challenges during VIT. These indicate that the results of a
tolerated sting challenge in patients on VIT are reliable as
long as the treatment continues (92, 132).
Sting challenges have also been performed 1 year or
more after stopping VIT in order to monitor the duration
of the protection afforded by the treatment (132, 139–
141). Sting challenges for these purposes should be
restricted to scientific studies. This procedure is not
recommended as a routine diagnostic method, as there is
a risk that these stings might boost already decreased
sensitization or even re-sensitizes the patient (132).
Future strategies
Potentially there is still much can be undergone to
improve the diagnosis of Hymenoptera venom allergy.
Thanks to modern molecular biology technology, a
considerable number of major venom allergens both
from the honeybee and various vespids are available
today in recombinant form (Table 4) (18, 142). Recombinant
venom allergens will certainly improve the diagnosis
of venom allergy in the near future. There is a very
close correlation with regard to their IgE-binding capacity
(143) (comparison with the respective natural purified
preparations). Some disparities have, however, been
disclosed by RAST-inhibition and Western blot studies,
which revealed that all natural preparations were contaminated
with trace amounts of other venom allergens.
Recombinant allergens will therefore be superior to
highly purified natural preparations when it comes to
the determination of the true clinical relevance of an
individual allergen. Recombinant technology has also
been very helpful in clarifying cross-reactivities between
venom allergens from different species, genera or even
families of Hymenoptera. Finally, the use of recombinant
cocktails for diagnosis is promising