Long-term follow-up of patients treated with a three-year course of cat or dog immunotherapy.

BACKGROUND: A 5-year follow-up study was conducted to investigate the duration of the effects of a 3-year course of immunotherapy with standardized cat or dog extracts in 32 children and adults with asthma caused by animal dander. METHODS: Thirty of the subjects could be reached with a questionnaire, 19 underwent bronchial allergen and histamine challenges, and four had only a histamine challenge. Specific IgE and IgG4 levels in serum were measured in those who underwent challenges. RESULTS: Almost all subjects (26 of 30) reported no change (17 subjects) or increased tolerance (9 subjects) on exposure to cats or dogs. In contrast, 17 of the 19 who underwent allergen challenges had increased allergen sensitivity compared with when therapy was stopped (p < 0.01), and the results were no longer significantly different from before therapy was started. Mean provocative concentration of histamine causing a 20% fall in peak expiratory flow was, however, still higher than before therapy in the cat immunotherapy group (p < 0.01) and had not changed significantly during the follow-up period. In the dog immunotherapy group there was no significant change during or after therapy. Specific IgG4 had decreased, and specific IgE in serum had remained low and was comparable to the levels measured at the end of the study period. CONCLUSIONS: Five years after stopping immunotherapy, objectively measured bronchial allergen sensitivity had increased and had approached pretreatment conditions. Asthma symptoms, according to patients' subjective evaluations, had continued to be mild in most patients, and bronchial histamine sensitivity had remained stable. These observations could reflect remaining effects of immunotherapy or the natural history of mild asthma.

Immunotherapy with cat- and dog-dander extracts. V. Effects of 3 years of treatment.

The effect of a 3-year course of cat or dog immunotherapy (IT) was evaluated in 32 patients with a history of asthma on exposure to cat or dog. Twenty-one subjects (14 children and seven adults) received cat IT and 11 subjects (six children and five adults) received dog IT. Bronchial challenges with allergen and histamine were performed once a year. Specific IgE, IgG1, and IgG4 were measured, and skin prick tests were done in connection with the challenges. Allergen sensitivity decreased significantly in both treated groups (p less than 0.001 and p less than 0.05 in the cat-allergen and dog-allergen treated groups, respectively). Bronchial hyperreactivity measured by the provocative concentration of histamine causing a 20% decrease in peak expiratory flow in the cat-allergen treated patients (p less than 0.001) but not in the dog-allergen treated patients. Skin sensitivity decreased in both groups (p less than 0.01 and p less than 0.05), whereas specific IgE increased initially but dropped to the pretreatment level during the second year. Specific IgG1 and IgG4 increased during the first and second year in the cat-allergen treated group (p less than 0.01 and p less than 0.001), whereas only IgG4 increased in the dog-allergen treated group (p less than 0.01). Five cat-allergen treated children and one of the adults who completed 3 years of therapy had mild systemic reactions. We conclude that cat IT ameliorated bronchial allergen sensitivity and bronchial hyperreactivity and resulted in an adequate antibody response. Dog IT was less efficacious but led to attenuation of bronchial allergen sensitivity.

Immunotherapy with cat- and dog-dander extracts. IV. Effects of 2 years of treatment.

Thirty-five patients (20 children and 15 adults) with animal-dander asthma completed 2 years of immunotherapy with partly purified and standardized cat- or dog-danger extracts. The first year of the study was performed double-blind with a placebo-treated control group. These 15 patients were transferred to active treatment for a second year. All patients were followed by use of the skin prick test (SPT), allergen and histamine bronchial challenges, and tests for allergen-specific IgE, IgG1, and IgG4 levels. In the group treated with active extracts for 2 years (group A), the previously reported decrease in bronchial responsiveness to cat extract (p less than 0.001) and histamine (p less than 0.01) was even more pronounced after the second year. After 1 year of active treatment in the original placebo group (group B), a significant decrease in the bronchial responsiveness to cat extract was noted (p less than 0.001). The responsiveness to histamine was decreased only in the patients treated with cat-dander extracts (p less than 0.05). A significant decrease in the SPT (p less than 0.001) and an increase in the allergen-specific IgE (p less than 0.001) and IgG4 (p less than 0.001) was also noted in patients (group B) treated with cat-dander extracts. The side effects in the two groups (A and B) were negligible, except for some systemic side effects, especially among the children during the initial phase of immunotherapy. The symptoms were mild and responded promptly to treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of an oral antihistamine, astemizole, as compared to a nasal steroid spray in hay fever.

The efficacy and side effects of the oral H1-antihistamine, astemizole, were compared with those of nasal beclomethasone in 158 adult birch-pollen allergic hay fever patients. 148 patients completed the 5-week, controlled trial which took place in Stockholm, May 1986, during the birch pollen season. Daily pollen counts were found to be at a rather low level throughout the study period. The effect and tolerability of both drugs were found to be excellent, although beclomethasone reduced nasal symptoms (sneezing, rhinorrhoea, blocked nose) significantly more effectively than astemizole. Eye symptoms were mild and equal in both groups. The results indicate that oral astemizole is an effective non-sedating antihistamine, though less so than nasal beclomethasone, in the treatment of nasal hay fever symptoms.

Flowers and other trigger factors in asthma and rhinitis--an inquiry study.

Six hundred and eighty adult patients with asthma and/or rhinitis were questioned about symptoms elicited by 46 different flowers and 10 common non-specific environmental trigger factors listed in a questionnaire. Flowers or birch twigs were reported to elicit symptoms in 79% of the patients, somewhat more often in rhinitis than in asthma patients, and caused symptoms as often in non-atopics as in atopics. Birch twig and marguerite most frequently induced symptoms, followed by strongly smelling flowers such as hyacinth, lilac, and lily of the valley. Unspecific irritants caused symptoms in 98% of the asthmatics and in 67% of patients with rhinitis. Tobacco smoke and perfumes were the most important troublemakers. A significant positive correlation was found for elicitation of symptoms from flowers and from certain non-specific irritants. It is concluded that non-specific hyperreactivity as well as reaginic hypersensitivity are the mechanisms involved when birch twigs and flowers elicit symptoms.

Immunotherapy with partially purified and standardized animal dander extracts. I. Clinical results from a double-blind study on patients with animal dander asthma.

Forty-one patients (21 adults and 20 children) with cat dander-or dog dander-induced asthma were selected for immunotherapy with standardized and partially purified cat- or dog-dander extracts by use of a double-blind protocol. Based on sex, age, clinical history, results of bronchial challenge, and crossed radioimmunoelectrophoresis studies, the patients were stratified in matched pairs, and the treatment alternatives were distributed randomly among the pairs. Twenty-two patients treated with allergen (15 with cat allergen and seven with dog allergen) and 17 patients receiving placebo therapy completed the first year of treatment. In the cat allergen-treated group, the bronchial sensitivity toward cat and histamine decreased (p less than 0.001 and p less than 0.05, respectively). Measured by bronchial challenge, the cat allergen-treated patients could tolerate 11 times more allergen at the end than at the start of the study, and they also demonstrated a tendency toward less pronounced symptoms after exposure to cat and dog allergens. No significant changes were observed in the dog allergen treated- or placebo-treated groups. The adverse effects in general were negligible except for some systemic side effects during rush hyposensitization, especially among the children, but these were mild and responded promptly to treatment.

Immunotherapy with cat- and dog-dander extracts. II. In vivo and in vitro immunologic effects observed in a 1-year double-blind placebo study.

The effects of immunotherapy on the skin prick test, allergen-specific IgE, and IgG in 39 patients (19 adults and 20 children), treated with partially purified cat- or dog-dander extracts or placebo for 1 year, were studied by use of a double-blind protocol. IgG levels were measured by three different assays: IgG RAST, IgG4 RAST, and Staph A IgG1, 2, and 4. The skin prick test reaction decreased continuously in the allergen-treated patients, the decrease being the first sign of an immunologic effect of the therapy. Allergen-specific IgE levels increased during the first 9 months in both children and adults. The RAST activity during the last 3 months continued to rise for the children, whereas it declined for the adults. IgG levels measured by all three methods demonstrated an increase in the allergen-treated patients and no increase in the placebo-treated patients. The children developed higher values on IgG RAST and IgG4 RAST than the adults. IgG RAST correlated negatively with IgE levels in the cat allergen-treated group. No correlation between skin prick test results, IgE levels, and IgG levels was found, nor was there any correlation between these parameters and the patients' own subjective evaluation or the allergen bronchial challenge test. In summary, the expected change in skin prick test reaction and allergen-specific IgE and IgG levels was found. The children tended to be more immunologically active than the adults.

Immunotherapy with cat- and dog-dander extracts. III. Allergen-specific immunoglobulin responses in a 1-year double-blind placebo study.

An investigation was made of the specific antibody response to individual antigens in 40 patients taking part in a double-blind placebo study of immunotherapy with cat- or dog-dander extracts. Antigen-specific IgE levels were measured by means of CRIE, and the results were expressed as scores. The patients demonstrated IgE specificities toward 1 to 5 antigens. Cat-dander antigens Nos. 4 (cat Ag 1) and 7, and dog antigens Nos. 6 and 13, produced the highest scores, but high IgE binding was also found for dog albumin. After 1 year of treatment, the IgE responses of the two treatment groups (allergen and placebo) were statistically indistinguishable from those before the start of treatment. There was a tendency toward a reduction in score for two of the dander antigens (cat Ag 1 and dog Ag No. 13), and no new IgE specificities appeared. Antigen-specific IgG levels were measured by means of CIE with patient serum incorporated in an intermediate gel, and the results were expressed as plus/minus precipitins. Only two patients had precipitating antibodies before the start of treatment (one against cat albumin and one against cat Ag 1). During the course of treatment, the production of antigen-specific IgGs was observed in 18/22 allergen- and 1/18 placebo-treated patients. For the cat allergen-treated group, the specificities were directed against cat antigens Nos. 2, 3 (cat albumin), 4 (cat Ag 1), and 7, and for the dog allergen-treated group, against dog antigens Nos. 2 (dog albumin), 13, and 20.(ABSTRACT TRUNCATED AT 250 WORDS)