- Background The mechanisms involved in the immune resistance to fungal infection of the skin are not well understood. We assessed the levels of the various lymphocyte subsets, the HLA haplotypes, the expression of various receptors on natural killer (NK) cells and the serum levels of cytokines, in a family in which four siblings had tinea corporis, while four others were healthy, in order to reveal potential factors of susceptibility to dermatophytes. Observations Normal numbers of T, B and NK cells were found in the peripheral blood, without significant differences between healthy and infected siblings. The frequency of CD14-positive monocytes was elevated in infected compared with healthy siblings. The proportion of NKG2A + NK cells was reduced in the patients compared with healthy siblings (23.8% vs. 33.8%), whereas CXCR3 + NK cells were increased (41.5% vs. 25.6%, respectively). MHC class I and class II haplotypes were disease independent. Elevated levels of intereron- γ , interleukin-8 (IL-8), IL-2 and tumour necrosis factor- α (TNF α ) were observed only in part of the infected siblings. The serum level of TNF α was strongly correlated with the percentage of CD14 + monocytes. Conclusions We studied here in detail the NK functions of a family of patients suffering from tinea corporis and observed skewed frequencies of specific NK receptors, which imply possible involvement of NK cells in susceptibility to fungal infection.