Immunohistochemical localization of alpha 2-macroglobulin receptors in human skin.

The localization of receptors for the proteinase inhibitor alpha 2-macroglobulin was studied in human skin by immunohistochemistry using a monoclonal mouse antibody. No epidermal staining was identified. alpha 2-Macroglobulin receptors were identified on dermal fibroblasts and dermal dendritic cells. Endothelial cells did not stain with the antibody, but positive staining cells were concentrated around dermal vessels. The myoepithelial layer of eccrine glands exhibited receptors; however, there was no staining of the eccrine epithelial layer. The distribution of alpha 2-macroglobulin receptors correlates with the reported distribution of alpha 2-macroglobulin: both are present in the dermal connective tissue and absent in epithelium and endothelium. The distribution of alpha 2-macroglobulin and its receptor in the dermis is consistent with a possible role in regulation of dermal proteolytic activity.