Immunotherapy with dog and cat extracts in children.

Hypersensitivity to dogs and cats causes asthma in many children. In this open controlled clinical study we wanted to establish whether immunotherapy can be recommended as a supplement to conventional medical therapy in dog- and cat-induced asthma in children. Twenty-seven children with mean age 10 7/12 years and with allergy to dog or cat according to anamnesis, skin prick test (SPT), specific IgE (RAST) and bronchial provocation test (BPT) entered the study. On the basis of age and bronchial sensitivity they were randomly allocated to either immunotherapy with dog or cat extract (active group, n = 14) or conventional medical therapy (control group, n = 13). Immunotherapy comprised subcutaneous injections with an alum-adsorbed depot extract (Alutard-SQ), and a maintenance dose of 100,000 SQ-U or the maximum tolerated dose. Before entering the study and after 9 months' therapy the patients were evaluated by BPT, SPT, RAST - and IgG4 analyses. The active group showed statistically significant change in bronchial tolerance (P less than 0.02), whereas no such change was found in the control group (P greater than 0.05). The change in skin sensitivity was significantly greater in the active group than in the control group (P less than 0.05), whereas no significant differences were found in RAST and IgG4. However, a significant (P = 0.05) increase in IgG4 was seen in the active but not in the control group. Frequency and degree of side effects in this study were acceptable.