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.