Having this type of blood can help protect you from severe malaria

Nearly half of the world's population is exposed to malaria, one of the most deadly diseases known to mankind. Each year, it kills over 400,000 people, most of whom are children under five.

Although it is possible to vaccinate against malaria, almost all of these cases are found in the African region, where protection is often only a simple throw of the dice. Now, a recent badysis of 23 articles suggests that people with O blood group have the genetic chance in their favor.

In sub-Saharan Africa, where severe malaria – caused by Plasmodium falciparum parasite – is endemic, there are many more people with O blood group than anywhere in Europe or the United States.

In Nigeria alone, where 97% of the country is at risk of malaria, more than half of the population belongs to this blood group. In Ethiopia and many others, the numbers are similar.

Abraham Degarege Mengist, co-author and epidemiologist of Robert Stempel College of Public Health and Social Work, says there is "evidence of evolutionary selection" there. Recent badysis of his team suggests that people with type O are better protected against severe malaria than people belonging to other blood groups.

The meta-badysis revealed that 15 of the 23 included studies had an increased risk of P. falciparum infection in persons with blood groups A, B, AB or non-O (A / B / AB).

At the same time, more than half of the studies showed that severe malaria was much more likely to occur in people whose blood group was non-O.

"Now that we are beginning to understand the mechanisms that allow the blood group to influence the course of the disease, we are exploring various options that may one day help people in areas where malaria is endemic," Mengist said. .

One of these options is transfusion of type O blood to people with malaria, an idea that could potentially stop the progression of this deadly infection.

A 2015 study included in this overview, for example, found that "rosetting" is more common in people with blood types A and B. This is a term used to describe how a blood cell infected red protects against the immune system.

Rosette formation occurs when a malaria-infected cell packs a group of uninfected red blood cells all around, forming a wall of at least ten others. In severe cases, these growing clusters can block blood vessels, potentially causing coma, brain damage and even death.

Having a blood group O, however, seems to have a protective effect. Without the A or B antigens, this blood group has different receptors on its red blood cells, which are not so easily absorbed by malaria.

"Therefore, rosettes formed in the blood group O [red blood cells] tend to be smaller, weaker and more unstable, "write the authors in the new article.

This, in turn, leaves these receptors free of antibody use, thus continuing an immune response that not only attacks malaria-infected blood cells but also disrupts clusters already present.

"As a result, the progression of simplicity P. falciparum Severe malaria infection is less likely to occur in people with blood group O ", conclude the authors.

If the blood transfusion of type O can in one way or another have this protective and depressing effect on people whose blood type is not O, it could help us fight the most lethal form of malaria.

This study was published in Blood critics.