[Acrosyringium and follicular infundibulum: immunomorphologic aspects].

Acrosyringium and infundibulum are epidermal structures with different morphology, but functional similarities regarding re-epithelialization, transport of antigens, and attraction of infiltrates. Immunomorphologically, the infundibula revealed an immunoreactivity of Langerhans cells and keratinocytes comparable with that of the interfollicular epidermis, whereas the acrosyringia reacted differently because of the permanent expression of MHC class II antigens and reduced Langerhans cells in the perisyringial region. Our findings suggest that these epidermal compartments differ with regard to their individual immunologic situations. While the mechanisms of epidermal immunity known from the interfollicular epidermis are possibly the same in the infundibula, we have to expect a basically different immunologic situation in the acrosyringia.