Flow cytometry as a tool for the study of cell kinetics in epidermis.

Flow cytometric measurements of the DNA content were performed on a large number of skin biopsies by an automated technique. Expressed as a percentage of all viable cells in the epidermis, the figures for cells in S-phase averaged 1.8% and for G2M 0.9%. No significant differences due to sex were found. Concomitantly with age the ratio S/G2M (representing the duration of S to the duration of G2M) increased. Also seasonal effects were clear, showing higher values for S and G2M in June compared to November and December. Lastly we found small differences dependent on body-site, the ratio S/G2M being greater in legs than in arms. The present status is discussed together with future lines of development.