NEW YORK (Reuters Health) — A new study provides more evidence that reactivation during pregnancy of Epstein-Barr virus, which causes mononucleosis, may be associated with a proportion of childhood leukaemia cases. What that proportion may be has yet to be defined, researchers say.In 2003, Dr. Matti Lehtinen from National Public Health Institute, Oulu, Finland and colleagues identified a link between maternal EBV reactivation and the development of acute lymphoblastic leukaemia (ALL) in offspring.

In that study — based on data from 550,000 Finnish and Icelandic mothers and their offspring — the presence of EBV antibodies suggesting reactivation of the virus were associated with a 2.9 adjusted odds ratio for ALL.

To confirm EBV’s role in ALL, they analysed first-trimester serum samples of mothers whose offspring later developed leukaemia for different EBV antibodies that are known indicators of EBV reactivation.

Altogether, they analysed sera from mothers of 304 ALL cases and 39 non-ALL leukaemia cases and 943 mothers of controls.

“We found some further confirmation to our (earlier) findings, suggesting an association between maternal EBV infection and risk of leukaemia in the offspring,” Lehtinen told Reuters Health.

“We are preparing for a four times larger study, which should verify or falsify our observations,” Lehtinen told