TH2-inducing dendritic cell precursors (pre-DC2) are derived from hematopoietic stem cells (HSC) in bone marrow.

Signals regulating HSC differentiation into pre-DC2 are currently unknown. G-CSF appears to mobilize bone marrow pre-DC2 into peripheral blood. Recipients of blood stem cell transplantation from G-CSF–treated donors received 5- to 6-fold more pre-DC2 than did recipients of bone marrow stem cell products. Pre-DC2 may capture alloantigen and undergo maturation after transfer into the host. These DC2 may present alloantigen to donor T cells and induce them to undergo TH2 differentiation and to limit GVHD.