Immunological response and clinical profile in patients with recurrent dermatophytosis.

BACKGROUND An alarming increase in the number of patients with chronic and recurrent dermatophytosis has invoked the need to study the immunological parameters of the host. OBJECTIVES To evaluate delayed type of hypersensitivity (DTH) response and immediate hypersensitivity (IH) response by flow cytometry evaluation of immune cells from peripheral blood and intradermal trichophytin skin test in patients with recurrent dermatophytosis. METHODS A hundred patients with recurrent dermatophytosis and 50 controls (healthy controls and acute dermatophytosis controls) were included. Relevant risk factors for recurrence were analyzed and serum IgE levels were estimated. Flow cytometry evaluation of immune cells in peripheral blood and intradermal trichophytin skin test was done. Dermatophyte pathogens were isolated and antifungal susceptibility was performed. RESULTS Trichophyton mentagrophytes complex (95.84%) and T. rubrum(4.16%) was isolated in culture. Serum IgE was elevated in 83.15 % cases (P= 0.01). IFN-γ+ cells (P=0.0501, P=0.0001, P=0.0014), Th1 cells (P=0.1197, P=0.0024, P=0.0169), IL-17+ cells (P=0.0127, P=0.0006, P=0.0007), Th17 cells (P=0.0634, P=0.0001, P=0.0054) were reduced and IL-4+ cells (P=0.0108, P=0.0175, P=0.0018) were increased in cases. Intradermal test demonstrated negative DTH response in all cases (P<0.001, P<0.001, P<0.001), strongly positive IH response in 6%, and borderline positive IH response in 85% cases (P=0.018, P<0.001, P<0.001). Topical corticosteroids application, undergarment types (tight fit), poor frequency of washing clothes, family history of tinea, sharing of towels were significant risk factors for recurrent dermatophytosis. CONCLUSIONS Reduced IFN-γ+, Th1, IL-17+, and Th17 cells population along with impaired DTH response by the intradermal test was observed in patients with recurrent dermatophytosis.