Original Paper Int Arch Allergy Immunol 2002;128:123–129 Trisetum paniceum (Wild Oats) Pollen Counts and Aeroallergens in the Ambient Air of Madrid, Spain M. Cabrera a C. Martı´nez-Co ´cera a E. Ferna ´ndez-Caldas b J. Carnés Sa ´nchez b L. Boluda b J. Tejada d J.L. Subiza e J. Subiza c M. Jerez c a Alergia e Inmunologia, Hospital Clı ´nico San Carlos, b C.B.F. LETI, S.A., c General Pardiñas Center for Allergy and Clinical Immunology, d Department of Statistics and Operative Research, Complutense University of Madrid, e Inmunotek, Madrid, Spain Received: August 2, 2001 Accepted after revision: January 24, 2002 Correspondence to: Dr. Martha Cabrera Sierra Ronda de la Luna 20, 5A E–28760 Tres Cantos, Madrid (Spain) Tel. +34 91 803 8838, Fax +34 91 807 0302 E-Mail diecab@teleline.es ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2002 S. Karger AG, Basel 1018–2438/02/1282–0123$18.50/0 Accessible online at: www.karger.com/journals/iaa Key Words Grass allergens W Aeroallergens W Allergenic activity W Pollinosis W Trisetum paniceum W Aerobiology Abstract Background: Madrid has a short but intensive grass pol- len season, in which 79% of the total grass pollen load is released from the middle of May to the middle of June. The main objectives of this study were to quantify Trise- tum paniceum (wild oats) aeroallergen in the atmo- sphere in Madrid from February to December 1996 and to correlate the aeroallergen concentrations with grass pollen counts. M ethods: Two different samplers were used to assess allergen exposure; a Burkard spore trap was used to collect pollen grains and a high-volume air sampler to collect airborne particles. A total of 182 air filters were collected and extracted in 1 ml of PBS and analysed by ELISA inhibition, using pooled sera from highly allergic individuals. Results: T. paniceum aeroal- lergens were detected not only during the grass pollen season, but also before and after. Wild oat allergens had two main peaks of 1 and 1.9 Ìg/m 3 , occurring in late May and July, respectively. The time series analysis estab- lished the existence of lags between the two main vari- ables pollen counts and aeroallergen activity. Analysis of the data by the Spearman rank test and linear regression showed a weak correlation between grass allergenic activity and grass pollen counts (Spearman’s rho = 0.29). Data obtained from time series analysis demonstrated that grass allergenic activity correlated strongly with cur- rent and 5-week-old grass pollen grain counts (r 2 = 0.73). Conclusions: Wild oats allergenic activity was detected during the entire year and not only during the pollen sea- son. This fact is an important aspect to be considered in the clinical follow-up and treatment of grass pollen-sen- sitised patients in Madrid. Copyright © 2002 S. Karger AG, Basel Introduction It has been shown that clinical symptoms of pollen- allergic patients correlate with atmospheric pollen grain counts [1]. However, the existence of extra-seasonal pol- len aeroallergen activity has been demonstrated, and pol- len-sensitive patients often report clinical symptoms out- side of the pollen season [2, 3]. Therefore, it has been sug-