HIV antigen stimulates basophil leukocytes from AIDS patients to release histamine due to type I allergy.

HIV antigen-induced histamine release was examined in leukocyte suspensions from 12 patients with AIDS and 10 healthy controls. Nine of the twelve patients released histamine, while no release was obtained in cells from the control group. The mechanism was examined by removal of immunoglobulins (Ig) from the patient cells before stimulation with HIV antigen, which resulted in an abolition of the histamine release. Transfer of the Ig to cells from normal individuals rendered these cells able to respond to HIV. The removal and fixation of Ig were followed by disappearance and reappearance of the response to anti-IgE. These findings indicate that the histamine release by HIV is caused by a type I (IgE-mediated) reaction.