High spontaneous release of histamine in vitro from leukocytes of persons hypersensitive to food.

In vitro studies of antigenic release of histamine from peripheral leukocytes (basophils) have been done in more than 600 allergic children. Ordinarily only about 5% to 10% of the histamine content of leukocytes will leak out or be released "spontaneously" during incubation of suspensions in vitro, without the addition of antigen. A small percentage of children were found to have leukocytes that released 25% to 100% of the histamine content spontaneously during incubation. The significance of this was not apparent until recently, when studies were concentrated on children suspected of hypersensitivity reactions to foods, among whom a much greater prevalence of spontaneous histamine release from leukocytes was encountered. Of children proved by a double-blind food challenge to react with manifestations of immediate hypersensitivity, 100% had leukocytes that consistently released over 25% (usually between 50% and 100%) of the histamine content spontaneously without the addition of antigen. Such high spontaneous histamine release appears to be characteristic of persons with clinical evidence of hypersensitivity to food.