Germ-free homes may lead to childhood leukaemia
KEEPING children cocooned in ultra-clean homes away from other youngsters could trigger childhood leukaemia, a study has suggested.
An analysis by Britain’s leading leukaemia expert has concluded that a deadly chain of events is set in motion when susceptible children are not exposed to enough bugs to prime their immune system at an early age.
If vulnerable youngsters then catch even a relatively harmless virus such as flu, the immune system creates far more infection-fighting white blood cells than needed, causing leukaemia.
Prof Mel Greaves, of The Institute of Cancer Research in London, said it was a “paradox of progress in modern societies” that advances in cleanliness had caused such a devastating condition.
The study, which compiled 30 years of research into the cancer, raises the prospect that acute lymphoblastic leukaemia (ALL) could become a preventable disease.
Allowing children to attend a day nursery so that they come into contact with germ-laden youngsters, breastfeeding, outdoor play and not overly cleaning the house could all help boost immunity, the study suggests.
Prof Greaves, director of the Centre for Evolution and Cancer at the
institute, said: “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.
“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.”
The research is the most comprehensive analysis carried out into the illness, the most common type of childhood cancer, which affects more than 600 children each year in Britain.
ALL is prevalent in advanced, affluent societies and is increasing in incidence at around 1 per cent per year.
The study found that it is partially caused by a genetic mutation which predisposes some children to the disease. However, only 1 per cent of children born with this genetic change go on to develop cancer.
Prof Greaves concluded that the disease is triggered later in childhood when youngsters are exposed to common infections, particularly if they had experienced “clean” childhoods in the first year of life.
The study rules out environmental causes such as ionising radiation, electricity cables, electromagnetic waves or man-made chemicals.
Dr Alasdair Rankin, the director of research at Bloodwise, the blood cancer charity, said: “If we could stop this type of leukaemia from happening in the first place it would be enormously exciting, but many more questions still need to be answered.”
Prof Paul Workman, the chief executive of The Institute of Cancer Research, added: “It’s exciting to think that, in future, childhood leukaemia could become a preventable disease.”
The research was published in the journal Nature Reviews Cancer.