Coexistence and Relationship of Antikeratinocyte and Antimelanocyte Antibodies in Patients with Non-Segmental-Type Vitiligo

Abstract

To test for autoantibodies in patients with vitiligo, skin biopsies from 16 patients with active vitiligo and 12 patients with stable vitiligo were examined by direct immunofluorescence. In periodate-lysine-paraformaldehyde-fixed biopsy specimens, the presence of IgG deposits in keratinocytes and the number of keratinocytes with focal IgG in active vitiligo were significantly greater than in stable vitiligo. To test whether the antibodies to normal human keratinocytes or melanocytes are present in vitiligo, we used an indirect immunofluorescent test and enzyme-linked immunosorbent assay to test the serum of 43 patients. With unfixed viable melanocytes, we found a granular pattern of IgG staining on the plasma membrane of melanocytes incubated with patients' sera but not in cells incubated with the control sera. With methanol-fixed melanocytes, however, we found a homogeneous pattern of IgG staining in the cytoplasm of melanocytes. With unfixed viable keratinocytes as targets, there was no deposit of IgG on the cells. A homogeneous pattern of IgG binding in the cytoplasm of methanol-fixed keratinocytes suggested the presence of antikeratinocyte autoantibodies to cytoplasmic keratinocyte components. The fluorescence staining for IgG binding was more prominent in active or extensive vitiligo. Vitiligo sera were cytotoxic for melanocytes but not for keratinocytes in vitro. Antimelanocytic antibodies may play a role in melanocytotoxicity, whereas antikeratinocyte antibodies may occur secondary to cellular damage.