NEW YORK (Reuters Health) -
For people who are strongly
allergic to bee venom, desensitization using sublingual (i.e.,
under-the-tongue) immunotherapy may be a safer than injection
immunotherapy, according to a proof-of-concept clinical trial
conducted in Italy.

“Our research opens a new possible application of
sublingual immunotherapy, which was never proposed for
hymenoptera allergy,” Dr. Giovanni Passalacqua told Reuters
Health.

The standard way to desensitize patients with bee sting
allergy is to administer small, increasing doses of venom by
subcutaneous injections. However, there is a “particular risk
of systemic/severe reactions” with this approach, the research
team notes in the Journal of Allergy and Clinical Immunology.

On the other hand, they say, “systemic side effects are
rare, severe adverse events are exceptional, and the common
local side effects are mild and self-limiting” with sublingual
immunotherapy, or SLIT.

To evaluate SLIT's suitability for hymenoptera allergy,
Passalacqua, at the University of Genoa, and his associates
conducted a trial involving patients who had experienced large
local reactions — swellings of 10 centimeters or more lasting
more than 24 hours — to bee stings.

Venom extract was administered under the tongue daily,
starting with a tiny amount and building to bigger doses over 6
months. The trial was completed by 14 patients randomly
assigned to SLIT and 12 assigned to placebo.

The maximum diameter of the local reaction when
participants were deliberately exposed to a “challenge” sting
was significantly reduced only in the active treatment group,
the investigators report.

SLIT with honeybee venom was well tolerated, the report
indicates, with no adverse events or discomfort reported by the
subjects.

“Other studies are currently ongoing to better define the
mechanisms of action of SLIT, and to assess its safety when
multiple allergens are used in the same patient,” Passalacqua
noted.

SOURCE: Journal of Allergy and Clinical Immunology, July
2008.