Augmented local anaphylaxis at sites of delayed hypersensitivity skin reactions.

The magnitude of passive anti-ovalbumin IgE-mediated reactions was quantified at normal skin sites and sites of tuberculin reactions in rats by measurement of induration. It was found that significantly greater immediate reactions occurred at sites of positive tuberculin reactions than at normal skin sites. The augmentation of IgE-mediated reactions was maximal in tuberculin reactions elicited 1 week after active immunization but was still significant in reactions elicited 6 weeks after immunization. The magnitude of the delayed reaction influenced the degree of augmentation of the IgE-mediated reaction observed, greater tuberculin reactions producing greater augmentation. Similar degrees of augmentation by the tuberculin reaction were observed in IgE-mediated reactions elicited 24, 48, and 72 hs after elicitation of the delayed skin test.