Childhood leukaemia triggered by babies being 'too clean', breakthrough study suggests

Childhood leukaemia is likely caused by keeping babies too clean, according to a breakthrough new scientific study that could revolutionise treatment of the disease.

Acute lymphoblastic leukaemia may be trigged by common infections such as flu, but only in those who are raised in germ-free environments, according to the “landmark” analysis.

This means that exposing young children to other babies may actually protect them from the illness by preparing their immune systems against infections they may develop later.

The theory was developed by one of Britain’s leading cancer scientists, Professor Mel Greaves of the Institute of Cancer Research, who brought together more than 30 years of research to complete the study.

Professor Greaves explained his findings in a paper published in Nature Reviews Cancer.

He said most cases are caused by two crucial steps.

The first occurs in the womb when a random genetic mutation predisposes the baby to leukaemia, but only 1 per cent of children born with the alteration go on to develop the disease.

The second is caused by exposure to one or more common infections, particularly if children have had “clean” upbringings with very little exposure to bugs.

The findings suggest that exposing babies with the first stage mutation to benign microbes early in life could be enough to protect them from developing leukaemia.

"The research strongly suggests that ALL has a clear biological cause, and is triggered by a variety of infections in predisposed children whose immune systems have not been properly primed," Prof Greaves said.

"The most important implication is that most cases of childhood leukaemia are likely to be preventable.

"It might be done in the same way that is currently under consideration for autoimmune disease or allergies - perhaps with simple and safe interventions to expose infants to a variety of common and harmless bugs."