[The determination of the aggressiveness of allergizing types of pollen (author's transl)]

It is a well-known fact that the same amount of various pollen does not cause the same intensity of complaints in different patients with hay fever. This empirically obtained fact has been made objective and applied to the needs of practical allergology. From 1976 to 1978 qualitative and quantitative measurements were carried out on the pollen content of the air in Vienna. At the same time 300 patients with hay fever, who had been thoroughly investigated, made daily recordings of their complaints during the pollen season. A comparison of the two sets of data shows that they correspond well at the time of grass blossoming, yet differ strikingly during the blossoming of trees and herbs. Therefore, the grass pollen count is taken as the basis for any further calculations. By adjusting the amount of all the other types of pollen to the patients' complaints, "correction factors" are established for those types of pollen that are allergologically most important. These correction factors indicate the relative aggressiveness of the individual types in comparison with the grass pollens. In addition, the frequency of sensitization to individual types of pollen was determined in 500 patients at the First Otolaryngological Department of the University Hospital of Vienna. By multiplying the frequency by the correction factor we arrive at the "potency factor" as a measure of the allergological significance of the respective pollen type. The threshold value is indicated as a further parameter. The threshold value is the pollen count per cubic metre of air required to elicit complaints in the average number of sensitized patients. The threshold value for grass pollens is 50 per cubic metre of air; hence the following formula is derived for the determination of the threshold value: (formula: see text). The potency factor and the threshold factor are valuable parameters in the diagnosis, prophylaxis and therapy of hay fever.