Contact dermatitis - New pathogenetic aspects and suppression by magnesium ions

Recent studies suggest that the following immune reactions have to be considered in the pathogenesis of contact dermatitis: (1) phagocytosis of foreign antigen molecules by epidermal Langerhans' cells (ELC) and presentation of these molecules to T-lymphocytes (T-inducer cells); (2) clonal growth of these cells, stimulated by interleukin 2, and transition of them to cytotoxic T-lymphocytes (CD4⁺/CD29⁺ and CD3⁺/CD8⁺ lymphocytes, respectively); and (3) antigen recognition and cytotoxic damage of epidermal cells, which on their surface express the antigens originally phagocytized by ELC. Furthermore, the recognition of antigens does not only depend on the structure of the antigen, but is also largely influenced by gene products derived from the host (class I alloantigens: HLA-A, -B, -C).