Newborns with the common virus in the herpes family known as congenital cytomegalovirus have an increased risk of developing acute lymphocytic leukemia, according to a new analysis. The authors say the risk is even greater in Hispanic children, who are already at the highest risk for developing ALL.

Up to 80 percent of Americans are infected with congenital cytomegalovirus, which is normally dormant, but during pregnancy the virus can flare up and be transmitted to the fetus, causing serious consequences such as birth defects and hearing loss in newborns.Some have suspected that infection plays a role in childhood acute lymphocytic leukemia, the most common form of childhood leukemia, but this is the first time anyone has claimed to link acute lymphocytic leukemia to a specific virus.

To do so, the researchers first identified all known infections present in the bone marrow of 127 children diagnosed with
acute lymphocytic leukemia
and 38 children diagnosed with acute myeloid leukemia (AML). An assay screened samples for all known viruses. They detected CMV DNA in the bone marrow samples from children with ALL but rarely in those with AML. Next, the scientists used a digital droplet screen to examine newborn blood samples for
congenital cytomegalovirus
from 268 children who went on to develop ALL. They compared the samples with healthy children (270).  Acute lymphocytic leukemia  typically develops in children between the ages of two and six.

Statistically, children who went on to develop ALL are 3.71 times more likely to be  congenital cytomegalovirus-positive at birth. Moreover, stratification by Hispanic ethnicity shows a 5.9-fold increased risk of ALL in Hispanics infected perinatally with CMV.