The viral infection
A research team from the USA shows in a new study that people with Down syndrome contract viral infections less frequently, but more severely. A dysregulation of the immune response is responsible.
People with Down syndrome are more likely to be hospitalized with the flu or the severe acute respiratory syndrome resulting from CoV infection than people without the chromosomal abnormality. After a viral infection, they are more likely to develop pneumonia or sepsis. 20 to 40 percent of deaths in people with Down syndrome are related to a virus. A study now shows why those affected become so seriously ill with viral infections Studywhich was published in the specialist journal “Immunity”. The researchers from the USA examined a special function of the immune system.
Strong immune response
Interferon are important messenger substances that are released in the body during an infection and help to fight off viruses. To do this, they bind to a specific receptor and inform surrounding cells about the virus. A mechanism is then triggered that ensures that the messenger substances can no longer bind to their receptors. This negative feedback is important because too many interferons can lead to an inflammatory reaction.
People with Down syndrome have an additional chromosome 21, which is why it is also called trisomy 21. The anomaly usually manifests itself in physical and mental disabilities. The blueprint for the interferon receptors is also located on chromosome 21. This means that because those affected have three chromosomes instead of two, they also have more receptors than usual, which makes them hypersensitive to the messenger substance. So if people with trisomy 21 become infected with a virus, the immune response is initially very strong and they get sick less often.
Just the tip of the iceberg
However, the results of the study show that the overactivity of the messenger substances and their receptors also leads to an overactivity of the negative feedback. This excessively prevents the messenger substances from binding to their receptors. This prevents the body from taking further important steps to defend itself against the virus. This under-regulation causes people with Down syndrome to contract viral infections much more severely once they are infected.
study author Louise Malle calls this knowledge only “the tip of the iceberg”. Because there is still a lot to be researched about the complex immune system of people with Down syndrome. In the study, she and the other authors suggest that temporarily interrupting or suppressing a certain part of this immune response could help people with trisomy 21 fight a virus. But this needs to be further investigated.