BACKGROUND:: Human cytomegalovirus (HCMV) infection can damage the hematopoietic system, and even cause bone marrow failure. HCMV infection inhibited erythroid progenitor cell proliferation and differentiation, and whether the proliferation of erythroid progenitor cells associated with abnormal expression of genes? OBJECTIVE:: To investigate the expressions of the Hoxb2 gene and Hoxb4 gene after the differentiation and proliferation of the hematopoietic stem cells to the colony forming erythroid progenitor cells (CFU-E) in vitro, which infected by HCMV and/or affected by all-trans retinoic acid (ATRA). METHODS:: Cord blood was collected from fetal placenta umbilical vein of 12 cases. With the colony culture in vitro and the fluorescence quantity reverse transcriptase polymerase chain reaction method, HCMV-AD169 and (or) ATRA (6×10 mol/L) was used to intervene the CFU-E colony formation. The expressions of Hoxb2 and Hoxb4 genes on the differentiation progress of hematopoietic stem cells to CFU-E affected by HCMV and/or ATRA were observed in the blank, ATRA, HCMV-AD169, ATRA+HCMV groups at 3, 7 and 10 days. RESULTS AND CONCLUSION:: The quantity of Hoxb2 and Hoxb4 genes was expressed on day 3, obviously increased on day 7 and highest on day 10 in each group. Compared with the blank group, expressions of Hoxb2 and Hoxb4 genes were down-regulated obviously in the HCMV group. Compared with the HCMV group, expressions of Hoxb2 and Hoxb4 genes were obviously up-regulated in the HCMV+ATRA group (P < 0.05). Results suggest that abnormal expression of Hoxb2 and Hoxb4 gene induced by HCMV may play an important role in abnormal hematogenic damage. Hoxb2 and Hoxb4 gene were correlated to the process of in the proliferation and differentiation of erythroid progenitor cells. ATRA (6×10 mol/L) can up-regulate the expression of Hoxb2 and Hoxb4 gene significantly in normal erythroid progenitor cells, and those infected by HCMV.(Figure is included in full-text article.)