CSF3 and infection: Upon infection, neutrophils are released from the bone marrow into the blood stream in large numbers through the actions of chemokines KC and MIP-2 (that act on receptor CXCR2) and granulocyte colony stimulating factor (G-CSF) that reduces bone marrow retention of neutrophils by down-regulating chemokine (C-X-C motif) receptor 4 (CXCR4) expression [3].