It wouldn’t be surprising to anyone with Long-COVID (chronic-COVID, etc) the fact that most (if not all) their examinations come fine, which tends to create an important disbelieve by the medical community. In addition, not knowing what is not right makes it harder to find a solution.
Luckily for Long-Haulers, scientists at IncellDx seem to have found blood markers that show biological disturbance in Long Haulers (see paper here). Furthermore, they have developed a Long Hauler Index algorithm. This algorithm when training was capable of predicting with 97% precision who is a severe case of COVID-19, a long hauler and a non-severe-non-long hauler. After, in the testing split, this predictor was 100% precise with a 100% recall.
In summary, the paper has identified the following markers:
- Interleukin-2 is significantly elevated in Long-Covid. This is a type of cytokine signaling molecule that regulates the activity of white blood cells.
- Interleukin-4 is significantly elevated in Long-Covid. This is a cytokine (produced by mast cells) that induces differentiation of naive helper T cells
- CCL3 is significantly elevated in Long-Covid. This is a chemokine involved in the acute inflammatory state. It also recruits and activates polymorphonuclear leukocytes.
- Interleukin-6 is significantly elevated in Long-Covid. This is a type of cytokine (secreted by macrophages) that stimulates the production of neutrophils in the bone marrow.
- Interleukin-10 is significantly elevated in Long-Covid.
- IFNγ is significantly elevated in Long-Covid. This is a type of cytokine produced by NK and NKT cells as immune response.
- VEGF is significantly elevated in Long-Covid. This protein stimulates the formation of blood vessels.
- GM-CSF is significantly decreased in Long-Covid. Cytokine that promotes neutrophil proliferation and maturation.
- CCL4 is significantly decreased in Long-Covid.
In addition, there were 3 extra findings:
- There was no evidence of T-cell exhaustion.
- Long Haulers, mild and severe cases all show elevated CCL5 (RANTES).