Evidence for the involvement of bacterial superantigens in psoriasis, atopic dermatitis, and Kawasaki syndrome.

A growing body of evidence implicates streptococcal and staphylococcal superantigens in the development of psoriasis, atopic dermatitis and Kawasaki syndrome. In each of these illnesses, an abnormal state of immunologic activity is observed. Superantigens, which have a unique ability to activate large numbers of lymphocytes, are likely to contribute to these disorders in a number of ways. The demonstrated activities of bacterial superantigens include increasing the number of circulating lymphocytes, with activation of autoreactive subsets, upregulation of tissue homing receptors on circulating lymphocytes, and local activation of immune cells within affected tissues. Through these and other mechanisms, superantigens have a proven ability to induce high levels of inflammatory cytokines and/or initiate autoimmune responses that contribute to the development of skin and vascular disorders. Though development of the illnesses discussed in this review are highly complex processes, superantigens may well play a critical role in their onset or maintenance. Understanding superantigen function may elucidate potential therapeutic strategies for these disorders.