In some cases, immune cells in the lungs may speed up the virus's attack;Recently, a new study published in the international journal on Immunity in the report, from the Swedish karolinska institute of institutions such as scientists have revealed the immune cells called macrophages in lung development of molecular mechanism, and which of these immune cells or behind will be a serious lung disease, the related research results or is expected to help develop a new type of therapy to treat diseases such as COVID - 19.

The structure of the lungs often exposes them to viruses and bacteria in the air and blood.Macrophages are specialized immune cells that protect the lungs from such attacks;But in some cases, macrophages in the lungs may be responsible for the development of serious lung diseases, such as COPD and COVID-19.Until now, scientists have studied very little about the development mechanism of human lung macrophages.

Macrophages have different origins and development, among which leukocytes, monocytes and other cells are classified into the main types determined by genetics.In humans, two of these are classical CD14+ monocytes and non-classical CD16+ monocytes.This study, the researchers used a new type of model directly in the lung tissue in vivo was studied, in the development of pulmonary macrophages, they will model and RNA sequencing technology, a research of gene activity in a single cell technology) to study the combined, reveals how the mononuclear cells in the blood into the human lung macrophages.

Researchers Tim Willinger said, in this study, we revealed the classic mononuclear cells can migrate into the trachea and lung tissue and translated into macrophages to protect the health and function of the lungs, in addition we also identified a called HLA - Drhi mononuclear cells, it is the blood mononuclear cells, and airway macrophages an intermediate between type of immune cell;These HLA-Drhi monocytes are able to leave the bloodstream and migrate to the lung tissue.However, non-classical monocytes can develop into macrophages in many blood vessels in the lungs and do not migrate to the lung tissue.

Certain types of macrophages in the lungs may be associated with a variety of serious lung diseases, such as respiratory infections, where monocytes in the lungs develop into macrophages, which help fight off bacteria and viruses.But certain types of macrophages may promote severe inflammation and infection in the body.In SARS-CoV-2 infections, the researchers found that protective anti-inflammatory macrophages may be replaced by pro-inflammatory pulmonary macrophages from blood monocytes.In other studies, researchers have found that the presence of these blood monocytes derived macrophages may be directly related to the severity of disease in patients with COVID-19, as well as to the extent of lung damage.The blood of patients with severe COVID - 19 tend to lower levels of HLA - Drhi mononuclear cells, mainly because of its migrate from the blood to the lung tissue, considering its important role in the rapid inflammation, the researchers pointed out that the focus of the future development of novel therapies may focus on inflammatory macrophages and monocytes, in order to reduce lung injury and mortality in patients with severe COVID 18-19.