SORU: aşağıdaki parçaya göre cevaplayınız
The passage points out that the prevalence of eczema among children in America ----.
Asthma is a life-threatening, allergy-driven lung disease
common in wealthy countries. But exactly what causes
it is unknown. Researchers at Washington University
believe the direct cause of asthma is a chemical distress
signal produced in skin that is damaged by another
hazard of modern life: eczema. Unlike asthma, it is not
dangerous, so people rarely worry about it.
Nevertheless, 17% of children in America have it, and
similarly high figures are found in Australia, Britain, and
New Zealand. What is particularly intriguing is that many
people with eczema go on to develop asthma (in
America, the figure is 70%). That compares with an
asthma prevalence of 4-8% in the general population.
The Washington University group theorizes that the link
between the two conditions is formed by thymic stromal
lympho-poietin (TSLP), a signalling molecule secreted
by damaged skin cells that elicits a strong immune
response from the body to fight off invaders. Thus,
eczema-induced TSLP enters the bloodstream and,
when it arrives at the lungs, sensitizes them so that they
react to allergens that would not previously have
bothered them. In other words, they become asthmatic.
Several experiments carried out by the researchers,
only on mice, have confirmed that skin damage creates
susceptibility to asthma by releasing TSLP.