Cause of Lung Damage in COVID-19 Patients Revealed by Korean Researchers

New Strategy for Immunotherapy in Severe Patients Expected to Be Established

[Asia Economy Reporter Kim Bong-su] Domestic researchers have identified the cause of severe lung damage occurring in COVID-19 infected patients. This is regarded as a milestone for establishing effective treatment strategies for severe patients.

The Korea Advanced Institute of Science and Technology (KAIST) announced on the 4th that a research team led by Professor Park Soo-hyung of the Graduate School of Medical Science, in collaboration with Professor Choi Young-gi of Chungbuk National University College of Medicine and Dr. Lee Jung-seok's team at Genome Insight, elucidated the quantitative and qualitative changes in immune responses occurring from the peak to the recovery phase of COVID-19 virus proliferation, identifying the characteristics and origin of specific immune cells that cause lung damage.

When infected with COVID-19, immediate activation of immune cells occurs within the lung tissue where the virus initially invades and infects. Most of these immune cells are macrophages; after infection, activated monocytes in the bloodstream enter the lung tissue and further differentiate into macrophages, removing virus-infected lung tissue cells as an initial defense response.

Studying the early immune response and its temporal changes in the lungs by repeatedly obtaining immune cells is impossible in patients. Therefore, respiratory infection animal models such as ferrets play a crucial role in revealing the precise nature of immune responses after viral infection. Professor Choi Young-gi's research team at Chungbuk National University was the first in the world to report that ferrets, experimental animals, are susceptible to the SARS-CoV-2 virus.

In this study, the KAIST-Chungbuk National University-Genome Insight joint research team used a COVID-19 virus-infected animal model to precisely analyze changes in lung immune cells during infection progression using advanced single-cell sequencing techniques. They classified macrophages, which constitute the majority of lung immune cells, into ten subtypes and tracked which macrophage groups contribute to lung damage.

The research team confirmed that from two days post-infection, activated monocytes in the bloodstream rapidly infiltrate lung tissue and differentiate into macrophages, increasing quantitatively. Notably, these blood-origin infiltrating macrophages strongly exhibit inflammatory macrophage properties and were found to contribute not only to virus elimination but also to tissue damage, potentially being the main culprits. Furthermore, the pattern of macrophage differentiation showed a high similarity to changes observed in lung tissues of severe COVID-19 patients.

The research results were published on the 28th of last month in the international academic journal Nature Communications.

The joint research team is currently conducting longitudinal tracking of immune response changes in COVID-19 patients treated with immunosuppressants, pursuing follow-up studies to elucidate appropriate control of the excessive immune response in fatal severe COVID-19 cases such as 'cytokine storms' and the immunological effects of drugs.

Ko Jun-young, a doctoral student at KAIST, explained, "The greatest achievement of this study was precisely elucidating the temporal changes immediately after COVID-19 infection compared to before infection," adding, "By identifying that lung damage after infection is caused by specific inflammatory macrophages, we have provided a basis to refine immunosuppressive treatment strategies used in severe COVID-19 patients."

This content was produced with the assistance of AI translation services.