Japanese researchers have recently conducted a preclinical study to evaluate the potential role of titanium dioxide nanoparticles in the development of atopic dermatitis (AD)-like skin lesions. Male NC/Nga mice (a model of skin barrier dysfunction/defect) were given intradermal injections of titanium dioxide nanoparticles of three sizes (15, 50 or 100 mm) and/or mite allergen into their right ears. Compared to mite allergen alone, use of titanium dioxide nanoparticles resulted in more severe AD-like lesions. In addition, the nanoparticles were associated with overproduction of interleukin (IL)-4 in skin, greater histamine levels in serum and IL-13 expression in the ear, and reduced local expression of interferon-gamma in the presence of the allergen. These ...