After catching the coronavirus, up to one in ten people in Germany keep feeling sick for a long time. This is called Long COVID. They may feel very tired, have trouble thinking, find it hard to breathe, or have nerve problems. The symptoms can last months or even years, and each person experiences them differently.
What Scientists Looked At
Researchers wanted to know why the illness lasts so long. They studied blood samples from people with Long COVID. They measured tiny signaling proteins called cytokines that show inflammation. They also sorted the patients based on how severe their original COVID infection was. This let them see differences in the immune system.
Key Immune Cell Found
The team used a special technique that looks at single cells. They discovered a particular kind of white‑blood cell, a CD14‑positive monocyte, that often showed a unique molecular pattern. They named this pattern “LC‑Mo.” People who had mild or moderate COVID but later got Long COVID had more of these LC‑Mo cells.
More LC‑Mo cells were linked to stronger fatigue and breathing problems. They also matched higher cytokine levels in the blood, which means more inflammation.
Why This Matters
Finding LC‑Mo gives a new clue about Long COVID. Scientists still need to learn how these cells cause the symptoms, but the discovery could help develop personalized medicines and study genetic risk factors.
The work was supported by several research grants and ministries.