Saturday November 28, 2020
Infections with the coronavirus are often mild or even symptom-free. On the other hand, other sick people develop severe symptoms and even die from them. Scientists look for molecular fingerprints in the blood that indicate a severe course early on. And find them.
An international team of researchers has identified certain cell types in the blood that indicate the severity of the disease in Covid-19. In blood samples from patients who later died, the scientists discovered a particularly large number of immature cells that are normally found in the bone marrow, but which are also washed into the blood in the event of blood poisoning.
These are so-called megakaryocytes, precursor cells of blood platelets, which ensure that the blood clots. This is particularly surprising because these precursor cells are normally not in the blood, but in the bone marrow, “explains Florian Tran, who conducts research at the Institute for Clinical Molecular Biology at the University of Kiel , for example in bacterial sepsis (blood poisoning), “says Tran. This has not been described in this way for Covid-19. The researchers now suspect that these cells lead to coagulation problems. Blood clots in the lungs are one of the most common direct causes of death in Covid -19.
In addition, more immature red blood cells were discovered, which are later supposed to carry oxygen. This indicates a lack of oxygen and is often an emergency response to severe lung disease.
Tests for severe course possible?
To do this, the team examined blood samples from patients who were hospitalized at the university hospitals in Kiel, Bonn, Cologne and Nijmegen for Covid-19 disease. In a group of 14 patients, the cells in the blood were analyzed at different times during the disease. Blood samples from healthy people were used as a comparison variable.
“The special thing is that with the help of so-called single cell genomics, we analyzed hundreds of thousands of cells in parallel by sequencing and were thus able to identify rarer cell types,” explains Dr. Joana Pimenta Bernardes, who also conducts research at the Institute for Clinical Molecular Biology at Kiel University. “Together with other data such as clinical laboratory values and measurements of inflammatory messenger substances, we were able to create a type of fingerprint, a signature of the changed functioning of these cells, and track it over time,” says Dr. Neha Mishra from the same research group.
The research team published its results in the renowned Immunity magazine. According to the scientists, the study could form the basis for diagnostic test procedures that use blood samples to detect severe disease at an early stage. In this way, the care of particularly severely affected patients could be improved in a targeted manner.