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Objective: At
present, no reliable
in vitro test is
available to monitor
the success of
specific venom
immunotherapy (VIT)
in preventing insect
venom anaphylaxis.
We investigated
usefulness of the
basophil activation
test (BAT) in
predicting the
outcome of sting
challenge in bee
venomallergic
patients after VIT.
Patients and
Methods:
Twenty-one patients
with bee venom
anaphylaxis at the
end of VIT and 6
control participants
were enrolled. BAT
(flow-cytometric
evaluation of
allergen-induced
expression of CD63),
skin testing, and
specific
immunoglobulin (Ig)
E determination were
performed prior to
sting challenge.
Results: Five
of the 21 patients
(23.8%) reacted to
sting challenge. At
a bee venom
concentration of 100
ng/mL, the mean
proportion of
basophils expressing
CD63 was 56% in
reactors and 13.2%
in nonreactors
(P=.0321). Four of
the 5 reactors had
positive results and
14 of the 16
nonreactors had
negative results.
Thus, using 18.4%
and 21.6% (receiver
operating
characteristic curve
analysis) as the
cutoff
for expression of
the CD63 marker, the
positive and the
negative predictive
values were 67% and
93%, respectively,
and specificity and
sensitivity for BAT
were 80% and 83%,
respectively.
However, at a
concentration of
1000 ng/mL, no
significant
differences in
basophil activation
were observed
between reactors and
nonreactors.
Conclusion:
We found BAT to be a
helpful tool in
predicting the
clinical sensitivity
of bee
venomallergic
patients after VIT
(correlation between
BAT at submaximal
venom concentration
and sting
challenge).
Key words:
Basophil activation
test. CD63. Bee
venom anaphylaxis.
Sting challenge.
Specific venom
immunotherapy.
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