Humoral antibody responses in the immunopathogenesis of dermatophytosis

Cell-mediated immunity is generally considered as the principal immunological response to dermatophyte infection. However, certain clinical manifestations associated with a humoral antibody response occasionally occur as complications to dermatophytosis (e.g. vasculitis, urticaria). Immediate wheal reaction to intradermal application of "trichophytin" is frequent in patients with chronic T. rubrum infection and can be passively transferred with serum, which demonstrates the presence of specific IgE antibodies in these patients. Crossed immunoelectrophoresis and modifications thereof were applied for studies of (i) the antigenic structure of dermatophytes in sera from patients with dermatophytosis. The antigenic composition was found to differ between species but was characteristic and constant for different strains of the same species. Partial cross reactivity between different species, especially T. rubrum and T. mentagrophytes was noted. The presence of specific IgG antibodies towards corresponding dermatophytes was associated with tinea capitis (100%), tinea pedis with dermatophytid eruption (62%) and chronic T. rubrum infection (25%). Sera from 50 healthy persons were all negative. Specific IgE antibodies toward T. rubrum were demonstrated in serum from eight patients with chronic T. rubrum infection while specific IgE antibodies were not present in sera from ten patients with tinea capitis and four controls. The possible role of IgG and IgE antibodies in inflammatory and non-inflammatory dermatophyte infections is discussed.