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.