Abstract: Objective To investigate the expression of haptoglobin in normal human skin,its mRNA and protein levels,its role in the skin and the relationship with Langerhans cell.Methods The expression of haptoglobin in the skin was detected by immunohistochemistry and in situ hybridization in 30 normal individuals.Results Weak to mild expression of haptoglobin mRNA was found in keratinocytes,hair follicles,eccrine glands,the ducts of sebaceous glands,and glandular epithelia.No expression was observed in dermal fibroblasts and the endothelial cells of blood vessel.In immunohistochemistry study,positive staining was found in the cytoplasm of some dentritic cells.These dendritic cells were confirmed to be Langerhans cells by double-labelled immunofluorescence.Conclusions Skin is another extrahepatic organ where haptoglobin mRNA is expressed,mainly on keratinocytes and cells originated from epithelium.Expression of haptoglobin in the cytoplasm of Langerhans cells is observed only in the lower-middle epidermis,hair follicles,and the ducts of sebaceous gland.The expression of haptoglobin mRNA in keratinocytes might be related to the presence of haptoglobin in the cytoplasm of Langerhans cells.Haptoglobin might take part in the process of immune reaction in the skin.

Key words: Globin, Skin