Original article Clinical and immunologic evaluation of Cedrus deodara pollen: a new allergen from India Background: Allergy to pollen from gymnosperms is well documented in the West. However, many allergenic species are native to the Himalayan region of India, and Cedrus deodara (Pinaceae) was selected for allergologic investigation. The objective was to de®ne the allergologic and immunochemical aspects of C. deodara pollen. Methods: Pollen antigen from C. deodara (CD) was prepared and characterized by biochemical and biologic assays. Speci®c IgE binding was determined by means of ELISA and immunoblotting. Results: CD pollen antigen caused marked skin sensitivity in 7.5% of an atopic population. A signi®cantly elevated level of CD-speci®c IgE antibodies was observed in 65.8% of the skin-positive patients. Immunoblotting showed protein fractions of 37, 44, 58, and 78 kDa with 100% binding with the patients' sera suspected to be due to carbohydrate moieties. Conclusions: Patients from the Himalayan region, where CD occurs naturally, were sensitized more than patients from distant places. The immunochemical characterization revealed multiple protein fractions from low to very high molecular mass (14±126 kDa) mostly in the acidic pI range. CD pollen has been recognized as a new allergen from India for the ®rst time. A. Rawat, A. Singh, A. B. Singh Aerobiology and Allergy Laboratory, Centre for Biochemical Technology, Delhi S. N. Gaur V.P. Chest Institute, Delhi L. Kumar Department of Pediatrics, PGI, Chandigarh I. Roy Institute of Child Health, Calcutta P. Ravindrun Medical College, Trivandrum, India Key words: allergen characterization; Cedrus deodara; Himalayan tree; sensitization. Dr A. B. Singh Aerobiology and Allergy Laboratory Centre for Biochemical Technology Delhi University Campus Mall Road Delhi-110 007 India Accepted for publication 15 February 2000 The role of pollen as a causative agent of respiratory allergic disorders is very well established, as is evident from the recent increase of reports from across the world (1±4). India is blessed with the richest ¯ora on the earth, from alpine tundra to Rajasthan desert. Conse- quently, it provides considerable variation in the quality and quantity of airborne pollen in different ecogeo- graphic regions of the country (5±8). Although studies on the allergenic properties of airborne pollen from various species have been carried out by several workers in India (9±12), information on allergy to aerial pollen from Himalayan tree species has been completely lacking, although a sizable population is exposed to various Himalayan airborne pollens, and many are likely to be sensitized. Pine pollen, one of the important components of Himalayan air spora, is not considered to be highly allergenic although some reports suggest sensitization to its pollen as well (13±15). Beside natural pine forests in the Himalayan region, pine trees are also planted in parks and gardens in various parts of the country, and people are exposed to variable concentrations of its pollen. Cedrus deodara (CD), also belonging to the family Pinaceae, is a large evergreen tree and occurs as natural forest cover in the outer Himalayas from Kashmir to Garhwal at an altitude of 1300±3500 m above msl. It has been reported to be one of the important components of airborne pollen in the Himalayan region. Its pollen is present in the air from Abbreviations. CD: Cedrus deodara; ELISA: enzyme-linked immuno- sorbent assay; IEF: isoelectric focusing; NC: nitrocellulose; OD: optical density; SDS±PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis. Allergy 2000: 55: 620±626 Printed in UK. All rights reserved Copyright # Munksgaard 2000 ALLERGY ISSN 0105-4538 620