FLT3LG and acute myeloid leukemia: In the hematopoietic compartment, loss of peripheral blood and tissue mononuclear cells (dendritic cell, monocyte, B and NK cells deficiency; DCML deficiency), associated with a high serum Flt3 ligand, is an almost universal finding at presentation [36] although de-novo acute myeloid leukaemia (AML) can develop without prior clinical immunodeficiency [34].