Severe COVID-19 infection triggers changes that affect gene expression in immune system stem cells, causing long-lasting alterations in the body’s immune response, according to a new study by Weill Cornell Medicine and Jackson Laboratory investigators. The finding could help explain symptoms of prolonged inflammation and “long COVID” in people who have had the disease.
The research team, led by Dr. Steven Josefowicz, an associate professor of pathology and laboratory medicine at Weill Cornell Medicine, and Dr. Duygu Ucar, an associate professor at Jackson Laboratory for Genomic Medicine, published the work Aug. 18 in Cell. For the study, the team developed a new technique to isolate and analyze rare stem cells found in human blood called CD34+ hematopoietic stem and progenitor cells.
Using such cells from patients who had recovered from severe COVID-19, they examined changes to the way the DNA was packaged and condensed, collectively known as the epigenetic landscape. These epigenetic alterations determine the probability or level that a gene will be turned on in both the stem cells and their offspring, which are mature immune cells. The investigators found that the patients’ stem cells acquired more accessible DNA, thereby permitting gene activation, especially at genes that drive inflammation and genes that determine whether the cells develop into inflammatory cell types. The mature immune cells that derived from these stem cells were also sensitized