December 30, 2018

"PREPARE THE CHILD FOR THE ROAD, NOT THE ROAD FOR THE CHILD":

'For 30 years I've been obsessed by why children get leukaemia. Now we have an answer': Newly knighted cancer scientist Mel Greaves explains why a cocktail of microbes could give protection against disease (Robin McKie,  30 Dec 2018, The Guardian)

"It is a feature of developed societies but not of developing ones," Greaves adds. "The disease tracks with affluence."

Acute lymphoblastic leukaemia is caused by a sequence of biological events. The initial trigger is a genetic mutation that occurs in about one in 20 children.

"That mutation is caused by some kind of accident in the womb. It is not inherited, but leaves a child at risk of getting leukaemia in later life," adds Greaves.

For full leukaemia to occur, another biological event must take place and this involves the immune system. "For an immune system to work properly, it needs to be confronted by an infection in the first year of life," says Greaves. Without that confrontation with an infection, the system is left unprimed and will not work properly."

And this issue is becoming an increasingly worrying problem. Parents, for laudable reasons, are raising children in homes where antiseptic wipes, antibacterial soaps and disinfected floorwashes are the norm. Dirt is banished for the good of the household.

In addition, there is less breast feeding of infants and a tendency for them to have fewer social contacts with other children. Both trends reduce babies' contact with germs. This has benefits - but also comes with side effects. Because young children are not being exposed to bugs and infections as they once were, their immune systems are not being properly primed.

"When such a baby is eventually exposed to common infections, his or her unprimed immune system reacts in a grossly abnormal way," says Greaves. "It over-reacts and triggers chronic inflammation."

As this inflammation progresses, chemicals called cytokines are released into the blood and these can trigger a second mutation that results in leukaemia in children carrying the first mutation.

"The disease needs two hits to get going," Greaves explains. "The second comes from the chronic inflammation set off by an unprimed immune system."

In other words, a susceptible child suffers chronic inflammation that is linked to modern super-clean homes and this inflammation changes his or her susceptibility to leukaemia so that it is transformed into the full-blown condition.

From this perspective, the disease has nothing to with power lines or nuclear fuel reprocessing stations, as has been suggested in the past, but is caused by a double whammy of interacting prenatal and environmental events, as Greaves outlined in the journal Nature Reviews Cancer earlier this year.

Crucially, this new insight offers scientists a chance to intervene and to stop leukaemia from developing in the first place, he adds. "We do not yet know how to prevent the occurrence of the initial prenatal mutation in the womb, but we can now think of ways to block the chronic inflammation that happens later on."

The slogan in the title above comes from the best book I read this year, The Coddling of the American Mind by Jonathan Haidt and Greg Lukianoff, which expands on their essay in the Atlantic. While much of the book focuses on the way parents, administrators and students have sought to make Academia similarly antiseptic, with similarly disastrous (if not lethal) results, there's an excellent discussion of how trying to remove every conceivable danger from children's physical lives has been counterproductive.





Posted by at December 30, 2018 8:28 AM

  

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