CIRCADIAN-RHYTHMS AND DIFFERENCES IN EPIDERMAL AND IN DERMAL CELL-PROLIFERATION IN UNINVOLVED AND INVOLVED PSORIATIC SKIN INVIVO

[摘要] Using in vivo DNA labeling procedures, a detailed comparative analysis of circadian rhythms in labeling indexes (Is), mitotic indexes (Im) and Is/Im ratios in uninvolved and in involved psoriatic epidermis was made. Twelve patients were studied at 6-h intervals over a 24-h period. Comparable data on the rates of epidermal DNA synthesis and on the proliferative activity of dermal infiltrate cells is provided. There are no circadian-diurnal variations in epidermal or in dermal infilftrate cell proliferation in either inactive (uninvolved) or in active (involved) lesions of psoriatic skin. The rates of epiderml DNA synthesis were lower at 900 and 1500 h; higher at 2100 and 0300 h in both uninvolved and involved epidermis. The following cell kinetic information was derived from 78 biopsy samples taken from epidermal mitotic and labeled nuclei counts in .apprx. 100-mm unit lengths of epidermis per biopsy; DNA labeling indexes, 6.1 vs. 21.2%; mitotic indexes, 0.13 vs. 0.43%; and Is/Im ratios, 152/1 vs. 70/1 in uninvolved vs. involved psoriatic epidermis in vivo. There was an overall 20% decrease in the rate of cycling epidermal cell DNA synthesis in involved epidermis, and a 5-fold increase in the overall proliferative activity of dermal infiltrate cells in involved psoriatic skin. These results are discussed in relation to the clinical use of circadian rhythms for the chronotherapy of proliferative diseases in man, in relation to cell cycle aspects of psoriasis and psoriatic epidermal responses to therapy, and in relation to cell proliferation in human epidermis in vivo.