Staphylococcal enterotoxin B upregulates fas-mediated apoptosis of peripheral blood mononuclear cells in childhood atopic dermatitis.

Staphylococcal infection-producing superantigens, such as staphylococcal enterotoxin B (SEB), are presumed to play an important role of inflammatory processes in atopic dermatitis (AD). The aim of this study was to elucidate the apoptotic response of peripheral blood mononuclear cells (PBMCs) from children with AD. PBMCs from AD children were sampled and cultured with SEB stimulation. Levels of apoptosis and Fas expression were measured using flow cytometry; the soluble Fas ligand (sFasL) was also measured using the enzyme-linked immunosorbent assay method, and the expression of FasL in PBMCs was observed using reverse transcriptase-polymerase chain reaction. There was no difference in the initial levels of apoptosis and Fas expression in precultured PBMCs of AD patients and healthy donors. After culturing for 48 h under SEB stimulation, the apoptosis level and Fas expression were significantly upregulated in the PBMCs from AD children compared with that from the normal controls. In patients, the sFasL was significantly increased, and the expression of FasL was observed in messenger RNA of peripheral monocytes. These results suggest that the Fas/FasL system is involved in the apoptosis induced by SEB in AD, with simultaneous increases in sFasL and expression of FasL.