Hypersensitivity to bacteria in eczema. I. Bacterial culture, skin tests and immunofluorescent detection of immunoglobulins and bacterial antigens.

A study was made of the cytotoxic effect of antibacterial antibody and complement reacting with bacterial antigens firmly adsorbed to epidermal cells. It is believed that this phenomenon enhances the severity of the lesions and their spread in some cases of disseminated eczema. In this first part of the study it is confirmed that Staphylococcus aureus and micrococci are frequently present on lesions and 'unaffected' skin of patients with disseminated eczema. Intradermal skin tests with antigens of staphylococci and micrococci on 122 eczematous patients elicited immediate, or combined immediate and 4 h (Arthus-like) responses, in a large proportion, but few showed uncombined 4 h responses or delayed hypersensitivity, in contrast to findings reported by others. Immunofluorescence tests on skin of thirty patients showed that IgG and IgM diffused into the epidermis, sometimes to the skin surface, of lesional skin, and more immunoglobulin was found in skin of 'unaffected' areas than in skin of normal healthy persons, indicating that clinically unaffected skin in patients with disseminated eczema is abnormal. IgD was present in three of eight samples of unfixed, and six of eight samples of fixed eczematous skin. Staphylococcal and micrococcal antigen was shown on the skin surface and also diffusely in the cytoplasm of cells in the dermis beneath the surface deposits, indicating percutaneous absorption. Further small amounts of antigen were adsorbed to some epidermal cells. These results show that the predisposing conditions for a cytotoxic reaction mediated by hypersensitivity to bacteria do occur. Increased growth of staphylococci and micrococci on eczematous skin would result in increased deposits of antigen. Bacterial antigens are absorbed into the skin and bind with epidermal cells, and immunoglobulins diffuse into the epidermis. Furthermore, skin tests showed that many eczematous patients were hypersensitive to bacteria. Studies on the nature of the antibacterial antibody will be published in the succeeding reports.