Search This Blog

Monday, November 29, 2010

Osteopontin implicated in maintenance of chronic allergic contact dermatitis

Acute allergic contact dermatitis (ACD) has been previously linked to secreted osteopontin (sOPN), a glycoprotein with cytokine and chemokine functions. OPN is known to attract myeloid dendritic cells (mDCs) to activate naïve T cells in draining lymph nodes in the skin and induce a TH1 phenotype.

Seier et al. (Am J Path 2010, 176:246-258) follow up on their work identifying osteopontin as a principal player in acute ACD with investigations into the pathophysiology that leads to the chronic condition, which is associated with severe eczema. They discover that OPN attracts memory T cells, monocytes, macrophages, and DCs to the skin in acute exposure. Cytokine function of OPN specifically induces IL-12 secretion and suppresses IL-10 production in macrophages. Then, OPN-related IL-12 production establishes Th1 conditions by skewing mDCs toward IL-12 production, which in turn, augments further OPN secretion. The authors also find that IFN-γ from antigen-specific T cells is critical for activation of OPN production in keratinocytes. The Th1 environment in the epidermis is maintained through cybernetic mechanisms involving OPN, IL-12, and antigen-specific T cells, which support persistent, chronic inflammatory conditions in the skin.

Seier et al. also report that anti-OPN antibody treatment can suppress response in established chronic ACD, suggesting possible prevention and intervention possibilities.

Please feel free to post your own comments below. Topics and articles that you think would be of interest in our NBOP section and/or this blog can be sent to the JACI Editorial Office at

No comments:

Post a Comment