An immunohistopathological study on the synthesis of immunoglobulins and complement in normal and pathological skin and the adjacent mucous membranes

SUMMARY To visualize the cells in skin and mucous membranes in which synthesis of immunoglobulins and complement had been demonstrated, the direct and indirect immunofluorescence techniques were applied, using a fluorescence microscope with epi‐illumination, and blue narrow‐band excitation light. Ig‐positive cells were found in the lesional skin of patients with discoid lupus erythematosus, (bullous) pemphigoid, dermatitis herpctiformis, mycosis fungoides, atopic dermatitis, and lichen planus, and in the normal mucous membranes deriving from the conjunctiva, the nasal septum, the oral cavity and vagina, but not in the normal skin. The lesional skin showed mainly IgG‐positive cells, and the mucous membranes generally had IgG‐ and IgA‐positive cells. In the mucous membranes, with the exception of the oral mucosa, there was a predominance of IgA‐positive cells. The Ig‐positive cells were morphologically plasma cells and lymphocytes, and occurred not in groups but scattered in the dermis of the skin and in the lamina propria of the mucous membranes. These cells could be distinguished rather easily from eosinophilic granulocytes, which showed nonspecific fluorescence. The results of the immunofluorescence study were in good agreement with those obtained with the tissue culture technique. Complement‐positive cells could not be demonstrated with the polyvalent antiserum used. A possible explanation for this failure is discussed.