Single-Arm, Multicenter Phase I/II Clinical Trial for the Treatment of Envenomings by Massive Africanized Honey Bee Stings Using the Unique Apilic Antivenom.

We evaluated the safety, optimal dose, and preliminary effectiveness of a new-approach Africanized honeybee (Apis mellifera) Antivenom (AAV) in a phase I/II, multicenter, non-randomized, single-arm clinical trial involving 20 participants with multiple stings. Participants received 2 to 10 vials of AAV depending on the number of stings they suffered, or a predefined adjuvant, symptomatic, and complementary treatment. The primary safety endpoint was the occurrence of early adverse reactions within the first 24 h of treatment. Preliminary efficacy based on clinical evolution, including laboratory findings, was assessed at baseline and at various time points over the four following weeks. ELISA assays and mass spectrometry were used to estimate venom pharmacokinetics before, during, and after treatment. Twenty adult participants, i.e., 13 (65%) men and 7 (35%) women, with a median age of 44 years and a mean body surface area of 1.92 m2 (median = 1.93 m2) were recruited. The number of stings ranged from 7 to > 2,000, with a median of 52.5. Symptoms of envenoming were classified as mild, moderate, or severe in 80% (16), 15% (3), and 5% (1) of patients, respectively; patients with mild, moderate, or severe envenoming received 2, 6, and 10 vials of AAV as per the protocol. None of the patients had late reactions (serum sickness) within 30 d of treatment. There was no discontinuation of the protocol due to adverse events, and there were no serious adverse events. One patient had a moderate adverse event, transient itchy skin, and erythroderma. All participants completed the intravenous antivenom infusion within 2 h, and there was no loss to follow-up after discharge. ELISA assays showed venom (melittin and PLA2) concentrations varying between 0.25 and 1.479 ng/mL prior to treatment. Venom levels decreased in all patients during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and the absence of symptoms, venom levels increased again during outpatient care 10 d after discharge. Mass spectrometry showed melittin in eight participants, 30 d after treatment. Considering the promising safety results for this investigational product in the treatment of massive Africanized honeybee attack, and its efficacy, reflected in the clinical improvements and corresponding immediate decrease in blood venom levels, the AAV has shown to be safe for human use. Clinical Trial Registration: UTN: U1111-1160-7011, identifier [RBR-3fthf8].

Cross-Reactive Carbohydrate Determinant in Apis mellifera, Solenopsis invicta and Polybia paulista Venoms: Identification of Allergic Sensitization and Cross-Reactivity.

Allergic reactions to Hymenoptera venom, which could lead to systemic and even fatal symptoms, is characterized by hypersensitivity reactions mediated by specific IgE (sIgE) driven to venom allergens. Patients multisensitized to sIgE usually recognize more than one allergen in different Hymenoptera species. However, the presence of sIgE directed against Cross-Reactive Carbohydrate Determinant (CCD), which occurs in some allergens from Hymenoptera venom, hampers the identification of the culprit insects. CCD is also present in plants, pollen, fruits, but not in mammals. Bromelain (Brl) extracted from pineapples is a glycoprotein commonly used for reference to sIgE-CCD detection and analysis. In sera of fifty-one Hymenoptera allergic patients with specific IgE ≥ 1.0 KU/L, we assessed by immunoblotting the reactivity of sIgE to the major allergens of Apis mellifera, Polybia paulista and Solenopsis invicta venoms. We also distinguished, using sera adsorption procedures, the cases of CCD cross-reaction using Brl as a marker and inhibitor of CCD epitopes. The presence of reactivity for bromelain (24-28 kDa) was obtained in 43% of the patients, in which 64% presented reactivity for more than one Hymenoptera venom in radioallergosorbent (RAST) tests, and 90% showed reactivity in immunoblot analysis to the major allergens of Apis mellifera, Polybia paulista and Solenopsis invicta venoms. Sera adsorption procedures with Brl lead to a significant reduction in patients' sera reactivity to the Hymenoptera allergens. Immunoblotting assay using pre- and post-Brl adsorption sera from wasp-allergic patients blotted with non-glycosylated recombinant antigens (rPoly p1, rPoly p5) from Polybia paulista wasp venom showed no change in reactivity pattern of sIgE that recognize allergen peptide epitopes. Our results, using Brl as a marker and CCD inhibitor to test sIgE reactivity, suggest that it could complement diagnostic methods and help to differentiate specific reactivity to allergens' peptide epitopes from cross-reactivity caused by CCD, which is extremely useful in clinical practice.

Thymoquinone ameliorates Pachycondyla sennaarensis venom-induced acute toxic shock in male rats.

BACKGROUND: For many decades, the sting of Samsun ant (Pachycondyla sennaarensis) has been a serious clinical challenge for the people living in some of the major Middle East and Asian countries. In the present study, the therapeutic potential of Nigella sativa derived plant extract component, thymoquinone (TQ) has been tested against the Samsun ant venom (SAV) at the toxic dose in the rats. METHODS: The adult male rats were divided into four groups (n = 10): control, SAV treated, SAV + TQ treated and TQ alone treated. It was found that the sub-lethal dose of SAV alters not only many of the kidney and liver function markers but also induces oxidative stress in the animals. Moreover, the SAV also disturbs various immunological parameters including expression of PMNs, CD-80, CD-86, interleukins and other cytokines compromising the affected organism towards mild to severe allergic reactions including life-risking anaphylaxis. RESULTS: The plant extract, TQ, effectively restores many of the biochemical and oxidative stress parameters comparable to the normal concomitant with improving the immunological aspects that might attributive in relieving from SAV-induced toxicity and allergic reactions in the affected organism to a greater extent. CONCLUSION: Hence, TQ has an excellent antidote property against SAV-induced toxicities in vivo. Although the study is a vivid indication of the potential therapeutic potential of TQ against the SAV induced in vivo toxicity, yet the actual mechanism of interaction translating the toxicity amelioration warrants further investigations.

Value of component based diagnostics in IgE-mediated hymenoptera sting reactions.

BACKGROUND: Stings by insects can precipitate many signs and symptoms of dermatological and ocular diseases. Of particular importance is the anaphylaxis after Hymenoptera stings. Selection of the appropriate venom for immunotherapy requires a precise diagnosis, which is frequently difficult to confirm since the history presented by the patient is many times not conclusive and diagnostic tests are often positive for bee venom (BV) and vespula venom (VV). This double positivity is either caused by true double sensitization or by antibodies cross-reactive to homologous peptide sequences or to cross-reactive carbohydrate determinants (CCDs). In this study, we analyzed in 39 patients, tested positive for specific immunoglobulin E (sIgE) against BV and VV and CCDs whether the routine detection of sIgE against the recombinant species-specific major allergens (SSMAs) rApi m1 and rVes v5 enables the discrimination between genuine double sensitization and cross reactivity and therefore may be superior to other in vitro assays such as IgE-inhibition test or the basophil activation test. MATERIALS AND METHODS: Thirty-nine patients each with allergic reactions to vespula and/or honey bee stings and tested positive for sIgE antibodies against CCDs were analyzed for sIgE against BV, VV, CCDs (MUFX3) and SSMAs by UNICAP (CAP) and to BV, VV, bromelain, horseradish peroxidase and ascorbat oxidase by Immulite 2000 (IMMU). In 12 cases results from a basophil activation test, in nine cases results from IgE-inhibition assays and in 10 cases an unambiguous history of the patient were taken into consideration. RESULTS: A definite diagnosis could be assigned to each patient: sensitization to BV n = 7, sensitization to VV n = 29 and true double sensitization to both venoms n = 3. Detection of sIgE against BV and VV by CAP leads in three cases to the diagnosis BV allergy, in 35 cases to the diagnosis double sensitization and in one case to the diagnosis VV allergy. Detection of sIgE against BV and VV by IMMU leads in five cases to the diagnosis BV allergy, in 27 cases to the diagnosis double sensitization and in seven cases to the diagnosis VV allergy. Detection of sIgE against rApi m1 and rVes v5 by CAP leads in six cases to the diagnosis BV allergy, in eight cases to the diagnosis double sensitization, in 21 cases to the diagnosis VV allergy and in four cases to a false double-nagative result implicating no allergy. DISCUSSION AND CONCLUSION: Detection of sIgE to rApi m 1 and rVes v 5 by CAP is the most reliable diagnostic procedure to discriminate between true double sensitization and cross reactivity in patients with double-positive IgE results to venom extracts in the presence of sIgE against CCDs. In this study, however, we demonstrate that in nine of 39 patients tested positive for sIgE against CCDs, even the allergen component based diagnostic produces false double-positive and also false double-negative test results. Thus, we conclude that especially in hard to diagnose CCD positive patients beside the detection of sIgE, in vitro assays such as the IgE-inhibition test or the basophil activation test are still of importance. Detection of sIgE against only two SSMAs is not sufficient for a precise diagnosis. We propose inclusion of further SSMAs in diagnostic procedures.