Credit: Chad McNeeley
Researchers have found evidence suggesting that perivascular mesenchymal stromal cells (MSCs) are a reservoir of human cytomegalovirus (HCMV).
This opens up the possibility of therapeutically targeting these cells, which surround blood vessels in the organs and can be found in the bone marrow.
If effective, such a treatment method could prove life-saving for individuals who experience HCMV reactivation, such as transplant recipients and patients receiving chemotherapy.
“There are antiviral medications designed to prevent HCMV from re-activating, but HCMV infection remains one of the major complications after both organ and bone marrow transplants,” said study author Graca Almeida-Porada, MD, PhD, of Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.
“The question scientists have been asking for years is, ‘Where does the virus hide when it is latent?’ Maybe if we knew, we could target it.”
Previous research showed that hematopoietic stem cells can harbor HCMV. Dr Almeida-Porada and her colleagues hypothesized that other cell populations may also harbor the virus, and they suspected that perivascular MSCs were a likely culprit.
The team’s suspicions were confirmed when testing revealed that perivascular MSCs are susceptible to HCMV infection and that the virus can grow within these cells.
The researchers also compared the susceptibility of perivascular MSCs from the liver, brain, lung, and bone marrow. And they found the highest rate of HCMV infection in cells from the lung.
“This may explain why pneumonia is the primary manifestation of the HCMV infection in bone marrow transplant recipients,” Dr Almeida-Porada said.
To expand upon these findings, she and her colleagues analyzed bone marrow samples from 19 healthy individuals who had tested positive for HCMV. Quantitative PCR revealed HCMV DNA in perivascular MSCs from 7 of the subjects.
This suggests bone marrow-derived perivascular MSCs may be a natural HCMV reservoir, according to the researchers.
“We have found another source of cells that can harbor HCMV virus,” Dr Almeida-Porada concluded. “Knowing the identity of the cells opens the possibility of targeting treatments to stop its re-activation.”
Dr Almeida-Porada and her colleagues recounted their discoveries in the American Journal of Transplantation.
