CXCL12 and neutropenia: One of the other four candidates (Table 1) was the ligand of CXCR4, chemokine (C-X-C motif) ligand 12 (CXCL12), which may result in a similar phenotype to disruption of CXCR4. Another candidate was the anti-apoptotic factor, BCL2-like 1 (BCL2L1), which has been shown to be down-regulated in cases of neutropenia [8].