正常皮肤中单核巨噬细胞和树枝状细胞的分布规律

The distribution pattern of monocytes/macrophages and dendritic cells in normal human dermis

目的：观察正常真皮内的单核-巨噬细胞和树枝状细胞的分布、排列规律，探讨单核-巨噬细胞在皮肤免疫防御中的作用。方法：正常皮肤8例，取面部、躯干、四肢近端、四肢远端、手掌和足跖6个部位皮肤，进行纵行与水平切片。CD1a和CD68单克隆抗体染色，观察朗格汉斯细胞（LC）和单核．巨噬细胞的分布形态和密度。结果：真皮浅层CD68阳性细胞呈网状分布，其密度为361-562个／mm^2。真皮内血管周围及附属器周围亦见CD68阳性细胞。真皮深层CD68阳性细胞多为树枝状，散在分布于粗大的胶原纤维之间。不同解剖部位真皮浅层CD68阳性细胞密度分别为：四肢远端562个／mm^2，腹部517个／mm^2，面部509个／mm^2，手掌507个／mm^2，四肢近端472个／mm^2，足跖361个／mm^2。真皮浅层CD68阳性细胞在手掌和足跖部位高于相应部位的表皮内CD1a和CD68细胞。结论：在真皮浅层形成数层单核．巨噬细胞网，此网在接近真表皮交界处较致密。真皮内单核-巨噬细胞的这种分布形式说明这些细胞在真皮内有明确的方向性，其防御的方向是穿透表皮进入真皮的入侵物。

Objective： To observe the distribution, morphology and density of monocytes/maerophages and dendritic ceils in the normal human dermis. Methods：Normal skin from 6 locations such as the face, trunk, proximal limbs, distal limbs, and palms and soles of 8 subjects were collected for the study. The horizontal and longitudinal sections of the skin were stained with an ABC immunoperoxidase procedure with anti-CDla and anti-CD68 monoclonal antibodies. Results： In the superficial dermis CD68 positive monocytes/macrophages form a dense network with a density in a 6-micron section ranging from 361/mm^2 to 562/mm^2. These network of CD68 positive cells continued on to surround the blood vessels and skin appendages. Lower densities of CD68 positive dendritic cells were found in the deep（reticular） dermis, dispersed between collagen bundles. The CD68 positive cells were detected within the superficial dermis with variable densities： distal limbs 562/mm^2, trunk 517/mm^2, face 509/mm^2, palms 507/mm^2, proximal limbs, 472/mm^2, and soles 361/mm^2. Conclusion：There exists in the superficial dermis a relatively dense network of CD68 positive monocytes/macrophages. Such a distribution might indicate the clear polarity of the dermal monocytes/macrophages, with their direction of defense towards to the dermal-epidermal junction.