Osteopontin and allergic disease: pathophysiology and implications for diagnostics and therapy

Abstract

Osteopontin (OPN) is a phosphoglycoprotein that is expressed by various immune cells in a secreted and intracellular form. It has cytokine, chemotactic and cell signaling functions enhancing Th1 and Th17 immunity and protects against apoptosis. Recent studies found OPN to be modulatory in cell-mediated and immediate-type allergic diseases. In allergic asthma, OPN enhances sensitization but downmodulates Th2-driven IL-4-dominated inflammation. The finding that OPN expression is augmented during specific immunotherapy supports a Th2 suppressive effect of OPN. In Th1-driven delayed-type allergy, such as allergic contact dermatitis, OPN supports dendritic cell migration and IL-12 expression and is secreted by T effector cells and keratinocytes, augmenting Th1-mediated allergy and supporting disease chronification. There are numerous missing links as to how OPN variants modulate allergic inflammation through different OPN receptors. OPN research in allergy is an interesting, rapidly expanding field that has high potential for translational research.

Keywords::

• allergy
• asthma
• CD44
• contact dermatitis
• contact hypersensitivity
• dendritic cells
• inflammation
• integrins
• lung
• lymphocytes
• osteopontin
• skin
• Th1
• Th2
• Th17

Financial & competing interests disclosure

This work was supported by grants to Johannes M Weiss from the Baden-Württemberg Stiftung ‘Research Program Allergology’ and the German Research Foundation: WE1919. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.