Australian researchers have made a breakthrough in understanding how a common herpes virus reactivates and causes life-threatening complications in patients with compromised immune systems.
The study was led by QIMR Berghofer Senior Scientist Professor Geoffrey Hill and Lions Eye Institute researcher Professor Mariapia Degli-Esposti. It has been published today in the prestigious journal Science.
Cytomegalovirus (CMV) infection is the most common complication of bone marrow transplantation. The virus is present in about half of the population in developed countries, but remains dormant in most people.
“Healthy people don’t see any symptoms of CMV because their immune systems keep the virus in check,” Professor Hill said.
“But it can roar back to life in anyone with a compromised immune system, particularly blood cancer patients who receive bone marrow transplants that wipe out their immune systems. In this setting the virus can cause life-threatening disease and requires treatment with prolonged courses of, often toxic, anti-viral medications.
“This study is a big deal for the bone marrow transplantation field. We have shown for the first time that antibodies can play a dominant role in controlling CMV reactivation.
“Previous research on CMV reactivation focused on T cells, the frontline fighters of the immune system, but we found that in fact antibody-producing B cells are responsible for keeping CMV suppressed in mice, without the need for any other immune cells.
“Based on these findings, we hope to develop a new way of preventing CMV reactivation in transplant patients.
“Our goal is to eventually collect a patient’s CMV-fighting antibodies prior to the transplant, purify and multiply the antibodies in the lab, and return them to the patient after the transplant.”
Professor Degli-Esposti said an important aspect was understanding the impact of infection with different strains of CMV.
“There are many different strains of cytomegalovirus, something that has been somewhat overlooked,” she said.
“We found that mice were only protected from CMV reactivation when they were given antibodies specific to the exact strain of the virus they were infected with.
“This helps to explain why previous clinical trials using pooled antibody preparations to fight the virus have been disappointing.”
The study was funded by the National Health and Medical Council.
Professor Hill is now the Director of Hematopoietic Stem Cell Transplantation at the Fred Hutchinson Cancer Research Center in the United States.
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