Autoantibodies to melanocytes and characterization of melanophages in patients affected by a new variant of endemic pemphigus foliaceus

J Cutan Pathol. 2011 Sep;38(9):710-9. doi: 10.1111/j.1600-0560.2011.01746.x. Epub 2011 Jul 14.

Abstract

Background: Melanin and melanophages are commonly seen under the basement membrane zone of the skin in patients affected by a new variant of endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF).

Objective: Our study was conducted to determine the nature of these pigmentary alterations.

Methods: We utilized clinical, histopathologic and immunologic techniques including direct and indirect immunofluorescence, immunohistochemistry, Bielschowsky staining and immunoelectron microscopy studies.

Results: In the El Bagre-EPF patients, we detected dermal melanin in melanophages and antigen-presenting cells, in close proximity to neural and vascular markers. The melanophages consisted of a mixed population expressing CD68, myeloid/histoid antigen and S-100 protein. By immunoelectron microscopy, the presence of autoantibodies in proximity to melanin granules was confirmed within the melanocytes utilizing 10-nm gold particles.

Conclusion: Dermal antigen-presenting cells, including melanophages, seem to contain a diverse combination of molecules, representative of an immunologic process where these cells are engulfing both autoantigens and/or cellular debris in El Bagre-EPF. Autoantibodies to discrete components of melanocytes were also identified; the clinical and immunologic significance of these findings remains unknown. Our work may provide a possible explanation of a darkened complexion in patients affected by endemic pemphigus foliaceus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen-Presenting Cells / immunology
  • Antigen-Presenting Cells / pathology
  • Antigens, CD / immunology
  • Antigens, Differentiation, Myelomonocytic / immunology
  • Autoantibodies / immunology*
  • Basement Membrane / immunology*
  • Basement Membrane / ultrastructure*
  • Colombia
  • Dermis / immunology
  • Dermis / pathology
  • Endemic Diseases
  • Female
  • Humans
  • Male
  • Melanins / immunology*
  • Melanocytes / immunology*
  • Melanocytes / ultrastructure*
  • Pemphigus
  • S100 Proteins / immunology

Substances

  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • Autoantibodies
  • CD68 antigen, human
  • Melanins
  • S100 Proteins