Exploring oak processionary caterpillar induced lepidopterism (part 2): ex vivo bio-assays unmask the role of TRPV1.

As human skin comes into contact with the tiny hairs or setae of the oak processionary caterpillar, Thaumetopoea processionea, a silent yet intense chemical confrontation occurs. The result is a mix of issues: skin rashes and an intense itching that typically lasts days and weeks after the contact. This discomfort poses a significant health threat not only to humans but also to animals. In Western Europe, the alarming increase in outbreaks extends beyond areas near infested trees due to the dispersion of the setae. Predictions indicate a sustained rise in outbreaks, fueled by global changes favoring the caterpillar's survival and distribution. Currently, the absence of an efficient treatment persists due to significant gaps in our comprehension of the pathophysiology associated with this envenomation. Here, we explored the interaction between the venom extract derived from the setae of T. processionea and voltage- and ligand-gated ion channels and receptors. By conducting electrophysiological analyses, we discovered ex vivo evidence highlighting the significant role of TPTX1-Tp1, a peptide toxin from T. processionea, in modulating TRPV1. TPTX1-Tp1 is a secapin-like peptide and demonstrates a unique ability to modulate TRPV1 channels in the presence of capsaicin, leading to cell depolarization, itch and inflammatory responses. This discovery opens new avenues for developing a topical medication, suggesting the incorporation of a TRPV1 blocker as a potential solution for the local effects caused by T. processionea.

Exploring oak processionary caterpillar induced lepidopterism (Part 1): unveiling molecular insights through transcriptomics and proteomics.

Lepidopterism, a skin inflammation condition caused by direct or airborne exposure to irritating hairs (setae) from processionary caterpillars, is becoming a significant public health concern. Recent outbreaks of the oak processionary caterpillar (Thaumetopoea processionea) have caused noteworthy health and economic consequences, with a rising frequency expected in the future, exacerbated by global warming promoting the survival of the caterpillar. Current medical treatments focus on symptom relief due to the lack of an effective therapy. While the source is known, understanding the precise causes of symptoms remain incomplete understood. In this study, we employed an advanced method to extract venom from the setae and identify the venom components through high-quality de novo transcriptomics, venom proteomics, and bioinformatic analysis. A total of 171 venom components were identified, including allergens, odorant binding proteins, small peptides, enzymes, enzyme inhibitors, and chitin biosynthesis products, potentially responsible for inflammatory and allergic reactions. This work presents the first comprehensive proteotranscriptomic database of T. processionea, contributing to understanding the complexity of lepidopterism. Furthermore, these findings hold promise for advancing therapeutic approaches to mitigate the global health impact of T. processionea and related caterpillars.

The venom and telopodal defence systems of the centipede Lithobius forficatus are functionally convergent serial homologues.

BACKGROUND: Evolution of novelty is a central theme in evolutionary biology, yet studying the origins of traits with an apparently discontinuous origin remains a major challenge. Venom systems are a well-suited model for the study of this phenomenon because they capture several aspects of novelty across multiple levels of biological complexity. However, while there is some knowledge on the evolution of individual toxins, not much is known about the evolution of venom systems as a whole. One way of shedding light on the evolution of new traits is to investigate less specialised serial homologues, i.e. repeated traits in an organism that share a developmental origin. This approach can be particularly informative in animals with repetitive body segments, such as centipedes. RESULTS: Here, we investigate morphological and biochemical aspects of the defensive telopodal glandular organs borne on the posterior legs of venomous stone centipedes (Lithobiomorpha), using a multimethod approach, including behavioural observations, comparative morphology, proteomics, comparative transcriptomics and molecular phylogenetics. We show that the anterior venom system and posterior telopodal defence system are functionally convergent serial homologues, where one (telopodal defence) represents a model for the putative early evolutionary state of the other (venom). Venom glands and telopodal glandular organs appear to have evolved from the same type of epidermal gland (four-cell recto-canal type) and while the telopodal defensive secretion shares a great degree of compositional overlap with centipede venoms in general, these similarities arose predominantly through convergent recruitment of distantly related toxin-like components. Both systems are composed of elements predisposed to functional innovation across levels of biological complexity that range from proteins to glands, demonstrating clear parallels between molecular and morphological traits in the properties that facilitate the evolution of novelty. CONCLUSIONS: The evolution of the lithobiomorph telopodal defence system provides indirect empirical support for the plausibility of the hypothesised evolutionary origin of the centipede venom system, which occurred through functional innovation and gradual specialisation of existing epidermal glands. Our results thus exemplify how continuous transformation and functional innovation can drive the apparent discontinuous emergence of novelties on higher levels of biological complexity.

Diversely evolved xibalbin variants from remipede venom inhibit potassium channels and activate PKA-II and Erk1/2 signaling.

BACKGROUND: The identification of novel toxins from overlooked and taxonomically exceptional species bears potential for various pharmacological applications. The remipede Xibalbanus tulumensis, an underwater cave-dwelling crustacean, is the only crustacean for which a venom system has been described. Its venom contains several xibalbin peptides that have an inhibitor cysteine knot (ICK) scaffold. RESULTS: Our screenings revealed that all tested xibalbin variants particularly inhibit potassium channels. Xib1 and xib13 with their eight-cysteine domain similar to spider knottins also inhibit voltage-gated sodium channels. No activity was noted on calcium channels. Expanding the functional testing, we demonstrate that xib1 and xib13 increase PKA-II and Erk1/2 sensitization signaling in nociceptive neurons, which may initiate pain sensitization. Our phylogenetic analysis suggests that xib13 either originates from the common ancestor of pancrustaceans or earlier while xib1 is more restricted to remipedes. The ten-cysteine scaffolded xib2 emerged from xib1, a result that is supported by our phylogenetic and machine learning-based analyses. CONCLUSIONS: Our functional characterization of synthesized variants of xib1, xib2, and xib13 elucidates their potential as inhibitors of potassium channels in mammalian systems. The specific interaction of xib2 with Kv1.6 channels, which are relevant to treating variants of epilepsy, shows potential for further studies. At higher concentrations, xib1 and xib13 activate the kinases PKA-II and ERK1/2 in mammalian sensory neurons, suggesting pain sensitization and potential applications related to pain research and therapy. While tested insect channels suggest that all probably act as neurotoxins, the biological function of xib1, xib2, and xib13 requires further elucidation. A novel finding on their evolutionary origin is the apparent emergence of X. tulumensis-specific xib2 from xib1. Our study is an important cornerstone for future studies to untangle the origin and function of these enigmatic proteins as important components of remipede but also other pancrustacean and arthropod venoms.

Basophil activation in insect venom allergy: comparison of an established test using liquid reagents with a test using 5-color tubes with dried antibody reagents.

BACKGROUND: Flow cytometry-based basophil activation tests (BAT) have been performed with various modifications, differing in the use of distinct identification and activation markers. Established tests use liquid reagents while a new development involves the use of tubes with dried antibody reagents. The aim of this pilot study was to compare these two techniques in patients with insect venom allergy. METHODS: Seventeen patients with an insect venom allergy were included in the study. The established "BAT 1" utilizes conventional antibody solutions of anti-CCR3 for basophil identification and anti-CD63 to assess basophil activation, whereas "BAT 2" uses dried anti-CD45, anti-CD3, anti-CRTH2, anti-203c and anti-CD63 for identification and activation measurement of basophils. Negative and positive controls as well as incubations with honey bee venom and yellow jacket venom at three concentrations were performed. RESULTS: Seven patients had to be excluded due to low basophil counts, high values in negative controls or negative positive controls. For the remaining 10 patients the overall mean (± SD) difference in activated basophils between the two tests was 0.2 (± 12.2) %P. In a Bland-Altman plot, the limit of agreement (LoA) ranged from 24.0 to -23.7. In the qualitative evaluation (value below/above cut-off) Cohen's kappa was 0.77 indicating substantial agreement. BAT 2 took longer to perform than BAT 1 and was more expensive. CONCLUSION: The BAT 2 technique represents an interesting innovation, however, it was found to be less suitable compared to an established BAT for the routine diagnosis of insect venom allergies.

Selection Across the Three-Dimensional Structure of Venom Proteins from North American Scolopendromorph Centipedes.

Gene duplication followed by nucleotide differentiation is one of the simplest mechanisms to develop new functions for genes. However, the evolutionary processes underlying the divergence of multigene families remain controversial. We used multigene families found within the diversity of toxic proteins in centipede venom to test two hypotheses related to venom evolution: the two-speed mode of venom evolution and the rapid accumulation of variation in exposed residues (RAVER) model. The two-speed mode of venom evolution proposes that different types of selection impact ancient and younger venomous lineages with negative selection being the predominant form in ancient lineages and positive selection being the dominant form in younger lineages. The RAVER hypothesis proposes that, instead of different types of selection acting on different ages of venomous lineages, the different types of selection will selectively contribute to amino acid variation based on whether the residue is exposed to the solvent where it can potentially interact directly with toxin targets. This hypothesis parallels the longstanding understanding of protein evolution that suggests that residues found within the structural or active regions of the protein will be under negative or purifying selection, and residues that do not form part of these areas will be more prone to positive selection. To test these two hypotheses, we compared the venom of 26 centipedes from the order Scolopendromorpha from six currently recognized species from across North America using both transcriptomics and proteomics. We first estimated their phylogenetic relationships and uncovered paraphyly among the genus Scolopendra and evidence for cryptic diversity among currently recognized species. Using our phylogeny, we then characterized the diverse venom components from across the identified clades using a combination of transcriptomics and proteomics. We conducted selection-based analyses in the context of predicted three-dimensional properties of the venom proteins and found support for both hypotheses. Consistent with the two-speed hypothesis, we found a prevalence of negative selection across all proteins. Consistent with the RAVER hypothesis, we found evidence of positive selection on solvent-exposed residues, with structural and less-exposed residues showing stronger signal for negative selection. Through the use of phylogenetics, transcriptomics, proteomics, and selection-based analyses, we were able to describe the evolution of venom from an ancient venomous lineage and support principles of protein evolution that directly relate to multigene family evolution.

Occupational anaphylaxis-Data from the anaphylaxis registry.

BACKGROUND: Epidemiologic data on occupational anaphylaxis is scarce, and there is a need of more knowledge about work-related anaphylactic episodes. METHODS: Based on the data of the Anaphylaxis Registry, we identified cases related to occupational exposure and analyzed the elicitors, demographics, severity of clinical reaction and management. RESULTS: Since 2017, 5851 cases with an information about the occupational relation of the anaphylactic episode were registered whereby 225 (3.8%) were assigned to be caused by an occupational allergen. The vast majority of these occupational anaphylaxis cases were caused by insects (n = 186, 82.7%) followed by food (n = 27, 12.0%) and drugs (n = 8, 3.6%). Latex elicited occupational anaphylaxis in only two cases. Beekeepers, gardeners, farmers, and individuals working in professions associated with food handling, for example, employees in restaurants, bakery, pastry, and cooks were most frequently affected. The comparison of the occupational insect venom-induced anaphylaxis to a group of non-occupational insect anaphylaxis in adults (n = 1842) revealed a significant younger age in occupational anaphylaxis (46 vs. 53 years), a predominance of bee-induced cases (38% vs. 17%), and a higher rate of venom immunotherapy in a primary care setting (3.3% vs. 1.3%, p = .044). In the occupational- versus non-occupational adults with food-induced anaphylaxis atopic dermatitis as concomitant atopic disease was observed more frequently (n = 486; 20% vs. 10%), although this was not significant. CONCLUSION: Our data demonstrate the impact of venom allergy in work-related anaphylaxis. Foods and drugs are less frequently elicitors, and latex-induced occupational anaphylaxis was rare. More data are needed to determine risk factors associated with occupational anaphylaxis.

High burden of clonal mast cell disorders and hereditary α-tryptasemia in patients who need Hymenoptera venom immunotherapy.

BACKGROUND: In patients who require venom immunotherapy (VIT), there is a need to identify underlying mast cell (MC) disorders since these may affect the risk and severity of future sting reactions and the long-term effectiveness of VIT. METHODS: 1319 individuals with Hymenoptera venom allergy (HVA) who needed VIT from referral centers in Slovenia, Austria, Croatia, and Poland underwent examination for KIT p.D816V in peripheral blood leukocytes (PBL) using a highly sensitive PCR test and tryptase genotyping by digital droplet PCR. We also included 183 control individuals with large local reactions (LLRs) to Hymenoptera stings and with asymptomatic sensitization to Hymenoptera venoms. RESULTS: 285 of 1319 individuals recommended for VIT (21.6%) were positive for KIT p.D816V in PBL, preferably those who present with severe reaction (33.9% [n = 207 of 610] with Ring-Messmer grade 3-4 vs. 11% [n = 78 of 709] with Grade 1-2; p < .0001), whereas only 1.3% (n = 2 of 152) of controls with LLR and none with asymptomatic sensitization (n = 31) had KIT p.D816V. KIT p.D816V allelic burden was higher in those with severe reaction (median 0.018% [n = 207] in Grade 3-4 vs. 0.001% [n = 78] in Grade 1-2; p < .0001), and the majority had normal baseline serum tryptase levels (69% [n = 196 of 285]). All KIT p.D816V-positive individuals (n = 41) who underwent bone marrow (BM) biopsy were found to have underlying clonal diseases, principally BM mastocytosis. HαT was also associated with severe HVA and symptoms (p < .01), and remarkably, 31.0% (n = 31 of 100) were found to have concomitant KIT p.D816V. Concomitant HαT and KIT p.D816V showed an additive effect, and having both was associated with the highest risk for severe HVA, even higher than having either HαT or KIT p.D816V alone (OR = 3.8; p < .01). CONCLUSIONS: By employing prospective universal tryptase genotyping and examination for KIT p.D816V in PBL in large HVA populations, we have demonstrated a high burden of clonal MC disorders and HαT in patients who require VIT.

Evaluating Hymenoptera Venom Allergy Severity: A Data-Centric Comparison of Grading Instruments.

INTRODUCTION: While a consensus seems to have been reached with regard to the definition of anaphylaxis, there is no universal instrument for scoring allergic reaction severity despite more than 30 having been proposed by the time of writing. This severely hampers comparison of data between studies. While scales have been compared with regard to their utility in grading food-related reactions, no such comparisons have been made for Hymenoptera venom-associated reactions. METHODS: The study conducted a retrospective analysis to compare the severity of Hymenoptera venom allergy reactions in 104 participants with suspected Hymenoptera venom allergy. The study applied six grading instruments to each reaction, also evaluating them against the NIAID/FAAN anaphylaxis criteria. Sensitivity, specificity, and receiver operating characteristic area under the curve (AUC) for identifying anaphylaxis were calculated. Severity scales were simplified into "mild," "moderate," and "severe" categories. The most common severity grade across the five scales was determined using a custom function to establish a consensus severity grade. RESULTS: The most common culprit insects were honeybees (49.0%). Among the 88 participants with generalized reactions, the highest proportion had involvement of four organ systems. The scales showed high specificity for detecting anaphylaxis, especially when using higher grades of the Mueller, WAO, and Dribin scales. The diagnostic yields (AUC) varied, with the WAO scale having the highest AUC (0.94) for grades 3, 4, and 5. Spearman correlation analysis showed the strongest correlations seen between the Brown and Dribin, Ring and Messmer and Dribin, and Ring and Messmer and Reisman scales. The lowest correlations were observed with the Mueller scale when paired with the WAO, Reisman, and Dribin scales. An inter-rater reliability analysis showed substantial agreement between scales with the same number of grading levels. The agreement was highest for the Brown and Dribin scales, indicating a strong consistency in reaction severity classification across different instruments. CONCLUSION: While all instruments were effective in stratifying reactions, they showed limitations in differentiating milder phenotypes. The Brown and Dribin scales stood out for their high agreement with the consensus score and sensitivity in identifying anaphylaxis. Our findings suggest that adopting either of these scales could significantly unify the reporting of allergic reactions. We believe the format of an instrument should be tailored to its intended purpose, with clinical decision aids being simpler and research tools being more detailed.

Efficacy and safety of hymenoptera venom immunotherapy.

Background: Being stung by Hymenoptera species can cause life-threatening anaphylaxis. Although venom immunotherapy (VIT) seems to be the most effective treatment, its long-term efficacy, and risk factors for adverse events remain unclear. Objective: The objective was to investigate the long-term efficacy of VIT and evaluate adverse events and risk factors related to this. Method: Patients who received VIT in a tertiary-care adult allergy clinic between January 2005 and July 2022 were included. Patients' data were compared with those of individuals who had been diagnosed with bee and/or wasp venom allergy during the same period but had not received VIT and experienced field re-stings. Results: The study included 105 patients with venom allergy, of whom 68 received VIT and 37 did not receive VIT. Twenty-three patients (34%) completed 5 years of VIT, and the overall mean ± standard deviation VIT duration was 46.9 ± 20.9 months. Re-stings occurred in 5 of 23 patients who completed 5 years of VIT, and none of them developed a systemic reaction. Eighteen patients (40%) experienced re-stings after prematurely discontinuing VIT, of whom eight (44%) developed a systemic reaction. In the control group of patients who did not receive VIT, 26 patients (70.3%) experienced re-stings, and all had systemic reactions (100%), with no change in their median Mueller scores. There was a significant difference in the median Mueller score change between the patients who received VIT and the controls who did not (p = 0.016). A total of 13 patients (19%) experienced adverse events while receiving VIT, which were systemic reactions in nine honeybee VIT. The use of ß-blockers was determined as the most important risk factor (odds ratio 15.9 [95% confidence interval, 1.2-208.8]; p = 0.035). Conclusion: It was confirmed that VIT was effective in both reducing the incidence and the severity of re-sting reactions. These effects were more pronounced in the patients who completed 5 years of VIT.

Clinical features, severity, and immunological changes during venom immunotherapy in children and adults.

Background: Hymenoptera venom allergy (HVA) is among the most common causes of severe allergic reactions worldwide. Objective: To investigate clinical features and factors that affect the severity of HVA and to determine the alterations in immunologic biomarkers after venom immunotherapy (VIT). Methods: Seventy-six adults and 36 children were prospectively investigated. We analyzed specific immunoglobulin E (sIgE) and sIgG4 levels of venom extracts and components (rApi m1, rApi m10, rVes v1, rVes v5, rPol d5) before and after the first year of VIT. Results: Although cardiovascular symptoms were more common in adults (p < 0.001), the skin was the most affected organ in children (p = 0.009). Serum basal tryptase (sBT) levels were higher in the adults than the children (p < 0.001). The absence of urticaria (odds ratio [OR] 4.208 [95% confidence interval {CI}, 1.395-12.688]; p = 0.011) and sBT ≥ 5.2 ng/mL (OR 11.941 [95% CI, 5.220-39.733]; p < 0.001) were found as the risk factors for grade IV reactions. During VIT, changes in sIgE levels were variable. In the Apis VIT group, we observed remarkable increases in sIgG4 levels in Apis extract and rApi m1 but not in Api m10. Vespula extract, rVes v1, and rVes v5 sIgG4 levels were significantly increased in Vespula VIT group, we also detected significant increases in the Polistes extract and rPol d5 sIgG4 levels, which were not observed in the Apis VIT group. In the patients who received both Apis and Vespula VIT, increases in sIgG4 levels were observed for both venoms. Conclusion: Adults and children can have different clinical patterns. After 1 year, VIT induced a strong IgG4 response. Although Apis immunotherapy (IT) induced Apis sIgG4, excluding Api m10, Vespula IT induced both Vespula and Polistes sIgG4.

Health disparities in hymenoptera venom allergy management.

Background: Hymenoptera venom anaphylaxis (HVA) is reported in up to 3% of stings and accounts for approximately 40 US deaths annually. HVA patients require immediate availability of epinephrine and Allergist referrals for consideration of venom immunotherapy. Data regarding epinephrine autoinjector prescriptions, Allergist referral rates, and potential racial disparities are limited. Objective: The primary objective was to determine if there were statistically significant differences in epinephrine autoinjector prescriptions and Allergist referrals between white and African American patients. The secondary objectives were to determine if there were statistically significant differences between adult and pediatric patients and to determine if there were significant differences between epinephrine prescriptions between patients with and without Allergist referrals. Method: This study is a retrospective, descriptive chart review analyzing patients seen between January 01, 2019 and December 31, 2021. Data were obtained utilizing the Epic Systems (Verona, WI) application Slicer Dicer. Individual chart review was performed for age, race, epinephrine autoinjector prescription, and Allergist referral. Results: 342 patients were identified as having HVA. White patients (60 out of 219; 27.4%) were more likely to get epinephrine autoinjector prescriptions than African American patients (17 out of 109; 15.6%) (p = 0.018). Adult patients (25 out of 314; 8.0%) were less likely than pediatric patients (8 out of 28; 28.6%) to have Allergist referrals (p = 0.004). Patients with Allergist referrals (25 out of 32; 78.1%) were more likely to be prescribed an epinephrine autoinjector than patient without Allergist referrals (54 out of 310; 17.4%) (p < 0.00001). Conclusion: Epinephrine autoinjector prescriptions and Allergist referrals are low overall in HVA. Racial disparities were identified with African American patients being significantly less likely to receive epinephrine autoinjector prescriptions. Additionally, adult patients, who may be at increased risk, were less likely to receive Allergist referrals.

Hymenoptera venom immunotherapy: Safety and efficacy of an accelerated induction regimen with depot aluminum adsorbed extracts.

Introduction: Hymenoptera venom immunotherapy (VIT) is the only therapy that protects patients with Hymenoptera venom allergy by preventing systemic reactions after a new sting. Various extracts for VIT are available and used. VIT administration consists of an induction phase and a maintenance phase. Depot preparations of Hymenoptera VIT extracts are typically used for cluster and conventional protocols, and the maintenance phase. Many patients with Hymenoptera allergy need to achieve tolerance quickly because of the high risk of re-sting and possible anaphylaxis. Objective: Our study aimed to show the safety and efficacy of an accelerated regimen with depot preparations on aluminum hydroxide by using relatively high starting doses in a heterogeneous group of patients. Methods: The research focused on a group of patients with a history of severe systemic reactions to Hymenoptera stings, with the necessity of swift immunization due to high occupational risks. Aluminum hydroxide depot extracts either of Vepula species or Apis mellifera extracts were used. Results: The induction protocol was started with the highest concentration of depot venom extract of 100,000 standard quality unit and was well tolerated by 19 of 20 patients. Onne patient presented with a mild systemic reaction during the accelerated induction schedule, which was promptly treated with intravenous steroids and intramuscular H1 antihistamine; when switched to a conventional induction protocol, he had a similar reaction but finally reached maintenance with an H1-antagonist premedication. Conclusion: If validated, the accelerated induction protocol by using depot aluminum adsorbed extracts with the highest concentration of venom from the beginning could offer a streamlined and accessible treatment modality for patients diagnosed with anaphylaxis from bee and wasp venoms in need of rapid desensitization.

Production, composition, and mode of action of the painful defensive venom produced by a limacodid caterpillar, Doratifera vulnerans.

Venoms have evolved independently several times in Lepidoptera. Limacodidae is a family with worldwide distribution, many of which are venomous in the larval stage, but the composition and mode of action of their venom is unknown. Here, we use imaging technologies, transcriptomics, proteomics, and functional assays to provide a holistic picture of the venom system of a limacodid caterpillar, Doratifera vulnerans Contrary to dogma that defensive venoms are simple in composition, D. vulnerans produces a complex venom containing 151 proteinaceous toxins spanning 59 families, most of which are peptides <10 kDa. Three of the most abundant families of venom peptides (vulnericins) are 1) analogs of the adipokinetic hormone/corazonin-related neuropeptide, some of which are picomolar agonists of the endogenous insect receptor; 2) linear cationic peptides derived from cecropin, an insect innate immune peptide that kills bacteria and parasites by disrupting cell membranes; and 3) disulfide-rich knottins similar to those that dominate spider venoms. Using venom fractionation and a suite of synthetic venom peptides, we demonstrate that the cecropin-like peptides are responsible for the dominant pain effect observed in mammalian in vitro and in vivo nociception assays and therefore are likely to cause pain after natural envenomations by D. vulnerans Our data reveal convergent molecular evolution between limacodids, hymenopterans, and arachnids and demonstrate that lepidopteran venoms are an untapped source of novel bioactive peptides.

Severe food allergy reactions are associated with α-tryptase.

BACKGROUND: Increased TPSAB1 copy numbers encoding ⍺-tryptase are associated with severe reactions in adults with Hymenoptera venom allergy, systemic mastocytosis, and idiopathic anaphylaxis. OBJECTIVE: The primary objective was to assess the association between ⍺-tryptase and severity of food allergy. METHODS: A total of 119 subjects underwent tryptase genotyping; 82 of them were from an observational food allergy cohort at the National Institute of Allergy and Infectious Disease (NIAID), and 37 were from a cohort of children who reacted to peanut oral food challenge (OFC) at Lurie Children's Hospital of Chicago. The primary predictor was presence or absence of ⍺-tryptase. The primary outcomes for both cohorts were measures of severity of food allergy reaction. Secondary outcomes included OFC symptom scores (Bock/Practical Allergy [PRACTALL] and Severity Grading Score for Acute Reactions [SGSAR]). Correlation between total α-tryptase isoforms and OFC scores was also assessed to account for gene dosage effects. RESULTS: Among the subjects in the NIAID cohort, the presence of ⍺-tryptase was associated with a higher prevalence of food-triggered anaphylaxis than in those with only ß-tryptase (P = .026). Similarly, only 1 of 6 subjects in the OFC cohort with only ß-tryptase (17%) had a severe reaction, whereas 20 of 31 of subjects with α-tryptase (65%) had a severe reaction (P = .066). Subjects with ⍺-tryptase also had higher total SGSAR scores than did the subjects with no ⍺-tryptase (P = .003). In addition, there were also significant positive correlations between ⍺-tryptase isoform copy numbers and both higher total SGSAR and Bock/PRACTALL OFC scores (P = .008 and P = .003, respectively). CONCLUSION: The presence of α-tryptase in subjects is correlated with a higher prevalence of anaphylaxis or severe reaction to food than in subjects without any α-tryptase.

Blood Transcriptomics Identifies Multiple Gene Expression Pathways Associated with the Clinical Efficacy of Hymenoptera Venom Immunotherapy.

Allergen-specific venom immunotherapy (VIT) is a well-established therapy for Hymenoptera venom allergy (HVA). However, the precise mechanism underlying its clinical effect remains uncertain. Our study aimed to identify the molecular mechanisms associated with VIT efficiency. We prospectively included 19 patients with HVA undergoing VIT (sampled before the beginning of VIT, after reaching the maintenance dose, one year after finishing VIT, and after a sting challenge) and 9 healthy controls. RNA sequencing of whole blood was performed on an Illumina sequencing platform. Longitudinal transcriptomic profiling revealed the importance of the inhibition of the NFκB pathway and the downregulation of DUX4 transcripts for the early protection and induction of tolerance after finishing VIT. Furthermore, successful treatment was associated with inhibiting Th2, Th17, and macrophage alternative signalling pathways in synergy with the inhibition of the PPAR pathway and further silencing of the Th2 response. The immune system became activated when reaching the maintenance dose and was suppressed after finishing VIT. Finally, successful VIT restores the immune system's balance to a state similar to that of healthy individuals. Our results underline the important role of the inhibition of four pathways in the clinical effect of VIT: Th2, Th17, NFκB, and macrophage signalling. Two biomarkers specific for successful VIT, regardless of the time of sampling, were C4BPA and RPS10-NUDT3 and should be further tested as potential biomarkers.

Isolation and structural identification of a potassium ion channel Kv4.1 inhibitor SsTx-P2 from centipede venom. / 蜈蚣毒液中钾离子通道Kv4.1抑制剂SsTx-P2的分离和结构鉴定.

OBJECTIVES: To isolate a potassium ion channel Kv4.1 inhibitor from centipede venom, and to determine its sequence and structure. METHODS: Ion-exchange chromatography and reversed-phase high-performance liquid chromatography were performed to separate and purify peptide components of centipede venom, and their inhibiting effect on Kv4.1 channel was determined by whole-cell patch clamp recording. The molecular weight of isolated peptide Kv4.1 channel inhibitor was identified with matrix assisted laser desorption ionization-time-of-flight mass spectrometry; its primary sequence was determined by Edman degradation sequencing and two-dimensional mass spectrometry; its structure was established based on iterative thread assembly refinement online analysis. RESULTS: A peptide SsTx-P2 was separated from centipede venom with the molecular weight of 6122.8, and its primary sequence consists of 53 amino acid residues NH2-ELTWDFVRTCCKLFPDKSECTKACATEFTGGDESRLKDVWPRKLRSGDSRLKD-OH. Peptide SsTx-P2 potently inhibited the current of Kv4.1 channel transiently transfected in HEK293 cell, with 1.0 µmol/L SsTx-P2 suppressing 95% current of Kv4.1 channel. Its structure showed that SsTx-P2 shared a conserved helical structure. CONCLUSIONS: The study has isolated a novel peptide SsTx-P2 from centipede venom, which can potently inhibit the potassium ion channel Kv4.1 and displays structural conservation.

Clonal mast cell disorders and hereditary α-tryptasemia as risk factors for anaphylaxis.

The association between Hymenoptera venom-triggered anaphylaxis (HVA) and clonal mast cell-related disorders (cMCD) has been known for decades. However, recent breakthroughs in peripheral blood screening for KIT p.D816V missense variant have revealed the true extent of this clinical association whilst adding to our understanding of the underlying aetiology. Thus, recent large studies highlighted the presence of KIT p.D816V among 18.2% and 23% of patients with severe Hymenoptera venom-triggered anaphylaxis. A significant proportion of those patients have normal serum basal tryptase (BST) levels, with no cutaneous findings such as urticaria pigmentosa or other systemic findings such as organomegaly that would have suggested the presence of cMCD. These findings of an increased prevalence suggest that the impact of cMCD on anaphylaxis could be clinically underestimated and that the leading question for clinicians could be changed from 'how many patients with cMCD have anaphylaxis?' to 'how many patients with anaphylaxis have cMCD?'. The discovery of hereditary α-tryptasemia (HαT)-a genetic trait caused by an increased copy number of the Tryptase Alpha/Beta 1 (TPSAB1) gene-, first described in 2016, is now known to underlie the majority of cases of elevated BST outside of cMCD and chronic kidney disease. HαT is the first common heritable genetic modifier of anaphylaxis described, and it is associated with increased risk for severe HVA (relative risk = 2.0), idiopathic anaphylaxis, and an increased prevalence of anaphylaxis in patients with cMCD, possibly due to the unique activity profile of α/ß -tryptase heterotetramers that may potentiate immediate hypersensitivity reaction severity. Our narrative review aims to highlight recent research to have increased our understanding of cMCD and HαT, through recent lessons learned from studying their association with HVA. Additionally, we examined the studies of mast cell-related disorders in food and drug allergy in an effort to determine whether one should also consider cMCD and/or HαT in cases of severe anaphylaxis triggered by food or drugs.

Allergy to stings and bites from rare or locally important arthropods: Worldwide distribution, available diagnostics and treatment.

Insect venom allergy is the most frequent cause of anaphylaxis in Europe and possibly worldwide. The majority of systemic allergic reactions after insect stings are caused by Hymenoptera, and among these, vespid genera induce most of the systemic sting reactions (SSR). Honey bees are the second leading cause of SSR. Depending on the global region, other Hymenoptera such as different ant genera are responsible for SSR. Widely distributed hornets and bumblebees or local vespid or bee genera rarely induce SSR. Hematophagous insects such as mosquitoes and horse flies usually cause (large) local reactions while SSR occasionally occur. This position paper aimed to identify either rare or locally important insects causing SSR as well as rarely occurring SSR after stings or bites of widely distributed insects. We summarized relevant venom or saliva allergens and intended to identify possible cross-reactivities between the insect allergens. Moreover, we aimed to locate diagnostic tests for research and routine diagnosis, which are sometimes only regionally available. Finally, we gathered information on available immunotherapies. Major allergens of most insects were identified, and cross-reactivity between insects was frequently observed. While some diagnostics and immunotherapies are locally available, standardized skin tests and immunotherapies are generally lacking in rare insect allergy.

Hymenoptera venom skin testing: Adopting an accelerated test protocol.

BACKGROUND: The standard method of Hymenoptera venom intradermal skin test is performed at a starting concentration of 0.001 to 0.01 µg/mL and increased by 10-fold concentrations until positive or a maximum concentration of 1 µg/mL. Accelerated methods that start at higher concentrations have been reported as safe; however, many institutions have not adopted this approach. OBJECTIVE: To compare the outcome and safety of standard and accelerated venom skin test protocols. METHODS: This was a retrospective chart review of patients with suspected venom allergy who underwent skin testing at 4 allergy clinics within a single health care system from 2012 to 2022. Demographic data, test protocol (standard vs accelerated), test results, and adverse reactions were reviewed. RESULTS: Of 134 patients who underwent standard venom skin test, 2 (1.5%) experienced an adverse reaction, whereas none of the 77 patients who underwent accelerated venom skin test experienced an adverse reaction. One patient, with a history of chronic urticaria, experienced urticaria. The other experienced anaphylaxis requiring an epinephrine although had tested negative to all venom concentrations. Within the standard testing protocol, more than 75% of the positive results occurred at concentrations of 0.1 or 1 µg/mL. Within the accelerated testing protocol, more than 60% of the positive results occurred at 1 µg/mL. CONCLUSION: The study underscores the overall safety of venom intradermal skin test. Most of the positive results occurred at 0.1 or 1 µg/mL. Adopting an accelerated approach would reduce time and cost associated with testing.