[Superantigens and their importance for inflammatory skin diseases]

Superantigens are a group of bacterial and viral proteins that are characterized by their capacity to stimulate a large number of T-cells simultaneously. Superantigens bind directly to the MHC class II molecule on the antigen-presenting cell and crosslink the cell with T-cells expressing certain V beta-chains on their T-cell receptor which leads to a vigorous polyclonal T-cell activation. Staphylococcal superantigens seem to be involved in the pathogenesis of systemic diseases such as toxic shock syndrome and Kawasaki syndrome. Furthermore, superantigens seem to play an important role in the induction and maintenance of inflammatory skin diseases such as atopic dermatitis and psoriasis. The skin of patients with atopic dermatitis is often colonized with superantigen-releasing Staphylococcus aureus, and application of staphylococcal superantigen on intact human skin induces a local dermatitis reaction. Guttate psoriasis is often preceded by a streptococcal throat infection, and T-cells specific for streptococcal superantigens have been identified in fresh guttate psoriasis lesions.