Hymenoptera Anaphylaxis and C-kit Mutations: An Unexpected Association

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

Fatal hymenoptera venom anaphylaxis by undetected clonal mast cell disorder: A better identification of high risk patients is needed

Hymenoptera venom anaphylaxis is the most frequent cause of anaphylaxis and responsible for about 20% of all fatal anaphylaxis cases in adults. We report two cases of fatal hymenoptera venom anaphylaxis with undiagnosed underlying mastocytosis and review the risk factors for severe or fatal hymenoptera venom anaphylaxis, as well as the specificities of its association with mastocytosis. As hymenoptera venom allergic patients with underlying clonal mast cell disorder generally lack typical skin lesions of mastocytosis, its diagnosis can easily be missed, underscoring the importance and need for diagnostic strategies in order to correctly identify these patients. Predominant cardiovascular symptoms in the absence of urticaria or angioedema following an insect sting are suggestive of underlying clonal mast cell disorder, and should be distinguished from panic attack or vasovagal syncope. Similarly, an unexplained syncope or an "idiopathic" anaphylaxis might reveal mastocytosis or hereditary alpha-tryptasemia. Acute and basal serum tryptase measurements should always be integrated in the diagnostic work-up of an insect sting reaction or unexplained syncope or shock of any origin.

Microarray-Based Detection of Allergen-Reactive IgE in Patients with Mastocytosis

BACKGROUND

Because of a high risk to develop fatal anaphylaxis, early detection of immunoglobulin E (IgE)-dependent allergy is of particular importance in patients with mastocytosis.

OBJECTIVE

We examined whether microarray-based screening for allergen-reactive IgE (allergen-chip) is a sensitive and robust approach to detect specific IgE in patients with mastocytosis.

METHODS

Sera for 42 patients were analyzed, including 4 with cutaneous mastocytosis, 2 with mastocytosis in the skin, and 36 with systemic mastocytosis. In addition, sera from an age- and sex-matched control cohort (n = 42) were analyzed.

RESULTS

In 15 of 42 patients with mastocytosis (35.7%), specific IgE was detected by allergen-chip profiling. Ves v 5 and Bet v 1 were the most frequently detected allergens (Ves v 5: 16.7% of patients; Bet v 1: 11.9% of patients). Allergen reactivity was confirmed by demonstrating upregulation of CD203c on blood basophils upon exposure to the respective allergen(s) in these patients. Specific IgE was identified by chip studies in 11 of 26 patients with mastocytosis with mediator-related symptoms (42.3%) and in 4 of 14 patients with mastocytosis without symptoms (28.6%). In the cohort with known allergy, 9 of 9 patients (100%) had a positive allergen-chip result. In patients with mastocytosis without a known allergy (n = 31), the chip identified 6 positive cases (19.5%). The prevalence of chip-positive patients was slightly lower in the mastocytosis group (35.7%) compared with age- and sex-matched controls (40.5%).

CONCLUSIONS

Although specific IgE may not be detectable in all sensitized patients with mastocytosis, allergy chip-profiling is a reliable screening approach for the identification of patients with mastocytosis suffering from IgE-dependent allergies.

Component Resolved Diagnosis in Hymenoptera Anaphylaxis

PURPOSE OF REVIEW

Hymenoptera anaphylaxis is one of the leading causes of severe allergic reactions and can be fatal. Venom-specific immunotherapy (VIT) can prevent a life-threatening reaction; however, confirmation of an allergy to a Hymenoptera venom is a prerequisite before starting such a treatment. Component resolved diagnostics (CRD) have helped to better identify the responsible allergen.

RECENT FINDINGS

Many new insect venom allergens have been identified within the last few years. Commercially available recombinant allergens offer new diagnostic tools for detecting sensitivity to insect venoms. Additional added sensitivity to nearly 95% was introduced by spiking yellow jacket venom (YJV) extract with Ves v 5. The further value of CRD for sensitivity in YJV and honey bee venom (HBV) allergy is more controversially discussed. Recombinant allergens devoid of cross-reactive carbohydrate determinants often help to identify the culprit venom in patients with double sensitivity to YJV and HBV. CRD identified a group of patients with predominant Api m 10 sensitization, which may be less well protected by VIT, as some treatment extracts are lacking this allergen. The diagnostic gap of previously undetected Hymenoptera allergy has been decreased via production of recombinant allergens. Knowledge of analogies in interspecies proteins and cross-reactive carbohydrate determinants is necessary to distinguish relevant from irrelevant sensitizations.

Simplification of intradermal skin testing in Hymenoptera venom allergic children

BACKGROUND

The direct comparison between children and adults with Hymenoptera venom anaphylaxis (HVA) has never been extensively reported. Severe HVA with IgE-documented mechanism is the recommendation for venom immunotherapy, regardless of age.

OBJECTIVE

To determine the differences in the basic diagnostic profile between children and adults with severe HVA and its practical implications.

METHODS

We reviewed the medical records of 91 children and 121 adults.

RESULTS

Bee venom allergy was exposure dependent, regardless of age (P < .001). Atopy was more common in children (P = .01), whereas cardiovascular comorbidities were present almost exclusively in adults (P = .001). In the bee venom allergic group, specific IgE levels were significantly higher in children (29.5 kU_A/L; interquartile range, 11.30-66.30 kU_A/L) compared with adults (5.10 kU_A/L; interquartile range, 2.03-8.30 kU_A/L) (P < .001). Specific IgE levels for culprit insect venom were higher in bee venom allergic children compared with the wasp venom allergic children (P < .001). In adults, intradermal tests revealed higher sensitivity, accompanied by larger area of skin reactions, regardless of type of venom. At concentrations lower than 0.1 μg/mL, 16% of wasp venom allergic children and 39% of bee venom allergic children had positive intradermal test results. The median tryptase level was significantly higher in adults than in children for the entire study group (P = .002), as well as in bee (P = .002) and wasp venom allergic groups (P = .049).

CONCLUSION

The basic diagnostic profile in severe HVA reactors is age dependent. Lower skin test reactivity to culprit venom in children may have practical application in starting the intradermal test procedure with higher venom concentrations.

Current and future biomarkers in allergic asthma

Diagnosis early in life, sensitization, asthma endotypes, monitoring of disease and treatment progression are key motivations for the exploration of biomarkers for allergic rhinitis and allergic asthma. The number of genes related to allergic rhinitis and allergic asthma increases steadily; however, prognostic genes have not yet entered clinical application. We hypothesize that the combination of multiple genes may generate biomarkers with prognostic potential. The current review attempts to group more than 161 different potential biomarkers involved in respiratory inflammation to pave the way for future classifiers. The potential biomarkers are categorized into either epithelial or infiltrate-derived or mixed origin, epithelial biomarkers. Furthermore, surface markers were grouped into cell-type-specific categories. The current literature provides multiple biomarkers for potential asthma endotypes that are related to T-cell phenotypes such as Th1, Th2, Th9, Th17, Th22 and Tregs and their lead cytokines. Eosinophilic and neutrophilic asthma endotypes are also classified by epithelium-derived CCL-26 and osteopontin, respectively. There are currently about 20 epithelium-derived biomarkers exclusively derived from epithelium, which are likely to innovate biomarker panels as they are easy to sample. This article systematically reviews and categorizes genes and collects current evidence that may promote these biomarkers to become part of allergic rhinitis or allergic asthma classifiers with high prognostic value.