PSORIASIN - A NOVEL CHEMOTACTIC PROTEIN

Inflammatory skin disorders such as psoriasis show a preferential epid ermal infiltration of neutrophils and T lymphocytes, This observation raises a question as to which factors determine the appearance and com position of leukocyte tissue infiltrations. Previously, we described a low molecular mass calcium-binding protein (psoriasin, molecular mass 11,457 Da, pI 6.77) belonging to the S100 family that is highly upreg ulated in psoriatic keratinocytes and whose expression patterns implie d a role in the inflammatory response. Here we report that human psori asin is a potent and selective chemotactic inflammatory protein for CD 4(+) T lymphocytes and neutrophils at concentrations of about 10(-11) M. Psoriasin is not structurally related to the alpha or the beta chem okine subfamilies or to lymphotactin, a member of a newly described cl ass of chemokines. Thus, we have observed a chemotactic protein outsid e the chemokine subfamilies that could be an important new inflammator y mediator.