No risk of maternal EBV infection for childhood leukemia.

We performed a large nested case-control study within the Finnish and Icelandic maternity cohorts to verify/falsify the association of maternal EBV infection with an increased risk of acute lymphoblastic leukemia (ALL) in the offspring found in previous studies. All hematologic malignancies diagnosed among children born during 1983 to 2006 in Finland and 1997 to 2005 in Iceland were identified through national cancer registries. For each index mother of a leukemia case, three matched control mothers with cancer-free offspring were identified. First trimester sera from 561 ALL and 144 non-ALL index mothers and from 2,105 control mothers were analyzed for antibodies to EBV viral capsid antigen (IgG and IgM), early antigen (IgG) and ZEBRA protein (IgG). Conditional logistic regression-based estimates of odds ratios and 95% confidence intervals adjusted for birth order and sib-ship size were calculated. Overall, there was no evidence of increased risk of ALL associated to EBV viral capsid antigen IgM (odds ratio, 0.9; 95% confidence interval, 0.5-1.8). The early antigen and ZEBRA antibodies (EBV reactivation markers) were also not associated with risk. The data argue against a role of EBV in ALL.