HLA-D region antigen expression by human epidermal Langerhans cells.

We have systematically examined HLA-D region antigen expression by normal human epidermal Langerhans cells with an improved double label indirect immunofluorescence technique in order to better understand the immunologic potential of this human interstitial dendritic cell type. The results of this study which differ somewhat from earlier observations strongly suggest that 100% of OKT-6-positive epidermal Langerhans cells constitutively express HLA-DQ and HLA-DP as well as HLA-DR molecules. Since HLA-DQ expression has been positively correlated with the ability to present nominal antigen, our findings would suggest the possibility that epidermal Langerhans cells, like other members of the human dendritic cell series, might be more efficient than monocytes at nominal antigen presentation since only about 50% of peripheral blood monocytes express HLA-DQ molecules.