Surface receptors of epidermal Langerhans cells

Langerhans cell presentation of sheep red blood cells induces antibody production

Mouse epidermal Langerhans cells (LC) were found to be capable of presenting sheep red blood cells (SRBC) to immune spleen lymphocytes, resulting in antibody production as assessed by a direct plaque cell assay. Spleen lymphocytes, prepared by removal of adherent cells, were unable to respond to SRBC in a 5-day culture; however, when co-cultured with either epidermal cells or splenic adherent cells, a response to SRBC occurred, as demonstrated by an increase in the number of antibody-producing cells. The LC were shown to be the antigen-presenting cells in these cultures, as depletion of LC via their Fc receptors abrogated the response. A similar reduction in the number of epidermal LC added to cultures likewise failed to induce antibody production. These experiments demonstrate that LC are able to present complex cellular antigens to the immune system, resulting in a B lymphocyte response.

Immunopathology of cutaneous human lupus erythematosus defined by murine monoclonal antibodies

Skin biopsy specimens obtained from involved skin from sixteen patients with systemic and discoid lupus erythematosus were studied. Murine monoclonal antibodies with a biotin-avidin-horseradish peroxidase staining system were used. The findings consisted of a marked reduction in the number of epidermal Langerhans cells defined by surface antigens, reduced HLA-DR (Ia-like) antigens on the surface of dermal capillary endothelium, and mononuclear cell infiltrates characterized by a predominance of helper T lymphocytes and an increase in the number of mononuclear phagocytic cells. B lymphocytes were rarely identified. The number of T lymphocytes within the dermis correlated inversely with both the number of HLA-DR-positive epidermal Langerhans cells (p less than 0.01) and the HLA-DR staining of dermal capillary endothelium (p less than 0.01). These findings suggest that a T lymphocyte-mediated immune response associated with a reduction in Langerhans cells and capillary endothelium HLA-DR antigens is involved in the inflammatory process of lupus erythematosus skin.

Heterogeneity of dermal OKT6+ cells in inflammatory and neoplastic skin diseases

This immunopathologic study of both normal and pathologic skin specimens (contact dermatitis [CD], lichen planus [LP], cutaneous T cells lymphoma [CTCL], and histiocytosis X [HX]) allowed as to differentiate four types of dermal OKT6+ cells: (1) cells with the same morphologic features as epidermal Langerhans cells (LCs), rarely found in either normal or pathologic dermis; (2) cells structurally similar to LCs but lacking Birbeck granules (BGs), found mainly in CD and LP; (3) larger cells rich in cytoplasmic organelles, only 5% of which contained BGs. They were especially common CTCL; and (4) cells typical of HX.