Spontaneous Release of Histamine from Basophils and Histamine-Releasing Factor in Patients with Atopic Dermatitis and Food Hypersensitivity

Patients with hypersensitivity to food documented by a double-blind, placebo-controlled oral food challenge have been reported to have a high rate of release of histamine from basophils in vitro. To determine whether patients with atopic dermatitis and food hypersensitivity had similar high rates of spontaneous histamine release in vitro, whether dietary elimination of relevant food antigens affected this release, and whether a cytokine, histamine-releasing factor, could account for it, we evaluated 63 patients with atopic dermatitis and food hypersensitivity (38 of whom had eliminated the offending foods from their diets), 20 patients with atopic dermatitis without food hypersensitivity, and 18 normal volunteers. Patients with atopic dermatitis and food hypersensitivity were found to have higher rates of spontaneous release of histamine from basophils than controls (mean ±SE, 35.1±3.9 percent vs. 2.3±0.2 percent; P<0.001). Those who had eliminated the offending food allergen from the diet for an extended period had a significantly lower rate of histamine release (3.7±0.5 percent; P<0.001). In patients with atopic dermatitis without food hypersensitivity, the rate (1.8±0.2 percent) did not differ from that in normal controls. Mononuclear cells from persons with food allergies spontaneously produced a histamine-releasing factor in vitro that provoked the release of histamine from the basophils of other food-sensitive persons, but not from those of normal controls. Patients who adhered to a restricted diet had a decline in the rate of spontaneous generation of the factor by their mononuclear cells. The histamine-releasing factor was found to activate basophils through surface-bound IgE. We conclude that in patients with food hypersensitivity, exposure to the relevant antigens produces a cytokine (histamine-releasing factor) that interacts with IgE bound to the surface of basophils, causing them to release histamine. WHILE evaluating the in vitro release of histamine by basophils in response to food antigens, May observed high rates of “spontaneous” histamine release in the basophils of 85 percent of children with food hypersensitivity as proved in a double-blind, placebo-controlled oral food challenge, but in only 5 percent of persons without food allergies.^1,2 More than 25 percent of the total basophil histamine was released when leukocyte preparations from the cells of food-sensitive persons were incubated at 37°C without the addition of antigen or other inducers of histamine release. However, these findings were not confirmed by other investigators.^3,4 Our purpose in…