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Summary.
Allergen
immunotherapy (IT)
has encouraging
therapeutic outcomes
but its safety is
still being
questioned because
of possible severe
systemic reactions.
The aim of this
study was to
determine the
frequency of
systemic reactions (SR),
and to identify
their correlation
with the
characteristics of
therapy, such as
allergen composition
and IT schedule, and
diagnosis. We
analyzed the data of
126 patients who
received IT between
2000-2003, and
suffered from
respiratory allergy
or hymenoptera venom
anaphylaxis. IT was
given by rush,
clustered or
conventional
schedules. The
standardized
allergen extracts
used were grass
pollen, house dust
mite and hymenoptera
venom in 88, 18 and
20 patients,
respectively. None
of the patients
received
premedication. A
total 4705
injections were
administered. One
hundred and twenty-three
adverse events (AE)
(2.6% per injection)
were documented in
46 patients. Sixty-one
of them were SRs
(1.3% SRs per
injection) and they
were seen in 28
patients. Asthmatics
had more tendency to
SRs (p=0.05). Rush
(1.8%) and clustered
(2.8%) IT protocols
were associated with
a higher rate of SRs
(per injection) when
compared to
conventional
schedule (0.9%) (rush
vs conventional;
p=0.013, clustered
vs conventional;
p=0.001). The
majority of SRs
corresponded to
grade 3 (49%). Forty-nine
(80%) of the 61 SRs
were observed during
the build-up phase,
and mostly with
pollen extracts
(75.5%). Patients
showed more severe
SRs during the build-up
phase (p<0.05).
Twenty-six (42.6%)
of the SRs were
immediate, whereas
35 (57.4%) SRs
appeared within 2
hours. Delayed SRs
were significantly
more frequent in
polysensitized
patients when
compared to
monosensitized
subjects (p=0.018).
Our data indicate
that rapid IT
regimens and the
presence of asthma
represent a greater
risk for SR
development. Since
the late SRs occur
as frequently as the
early ones, we
suggest a longer
waiting period
beyond 30 minutes,
especially in
polysensitized and
asthmatic patients.
Key words:
Immunotherapy,
systemic reactions,
safety, asthma. |
