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J ALLERGY CLIN IMMUNOL
VOLUME 125, NUMBER 2
Abstracts AB17
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64 House Dust Mite Population Growth and Allergen Production inCultures Maintained at Different TemperaturesL. G. Arlian, L. Yella, M. S. Morgan; Wright State University, Dayton,
OH.
RATIONALE: House dust mites are commercially cultured to produce
materials to make extracts for research, diagnostic tests and immunother-
apy. Culture conditions can influence the mite population growth and
allergen production in cultured house dust mites. The purpose of our
investigation was to determine how temperature influences the population
growth and allergen content of cultured Dermatophagoides pteronyssinus.
METHODS: D. pteronyssinus was cultured on comparable amounts of
media at 20 and 25C and the mite densities and allergen concentrations
of the cultures were determined at 2-week intervals until the culture media
was depleted.
RESULTS: At both temperatures, the mite population and allergen con-
centrations increased exponentially. The mite population and Der p1 and
Der p2 concentrations increased at faster rates and achieved higher levels
in cultures at 25C compared to 20C. The peak mite population density at
25C was 1.8 times greater than that at 20C. The Der p1 concentrations in-
creased faster than Der p2. At 10 weeks, whole cultures grown at 25C had
2.0 and 1.7 times more Der p1 and Der p2, respectively compared to cul-
tures grown at 20C. The concentrations of Der p1 and Der p2 in pure mite
bodies harvested from the cultures was 60% and 49% less than in whole
cultures grown at 25C.
CONCLUSION: Greater mite and allergen levels were achieved in cul-
tures grown at 25C compared to 20C demonstrating the importance of tem-
perature. Washing mite bodies harvested from cultures resulted in the loss
of large amounts of the allergen present in the mature whole cultures.
65 Biological Activity of Recombinant Tropomyosins from Ascarislumbricoides and Cockroach among Patients with Asthma and/or Rhinitis from Brazil
A. C. A. F. Sousa1, A. B. R. Santos1, M. C. R. Barbosa1, M. D. Chapman2,
L. K. Arruda1; 1School of Medicine of Ribeirao Preto, Ribeirao Preto,
BRAZIL, 2Indoor Biotechnologies Inc, Charlottesville, VA.
RATIONALE: Tropomyosins have been associated with IgE cross-reac-
tivity among invertebrates, including shrimp, cockroach, mites and para-
sites. We have reported the recombinant production of Ascaris
lumbricoides tropomyosin. The aim of this study was to investigate
whether recombinant A. lumbricoides tropomyosin has biological activity,
and to compare reactivity to that of recombinant cockroach tropomyosin
(rPer a 7).
METHODS: Frequency of positive skin tests to tropomyosins from A.lumbricoides and Periplaneta americana (rPer a 7), expressed in Pichia
pastoris, was evaluated in 36 cockroach allergic patients with asthma
and/or rhinitis, aged 12 to 70 years-old. All patients presented positive
skin tests to P. americana extract. Skin tests with recombinant allergens
were carried out at 10 mcg/ml concentration.
RESULTS: Positive skin tests to recombinant Ascaris tropomyosin and to
rPer a 7 were found in 16(44%) and 19(53%) patients, respectively. All 16
patients with positive skin tests to Ascaris tropomyosin were also positive
to rPer a 7. The median wheal diameter on skin test reactions to P. amer-
icana extract, Ascaris tropomyosin and rPer a 7 were 5mm, 5mm and
5.5mm, respectively. There was an excellent correlation of wheal diame-
ters on skin test reactions to Ascaris tropomyosin and to rPer a 7
(r50.86; p<0.0001). Six non-allergic control subjects presented negative
skin reactions. No adverse reactions were observed on subjects who under-
went skin testing.
CONCLUSIONS: Recombinant A. lumbricoides tropomyosin showed
good biological activity, comparable to that of rPer a 7 and of commercial
P. americana extract. Skin tests with recombinant allergens could be safely
performed in patients with asthma and/or rhinitis.
66 Extensive IgE Cross-reactivity towards Different US RagweedSpecies
L. H. Christensen, C. Hejl, H. Henmar, N. Johansen, H. Ipsen; ALK-
Abello, Horsholm, DENMARK.
RATIONALE: Ragweed is spreading throughout Europe at a tremendous
pace and already ranks among the most common allergen sources in US. In
Europe, there is only one dominant ragweed species whereas at least 25 dif-
ferent species exist in North America. The extent of structural similarity
between major allergens from these different US ragweed species is, how-
ever, currently unknown. This raises the question whether patient’s IgE an-
tibodies cross-react towards these different ragweed species.
METHODS: Extracts were made from pollens of 10 different ragweed
species - all of them naturally occurring in North America, including the
five most wide spread ones.
The cross-reactive properties of patient’s IgE-repertoires towards these
ragweed species were assessed using an IgE inhibition assay.
Pools of sera were tested in the full matrix i.e. towards all 10 ragweed
species and single US patient sera (n~50) towards the 3 most widespread
ones.
RESULTS: Extensive IgE cross reactivity was observed between most
species. The patients included in this study seemed to be primarily sensi-
tized towards Ambrosia artimisiifolia as this species was able to completely
inhibit all other species.
CONCLUSIONS: Our results show a high degree of patient’s IgE cross
reactivity towards different ragweed species indicating that common (cross
reactive) epitopes exist among all these different ragweed species.
Knowledge about IgE cross-reactivity patterns is pivotal when deciding
which species to include in products used for diagnosis as well as for spe-
cific immunotherapy.
67 Aeroallergen Sensitization Among Children with RespiratoryAllergy in Ramathibodi Hospital, Bangkok
N. Anantasit, W. Kamchaisatian, C. Direkwattanachai, W. Manuyakorn,
S. Vilaiyuk, S. Benjaponpitak; Department of Pediatric Allergy/Immunol-
ogy/Rheumatology, Faculty of Medicine, Ramathibodi Hospital, Mahidol
University, Bangkok, THAILAND.
RATIONALE: Aeroallergens have been identified to play a major role in
the pathogenesis of the allergic disease. We aim to evaluate the prevalence
of aeroallergens sensitization in Thai children with respiratory allergy.
METHODS: A retrospective review of skin prick test (SPT) results against
common aeroallergens in Thailand was performed in Pediatric Allergy
Clinic at Ramathibodi hospital during 2000-2009. The reaction was con-
sidered to be positive if mean wheal diameter was at least 3 mm. greater
than negative control.
RESULTS: The data were from 793 children aged between 2-18 years old
which found to have positive SPT in 564 patients (71.1%). The prevalence
of aeroallergen sensitization were 73.8% for Dermatophagoides pteronys-sinus, Dermatophagoides farinae 70.7%, American cockroach 34.6%,
German cockroach 25.4%, cat 23.8%, Bermuda grass 14.5%, dog
12.8%, carelessweed 8.7%, Cladosporium 8%, Aspergillus 1.8% and
Alternaria 1.4%. Among the positive SPT group, there were 63.3% of pa-
tients having allergic rhinitis (AR), 9.3% having asthma and 27.4 having
both. There was no significant difference among diagnosis for each aeroal-
lergen and for number of sensitized allergen. It was found to have more
sensitization to Cladosporium and dog in girls (p50.043 and 0.015, respec-
tively), and to Der f in boys (p50.001). Children less than five years old
were significantly sensitized to Bermuda grass than older age (21.5% vs.
13.2%, p50.038).
CONCLUSIONS: From our study, dust mite is still the most common
aeroallergen in Thai allergic children. Different causative aeroallergen be-
tween gender and age group should be concerned for proper environmental
control in allergic children.