Immunotherapy in spring-time hay fever. A clinical and immunological study comparing two different treatment extract compositions.

In a study of the efficacy of two different treatment schedules for perennial immunotherapy, 47 adult patients with spring-time hay fever due to allergy against birch and other deciduous trees were randomly assigned to three treatment groups: one group received birch, alder and hazel allergen in Allpyral, another group received the same Allpyral mixture and in addition all relevant tree pollens in aqueous extract and a control group received no injections. For determination of antibody titres the radioallergosorbent test (RAST) and the ammonium sulphate precipitation (ASP) technique were used. Cellular responsiveness was studied by measuring birch pollen (BP) induced leucocyte histamine release in peripheral blood. The clinical and immunological response was similar in the two treated groups. Treated patients had less symptoms and a lower consumption of antihistamine tablets during the pollen season than the control group. Non-IgE BP antibodies and IgE antibodies recorded with the ASP technique increased after immunotherapy while RAST values did not change significantly. A decrease of RAST values from postseasonal values during the first year to preseasonal values in the following year was seen in all patient groups but was less pronounced in treated than in untreated patients. The decrease was more pronounced in patients with high RAST values of postseasonal sera than in patients with low RAST values. Cellular reactivity increased slightly during the first phase of therapy but returned to the pre-treatment level later. Clinical improvement was positively correlated to the percentage increase of non-IgE antibody titre and to the pre-treatment non-IgE/IgE antibody ratio. Patients with high preseasonal RAST titres or high cellular sensitivity tended to have more severe symptoms during the pollen season. It is concluded that a mixture of birch, alder and hazel is sufficient for immunotherapy in spring-term hay fever. It is obvious that changes of a single immunological variable do not account for the therapeutic results in immunotherapy.