Vespa Velutina Nigritorax: A New Causative Agent in Anaphylaxis

We present the case of 71 year-old amateur beekeeper who was tolerant to bee stings. After being stung on the head by a wasp that the patient identified as "velutina", he immediately experienced paresthesia, genital pruritus that rapidly became generalized, hives on the chest, feeling of impending doom, and fainting. He was taken to a health center where scattered hives and hypotension were observed. A peripheral line was inserted to administer antihistamines and corticosteroids while awaiting the arrival of the ambulance. The patient subsequently underwent an allergy workup after he was shown several specimens of insects. He identified V velutina nigritorax. He had previously been stung twice by V velutina, although the reaction only occurred at the third sting.

* Skin test with A mellifera and P dominulus (positive 1 µg/mL), Vespula species (positive 0.1 µg/mL)

* IgE reactivity to complete extract and components: A mellifera positive; Vespula species, P dominulus, Vespa crabro, Dolichovespula maculata, Dochivespula arenaria, rApi m1, rVes v 1, rVes v 5 and rPol d 5 Negative

* Specific IgE against antigen components using the Advia Centaur platform: rApi m1, rVes v 1; negative; rVes v5, rPol d 5 Positive

* Specific IgE against antigen components using ImmunoCAP ISAAC 112 in the 112-allergen version which includes rApi m 1, nApi m 4, rVes v 5, and rPol d 5. The result was negative.

The wasp V velutina (Vespidae family) is from Asia. It reached other continents as a stowaway on ships and spread naturally. It arrived in the USA from Asia in 1840 and can now be found throughout the USA and Canada. It was first found in Europe at the end of 2005 in southern France, Since then, V velutina has spread naturally throughout 32 departments in France, reaching Spain 2011. Experts believe this wasp will have colonized the whole Iberian Peninsula in 10 years.

We report our first case of grade IV systemic reaction after a V velutina sting in an apiarist who was previously tolerant to bee venom. We used conventional techniques such as skin tests and specific IgE determination with comeplete extracts, as well as detection techniques such as Advia Centaur and ImmunoCAP. We verified positivity for vespid allergen antigen 5 and differences between techniques, as reported elsewhere.

Molecular diagnosis can help to avoid diagnostic errors due to panallergens, enables identification of genuine sensitization to a specific source of allergy, and, as in the present case, reveals the existence of cross-reactivity.

The detection of specific IgE for antigen 5 from other vespids suggests the presence of antigen 5 in V velutina that cross-reacts with the counterparts of the most common vespids. The question that remains to be answered is whether available immunotherapy for these counterparts could be effective in this patient with anaphylaxis after V velutina sting, since treatment with specific venom is not marketed.