Cracco C, Stella M, Teich Alasia S, Filogamo G
Dipartimento di Anatomia e Fisiologia Umana, Università di Torino, Italy.
Eur J Histochem. 1992;36(1):53-65.
Langerhans cells (LCs) seem to play a crucial role in the immune system of the skin. Changes in their density, distribution, phenotype and/or morphology have been described in a number of skin diseases, mostly immunologically mediated. For this reason, we investigated LCs in human hypertrophic scars, since these scars are presently believed to have an immunological basis. A preliminary analysis of the histological features was carried out on vertical serial sections, stained with hematoxylin and eosin. Both epidermal and dermal components of hypertrophic scar biopsies were examined. The total epidermal thickness and the thickness of the single epidermal layers were also measured; the values obtained were similar to those of control skin and normotrophic scars. Subsequently, CDla-positive LCs, revealed by indirect immunofluorescence and immunoperoxidase techniques, were studied to determine their position among the epidermal layers and within the dermis, their dimensions, their density and their morphology. According to these observations, two main types of hypertrophic scars were identified. In the first type (7 scars), LCs were widely clustered within both the whole epidermis and the dermis. Their density was increased (about 750 cells/mm2 of epidermal area), if compared to control skin and normotrophic scars (both about 400 cells/mm2 of epidermal area; p less than 0.001). The epidermal cell profiles, nearly three times larger than those of control skin, exhibited a dense network of interconnected dendrites. Further analysis for the presence of HLA-DR molecules revealed an anomalous expression of these antigens on keratinocytes. In the second type (3 scars), LCs density within the stratum Malpighii was unchanged, relative to control skin and normal scars, while CDla-positive cell bodies remained numerous in basal position and within the subpapillary corion. Epidermal LCs, only slightly larger than those evidentiated in control skin, displayed short and retracted dendritic projections. The aberrant expression of HLA-DR antigens on keratinocytes was very weak and sparse. The present results strongly suggest an immunologically activated state of the tissues examined; they provide morphological data that support the involvement of the immune system in hypertrophic scarring.
朗格汉斯细胞（LCs）似乎在皮肤免疫系统中发挥着关键作用。在许多主要由免疫介导的皮肤病中，已描述了它们的密度、分布、表型和/或形态的变化。因此，我们对人类增生性瘢痕中的朗格汉斯细胞进行了研究，因为目前认为这些瘢痕具有免疫学基础。对苏木精和伊红染色的垂直连续切片进行了组织学特征的初步分析。对增生性瘢痕活检的表皮和真皮成分均进行了检查。还测量了表皮总厚度和单个表皮层的厚度；获得的值与对照皮肤和正常营养性瘢痕的值相似。随后，通过间接免疫荧光和免疫过氧化物酶技术显示的CD1a阳性朗格汉斯细胞，被研究以确定它们在表皮层之间和真皮内的位置、大小、密度和形态。根据这些观察结果，确定了两种主要类型的增生性瘢痕。在第一类（7个瘢痕）中，朗格汉斯细胞广泛聚集在整个表皮和真皮内。与对照皮肤和正常营养性瘢痕（两者表皮面积均约为400个细胞/mm²；p小于0.001）相比，其密度增加（表皮面积约为750个细胞/mm²）。表皮细胞轮廓比对照皮肤的大三倍左右，呈现出密集的相互连接的树突网络。对HLA - DR分子存在情况的进一步分析显示，这些抗原在角质形成细胞上异常表达。在第二类（3个瘢痕）中，相对于对照皮肤和正常瘢痕，马尔皮基层内的朗格汉斯细胞密度未变，而CD1a阳性细胞体在基底位置和乳头下真皮内仍然很多。表皮朗格汉斯细胞仅比对照皮肤中明显的略大，显示出短而回缩的树突状突起。HLA - DR抗原在角质形成细胞上的异常表达非常微弱且稀疏。目前的结果强烈表明所检查的组织处于免疫激活状态；它们提供了支持免疫系统参与增生性瘢痕形成的形态学数据。
