Numbers and differentiation status of melanocytes in idiopathic guttate hypomelanosis.
The etiology and pathogenesis of idiopathic guttate hypomelanosis (IGH) are largely unknown. To investigate whether the pathologic alteration in IGH involves changes in melanocytic differentiation, cell number, or both, we studied nine lesions of IGH by immunoperoxidase, using monoclonal antibodies against the KIT receptor and a panel of melanocyte differentiation antigens (tyrosinase-related protein-1, tyrosinase, and gp100/pme117). In each case, compared with grossly normal non-lesional skin, IGH lesions showed markedly reduced numbers both of KIT+ cells and of cells expressing melanocyte differentiation antigens (p < 0.0001). Double immunofluorescence labeling of lesions revealed only scattered cells with a less-differentiated phenotype, i.e. cells positive for KIT but having low or undetectable TRP-1. These results indicate that the pathogenesis of IGH involves an absolute decrease in the number of melanocytes; a block in melanocyte differentiation does not appear to be a major component of the process.
Wallace
M L
ML
Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Grichnik
J M
JM
Prieto
V G
VG
Shea
C R
CR
D000328:Adult; D002454:Cell Differentiation; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D017496:Hypopigmentation / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D007124:Immunoenzyme Techniques; D008544:Melanocytes / Q000166:cytology* / Q000378:metabolism / Q000473:pathology*; D008562:Membrane Glycoproteins; D010088:Oxidoreductases; D011506:Proteins / Q000378:metabolism; D012867:Skin / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D012871:Skin Diseases / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology
D008562:Membrane Glycoproteins; D011506:Proteins; D010088:Oxidoreductases; C489799:TYRP1 protein, human; C064056:tyrosinase-related protein-1