Factors which influence late cutaneous allergic responses.

Increased doses of ragweed antigen E, grass pollen extract, and the IgG of sheep antiserum to human IgE (anti-IgE) were injected in intracutaneous tests in humans. With increasing doses of reactants, in individual subjects, there were the expected increases in the sizes of early wheal-and-flare responses; moreover, there was an associated increase in the magnitude and the frequency of late cutaneous allergic responses (LCAR). LCAR were shown to be a usual sequel to allergic reactions of sufficient intensity. In persons with allergic bronchopulmonary aspergillosis, cutaneous responses to Aspergillus fumigatus allergen were compared with responses to other allergens and to anti-IgE; in relation to early wheal-and-flare responses, the corresponding LCAR induced by A. fumigatus were approximately the same size as those induced by the other reactants. Skin reactions induced by the prick test method and by intracutaneous injection were compared; for early responses of given sizes, there were apparently equal tendencies to proceed to LCAR in reactions to allergen in the two types of administration. In one subject, anti-IgE-induced responses in the skin of a forearm with sensory denervation were compared with responses in the other normally innervated forearm. At the denervated site was the expected absence of the early flare but no apparent reduction in LCAR. Similarly, local anesthesia immediately prior to anti-IgE eliminated the flare of the early response but did not prevent the occurrence of a LCAR.