Late cutaneous allergic responses in isolated IgE-dependent reactions

Relationships between IgE-dependent reactions and late cutaneous allergic responses were examined. Heterologous whole antihuman IgE or its pepsin digest F(ab′)2 product injected intracutaneously produced “immediate” wheal and flare responses followed by late responses. Prausnitz-Küstner reactions were similar in appearance. The late responses were studied morphologically by conventional microscopy and by direct immunofluorescent techniques. The results support the thesis that in man, late cutaneous allergic responses can occur in reactions with an isolated involvement of IgE. There is a discussion of the possible relevance of these observations to antigen-induced allergic reactions in skin and in the respiratory tract.