Expression of Ia antigen-like molecules on cells in the corneal epithelium.

Ia antigens, known to be expressed preferentially on cells of the immune system, have been shown to be present on cells in the cornea. By immunofluorescence studies, it was shown that a specific rabbit anti-Ia antigen serum stained cells in the corneal epithelium. The stained cells were well integrated into the corneal epithelial architecture and displayed short dendritic processes. Their location in the cornea and corneal limbus and their morphological appearance make it reasonable to suggest that the Ia antigen-expressing cells of the cornea are equivalents of the Ia antigen-bearing Langerhans' cells of the epidermis.

Ia-like antigens in lichen planus.

The occurrence of Ia-like antigens in the skin of patients with lichen planus was studied by an indirect immunofluorescence (IIF) technique with use of immunosorbent-purified anti-Ia antibodies. Normal skin from the patients and skin from healthy persons showed dermal histiocytes and epidermal suprabasal dendritic cells expressing these antigens. In lichen planus lesions Ia-like antigens were found on virtually all mononuclear cells in the dermal infiltrate and showed an intercellular pattern in the epidermis. The finding of cells expressing Ia-like antigens in the dermal infiltrate, most probably activated T lymphocytes, renders likely a cell-mediated type of reaction in the pathogenesis of lichen planus.

Epidermal location of beta-2-microglobulin in human skin.

Beta-2-microglobulin (beta2-m) is associated with the epidermis in normal and pathological human skin and gives an immunofluorescence pattern similar to that of pemphigus antibodies and concanavalin A (Con-A). Inhibition experiments indicate, however, that the binding site of anti-beta2-m is not identical with that of pemphigus antibodies or Con-A. It is suggested that beta2-m might be an epidermal cell surface marker useful for the study of antigens associated with the epidermal cell surface.

Beta-2-microglobulin in basal cell carcinoma.

Differences in the cell surface of malignant cells, as compared with normal cells, are believed to be characteristic of many features of tumor cell behaviour. We have obtained evidence suggesting that solid and superficial basal cell carcinomas lack immuno-reactive beta-2-microglobulin (beta-2-m) on the cell surface, in contrast to normal epidermis and that of various non-malignant dermatoses, including basal cell papillomas.

Anti-Ia-reactive cells in mycosis fungoides: a study of skin biopsies, single epidermal cells and circulating T lymphocytes.

Skin sections, epidermal cells in suspension and circulating T lymphocytes were investigated for the presence of Ia-like antigens in a group of patients with the cutaneous T-cell lymphoma mycosis fungoides (MF) and in healthy controls. Highly purified anti-Ia antibodies were used in indirect immunofluorescence, indirect peroxidase and peroxidase-antiperoxidase techniques. Allogeneic and autologous mixed leukocyte reaction tests with epidermal cells from MF lesions as stimulator cells were also performed. The majority of the dermal lympho-histiocytes and mononuclear cells in the epidermal Pautrier microabscesses expressed Ia-like antigens. So also did a greater proportion of circulating T lymphocytes than in the controls. In some MF patients a high percentage of single epidermal cells of non-lymphoid character also reacted with the antibodies. The possible significance of the present findings for the pathogenesis of MF is discussed.