Lack of delayed reaction in presence of cell-mediated immunity in trichophytin hypersensitivity

Five patients with atopy who had chronic dermatophytosis manifested an immediate and strong trichophytin skin reaction but no delayed reaction. This phenomenon may be caused by the neutralization of injected antigen by serum antibodies during the immediate reaction. When we injected a second dose of trichophytin into the wheal of the immediate reaction, 20 minutes after the first injection, a strong delayed reaction was elicited, demonstrating cell-mediated immune responses in these patients.