Cutaneous manifestations in Hymenoptera and Diptera anaphylaxis: relationship with basal serum tryptase

Evidence-based data support strategies for the prevention of Hymenoptera venom anaphylaxis

PURPOSE OF REVIEW

This review aims to identify phenotypes at-risk of Hymenoptera venom-induced anaphylaxis (HVA), focusing on different perspectives (epidemiological, clinical, and therapeutic) in order to adapt future preventive strategies.

RECENT FINDINGS

HVA remains one of the leading causes of anaphylaxis, with a broad pattern of symptoms. Although most cases occur outside healthcare settings, data indicate a high emergency admission rate due to insect stings. Mortality is often underestimated because of the lack of witnesses and difficulties in recognizing the signs and the culprit. Targeting risk factors could be a clue to improve these statistics and the prognosis of the disease.Potential risk factors for severe HVA in the European population are basal serum tryptase (BST) above 8 μg, mast cell disorders, the absence of skin symptoms, and cardiovascular conditions requiring the use of beta blockers and ACE inhibitors. Identifying these criteria, mainly based on clinical patterns, helps to develop personalized strategies for management and prevention.

SUMMARY

With a personalized medicine approach, phenotypes must be characterized to adapt to the management of patients suffering from Hymenoptera venom anaphylaxis (HVA), including venom immunotherapy (VIT). In this systematic review, all articles mentioned systemic reactions with heterogeneous severity degrees. Half of those reported grade III-IV systemic reactions (Ring and Messmer). HVA clinical patterns could be worsened by one Hymenoptera sting, a patient's history with mast cell disorders, or cardiovascular diseases. VIT failure was attributed to bee venom extract and monotherapy in two-thirds of publications. Findings stress the difficulty of having uniform epidemiological data on HVA and the lack of financial support in some world regions to support appropriate management of these conditions. Although observing a heterogeneity of data, we were able to identify potential risk factors, in particular for the severe cases. We believe our work will support allergists and health professionals to implement improved personalized management of patients suffering from severe HVA.

Mimics of Allergy and Angioedema: Scombroid, Mast Cell Activation Disorders, and Hereditary Alpha Tryptasemia

Scombroid poisoning, systemic mastocytosis, and hereditary alpha tryptasemia all present with episodes that resemble allergic reactions. Knowledge regarding systemic mastocytosis and hereditary alpha tryptasemia is quickly evolving. Epidemiology, pathophysiology, and strategies to identify and diagnose are discussed. Evidence-based management in the emergency setting and beyond is also explored and summarized. Key differences are described between these events and allergic reactions.

Mimics of Allergy and Angioedema: Scombroid, Mast Cell Activation Disorders, and Hereditary Alpha Tryptasemia

Scombroid poisoning, systemic mastocytosis, and hereditary alpha tryptasemia all present with episodes that resemble allergic reactions. Knowledge regarding systemic mastocytosis and hereditary alpha tryptasemia is quickly evolving. Epidemiology, pathophysiology, and strategies to identify and diagnose are discussed. Evidence-based management in the emergency setting and beyond is also explored and summarized. Key differences are described between these events and allergic reactions.

Bone Marrow Mastocytosis: A Diagnostic Challenge

Bone marrow mastocytosis (BMM) represents a provisional, indolent subvariant of systemic mastocytosis (SM). Utilizing WHO criteria, BMM requires bone marrow (BM) involvement and the absence of mastocytosis skin lesions. BMM is characterized by male sex prevalence, a slight increase of serum tryptase levels, low BM mast cells (MC) burden, and an indolent clinical course. BMM shows a strong correlation with severe anaphylaxis, mainly due to an IgE-mediated allergy to bee or wasp venom and, less frequently, to unexplained (idiopathic) anaphylaxis. Furthermore, BMM is often associated with osteoporosis which could be the only presenting symptom of the disease. BMM is an undervalued disease as serum tryptase levels are not routinely measured in the presence of unexplained osteoporosis or anaphylaxis. Moreover, BMM patients are often symptom-free except for severe allergic reactions. These factors, along with typical low BM MCs infiltration, may contribute to physicians overlooking BMM diagnosis, especially in medical centers that lack appropriately sensitive diagnostic techniques. This review highlights the need for a correct diagnostic pathway to diagnose BMM in patients with suspected symptoms but lacking typical skin lesions, even in the case of normal serum tryptase levels. Early diagnosis may prevent potential life-threatening anaphylaxis or severe skeletal complications.

Basophils from Cancer Patients Respond to Immune Stimuli and Predict Clinical Outcome

Basophils are involved in manifestations of hypersensitivity, however, the current understanding of their propensity for activation and their prognostic value in cancer patients remains unclear. As in healthy and atopic individuals, basophil populations were identified in blood from ovarian cancer patients (n = 53) with diverse tumor histologies and treatment histories. Ex vivo basophil activation was measured by CD63 expression using the basophil activation test (BAT). Irrespective of prior treatment, basophils could be activated by stimulation with IgE- (anti-FcεRI and anti-IgE) and non-IgE (fMLP) mediated triggers. Basophil activation was detected by ex vivo exposure to paclitaxel, but not to other anti-cancer therapies, in agreement with a clinical history of systemic hypersensitivity reactions to paclitaxel. Protein and gene expression analyses support the presence of basophils (CCR3, CD123, FcεRI) and activated basophils (CD63, CD203c, tryptase) in ovarian tumors. Greater numbers of circulating basophils, cells with greater capacity for ex vivo stimulation (n = 35), and gene signatures indicating the presence of activated basophils in tumors (n = 439) were each associated with improved survival in ovarian cancer. Circulating basophils in cancer patients respond to IgE- and non-IgE-mediated signals and could help identify hypersensitivity to therapeutic agents. Activated circulating and tumor-infiltrating basophils may be potential biomarkers in oncology.

Tabanidae insect (horsefly and deerfly) allergy in humans: A review of the literature

Allergy to insects of the family Tabanidae (order Diptera), commonly called horseflies or deerflies, is anecdotally common, although the published literature is limited to case reports and small case series. This review summarizes the available literature, in which there is enormous variability in clinical detail, identification of species or even genus, and means and thoroughness of assessment of sensitization. The clinical utility of in vivo and in vitro assays remains unclear. Investigation and management of patients reporting anaphylaxis to suspected bites must therefore be pragmatic, by considering other insects (eg Hymenoptera), provision of a written action plan and self-injectable adrenaline if appropriate, and advice on avoidance.

Predictors of severe anaphylaxis in Hymenoptera venom allergy: The importance of absence of urticaria and angioedema

BACKGROUND

Severe anaphylaxis (SA) in Hymenoptera venom allergy has been associated with a number of risk factors. However, the effect of several of those risk factors on the severity of anaphylaxis is poorly defined.

OBJECTIVE

To evaluate risk factors for SA in Hymenoptera venom allergy.

METHODS

We evaluated data from 500 patients who were referred to our department for the diagnosis of Hymenoptera venom allergy during a period of 11 years to identify risk factors for SA.

RESULTS

Six significant risk factors for SA were identified (P < .05): short interval from sting to reaction, absence of urticaria or angioedema (U/A) during anaphylaxis, older age, male sex, elevation of baseline serum tryptase (BST) level, and diagnosis of systemic mastocytosis. Moreover, elevation in BST level was significantly associated with the absence of U/A and older age. No association could be established between SA and comorbidities, concurrent cardiovascular medication, or the severity of the systemic reaction during the initiation of venom immunotherapy.

CONCLUSION

Apart from BST and older age, male sex, short interval from sting to reaction, and absence of U/A are also risk factors for SA. The association between elevated BST level and SA was largely confined to those who had an absence of U/A after field sting, possibly because of the higher risk of concurrent systemic mastocytosis. Patients with an SA after a field sting do not have an elevated risk of systemic reactions during the initiation of venom immunotherapy compared with patients with mild anaphylaxis; therefore, additional preventive measures are not necessary.

Risk factors and indicators of severe systemic insect sting reactions

Hymenoptera venom allergy ranks among the top three causes of anaphylaxis worldwide, and approximately one-quarter of sting-induced reactions are classified as severe. Fatal sting reactions are exceedingly rare, but certain factors may entail a considerably higher risk. Delayed administration of epinephrine and upright posture are situational risk factors which may determine an unfavorable outcome of the acute anaphylactic episode and should be addressed during individual patient education. Systemic mastocytosis and senior age are major, unmodifiable long-term risk factors and thus reinforce the indication for venom immunotherapy. Vespid venom allergy and male sex likewise augment the risk of severe or even fatal reactions. Further studies are required to assess the impact of specific cardiovascular comorbidities. Available data regarding potential effects of beta-blockers and/or ACE inhibitors in coexisting venom allergy are inconclusive and do not justify recommendations to discontinue guideline-directed antihypertensive treatment. The absence of urticaria/angioedema during sting-induced anaphylaxis is indicative of a severe reaction, serum tryptase elevation, and mast cell clonality. Determination of basal serum tryptase levels is an established diagnostic tool for risk assessment in Hymenoptera venom-allergic patients. Measurement of platelet-activating factor acetylhydrolase activity represents a complementary approach but is not available for routine diagnostic use.

Bone lesions in systemic mastocytosis: Bone histomorphometry and histopathological mechanisms

Osteoporosis is considered the most frequent skeletal manifestation of systemic mastocytosis (SM). We performed a retrospective analysis of sixty patients (37 males and 23 females) who underwent a bone biopsy in the assessment of SM or in the assessment of unexplained bone fragility. Thirty-three had simultaneously a bone marrow biopsy with a Jamshidi's needle; this sample was used for immunohistochemical analysis (tryptase, c-KIT. CD20, VCAM-1). Bone biopsy was realized in 42 cases in the assessment of SM to provide histologic proof of the disease and in 18 cases in the assessment of unexplained bone fragility and surprisingly revealed a SM. An increased bone turnover was observed in patients with SM with elevated eroded surfaces, osteoclast number and bone formation rate. In addition to nodules of mast cells (MC), a high number of MC was directly apposed on the trabeculae, affixed on the osteoblasts or the lining cells. The VCAM-1 adhesion protein recognizing α4β7 and α4β1 integrins may be a candidate to explain this particular adherence. One third of the bone marrow biopsies did not exhibit MC nodules or MC infiltration and led to a false negative diagnosis for SM. SM can be discovered in the assessment of fracture or osteoporosis. Transiliac bone biopsy allows for the diagnosis of the disease more accurately than bone marrow biopsy; it also provides a histomorphometric analysis of bone remodeling.

Risk factors for severe systemic sting reactions in wasp (Vespula spp.) and honeybee (Apis mellifera) venom allergic patients

Background

Hymenoptera stings are a major cause of anaphylaxis. Various risk factors are discussed in literature. This study aims to investigate potential risk factors for severe sting reactions in wasp (Vespula spp.) and honeybee (Apis mellifera) venom allergic patients and analyses the correlation between diagnostic test results and the severity of the allergic reaction.

Methods

480 patients suffering from wasp or honeybee venom allergy were included in this retrospective case series. Only individuals allergic to Vespula spp. but not to other vespids such as Polistes were considered. The severity of their systemic field sting reaction was analysed with regard to the amount of specific IgE antibodies to whole venom extracts and to major allergens of honeybee and/or wasp venom. Furthermore, the following potential risk factors for severe sting reactions were examined: age, sex, latency time, skin symptoms, baseline serum tryptase levels and the concentration of venom inducing a positive intracutaneous test.

Results

The two following indicators for severe systemic sting reactions in honeybee and wasp venom allergic patients have been identified: a short latency time and the absence of skin symptoms. The patient’s age and baseline serum tryptase levels have been found to positively correlate with the grade of the sting reaction only in individuals allergic to wasp venom. No correlation could be found between the degree of sensitisation and the severity of the allergic reaction. Neither the amount of specific IgE antibodies to whole venom extracts nor to major allergens were significantly associated with the severity of the sting reaction.

Conclusion

The clinical history is essential for the allergological workup and therapeutic decision on Hymenoptera venom allergies. A short latency time and the absence of skin symptoms are indicators for severe systemic sting reactions, followed by the patient’s age and baseline serum tryptase levels.

Exclusive Bee Venom Allergy: Risk Factors and Outcome of Immunotherapy

INTRODUCTION

Venom immunotherapy (VIT) is considered to be the gold-standard treatment for patients with Hymenoptera venom allergy. Data regarding VIT in bee venom (BV) allergic patients are scarce.

AIM

The aim of this study was to evaluate the outcome of VIT in patients with exclusive BV allergy and to try to define risk factors for VIT-induced systemic reactions (VIT-ISR) and VIT failure.

METHODS

This is a retrospective study including data from all BV allergic patients that were treated by VIT in the Allergy Unit at the Meir Medical Center in the years 1995-2018.

RESULTS

Two hundred and forty-seven patients with exclusive BV allergy were included; 206 (83.4%) preferred to undergo rush buildup. Sixty-nine patients (27.9%) had at least 1 reaction during buildup, with the c-kit mutation being the only significant risk factor (100 vs. 28.9%, p = 0.02). Female gender (25.4 vs. 13.3%, p = 0.04), conventional buildup schedule (26.8 vs. 14.1%, p = 0.04), and c-kit mutation (100 vs. 16.8%, p < 0.01) but not tryptase level were found to be significantly more frequent in recurrent reactors. Females (20.3 vs. 9%, p = 0.03), patients with severe systemic reaction to the index sting (24.3 vs. 9.5%, p = 0.004), and c-kit mutation (66 vs. 12%, p = 0.05) but not tryptase level were found to be risk factors for severe systemic reactions.

CONCLUSION

Despite the considerably high rate of VIT-ISR in patients with exclusive BV allergy, VIT can be performed safely and efficiently. C-kit mutation, and not basal serum tryptase level, seems to be a preferable biomarker for VIT-ISR in these patients.

Samsum Ant Venom Exerts Anticancer Activity Through Immunomodulation In Vitro and In Vivo

Samsum ant venom (SAV) is a rich repertoire of natural compounds with tremendous pharmacological properties. The present work explores its antineoplastic activity in different cell lines followed by its confirmation in vivo. The cell lines, HepG2, MCF-7, and LoVo showed the differential dose-dependent antineoplastic effect with an increased level of significant cytokines, including Interleukin (IL)-1β, IL-6, and IL-8 and transcription factor, Nuclear factor-kappa B (NF-κB). However, the venom was more effective on HepG2 and MCF-7 cells than LoVo cells. Furthermore, the extract was administered to four groups (n = 8) of rats. Group I was taken as a control without any treatment, whereas group II received CCl₄ (1 mL/kg) for induction of mild hepatoma. Group III was given 100 μg/kg of SAV twice a week for 1 month. Group IV was pretreated with the CCl₄ (like group II) followed by dosing with SAV (100 μg/kg) for 2 months as per the authors' prestandardized dosing schedule. Intriguingly, the rats of group IV demonstrated significant decrease in key cytokines, IL-1β and IL-6, as well as the transcription factors, including Tumor Necrosis Factor-alpha (TNF-α), NF-κB, and Inhibitor-kappa B (I-κB) as compared with group II. Furthermore, increase in IL-10 and First apoptosis signal (FAS) in the same group confirmed that SAV induces apoptosis at the given dose through immunomodulation leading to enhanced tumor killing in vivo. Hence, SAV has an excellent antineoplastic activity that can be directly used to treat certain types of cancer. Moreover, study of its ingredients can pave ways to design novel anticancer drugs. However, further in-depth investigation is required before its clinical trials.

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.

Targeted Treatment Options in Mastocytosis

Mastocytosis refers to a heterogeneous group of disorders resulting from the clonal proliferation of abnormal mast cells and their accumulation in the skin (cutaneous mastocytosis when only in the skin, CM) or in various organs (systemic mastocytosis, SM). This leads to a wide variety of clinical manifestations resulting from excessive mediator release in CM and benign forms of SM (indolent SM, ISM) and from tissue mast cell infiltration causing multiorgan dysfunction and failure in more aggressive subtypes (aggressive SM, ASM, or mast cell leukemia). In addition, SM may be associated with hematological neoplasms (AHN). While treatment of ISM primarily aims at symptom management with anti-mediator therapies, cytoreductive and targeted therapies are needed to control the expansion of neoplastic mast cells in advanced forms of SM, in order to improve overall survival. Mast cell accumulation results from a gain-of-function mutation (mostly the D816V mutation) within the KIT tyrosine kinase domain expressed by mast cells and additional genetic and epigenetic mutations may further determine the features of the disease (ASM and AHN). Consequently, tyrosine kinase inhibitors and targeted therapies directed against the oncogenic signaling machinery downstream of KIT are attractive therapeutic approaches. A better understanding of the relative contribution of these genetic and epigenetic events to the molecular pathogenesis of mastocytosis is of particular interest for the development of targeted therapies and therefore to better choose patient subgroups that would best benefit from a given therapeutic strategy.

Mastocytosis and Anaphylaxis

This article updates current knowledge on epidemiology, risk factors, triggers, and management of anaphylaxis in patients with mastocytosis. Hyperactive mast cells and higher number of effector mast cells are speculated to facilitate anaphylaxis in this condition. In children, increased risk is limited to those with extensive skin involvement and high tryptase. In adults, manifestations of anaphylaxis are severe with high frequency of cardiovascular symptoms. Hymenoptera stings are the most common triggers for these reactions; however, idiopathic anaphylaxis and reactions to food or drugs occur. Patients with mastocytosis should be informed about risk of anaphylaxis and prescribing emergency self-medication and installing emergency preparedness before general anesthesia is considered.

Safety and tolerability during build-up phase of a rush venom immunotherapy

BACKGROUND

Safety and tolerability of venom immunotherapy (VIT) in patients with concomitant disease and comedications, especially β-blockers (BBs) and angiotensin-converting enzyme inhibitors (ACEIs), are under discussion.

OBJECTIVE

To identify risk factors for the occurrence of systemic reactions (SRs) during the build-up phase of a 3-day rush VIT with focus on comorbidities and related comedications.

METHODS

Data of 175 three-day rush VIT courses (Vespula venom, n = 161; honeybee venom, n = 14) were analyzed. Starting with 0.02 μg of venom, the maintenance dose of 100 μg was reached in 15-dose increments within 3 days. Local reactions (LRs) and SRs were documented during the build-up phase. Comorbidities and related comedications were registered. Univariate, bivariate, and multivariate data analysis was performed.

RESULTS

During the 3-day rush VIT, an LR was seen in 74 (42.3%) of 175, a large LR (>10-cm diameter) in 82 (46.9%) of 175, and SRs in 19 (10.9%) of 175 VIT courses. Multivariate logistic regression revealed that female sex (P = .01), immunotherapy with honeybee venom (P = .003), and accompanying ACEI medication (P = .03) were independent predictors of the development of SRs during the build-up phase of VIT.

CONCLUSION

This study revealed that female sex, honeybee VIT, and ACEI use independent predictors for SRs.

Added sensitivity of component-resolved diagnosis in hymenoptera venom-allergic patients with elevated serum tryptase and/or mastocytosis

BACKGROUND

Anaphylaxis caused by hymenoptera venom allergy is associated with elevation of baseline serum tryptase (sBT) and/or mastocytosis in about 5% of patients. Up to now, no information has become available on single venom allergen sIgE reactivity and the usefulness of component-resolved approaches to diagnose this high-risk patient group. To address the component-resolved sIgE sensitization pattern and diagnostic sensitivity in hymenoptera venom-allergic patients with elevated sBT levels and/or mastocytosis, a panel of yellow jacket and honeybee venom allergens was applied on a widely used IgE immunoassay platform.

METHODS

Fifty-three patients with mastocytosis and/or elevated sBT tryptase level and systemic reactions to hymenoptera venoms were analyzed for their IgE reactivity to recombinant yellow jacket and honeybee venom allergens by Immulite3 g.

RESULTS

sIgE reactivity to Ves v 1, Ves v 5, Api m 1 to Api m 4 and Api m 10 was found at a similar frequency in hymenoptera venom-allergic patients with and without elevated sBT levels and/or mastocytosis. However, the use of the recombinant allergens and a diagnostic cutoff of 0.1 kUA /L allowed the diagnosis of patients with otherwise undetectable IgE to venom extract. The diagnostic sensitivity of yellow jacket venom allergy using the combination of Ves v 1 and Ves v 5 was 100%.

CONCLUSIONS

In high-risk patients with elevated sBT levels and/or mastocytosis, the use of molecular components and decreasing the threshold sIgE level to 0.1 kUA /L may be needed to avoid otherwise undetectable IgE to hymenoptera venom extracts in about 8% of such patients.

Venom immunotherapy: clinical efficacy, safety and contraindications

Venom-specific immunotherapy (VIT) is considered for the treatment of patients with IgE-mediated systemic allergic reactions (SARs) after developing a Hymenoptera venom allergy. Tolerance is achieved in a majority of patients after only a few days or even hours of rush immunotherapy. After VIT discontinuation, the allergy returns in up to 15% of patients. During VIT, the majority of patients have local reactions at the site of venom injections. SARs to VIT are much more frequent in honeybee-treated patients than in wasp-treated patients. Increased baseline serum tryptase and increased allergen-specific sensitivity of basophils are other factors that might be associated with systemic reactions (SRs) during VIT. Severe SRs occur mainly during the build-up phase but can also occur in the maintenance phase of the VIT, even in patients with a well-tolerated dose-increase phase. Pre-treatment with humanized anti-IgE antibodies (omalizumab) is effective in patients with repeated SARs; however, this use of omalizumab is off-label. In highly exposed patients with a history of very severe reactions, there are virtually no absolute contraindications for VIT.

Outcomes of allergy/immunology follow-up after an emergency department evaluation for anaphylaxis

BACKGROUND

Anaphylaxis guidelines currently recommend referring patients with anaphylaxis seen in the emergency department (ED) to an allergist for follow up.

OBJECTIVE

The objective of our study was to evaluate outcomes of allergy/immunology follow-up after an ED visit for anaphylaxis.

METHODS

A retrospective health records review was conducted from April 2008 to August 2012. Charts were reviewed independently by 2 allergists to determine outcomes. Descriptive statistics with corresponding 95% CIs were calculated.

RESULTS

Among 573 patients seen in the ED who met anaphylaxis diagnostic criteria, 217 (38%) had a documented allergy/immunology follow-up. After allergy/immunology evaluation, 16 patients (7% [95% CI, 5%-12%]) had anaphylaxis ruled out. Among those with an unknown ED trigger (n = 74), 24 (32% [95% CI, 23%-44%]) had a trigger identified; and, among those who had a specific suspected ED trigger (n = 143), 9 (6% [95% CI, 3%-12%]) had a trigger identified in a category other than the one suspected in the ED, and 28 (20% [95% CI, 14%-27%]) had an unknown trigger. Thus, there were a total of 77 patients (35% [95% CI, 29%-42%]) who had an alteration in the diagnosis of anaphylaxis or trigger after allergy/immunology evaluation. Four patients (2% [95% CI, 0.7%-4.6%]) were diagnosed with a mast cell activation disorder, and 13 patients (6% [95% CI, 4%-10%]) underwent immunotherapy or desensitization.

CONCLUSION

Overall, 35% of the patients with suspected anaphylaxis in the ED had an alteration in the diagnosis or suspected trigger after allergy/immunology evaluation. These results underscore the importance of allergy/immunology follow-up after an ED visit for anaphylaxis.

Serum basal tryptase may be a good marker for predicting the risk of anaphylaxis in children with food allergy

A relationship between serum basal tryptase (sBT) levels, anaphylactic reactions, and clonal mast cell diseases was shown recently in adults with venom allergy, but the relationship between sBT levels and IgE-mediated food allergy and anaphylaxis is not known. In this study, children with food allergy (FA; n = 167) were analyzed in two groups according to the presence (FA+/A+; n = 79) or absence of anaphylaxis (FA+/A-; n = 88) and were compared with a control group (n = 113). Median sBT values in FA+/A+, FA+/A-, and control groups were 4.0 ng/ml (2.8-5.8), 3.6 (2.3-4.5), and 3.3 (2.4-4.4), respectively (P = 0.022). sBT measurements higher than the cutoff values of 5.7 and 14.5 were associated with 50% and 90% predicted probabilities, respectively, of moderate to severe anaphylaxis. Children with tree nuts/peanut allergies had significantly higher levels of sBT than children with milk and egg allergy (P = 0.022). Results suggest that sBT levels may predict moderate to severe anaphylaxis in children with food allergy, which may follow a particular pattern according to the food allergy phenotype.

Bioactivity of Samsum ant (Pachycondyla sennaarensis) venom against lipopolysaccharides through antioxidant and upregulation of Akt1 signaling in rats

Background

This study aimed at investigating the oxidative stress ameliorating effect, lipids profile restoration, and the anti-inflammatory effect of Samsum Ant Venom (SAV) in induced endotoxemic male rats, injected with bacterial lipopolysaccharides (LPS).

Results

Results revealed that LPS significantly increased the oxidative stress indications in LPS-injected rats. A significant increase of both malondialdehyde (MDA), and advanced oxidative protein products (AOPP), as well as a significant suppression of glutathione were all detected. Treatment with 100 μg/kg dose of SAV significantly restored the oxidative stress normal indications and increased the total glutathione levels. Treatment of the LPS-rats with 100 μg/kg dose of SAV showed a clear anti-inflammatory function; as the histological architecture of the hepatic tissue was partially recovered, along with a valuable decrease in the leukocytes infiltrated the hepatic tissues. Treatment of some rat groups with 600 μg/kg dose of SAV after LPS injection induced a severe endotoxemia that resulted in very high mortality rates. SAV versus the effects of LPS on AKT1, Fas, TNF-α and IFN-γ mRNA expression. SAV was found to significantly lower Fas gene expression comparing to the LPS group and restore the level of IFN-γ mRNA expression to that of the control group.

Conclusion

In conclusion, SAV, at the dose of 100 μg/kg body weight, maintained and restored the oxidative stability, the anti-inflammatory, and the hypolipidemic bioactivity in rats after induced disruption of these parameters by LPS injection. This improvement by SAV was mediated by upregulation of AKT1.

Human breast carcinoma cells are induced to apoptosis by samsum ant venom through an IGF-1-dependant pathway, PI3K/AKT and ERK signaling

In the present study we evaluated the anti-tumor potential of samsum ant venom (SAV) from Pachycondyla sennaarensis on the human breast carcinoma cell line MCF-7. We found that SAV induced growth arrest of MCF-7 cells without affecting the viability of MCF-10 (non-tumorigenic normal breast epithelial cells) and normal PBMCs. We then analyzed its impact on IGF-1-mediated MCF-7 cell proliferation and its effect on the underlying IGF-1 signaling pathways. Using flow cytometry analysis, we showed that the percentage of apoptotic cells was fourfold higher in SAV-treated cells as compared to untreated cells. More importantly, treatment with SAV induced a marked reduction in actin polymerization and a subsequent marked reduction in IGF-1-mediated cell proliferation. In addition to growth-inhibitory and pro-apoptotic effects, significant reductions were also observed in the phosphorylation of AKT and ERK, but not p38MAPK, in SAV-treated cells as compared to untreated cells. Our data reveal unique anti-tumor effects of samsum ant venom.

Venom immunotherapy in patients with mastocytosis and hymenoptera venom anaphylaxis

Systemic mastocytosis (SM) is typically suspected in patients with cutaneous mastocytosis (CM). In recent years, the presence of clonal mast cells (MCs) in a subset of patients with systemic symptoms associated with MC activation in the absence of CM has been reported and termed monoclonal MC activation syndromes or clonal systemic MC activation syndromes. In these cases, bone marrow (BM) MC numbers are usually lower than in SM with CM, there are no detectable BM MC aggregates, and serum baseline tryptase is often <20 µg/l; thus, diagnosis of SM in these patients should be based on careful evaluation of other minor WHO criteria for SM in reference centers, where highly sensitive techniques for immunophenotypic analysis and investigation of KIT mutations on fluorescence-activated cell sorter-purified BM MCs are routinely performed. The prevalence of hymenoptera venom anaphylaxis (HVA) among SM patients is higher than among the normal population and it has been reported to be approximately 5%. In SM patients with IgE-mediated HVA, venom immunotherapy is safe and effective and it should be prescribed lifelong. Severe adverse reactions to hymenoptera stings or venom immunotherapy have been associated with increased serum baseline tryptase; however, presence of clonal MC has not been ruled out in most reports and thus both SM and clonal MC activation syndrome might be underdiagnosed in such patients. In fact, clonal BM MC appears to be a relevant risk factor for both HVA and severe reactions to venom immunotherapy, while the increase in serum baseline tryptase by itself should be considered as a powerful surrogate marker for anaphylaxis. The Spanish Network on Mastocytosis has developed a scoring system based on patient gender, the clinical symptoms observed during anaphylaxis and serum baseline tryptase to predict for the presence of both MC clonality and SM among individuals who suffer from anaphylaxis.

Total serum tryptase levels are higher in young infants

BACKGROUND

Mast cells participate in immune defense and allergic disease. At baseline, serum tryptase levels primarily reflect mast cell burden, while mast cell degranulation leads to granule tryptase release, which may be detectable as a transitory elevation of serum tryptase levels. Thus, mast cell burden and mast cell activity are reflected by serum tryptase levels, but reports are scarce in infants under 1 yr. We aimed at defining levels of total serum tryptase levels in this population.

METHODS

Total serum tryptase levels (ImmunoCAP; Phadia) were measured in 372 sera from infants younger than 1 yr. Two hundred and forty-two sera came from non-atopic, non-allergic infants in good condition, who had blood drawn for routine follow-up or diagnosis of illnesses that are not known to induce changes in serum tryptase levels. Seventy-two sera were from atopic and/or allergic infants, and 58 sera were from non-atopic, non-allergic infants requiring intensive care.

RESULTS

Median serum tryptase levels were highest in infant2s under 3 months (6.12 ± 3.47 μg/l) and gradually decreased before reaching levels similar to those described in adults and older children (3.85 ± 1.8 μg/l between 9 and 12 months). Atopic/allergic status was associated with even higher tryptase levels (14.20 ± 10.22 μg/l in infants younger than 3 months). Intensive care patients had lower levels of serum tryptase (4.12 ± 3.38 μg/l in infants younger than 3 months). Longitudinal follow-up was performed in 27 patients and showed tryptase levels decrease over time in individual patients. Infants'sex was not found to interfere with serum tryptase levels.

CONCLUSION

Total serum tryptase levels are significantly higher in younger infants compared with older ones. In infants of the same age, serum tryptase levels may vary according to the clinical condition and thus suggest mast cell involvement in the physiologic as well as in the allergic immune responses of young infants.

Developments in the field of allergy in 2009 through the eyes of Clinical and Experimental Allergy

In 2009 the journal published in the region of 200 papers including reviews, editorials, opinion pieces and original papers that ran the full gamut of allergic disease. It is instructive to take stock of this output to determine patterns of interest and where the cutting edge lies. We have surveyed the field of allergic disease as seen through the pages of Clinical and Experimental Allergy (CEA) highlighting trends, emphasizing notable observations and placing discoveries in the context of other key papers published during the year. The review is divided into similar sections as the journal. In the field of Asthma and Rhinitis CEA has contributed significantly to the debate about asthma phenotypes and expressed opinions about the cause of intrinsic asthma. It has also added its halfpennyworth to the hunt for meaningful biomarkers. In Mechanisms the considerable interest in T cell subsets including Th17 and T regulatory cells continues apace and the discipline of Epidemiology continues to invoke a steady stream of papers on risk factors for asthma with investigators still trying to explain the post-second world war epidemic of allergic disease. Experimental Models continue to make important contributions to our understanding of pathogenesis of allergic disease and in the Clinical Allergy section various angles on immunotherapy are explored. New allergens continue to be described in the allergens section to make those allergen chips even more complicated. A rich and vibrant year helpfully summarized by some of our associate editors.