Effects of immunotherapy on histamine release: a study in allergy to dermatophagoides and house dust.

A group of 56 patients with allergy to house dust and dermatophagoides, and 50 healthy controls were studied. The histamine release test was carried out on these patients using the above mentioned antigens, and the results were evaluated considering the possible variations with respect to specific immunotherapy. The results showed that: --basal histamine values were increased in patients with respect to controls. Analogously, non-treated patients presented higher basal histamine levels than did treated patients. --total histamine values were highest in patients undergoing immunotherapy. --52% of patients with positive cutaneous tests presented positive histamine release in response to antigen challenge. The intensity of the positive response was greater in patients undergoing therapy, and when dermatophagoides antigen was used. Significant differences were found among positive cutaneous tests and house dust and dermatophagoides in the untreated group. This difference was less marked in treated patients.