Regional differences in the density of Langerhans cells, CD8-positive T lymphocytes and CD68-positive macrophages: a preliminary study using elderly donated cadavers.

To provide a better understanding of the local immune system in the face and external genitalia, i.e., the oral floor, lower lip, palpebral conjunctiva, anus and penis, we examined the distribution and density of CD1a-positve Langerhans cells, CD8-positive suppressor T lymphocytes and CD68-positive macrophages using specimens from 8 male elderly cadavers. The density of Langerhans cells showed an individual difference of more than (or almost) 10-fold in the lip (oral floor). In the oral floor, Langerhans cells were often spherical. Submucosal or subcutaneous suppressor lymphocytes, especially rich in the oral floor and penile skin, migrated into the epithelium at 4 sites, except for the anus. In the conjunctiva, macrophage migration into the epithelium was seen in all 8 specimens. The density of suppressor lymphocytes showed a significant correlation between the oral floor and the lip (r=0.78). In contrast, the anal and penile skins showed no positive correlation in the density of all three types of immunoreactive cells examined. Overall, irrespective of the wide individual differences, the oral floor and conjunctiva seemed to be characterized by a rich content of all three cell types, whereas the penile skin was characterized by an abundance of suppressor lymphocytes. Based on the tables, as mean value, the relative abundance of three different cell types were as follows; CD1a-positive Langerhans cells (anus), CD8-positive lymphocytes (penis), and CD68-positive macrophages (lip). The present observations suggest that the local immune response is highly site-dependent, with a tendency for tolerance rather than rejection.