Deposition of IgD, alpha-1-antitrypsin and alpha-1-antichymotrypsin on Demodex folliculorum and D. brevis infesting the pilosebaceous unit.

A total of seven routinely processed biopsy specimens of facial skin lesions with infestation of Demodex folliculorum or D. brevis were immunostained for plasma proteins and secretory proteins. The cuticular layer of the mites located within the pilosebaceous unit was selectively immunoreactive for IgD (delta chain), alpha-1-antitrypsin and alpha-1-antichymotrypsin. Negative results were obtained for IgG, IgA, IgM, IgE, albumin, fibrinogen, C3, amyloid P component, prealbumin, lysozyme and lactoferrin. These findings suggest a novel function of IgD and serum protease inhibitors as a protective host response to the mite.