[Autoimmune diseases of the peripheral cornea. Immunopathology, clinical aspects and therapy]

Noninfectious ulceration of the peripheral cornea remains a major diagnostic and therapeutic challenge. The pathogenesis in most of these disorders is unclear, however, on the basis of systemic connective tissue diseases, autoimmune mechanisms are most likely involved. The peripheral cornea has distinct morphological and immunological characteristics that predispose for inflammatory reactions. Major differences exist regarding humoral and cellular components of the immune system. In the peripheral cornea there is more high-molecular IgM and initial complement component C1 than in the central cornea and may predispose for immune complex formation. The close contact to the conjunctival vasculature provides the basis necessary to generate an immune response. Langerhans cells and macrophages as important antigen presenting and processing cells are present in higher number in the peripheral cornea. Autoimmune diseases that affect the peripheral cornea include collagen vascular diseases and Mooren's ulcer. Although this association is obvious in advanced rheumatoid arthritis more subtle forms of polyarteritis nodosa or systemic lupus erythematosus require careful medical evaluation and workup. Ocular manifestations may present as the initial clinical signs and require careful workup in these potentially lethal disorders.