In vivo and in vitro immune responses to trichophytin in dermatophytosis.

Cell-mediated immunity in patients with verified dermatophytosis was investigated by means of skin test and lymphocyte stimulation test (LST) using purified trichophytin, prepared by the ethylene glycol method, and commercially available trichophytin. The purified trichophytin seemed to be more specific and sensitive both in skin test and in LST. In the majority of cases skin-positive patients were also positive in LST, especially when T. mentagrophytes or E. floccosum was the causative organism. Patients with non-chronic infections also showed a close correlation between skin reactivity and LST. Patients with chronic mycosis or infected with T. rubrum, on the other hand, were often skin-negative. Their lymphocyte reactivity in vitro, however, was usually positive, thus showing a discrepancy in the ability of these two methods to measure cell-mediated immunity.