RUNX1 and infection: RUNX1 haploinsufficiency may result in exaggerated cytokine responses during infection, a short period of time when endogenous level of G-CSF and other cytokines can be greatly elevated for emergency granulopoiesis.36 RUNX1 haploinsufficient individuals may experience minor granulocyte differentiation blockage and accumulate HSPCs in the spleen and PB over an extended period of time.