A study on Demodex folliculorum mite density and immune response in patients with facial dermatoses.

In the present study, 40 patients with facial skin lesions and Demodex folliculorum (DF) mite density > 5/cm(2) by SSSB were evaluated for their immune response through counting T-cell subsets (CD3-CD4-CD8) and NK cells (CD16) numbers and IgG, M, D concentrations in peripheral blood in relation to DF mite density. They were 26 females and 14 males with overall mean age was 48.57+/-15.33 years. A control group of 40 healthy individuals without any skin diseases was enrolled. The mean DF mite density (MD) was 11.82+/-3.72/cm(2) in patients compared to 1.77+/-2.39 /cm(2) and a prevalence of 47.5% in controls. The difference was statistically significant. MD significantly correlated with age both in study and controls, but not with sex. A significant decrease in the absolute numbers of lymphocytes, T-cell subsets and NK cells was found in the study group in comparison with controls. Mean IgM level was significantly higher in patients. No significant correlation was observed between MD and the immune response. So, DF mites modulate the host cellular immune response to their advantage, as T-cell subsets and NK cells seem to be the target of immuno-suppression, favouring dermatosis development.