CSF2 and infection: In the context of infection, GM-CSF signals growth and differentiation of myeloid cells (granulocytes and macrophages) when more of these cells are needed to fight infection, and governs emergency myelopoiesis, expanding and mobilizing progenitor myeloid cells when needed (Metcalf, 1986; Damiani et al., 2020; Lang et al., 2020).