Washington [US], December 30 (ANI): In a new study, researchers have described how different types of immune cells, called macrophages, develop in the lungs and which of them may be behind serious lung diseases.
The study, which was published in Immunitet, may contribute to future treatments for, among other things, COVID-19.
The researchers at Karolinska Institute in Sweden said that the lung structure exposes them to viruses and bacteria from both the air and the blood. Macrophages are immune cells that, among other things, protect the lungs from such attacks.
However, under certain conditions, lung macrophages can also contribute to severe lung diseases, such as chronic obstructive pulmonary disease (COPD) and COVID-19.
To date, research on the development of human lung macrophages has been limited.
Macrophages can have different origins and develop, among other things, from white blood cells, monocytes, which are divided into different genetically determined main types. In humans, two of these are “classical” CD14 monocytes and “non-classical” CD16 monocytes.
In a new study at Karolinska Institutet, researchers have used a model to study the development of lung macrophages directly in a living lung. This has been combined with a method for studying gene activity in individual cells, RNA sequencing, and thereby discovering how blood monocytes become human lung macrophages.
“In our study, we show that classical monocytes migrate into the airways and lung tissue and are transformed into macrophages that protect the health and function of the lungs. We have also identified a special type of monocyte, HLA-DRhi, which is an intermediate immune cell between a blood monocyte. and an airway macrophage.These HLA-DRhi monocytes can leave the bloodstream and migrate into the lung tissue, says Tim Willinger, associate professor at the Department of Medicine, Huddinge, Karolinska Institutet, who led the study.
However, the non-classical monocytes develop into macrophages in the many blood vessels in the lungs and do not migrate into the lung tissue.
In an infection with the new coronavirus, SARS-COV-2, which causes COVID-19, researchers believe that protective, anti-inflammatory macrophages are being replaced by pro-inflammatory lung macrophages from blood monocytes.
“The presence of these blood monocyte-derived macrophages has been shown in other studies to correlate with how severely ill a person becomes in COVID-19 and how extensive the lung damage is. Patients with severe COVID-19 also have fewer HLA-DRhi monocytes in the blood, probably because they move away from the blood to the lungs, says Tim Willinger.
“Given their important role in rapid inflammatory responses, our results show that future treatments should focus on inflammatory macrophages and monocytes to reduce lung damage and mortality from severe COVID-19,” added Willinger. (ANI)
Source: sn.dk