Distribution of CD68+ Monocytes/Macrophages in Human Normal Dermis

Objective To study the distribution, morphology and density of CD68+ monocytes/macro,phages in normal human dermis. Methods Normal skin specimens from 6 sites including face, trunk, proximal limbs, distal limbs, palms and soles of 8 adults were collected. The epidermal sheets, horizontal and longitudinal sections of the specimens were stained with an ABC immunoperoxidase procedure with anti-CD68 monoclonal antibodies. Results The CD68+ cells were detected within the superficial dermis with various densities: 562 ± 230/mm2 at distal limbs, 517 ± 162/mm2 at trunk, 509 ± 235/mm2 at face, 507 ± 192/mm2 at palms, 472 ± 138/mm2 at proximal limbs and 361 ± 78/mm2 at soles. Lower densities of CD68+ cells with dendritic morphology were found in the deep (reticular) dermis, and dispersed among collagen bundles. Conclusions There are CD68+ monocytes and macrophages in the superficial dermis, forming a relatively dense network of defense. Such a distribution might indicate the clear polarity of the CD68+ monocytes/macrophages in the dermis, with their direction of defense towards the dermal-epidermal junction.