Microbes could prevent childhood leukaemia

– June 13, 2018

Mel Greaves, a prominent scientist from the Institute of Cancer Research in London, recently published an article in the prestigious Nature journal. He claims that a lack of contact with microbes can be responsible for childhood leukaemia. A less hygienic lifestyle could prevent the disease, according to Greaves.

Childhood leukaemia

Leukaemia represents one third of all cancer diagnoses in children. Acute lymphoblastic leukaemia (ALL) is recognised as the most frequent type of childhood cancer in the Western world today. Approximately 220 children in the Netherlands are diagnosed with this disease every year. ALL is a type of blood cancer that starts in the bone marrow, where new blood cells are created. It stops the normal maturing of these cells, which are important for the immune system. ALL effectively removes the brake on the production of blood cells. This process is fatal if left untreated. Today, the treatment of childhood leukaemia is a major success story for oncology. Chemotherapy currently cures 90% of all patients. However, the fact remains that prevention is better than cure, as the treatment can be traumatic for young patients and their families.

Two steps

Greaves cites a whole range of research projects from the last 30 years in his extensive article. Apart from other factors, the scientist shows a strong link between ALL and microbial infections. As cancer is a genetic disease, 1 in 20 children have a genetic predisposition to ALL. However, these children may still develop normal immune systems and live healthy lives. If a child is not exposed to enough microbes in its first year of life, its immune system will not be able to develop sufficiently. As a result, it will be difficult to cope with an infection. A child that also has a genetic predisposition to ALL could cause a second mutation to take place. The child could therefore become susceptible to ALL. This fact does not mean that a child will actually go on to develop ALL. Ultimately, just one per cent of children with a genetic predisposition do.

Hygiene

It turns out that the abnormal development of the immune system could be due to a lack of exposure to microbes in the first year of life. The environments that we live in today are often very clean. Other medical conditions in addition to ALL, including various kinds of allergies and autoimmune diseases, are now being linked to lifestyles that are far too 'clean'. The explanation for this phenomenon is referred to as the 'hygiene hypothesis'.

Source: Greaves (2018) - A causal mechanism for childhood acute lymphoblastic leukaemia