Low DEFB4 copy number and high systemic hBD-2 and IL-22 levels are associated with dermatophytosis

Dermatophytes initiate dermatophytosis, but susceptibility to infection is dictated by host genetic factors, although the role of some of these-such as human beta-defensin 2 (hBD-2) genomic (DEFB4) copy number (CN) variation and its induction by IL-22-remains unclear. This was investigated in this cross-sectional study in 442 unrelated Caucasian subjects, including 195 healthy controls and 247 dermatophytosis patients who were divided into five subgroups according to clinical presentation. DNA samples were evaluated for DEFB4 CN variation by relative quantification using the comparative CT method, and serum hBD-2 and IL-22 levels were determined by ELISA. DEFB4 CN in patients was significantly lower and, except in the tinea cruris subgroup, serum hBD-2 levels were higher than in controls. The positive correlation between hBD-2 levels and DEFB4 CN observed in controls was not detected in patients, who also had higher serum IL-22 levels that were positively correlated with hBD-2 levels. Moreover, unlike in control subjects, the serum IL-22 level was negatively correlated with DEFB4 CN in patients. Taken together, these findings suggest an association between decreased DEFB4 CN, elevated serum hBD-2 and IL-22 levels, and dermatophytosis, underscoring a gene/cytokine interaction in the occurrence of this infection.