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.