We studied effects of cell wall constituents of Staphylococcus aureus, peptideglycan (PG) and N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP: muramyl didpeptide) on IL-4 induced IgE synthesis, interleukin 6 (IL-6) and interferon γ (IFN γ) production in peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD). PBMCs from patients with AD whose IL-4 induced IgE synthesis was low (<2U/ml) showed an elevated IgE production by the addition of PG or MDP (P<0.45), while PMBCs from patients with AD whose IL-4 induced IgE synthesis was high (≥2U/ml) showed a suppressed IgE synthesis by the addition of PG, whereas IgE synthesis was enhanced with MDP. But PBMCs from healthy children showed no significant changes in IgE synthesis when PG or MDP were added. Both PBMCs from AD and healthy children showed mild increase in IL-6 generation by the addition of PG or MDP. The IFN-γ generated from PBMCs showed a significant increase (P<0.05) by the addition of PG, and not by the addition of MDP in both healthy and AD groups.
These results indicated that Staphylococcal cell wail constituents (PG or MDP) elevate IL-4 induced IgE synthesis in patients with atopic dermatitis which lead to exacerbation of skin lesion.