Dialysed extracts of alder (Alnus glutinosa) and hazel (Corylus avellana) pollens were characterized by immunochemical methods. The alder pollen extract contained at least 33 distinct antigens of which one, antigen 5, was classified as a major allergen, three, antigens 4, 10, and 17, were classified as intermediate allergens and two, antigens 19 and 23, were classified as minor allergens. The molecular weight and pI of the major allergen were determined to be 19,000 D and 5.2, respectively. The hazel pollen extract contained at least 40 distinct antigens, two of which were classified as major allergens, antigens 8 and 13, three as intermediate allergens, antigens 12, 17, and 26, and seven as minor allergens, antigens 6, 11, 16, 18, 29, 39, and 40. The molecular weights and pI's of the major allergens of hazel pollen were determined to be: antigen 8; Mw = 12,000 D, pI = 5.1 and less than 3.5, antigen 13; Mw = 26,000 D, pI = 5.1. Further, crossed line immunoelectrophoresis and tandem crossed immunoelectrophoresis of alder, birch and hazel strongly indicate that there exists an immunochemical partial identity between the major allergens (antigens 5 (alder), 23 (birch), and 13 (hazel)) from these tree pollens.

Patients allergic to tree pollen entered a 3-year course of immunotherapy (1980-83) with either birch pollen extracts alone (n = 26) or patient-tailored extracts of birch, alder and hazel pollen (n = 27). The clinical and immunological results of this study are published elsewhere. This paper contains an evaluation of skin prick test and nasal provocation test results. There were no significant differences between the two treatment groups concerning these two parameters. In both groups the allergen-specific sensitivity in the skin showed seasonal variations but a significant decrease. During the years of treatment there was also a significant decrease in the specific sensitivity of the nasal mucosa. With the present demands for purification and standardization of allergen extracts it is of practical and economic interest to know that tree pollen-allergic patients showing positive reactions to birch, alder and hazel extracts can be effectively treated using birch pollen extract alone.

Fifty-four adult patients with tree pollen-induced rhinitis (28), asthma (1), or rhinitis and asthma (25) were selected for immunotherapy with standardized and partly purified tree pollen extracts using a double blind protocol. The selection was based on clinical history, results of nasal or bronchial challenge, skin prick tests and RAST. Further, based on crossed radio-immunoelectrophoresis, sex, age and severity of symptoms, the patients were allocated in matched pairs and the treatment alternatives were randomly distributed within the pairs. Twenty-three patients treated with extracts composed of any combination of alder, birch and hazel pollen which matched their IgE response in CRIE (Group 1 (ABC)) and 22 patients receiving birch pollen extracts (Group 2 (B)) completed all 3 years of treatment. The in vivo results comprising symptom and medicine consumption scores are given here. Changes in specific skin and nasal reactivity as well as in immunological parameters are presented separately. No significant differences were demonstrated between the treatment groups in the two parameters. Both extracts were effective and reduced in general the symptom scores to one tenth of the starting level. Expressed another way, at the end of the study, the patients tolerated 30 times more pollen until symptoms of the same severity were elicited, compared to before. In the Nordic countries, spring-time asthma and rhino-conjunctivitis caused by pollen from deciduous trees can be effectively treated with an extract of birch pollen alone.

Patients allergic to pollen from alder, birch and hazel were hyposensitized during a 3-year period with either birch pollen extract alone (n = 24) or a mixture of one or more of alder, birch and hazel pollen extracts (n = 27). The effect of the treatment was evaluated by RAST and tandem crossed-radioimmunoelectrophoresis (tandem-CRIE). The patient' specific IgE response to the major allergens of alder (Aln g I), birch (Bet v I) and hazel (Cor a I and Cor a II), as measured by tandem-CRIE, and the total specific IgE response, measured by RAST, decreased significantly (Pc less than 0.05) during immunotherapy, irrespective of the extract used during the treatment. There was no significant difference (Pc less than 0.05) between the two treatment groups. The results obtained indicate either that birch pollen extract alone is adequate in the treatment of the studied patient group or the patients had been sensitized towards birch pollen alone.