Risk for leukemia was significantly lower among children in Taiwan who were infected with the enterovirus compared with children who were not infected, according to the results of a study published recently in Lancet Oncology.
According to Jiun-Nong Lin, MD, of the department of critical care at I-Shou University, Kaohsiung, Taiwan, and colleagues, this finding supports the Greaves hypothesis for the cause of childhood leukemia. This hypothesis states that children have a more vigorous immune response when exposure to common infections is delayed.
“Findings from this study strongly support the epidemiological evidence for the role of viral infection in childhood leukemia,” Lin and colleagues wrote. “Although this study does not show biological plausibility, experimental studies based on these findings to understand the pathogenesis of enteroviruses in leukemia are suggested.”
The study used data from Taiwan’s National Health Insurance Research Database. It included children with enterovirus aged younger than 18 (n = 286,360) and compared them with matched children not infected with enterovirus (n = 282,355). Only children with complete baseline data and three clinic visits with enterovirus infection were included.
The leukemia incidence was 3.26 per 100,000 person-years among children infected with enterovirus and 5.84 per 100,000 person-years among children not infected. The data showed that the risk for leukemia was significantly lower among children infected with enterovirus (adjusted subhazard ratio [SHR], 0.44 [95% confidence interval (CI), 0.31–0.60]; P < .0001).
“Lower risk of leukemia was noted in children with herpangina and hand-foot and-mouth disease; there were no other significant associations,” the researchers wrote.
The reduced risk for leukemia was seen in both lymphocytic leukemia (SHR, 0.44 [95% CI, 0.30–0.65]; P < .0001) and acute myeloid leukemia (SHR, 0.40 [95% CI, 0.17–0.97]; P = .04).
“Overall, enterovirus infection is a crucial issue in children worldwide. Some highly virulent serotypes of enterovirus, such as EV71, have posed a serious challenge to public health because of their severe clinical manifestations and complications,” the researchers wrote. “Additional investigations are needed to unravel the pathogenesis of enterovirus infections and childhood leukemia.”
Commenting on the study, Logan G. Spector, PhD, of the University of Minnesota Medical School, wrote, “In view of the general absence of strong, modifiable risk factors for childhood leukemia, this study is exciting because it alludes to the possibility of inoculation against the most frequent forms of cancer in children. Yet, a crisis of reproducibility exists in biomedical science, perhaps even more acute in observational research, and so the first priority should be to attempt replication of these findings in other datasets.”