Markers of anaphylaxis - a systematic review

Perioperative anaphylaxis: updates on pathophysiology

PURPOSE OF REVIEW

Perioperative anaphylaxis has historically been attributed to IgE/FcεRI-mediated reactions; there is now recognition of allergic and nonallergic triggers encompassing various reactions beyond IgE-mediated responses. This review aims to present recent advancements in knowledge regarding the mechanisms and pathophysiology of perioperative anaphylaxis.

RECENT FINDINGS

Emerging evidence highlights the role of the mast-cell related G-coupled protein receptor X2 pathway in direct mast cell degranulation, shedding light on previously unknown mechanisms. This pathway, alongside traditional IgE/FcεRI-mediated reactions, contributes to the complex nature of anaphylactic reactions. Investigations into the microbiota-anaphylaxis connection are ongoing, with potential implications for future treatment strategies. While serum tryptase levels serve as mast cell activation indicators, identifying triggers remains challenging. A range of mediators have been associated with anaphylaxis, including vasoactive peptides, proteases, lipid molecules, cytokines, chemokines, interleukins, complement components, and coagulation factors.

SUMMARY

Further understanding of clinical endotypes and the microenvironment where anaphylactic reactions unfold is essential for standardizing mediator testing and characterization in perioperative anaphylaxis. Ongoing research aims to elucidate the mechanisms, pathways, and mediators involved across multiple organ systems, including the cardiovascular, respiratory, and integumentary systems, which will be crucial for improving patient outcomes.

Mast Cells and Basophils in IgE-Independent Anaphylaxis

Anaphylaxis is a life-threatening or even fatal systemic hypersensitivity reaction. The incidence of anaphylaxis has risen at an alarming rate in the past decades in the majority of countries. Generally, the most common causes of severe or fatal anaphylaxis are medication, foods and Hymenoptera venoms. Anaphylactic reactions are characterized by the activation of mast cells and basophils and the release of mediators. These cells express a variety of receptors that enable them to respond to a wide range of stimulants. Most studies of anaphylaxis focus on IgE-dependent reactions. The mast cell has long been regarded as the main effector cell involved in IgE-mediated anaphylaxis. This paper reviews IgE-independent anaphylaxis, with special emphasis on mast cells, basophils, anaphylactic mediators, risk factors, triggers, and management.

Perioperative Anaphylaxis

Anesthesiologists routinely manage patients receiving drugs and agents, all of which have the potential for anaphylaxis, the life-threatening presentation of an allergic reaction. Clinicians must be ready to diagnose and manage the acute cardiopulmonary dysfunction that occurs.

Adult anaphylaxis: A state-of-the-art review

Anaphylaxis is the most severe among acute allergic diseases and potentially life threatening. Despite its increasing frequency and related burden, it remains often underdiagnosed and improperly managed. Its multisystemic involvement, protean clinical manifestations and its rapid onset are contributory factors. In recent years new acquisitions have shed light into its pathogenesis pathways (and related biomarkers), triggers, factors increasing its severity, along with peculiar clinical manifestations. These breakthrough discoveries have contributed to phenotyping and endotyping this disease, possibly paving the way to a personalized approach which is not available at present. Moreover, to disseminate awareness and standardize diagnostic criteria and management practices, several guidelines and consensus reports, albeit mainly intended for specialist care, have been issued. We here discuss the latest issues in the field of anaphylaxis from the perspective of the emergency and/or internal medicine physician, so to improve its early recognition and treatment in the acute setting and favor allergology referral to implement therapeutical and preventive strategies, such as allergen identification in unclear cases and desensitizing therapies when available (e.g., for Hymenoptera venom allergy).

Anti-KIT monoclonal antibody CDX-0159 induces profound and durable mast cell suppression in a healthy volunteer study

Background

Mast cells (MC) are powerful inflammatory immune sentinel cells that drive numerous allergic, inflammatory, and pruritic disorders when activated. MC‐targeted therapies are approved in several disorders, yet many patients have limited benefit suggesting the need for approaches that more broadly inhibit MC activity. MCs require the KIT receptor and its ligand stem cell factor (SCF) for differentiation, maturation, and survival. Here we describe CDX‐0159, an anti‐KIT monoclonal antibody that potently suppresses MCs in human healthy volunteers.

Methods

CDX‐0159‐mediated KIT inhibition was tested in vitro using KIT‐expressing immortalized cells and primary human mast cells. CDX‐0159 safety and pharmacokinetics were evaluated in a 13‐week good laboratory practice (GLP)‐compliant cynomolgus macaque study. A single ascending dose (0.3, 1, 3, and 9 mg/kg), double‐blinded placebo‐controlled phase 1a human healthy volunteer study (n = 32) was conducted to evaluate the safety, pharmacokinetics, and pharmacodynamics of CDX‐0159.

Results

CDX‐0159 inhibits SCF‐dependent KIT activation in vitro. Fc modifications in CDX‐0159 led to elimination of effector function and reduced serum clearance. In cynomolgus macaques, multiple high doses were safely administered without a significant impact on hematology, a potential concern for KIT inhibitors. A single dose of CDX‐0159 in healthy human subjects was generally well tolerated and demonstrated long antibody exposure. Importantly, CDX‐0159 led to dose‐dependent, profound suppression of plasma tryptase, a MC‐specific protease associated with tissue MC burden, indicative of systemic MC suppression or ablation.

Conclusion

CDX‐0159 administration leads to systemic mast cell ablation and may represent a safe and novel approach to treat mast cell‐driven disorders.

The Role of Cetirizine in the Changing Landscape of IV Antihistamines: A Narrative Review

Since 1955, the only available H1 antihistamines for intravenous administration have been first-generation formulations and, of those, only intravenously administered (IV) diphenhydramine is still approved in the USA. Orally administered cetirizine hydrochloride, a second-generation H1 antihistamine, has been safely used over-the-counter for many years. In 2019, IV cetirizine was approved for the treatment of acute urticaria. In light of this approval, this narrative review discusses the changing landscape of IV antihistamines for the treatment of histamine-mediated conditions. Specifically, IV antihistamines will be discussed as a treatment option for acute urticaria and angioedema, as premedication to prevent infusion reactions related to anticancer agents and other biologics, and as an adjunct treatment for anaphylaxis and other allergic reactions. Before the development of IV cetirizine, randomized controlled trials of IV antihistamines for these indications were lacking. Three randomized controlled trials have been conducted with IV cetirizine versus IV diphenhydramine in the ambulatory care setting. A phase 3 trial of IV cetirizine 10 mg versus IV diphenhydramine 50 mg was conducted in 262 adults who presented to the urgent care/emergency department with acute urticaria requiring antihistamines. For the primary efficacy endpoint, defined as change from baseline in a 2-h patient-rated pruritus score, non-inferiority of IV cetirizine to IV diphenhydramine was demonstrated (score - 1.6 vs - 1.5, respectively; 95% CI - 0.1, 0.3). Compared with IV diphenhydramine, IV cetirizine demonstrated fewer adverse effects including less sedation, a significantly shorter length of stay in the treatment center, and fewer returns to the treatment center at 24 and 48 h. Similar findings were demonstrated in another phase 2 acute urticaria trial and in a phase 2 trial assessing IV cetirizine for pretreatment for infusion reactions in the oncology/immunology setting. IV cetirizine is associated with similar patient outcomes, fewer adverse effects, and increased treatment center efficiency than IV diphenhydramine.

Hymenoptera heartaches -cardiac manifestation with hymenoptera stings, a retrospective study from a tertiary care hospital in South India

INTRODUCTION

Hymenoptera stings usually have a multitude of presentations from very subtle to life-threatening conditions. Various cardiac manifestations including Kounis syndrome often get missed due to lack of suspicion. The aim of the study was to describe the clinical profile of the cardiac etiologies associated with hymenoptera stings and review literature with focus on diagnosis and treatment strategies.

METHODOLOGY

A retrospective chart analysis was performed including all adult patients who had a hymenoptera sting during a two-year window (October 2018 - October 2020). Of these, patients with cardiac features were enrolled. A structured case record form was used to capture information like basic demography, clinical profile, and outcomes.

RESULTS

Thirteen cases presented with hymenoptera stings of which six cases had cardiac presentation and were considered. The most common presentations were breathlessness and generalised itching with only one patient complaining of chest pain. All patients(with available data) had ECG changes suggestive of ischemia and associated raised troponin levels with 2D echo changes. The diagnoses considered included Kounis syndrome, hypersensitivity myocarditis, and Takotsubo cardiomyopathy. Patients were managed conservatively with one patient undergoing a coronary angiography. All patients were stable at discharge.

CONCLUSION

Cardiac manifestations with hymenoptera stings although rare may complicate diagnosis and treatment.It should be borne in mind during assessment and standardised guidelines should be developed for ED treatment such as the one recommended in this study.

Hypersensitivity response has negligible impact on Hematopoietic Stem Cells

Immune cells are generated from hematopoietic stem cells (HSCs) in the bone marrow (BM). Immune stimulation can rapidly activate HSCs out of their quiescent state to accelerate the generation of immune cells. HSCs' activation follows various viral or bacterial stimuli, and we sought to investigate the hypersensitivity immune response. Surprisingly, the Ova-induced hypersensitivity peritonitis model finds no significant changes in BM HSCs. HSC markers cKIT, SCA1, CD48, CD150, and the Fgd5-mCherry reporter showed no significant difference from control. Functionally, hypersensitivity did not alter HSCs' potency, as assayed by transplantation. We further characterized the possible impact of hypersensitivity using RNA-sequencing of HSCs, finding minor changes at the transcriptome level. Moreover, hypersensitivity induced no significant change in the proliferative state of HSCs. Therefore, this study suggests that, in contrast to other immune stimuli, hypersensitivity has no impact on HSCs.

Diagnosing, managing and preventing anaphylaxis: Systematic review

BACKGROUND

This systematic review used the GRADE approach to compile evidence to inform the European Academy of Allergy and Clinical Immunology's (EAACI) anaphylaxis guideline.

METHODS

We searched five bibliographic databases from 1946 to 20 April 2020 for studies about the diagnosis, management and prevention of anaphylaxis. We included 50 studies with 18 449 participants: 29 randomized controlled trials, seven controlled clinical trials, seven consecutive case series and seven case-control studies. Findings were summarized narratively because studies were too heterogeneous to conduct meta-analysis.

RESULTS

It is unclear whether the NIAID/FAAN criteria or Brighton case definition are valid for immediately diagnosing anaphylaxis due to the very low certainty of evidence. There was also insufficient evidence about the impact of most anaphylaxis management and prevention strategies. Adrenaline is regularly used for first-line emergency management of anaphylaxis but little robust research has assessed its effectiveness. Newer models of adrenaline autoinjectors may slightly increase the proportion of people correctly using the devices and reduce time to administration. Face-to-face training for laypeople may slightly improve anaphylaxis knowledge and competence in using autoinjectors. We searched for but found little or no comparative effectiveness evidence about strategies such as fluid replacement, oxygen, glucocorticosteroids, methylxanthines, bronchodilators, management plans, food labels, drug labels and similar.

CONCLUSIONS

Anaphylaxis is a potentially life-threatening condition but, due to practical and ethical challenges, there is a paucity of robust evidence about how to diagnose and manage it.

Oleanolic acid protects against mast cell-mediated allergic responses by suppressing Akt/NF-κB and STAT1 activation

BACKGROUND

Oleanolic acid (OA) is an active compound found in a variety of medicinal herbs and plants. Though OA has been widely attributed with a variety of biological activities, studies focused on its anti-allergic inflammation properties are insufficient.

PURPOSE

Given the rapid increase in allergic diseases and the lack of fundamental treatment options, this study aimed to find a safe and effective therapy for allergic disorders.

METHODS

We evaluated the inhibitory effect of OA on allergic inflammatory response and the possible mechanisms underlying the effect using phorbol-12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated human mast cell (HMC)-1, and a mouse model of compound 48/80-induced anaphylactic shock.

RESULTS

OA suppressed pro-inflammatory cytokine expressions in PMACI-induced HMC-1 cells by inhibiting activation of the Akt, p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and signal transducer and activator of transcription (STAT) 1 signaling pathways. Moreover, OA showed a protective effect against compound 48/80-induced anaphylactic shock through inhibition of histamine release and immunoglobulin E level via regulation of NF-κB and STAT1 activation.

CONCLUSION

The results showed that OA suppressed mast cell-mediated allergic response by transcriptional regulation. We suggest that OA has potential effect against allergic inflammatory disorders, including anaphylaxis, and might be a useful therapeutic agent for allergic disease.

Diagnosis, Classification and Management of Mast Cell Activation Syndromes (MCAS) in the Era of Personalized Medicine

Mast cell activation (MCA) is seen in a variety of clinical contexts and pathologies, including IgE-dependent allergic inflammation, other immunologic and inflammatory reactions, primary mast cell (MC) disorders, and hereditary alpha tryptasemia (HAT). MCA-related symptoms range from mild to severe to life-threatening. The severity of MCA-related symptoms depends on a number of factors, including genetic predisposition, the number and releasability of MCs, organs affected, and the type and consequences of comorbid conditions. In severe systemic reactions, MCA is demonstrable by a substantial increase of basal serum tryptase levels above the individual’s baseline. When, in addition, the symptoms are recurrent, involve more than one organ system, and are responsive to therapy with MC-stabilizing or mediator-targeting drugs, the consensus criteria for the diagnosis of MCA syndrome (MCAS) are met. Based on the etiology of MCA, patients can further be classified as having i) primary MCAS where KIT-mutated, clonal, MCs are detected; ii) secondary MCAS where an underlying IgE-dependent allergy or other reactive MCA-triggering pathology is found; or iii) idiopathic MCAS, where neither a triggering reactive state nor KIT-mutated MCs are identified. Most severe MCA events occur in combined forms of MCAS, where KIT-mutated MCs, IgE-dependent allergies and sometimes HAT are detected. These patients may suffer from life-threatening anaphylaxis and are candidates for combined treatment with various types of drugs, including IgE-blocking antibodies, anti-mediator-type drugs and MC-targeting therapy. In conclusion, detailed knowledge about the etiology, underlying pathologies and co-morbidities is important to establish the diagnosis and develop an optimal management plan for MCAS, following the principles of personalized medicine.

The Protein Level and Molecular Weight Analysis in Different Children's Toothpaste, which Probably Induced Hypersensitivity

CONTEXT

A new case of an allergic reaction due to the use of toothpaste was found in California, United States, causing the death of an 11-year-old girl. Ingredients contained in toothpaste suspected as a cause of allergies are milk protein compounds.

AIMS

The aim is to compare the protein level and molecular weight in children's toothpaste.

SETTINGS AND DESIGN

Stratified random sampling.

SUBJECTS AND METHODS

Samples used were children's toothpaste products in society, namely, Pepsodent®, Cussons®, Enzyme®, Kodomo®, Formula®, Colgate®, the toothpaste contain recaldent of GC Tooth Moose® and pure cow's milk. Those samples were divided into eight groups, randomly selected according to the purpose (stratified random sampling), and then coded to maintain product confidentiality. Meanwhile, samples used as comparison groups were recaldent paste and pure cow's milk.

RESULTS

Each sample was analyzed for protein content using a biuret test and protein molecular weight using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis test. The protein content in toothpaste is compared with the similarity of the molecular protein weight in toothpaste that contains recaldent. Protein was found in samples 2, 3, 5, 6, 7, and 8 through a biuret test, with a concentration of 1.82; 1.53; 2.76; 1.92; 1.85; and 3.2 μg/mL. However, the protein bands were only found in sample 5 with a molecular weight of 20.7 kDa, sample 6 with a molecular weight of 19.1 kDa, sample 7 with a molecular weight of 17.7 kDa, and sample 8 with 2 bands, namely, 28.7 and 39.7 kDa.

CONCLUSIONS

We found the presence of protein in children's toothpaste. The protein molecular weight of recaldent paste is 17.7 kDa. Toothpaste containing protein with its molecular weight similar to recaldent's are found in samples 5 and 6.

Drug-Induced Anaphylaxis in a Vietnamese Pharmacovigilance Database: Trends and Specific Signals from a Disproportionality Analysis

INTRODUCTION

Despite the numerous studies investigating drug-induced anaphylaxis (DIA), understanding and quantitative data analysis in developing countries remain limited. The aim of our study is to describe and quantify DIA using the National Pharmacovigilance Database of Vietnam (NPDV).

METHODS

Spontaneous reporting of adverse drug reactions (ADRs) recorded between 2010 and 2016 were retrospectively analysed to identify DIA reports. The trend and characteristics of DIA cases were described. Multivariate disproportionality analysis was used for signal generation.

RESULTS

Overall, 4873 DIA cases (13.2% of total ADRs) were recorded in the NPDV, 111 of which resulted in death (82% of total ADR-induced deaths) over a 7-year period. There was a remarkable increase in DIA reporting over time (p < 0.001). The incidence rates of DIA reporting per total ADRs and per 100,000 inhabitants remained high (mean rates [95% CI] of 12.06 [9.88-14.24] and 0.77 [0.33-1.20], respectively). Concerning suspected drugs, systemic antibiotics (n = 3318, 68%) were mostly reported with a reporting odds ratio (ROR) and 95% CI of 2.35 [2.20-2.51]. In the case of antibiotic-induced anaphylaxis, the third-generation cephalosporins were predominant (n = 1961, 40.2%, ROR 2.39 [2.24-2.55]). We also noted drugs generally associated with DIA such as contrast agents (ROR 2.43 [2.04-2.88]) and anaesthetics (ROR 4.02 [3.30-4.89]). Furthermore, unexpected signals were observed for alpha-chymotrypsin (ROR 1.75 [1.23-2.44]) and amoxicillin/sulbactam (ROR 1.59 [1.18-2.10]), uncommonly reported in western countries.

CONCLUSION

In recent years, cases of drug-induced DIA have increased in Vietnam, mostly due to antibiotics and third-generation cephalosporins. The inappropriate use of these drugs should be taken into account. Our findings also highlighted typical Vietnamese signals for alpha-chymotrypsin- and amoxicillin/sulbactam-induced anaphylaxis, which may relate to a specific sociological context in resource-limited countries.

Anaphylactic Degranulation of Mast Cells: Focus on Compound Exocytosis

Anaphylaxis is a notorious type 2 immune response which may result in a systemic response and lead to death. A precondition for the unfolding of the anaphylactic shock is the secretion of inflammatory mediators from mast cells in response to an allergen, mostly through activation of the cells via the IgE-dependent pathway. While mast cells are specialized secretory cells that can secrete through a variety of exocytic modes, the most predominant mode exerted by the mast cell during anaphylaxis is compound exocytosis-a specialized form of regulated exocytosis where secretory granules fuse to one another. Here, we review the modes of regulated exocytosis in the mast cell and focus on compound exocytosis. We review historical landmarks in the research of compound exocytosis in mast cells and the methods available for investigating compound exocytosis. We also review the molecular mechanisms reported to underlie compound exocytosis in mast cells and expand further with reviewing key findings from other cell types. Finally, we discuss the possible reasons for the mast cell to utilize compound exocytosis during anaphylaxis, the conflicting evidence in different mast cell models, and the open questions in the field which remain to be answered.

Inflammation, not Cholesterol, Is a Cause of Chronic Disease

Since the Seven Countries Study, dietary cholesterol and the levels of serum cholesterol in relation to the development of chronic diseases have been somewhat demonised. However, the principles of the Mediterranean diet and relevant data linked to the examples of people living in the five blue zones demonstrate that the key to longevity and the prevention of chronic disease development is not the reduction of dietary or serum cholesterol but the control of systemic inflammation. In this review, we present all the relevant data that supports the view that it is inflammation induced by several factors, such as platelet-activating factor (PAF), that leads to the onset of cardiovascular diseases (CVD) rather than serum cholesterol. The key to reducing the incidence of CVD is to control the activities of PAF and other inflammatory mediators via diet, exercise, and healthy lifestyle choices. The relevant studies and data supporting these views are discussed in this review.