Study On The Expression Of CD1a And CD68 Antigens On Langerhans Cells In Normal Adult Human Epidermis

Background : Langerhans cells ( LC ) are important antigen - presenting dendritic cells in the skin. LC can express many surface antigens which are closely related to their functions. The expression of these antigens may change with the change of their functions. Some monocyte - macrophage markers can also be expressed by LC, e. g. CD68.ObjectivesTo study the expression of CD1 a and CD68 antigens by normal LC within the epidermis.Materials and MethodsSkin from the face, trunk and limbs of 8 normal subjects was included in the study for the expression of CD1 a and CD68 antigens by an ABC immunoper-oxidase and double immunofluorescence.ResultsCD la + LC are higher in density than CD68 -+ cells within the normal epidermis. CD la + LC are mainly situated in the mid - epidermis while CD68 + cells are equally distributed in the mid - and lower epidermis. The density of CD1 a + LC are 2. 5 times more dense than CD68 + cells in the mid - epidermis. By double immunofluorescence CD1 a + CD68 + cells are less than 50% of either GD1a 4- or CD68 4 cells within the epidermis. CD1 a + cells are more dendritic than CD + cells in morphology.with CD la + cells more dense, mainly in the mid - portion of the epidermis. There are 3 populations of dendritic cells within the epidermis based on the expression of surface markers; GDI a + CD68 + , GDI a + CD68 - and GDI a -CD68 +. Whether this indicate that there existed in the epidermis a population of non - LC dendritic cells remains to be clarified.