HCST and Splenomegaly: Finally, we generated Slc29a3−/− mice lacking both FcRγ and DAP10 (Slc29a3−/−Hcst−/−Fcer1g−/− mice), in which splenomegaly did not develop and splenic monocyte proliferation was reduced to the level of splenic monocytes of the WT mice (Fig. 5, F and G).