We are interested in examining the response of human dendritic cells to LPS with and without other stimulations, for a few genes of interest. The experiment is performed on human peripheral blood cells, without selecting for any population. We have seen that there is cellular proliferation, and are concerned that by using a "standard" house keeping gene like GAPDH, the results will be affected by the proliferation of other cells. Anyone have an idea for a general human DC-specific housekeeping gene with stable expression?