Basophil histamine release in patients with hay fever. Results compared with specific IgE and total IgE during immunotherapy.

Histamine release from leucocytes was demonstrated in grass pollen hay fever patients on in vitro challenge with extract of Pleum pratense (timothy). No release was found in persons without a history of grass pollen allergy. During preseasonal hyposensitization the following tendencies were found in cell sensitivity to allergen as well as in specific IgE antibody level of serum: an initial increase at the beginning of the therapy followed by a decrease during the pollen season. This is in contrast to untreated hay fever patients in whom an increase or no change at all of cell sensitivity and specific IgE was observed in the pollen season. Immunotherapy, therefore, can prevent such an increase in the pollen season. The mechanism might be due to a depression of the IgE production. In untreated as well as in treated patients the cell sensitivity was found to be significantly correlated to the grass specific IgE determined by RAST but not to the total serum level of IgE estimated by RIST. It seems likely that the sensitivity would be useful for evaluating the degree of allergy in grass pollen hay fever patients treated or not treated with immunotherapy.