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Background.
Although the
efficacy of allergen
immunotherapy has
been demonstrated in
seasonal pollen
allergy, there is no
report of a double-blind
placebo-controlled
trial with
standardized pollen
extract in seasonal
respiratory allergy
from India. In the
agricultural area of
eastern India,
Phoenix sylvestris
Roxb or date sugar
palm is grown or
cultivated and
seasonal allergic
rhinitis is common
during the pollen
season.
Objective:
The objective of the
present study was to
observe the clinical
and immunological
changes during a 2-year
double-blind
placebo-controlled
trial of
immunotherapy with
standardized P
sylvestris pollen
extract in
respiratory patients
sensitive to pollen
from this wild date
palm. Thirty-fi ve
subjects with
typical seasonal
allergic rhinitis
with or without
bronchial asthma
were selected. A
symptom medication
score (based on a
questionnaire and
diary) was
correlated with
pollen counts as
recorded in a
Burkard sampler.
Eighteen subjects
were randomized to a
specific
immunotherapy (SIT)
group receiving
regular injections
containing
standardized
allergen extract and
17 to a placebo
control group.
Changes in the level
of specific
immunoglobulin (Ig)
E, IgG1, and IgG4
were recorded at 3-month
intervals.
Measurement of wheal
diameter, total IgE
level and forced
expiratory volume in
1 second (FEV1) were
performed before
starting and a month
after finishing
therapy.
Results: The
SIT group showed
decreases of 33.5%
and 57% from the
baseline symptommedication
scores during the
first and second
treatment season,
respectively. This
group showed
significant
decreases in skin-reactivity
to P sylvestris
pollen extract and
in specific IgE
levels, and
significant
increases in FEV1,
specific IgG1 (1.95
3.2
times higher) and
IgG4 (21.24 30.83
times higher). There
were no significant
changes in total IgE
levels. The control
group showed no
significant changes
for any parameter
except the
development of new
sensitization in 2
cases (to Saccharum
officinarum pollen
grain and Alternaria
species spores). The
rate of local
adverse reactions
was 0.024%.
Conclusion:
After a 2-year study,
allergen
immunotherapy with
standardized P
sylvestris pollen
extract was found to
be effective in
seasonal respiratory
allergic subjects
susceptible to P
sylvestris pollen
with a narrow range
of sensitization.
Key Words:
Phoenix sylvestris
pollen. Seasonal
rhinitis. Double-blind
placebo-controlled
trial. Immunotherapy.. |
