CXCR4 and cytomegalovirus infection: Given the decreased secretion of CXCL12 following HCMV infection of SGHPL-4 cells, it is possible that HCMV-infected cells upregulate cell surface and mRNA expression of CXCR4 and CXCR7 as an attempt to compensate for lack of or dysregulated autocrine signaling.