Immunohistochemical distribution of CD44 and desmoplakin I & II in Hailey-Hailey's disease and Darier's disease.

The cell-surface glycoprotein CD44 is found on a wide variety of cells including epidermal cells. It is involved in cell to cell adhesion. Desmoplakin I & II are important components of the attachment plaque of desmosomes. In this study, we compared the distribution patterns of anti-CD44 and anti-desmoplakin I & II in Hailey-Hailey's disease and Darier's disease. In the normal skin, anti-CD44 stained the entire periphery of epidermal keratinocytes while anti-desmoplakin I & II produced dotted staining patterns along the periphery of epidermal keratinocytes. In Hailey-Hailey's disease and Darier's disease, the staining pattern of anti-CD44 on acantholized keratinocytes did not change, but anti-desmoplakin I & II lost their peripheral, dotted patterns and stained diffusely in the cytoplasm in most acantholytic cells. These results suggest that, in Hailey-Hailey's disease and Darier's disease, CD44 may be intact even in acantholytic cells but abnormalities of desmoplakin exist in such cells.