Flow cytometric quantification of human epidermal cells expressing keratin 16 in vivo after standardized trauma

The intermediate filament protein keratin 16 is expressed in hyperproliferative epidermis. The present study aims to clarify the relationship between the expression of this keratin type, hyperproliferation (percentage of cells in SG2M phases), and keratinization (keratin 10 expression). These three parameters were quantified in biopsy material taken at different time intervals following sellotape stripping--this being a dynamic in vivo model for the induction of hyperproliferation. From the biopsy specimens cell suspensions were prepared, labeled with antibodies KS8.12 (specially directed against keratin 16) and RKSE60 (directed against keratin 10), and analyzed using flow cytometry. Percentages of cells in SG2M phases were assessed by measuring the relative DNA content after propidium iodide staining. Keratin 16 expression in the suprabasal layer anticipated epidermal proliferation, suggesting a role of the suprabasal compartment in the induction of epidermal growth. Keratin 10 expression decreased about 1 day after the onset of keratin 16 expression, indicating that these processes do not depend directly upon each other.