Cytomegalovirus viral load in cord blood and impact of congenital infection on markers of hematopoietic progenitor cell potency

Abstract

Background: The low incidence of cytomegalovirus (CMV) infection in neonates decreases the risk of viral transmission with cord blood transplantation. Cord blood donors are screened by testing the maternal sample for total antibodies to CMV. Some cord blood banks also screen cord blood for CMV-DNA. The aim of this study was to develop and validate a multiplex real-time polymerase chain reaction assay to measure CMV viral load in cord blood from asymptomatic infants with congenital CMV infection and to assess the impact of CMV infection on cord blood hematopoietic progenitor cell concentrations and colony-forming unit functionality.

Study design and methods: CMV infection was evaluated in two groups of cord blood donors: 1) 30,308 neonates prospectively screened by saliva culture, including 41 positive cases (0.14%), all from mothers with total antibodies to CMV; and 2) 4712 newborns from mothers with total antibodies to CMV who were screened retrospectively by polymerase chain reaction, including 18 positive cases (0.38%). All 59 infants with CMV were asymptomatic at birth.

Results: Among the 59 positive cases, the average CMV viral load in cord blood was 20.6 × 10⁴ viral copies (vc)/mL; seven of 59 mothers (12%) had CMV-DNA detected, however, with no association to their newborns' CMV viral load. Levels of colony-forming units, CD34⁺ /CD45⁺ cells, and total nucleated cells measured in a cohort of CMV-positive cord blood samples were higher than those in the matched control group.

Conclusion: We developed and validated a multiplex real-time polymerase chain reaction assay to detect CMV-DNA in cord blood. In our study, maternal total antibodies to CMV or CMV-DNA at birth were poor predictors of infection in cord blood donors. Furthermore, our results suggest that CMV congenital infection impacts CD34⁺ /CD45⁺ cells and some hematopoietic progenitor cells toward higher proliferation.