Diagnosis of cypress pollen allergy: in vivo and in vitro standardization of a Juniperus ashei pollen extract.
BACKGROUND
Cypress pollen allergy is a major cause of rhinoconjunctivitis and asthma in the Mediterranean area. The nonstandardized cypress allergen extracts currently available for the diagnosis of cypress allergy have a low level of activity. The search for an active material has led to the selection of Juniperus ashei (Ja) pollen because of its very high cross-reactivity with cypress extracts and its superior allergenic activity. The aim of this study was to characterize in vitro and calibrate in vivo an in-house reference extract (IHRS) of J. ashei pollen and determine the specificity and sensitivity of a standardized Ja extract for the prick test diagnosis of cypress allergy.


METHODS
Juniperus ashei pollen extract was analysed by 2-D electrophoresis. The IHRS Ja extract was calibrated by skin prick testing in 28 cypress-allergic patients. The sensitivity and specificity of cypress allergy diagnosis using a standardized Ja extract was studied by skin prick test in 42 cypress-allergic patients and 53 nonallergic patients. Jun a 1 content of the IHRS was determined by a monoclonal antibody-based electrophoretic technique.


RESULTS
The Jun a 1 content of the 100 IR/ml Ja IHRS extract was 180 microg/ml. For in vivo diagnosis of cypress allergy, Ja pollen extract demonstrated a sensitivity of 95%, a specificity of 100%, a negative predictive value of 96%, and a positive predictive value of 100%.


CONCLUSIONS
Standardized Ja pollen extract is therefore a very appropriate tool for the in vivo diagnosis of cypress pollen allergy and good candidate for specific immunotherapy.
Hrabina
M
M
Département Scientifique et Médical, Stallergènes S.A., Antony, France; Aix en Provence, France.
Dumur
J-P
JP
Sicard
H
H
Viatte
A
A
Andre
C
C
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000032:analysis / Q000276:immunology*; D052179:Antigens, Plant; D003233:Conjunctivitis, Allergic / Q000175:diagnosis*; D005260:Female; D006801:Humans; D018653:Juniperus / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000032:analysis / Q000276:immunology; D010940:Plant Proteins / Q000032:analysis; D011058:Pollen / Q000276:immunology*; D011237:Predictive Value of Tests; D012130:Respiratory Hypersensitivity / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D012882:Skin Tests
D000485:Allergens; D052179:Antigens, Plant; D010936:Plant Extracts; D010940:Plant Proteins; C121951:jun a 1 protein, Juniperus ashei