A human skin window technique using micropore membranes

A skin window technique using micropore membranes is described. Eight micrometre pore-size membranes are placed on abrasions made with a dental stone and covered with moist filter paper and impermeable film: adhesive tape is placed overall. The assembly is unobtrusive and stable and may be worn during normal activities. For clinical studies, a series of membranes used over 4–5 h gives information on distribution of leucocyte emigration sites, numbers and types of emigrant cells, their rate of locomotion in the membrane (solely under the influence of endogenous factors) and any difference in form, surface phenotype or function between cells at the dermal surface and those which have traversed the membrane. This system, using a 3-dimensional labyrinthine structured membrane, avoids errors inherent in previous techniques, e.g., differential adhesiveness, competition for space, no quantification of locomotion after emergence or indication of the productive area of the abrasion. Incidential findings include no major change in the nature of the emigrating population over 24 h, the presence of monocytoid cells from the earliest phase in normal subjects, the origin of emigrating cells in discrete foci, and an even distribution of cells in a fully infiltrated membrane. The skin window technique is capable of greater clinical precision and experimental elaboration than hitherto realised.