms and showed no improvement in oxygen saturation after intravenous corticosteroids and intratracheal beta-2 agonists and that was successfully treated with sugammadex. The underlying pathophysiological mechanisms that explain the potential beneficial effect of sugammadex in this context are not completely known. We briefly review the literature regarding this topic.

Neuromuscular blockers and reversal agents and their impact on anesthesia practice

Neuromuscular blockers have long been an intricate part of the anesthesia regimen. The scientific progress in pharmacology and physiology has strengthened their clinical relevance, has helped to delineate with precision their medical role, and has enhanced the safety and effectiveness of their use. New frontiers in research will define further the role of these agents in modern anesthesia practice and guide their expanding and discrete clinical applications.

In Vitro Diagnosis of Immediate Drug Hypersensitivity Anno 2017: Potentials and Limitations

Background

For most physicians, quantification of drug-specific immunoglobulin E (drug-sIgE) antibodies constitutes the primary in vitro measure to document immediate drug hypersensitivity reactions (IDHR). Unfortunately, this is often insufficient to correctly identify patients with IgE-mediated IDHR and impossible for non-IgE-mediated IDHR that result from alternative routes of basophil and mast cell activation. In these difficult cases, diagnosis might benefit from cellular tests such as basophil activation tests (BAT).

Aim

The aim was to review the potential and limitations of quantification of sIgE and BAT in diagnosing IDHR. The utility of quantification of serum tryptase is discussed.

Methods

A literature search was conducted using the key words allergy, basophil activation, CD63, CD203c, diagnosis, drugs, hypersensitivity, flow cytometry, specific IgE antibodies; this was complemented by the authors’ own experience.

Results

The drugs that have been most studied with both techniques are β-lactam antibiotics and curarizing neuromuscular blocking agents (NMBA). For sIgE morphine, data are available on the value of this test as a biomarker for sensitization to substituted ammonium structures that constitute the major epitope of NMBA, especially rocuronium and suxamethonium. For the BAT, there are also data on non-steroidal anti-inflammatory drugs (NSAIDs) and iodinated radiocontrast media. For β-lactam antibiotics, sensitivity and specificity of sIgE varies between 0 and 85% and 52 and 100%, respectively. For NMBA, sensitivity and specificity varies between 38.5 and 92% and 85.7 and 100%, respectively. Specific IgE to morphine should not be used in isolation to diagnose IDHR to NMBA nor opiates. For the BAT, sensitivity generally varies between 50 and 60%, whereas specificity attains 80%, except for quinolones and NSAIDs.

Conclusions

Although drug-sIgE assays and BAT can provide useful information in the diagnosis of IDHR, their predictive value is not absolute. Large-scale collaborative studies are mandatory to harmonize and optimize test protocols and to establish drug-specific decision thresholds.

Dilemmas in Anesthetic Management of a Patient with History of Anaphylaxis to Vecuronium

Anaphylaxis during anesthesia is a life-threatening situation that occurs uncommonly. A 60-year-old woman with a history of anaphylaxis during previous anesthesia is scheduled to undergo elective open cholecystectomy. Her skin tests revealed sensitivity to vecuronium and nonsensitivity to injections of midazolam, fentanyl, and propofol. Due to high incidence of cross sensitivity among neuromuscular drugs, it was thought best to avoid general anesthesia. Spinal anesthesia was planned for the patient. The patient refused to give consent for spinal anesthesia, and she had to be taken up for surgery under general anesthesia. The only alternate neuromuscular blocking drug available to us was atracurium, which was tested for sensitivity by intradermal test. Atracurium was found to be not sensitive on intradermal test. We report here the dilemma and the challenges faced during management of general anesthesia in a patient with history of anaphylaxis to vecuronium.

Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or "Innate Hypersensitivity"?

Approximately 60% of perioperative anaphylactic reactions are thought to be immunoglobulin IgE mediated, whereas 40% are thought to be non-IgE mediated hypersensitivity reactions (both considered non-dose-related type B adverse drug reactions). In both cases, symptoms are elicited by mast cell degranulation. Also, pharmacological reactions to drugs (type A, dose-related) may sometimes mimic symptoms triggered by mast cell degranulation. In case of hypotension, bronchospasm, or urticarial rash due to mast cell degranulation, identification of the responsible mechanism is complicated. However, determination of the type of the underlying adverse drug reaction is of paramount interest for the decision of whether the culprit drug may be re-administered. Neuromuscular blocking agents (NMBA) are among the most frequent cause of perioperative anaphylaxis. Recently, it has been shown that NMBA may activate mast cells independently from IgE antibodies via the human Mas-related G-protein-coupled receptor member X2 (MRGPRX2). In light of this new insight into the patho-mechanism of pseudo-allergic adverse drug reactions, in which as drug-receptor interaction results in anaphylaxis like symptoms, we critically reviewed the literature on NMBA-induced perioperative anaphylaxis. We challenge the dogma that NMBA mainly cause IgE-mediated anaphylaxis via an IgE-mediated mechanism, which is based on studies that consider positive skin test to be specific for IgE-mediated hypersensitivity. Finally, we discuss the question whether MRGPRX2 mediated pseudo-allergic reactions should be re-classified as type A adverse reactions.

Utility of basophil activation testing to assess perioperative anaphylactic reactions in real-world practice

Introduction

Perioperative anaphylactic reactions due to drugs and substances associated with general anesthesia can potentially be life‐threatening. The objective of this study was to investigate the significance of the basophil activation test (BAT) for allergy diagnosis work up.

Methods

A total of 14 patients (5 men, 9 women; mean age: 57.8 years) with clinical records of anaphylactic reactions under general anesthesia were studied by means of anesthesia records, skin and serological tests. Eleven healthy subjects without any history of allergic sensitization to anaesthetic drugs served as controls. BATs based on stimulation of whole blood cells measuring CD63 activation of basophils and using CCR3 as basophil marker by flow cytometry (Flow CAST®, BÜHLMANN Laboratories AG, Schönenbuch, Switzerland) were performed with the following substances (in dependence on the history and the skin tests of the patient): analgesics (acetylsalicylic acid, celecoxib, diclofenac, ibuprofen, indometacin, metamizole, paracetamol, propyphenazone, tramadol), antibiotics (PPL (benzylpenicilloyl polylysine), MDM (minor determinant mixture), amoxicillin, cefuroxime, ciprofloxacin, doxycycline, erythromycin, roxithromycin, sulfamethoxazole, trimethoprim), local anesthetics (articaine, bupivacaine, lidocaine, prilocaine, procaine, methyl‐4‐hydroxybenzoate), narcotics and NMBA (atracurium, cisatracurium, etomidate, neostigmine, midazolam, mivacurium, pancuronium, propofol, pyridostigmine, succinylcholine, sufentanil, thiopental, vecuronium), and other individual substances.

Results

Three patients showed positive results in the BAT: One to metamizole, one to PPL, and one to pancuronium. BATs with these substances were negative in controls.

Conclusions

The BAT should be used complementary to skin tests, especially if IgE‐mediated mechanisms are presumed and skin tests are inconclusive. A positive reaction in BAT identifies the culprit agent with high probability.

General anaesthesia-induced anaphylaxis: impact of allergy testing on subsequent anaesthesia

BACKGROUND

Immunoglobulin E-mediated allergy to drugs and substances used during general anaesthesia as well as non-allergic drug hypersensitivity reactions may account for anaesthesia-induced anaphylaxis. As IgE-mediated anaphylaxis is a potentially life-threatening reaction, identification of the culprit allergen is essential to avoid anaphylaxis recurrence during subsequent general anaesthesia.

OBJECTIVE

To study whether preventive recommendations derived from allergy testing after intraoperative anaphylaxis were followed in subsequent general anaesthesia.

METHODS

Results of standardized allergy testing after anaesthesia-induced anaphylaxis and outcome of subsequent general anaesthesia were analysed retrospectively.

RESULTS

Fifty-three of 107 patients were diagnosed with IgE-mediated allergy to a drug or substance used during general anaesthesia, and 54 patients were test negative. Twenty-eight of 29 allergy patients tolerated subsequent general anaesthesia uneventfully. One patient with cefazolin allergy suffered from anaphylaxis recurrence due to accidental reapplication of cefazolin. Twenty-two of 24 test-negative patients tolerated subsequent general anaesthesia, whereas two patients again developed anaphylaxis despite pre-medication regimens.

CONCLUSION AND CLINICAL RELEVANCE

Our results confirm the practical impact of allergy testing in general anaesthesia-induced anaphylaxis. By identification of the allergen, it is possible to avoid allergic anaphylaxis during subsequent anaesthesia. In most cases, recommended pre-medication seems to prevent the recurrence of non-allergic drug hypersensitivity reactions.

Developments in the field of allergy in 2014 through the eyes of Clinical and Experimental Allergy

The pathogenesis of asthma continues to be a major topic of interest to our authors with reviews and original papers on the role of viruses, mechanisms of inflammation, biomarkers, and phenotypes of asthma being major topics. A number of papers described new treatments for asthma focusing on blocking the Th2 response reflecting the fact that two decades of work in this area is finally bearing fruit. The pathogenesis of chronic rhinosinusitis is a growing area of interest, but there has been less on the genetics of airways disease than in previous years possibly reflecting the degree of rigour (and therefore a smaller body of work), with which these sorts of studies are now being undertaken. There continues to be a wide range of papers dealing with mechanisms of allergic disease ranging from clinical-based studies to basic research and the use of in vivo animal models especially mice. As before, mechanisms and new approaches to immunotherapy are common themes. Several were published in the allergens section investigating modification of allergens to increase their effectiveness and reduce the risk of adverse events. Risk factors for allergic disease was a common theme in the epidemiology section and food allergy a common theme in clinical allergy with papers on the development of protocols to induce tolerance and attempts to find biomarkers to distinguish sensitization from allergic disease. This was another exciting year for the editors, and we hope the readers of the journal.

Quantification of specific IgE antibodies in immediate drug hypersensitivity: More shortcomings than potentials?

BACKGROUND

For many physicians, quantification of serum drug-specific IgE (sIgE) antibodies constitutes the first measure in the diagnostic approach of immediate drug hypersensitivity reactions (IDHR).

AIM

To review the accuracy and limitations of the main drug-sIgE tests, especially those that are commercially available.

METHODS

A literature search was conducted, using the key-words allergy, diagnosis, drugs, hypersensitivity, specific IgE antibodies; this was complemented by the authors' own experience.

RESULTS

The drugs that have mostly been studied appeared to be β-lactam antibiotics, neuromuscular blocking agents (NMBA) and morphine, the latter as a biomarker for sensitisation to substituted ammonium structures that constitute the major epitope of NMBA. For β-lactams sensitivity and specificity varied between 0-85% and 52-100%, respectively. For NMBA, sensitivity and specificity varied between 38.5-92% and 92-100%, respectively. With respect to sIgE to morphine it appears this drug to be a sensitive biomarker for sensitisation to rocuronium and suxamethonium but not for atracurium. However, sIgE morphine should not be applied in isolation to diagnose IDHR to NMBA nor opiates.

CONCLUSIONS

Although drug-sIgE assay can provide valuable information they should not be performed in isolation to establish correct diagnosis, as their predictive value is not per se absolute. Larger comprehensive studies are urgently required to determine the accuracy of drug-sIgE assays.

Diagnostic procedure after an immediate hypersensitivity reaction in the operating room

The diagnosis of a perioperative allergic reaction is based on clinical features associated with a suggestive timeline, the exclusion of other diagnoses, elevated concentrations of degranulation markers (histamine, tryptase), and positive allergy assessments (skin tests, specific IgE). After initiating appropriate treatment, the anesthesiologist should take blood samples to measure histamine and tryptase concentrations just after the reaction and repeat them 1-2hours later to validate the diagnosis of immediate hypersensitivity. A delayed measurement of basal tryptase is useful to rule out mastocytosis and to interpret moderate tryptase levels. The anesthesiologist must inform the patient of the reaction to obtain adhesion and consent to subsequent investigations and must record the timing of the reaction and of the blood sampling, the possible causal agents, and the treatment administered. These data must be shared with the laboratory and the allergist. An adverse drug reaction report must be filed. The gold standard for allergy assessment is skin testing. These tests should be done in an appropriate facility, with experienced staff and in compliance with current guidelines. Specific IgE assays and cellular assays can help when clinical features and skin tests are discordant. Provocation tests are sometimes required. After allergy assessment, the safest protocol for subsequent anesthesia is determined in collaboration with the anesthesiologist. The patient must be informed and carry an allergy alert card.

[Allergy to neuromuscular blocking agents]

Allergy to neuromuscular blocking agents (NMBAs) has been the first cause of perioperative anaphylaxis for decades, in most countries. The most frequently involved agents are suxamethonium and rocuronium. The allergy work-up is compulsory to demonstrate or rule out allergy to NMBAs, if there is a compatible clinical history. Doing otherwise exposes the patient to death if the same or related NMBA is re-injected. In cases of true allergy, assessing cross-reactivity to other NMBAs is mandatory. The cross-sensitization hypothesis is presently being investigated and if confirmed, it could allow primary prevention measures to be implemented.