Most times human cytomegalovirus (hCMV) infection, a form of the herpes virus goes unnoticed as it lays dormant in the body after initial infection. In a new study published in the journal PLOS ONE, the research team from VCU Massey Cancer Center have shown a genetic relationship between the reactivation of hCMV and the onset of graft-versus-host disease (GVHD), a potentially deadly condition in which the immune system attacks healthy tissue following a bone marrow or stem cell transplant.
This new finding is the latest in a line of research led by physician-scientist, Amir Toor, M.D. Toor and his colleagues have been working to create computer models that simulate immune system recovery following stem cell transplantation in hopes of reducing complications such as GVHD and making transplantation an option for more patients. While the relationship between GVHD and hCMV has been described in medical literature since the 1980s, the connection was not well understood until one of Toor's mentees, Charles Hall, M.S., showed genetic similarities between the virus and tissue expressing GVHD.
"Until now, physicians have taken a 'wait and see' approach to antiviral therapies following transplantation," says Toor, a hematologist-oncologist in the Bone Marrow Transplant Program and member of the Developmental Therapeutics research program at VCU Massey Cancer Center as well as professor in the Division of Hematology, Oncology and Palliative Care at the VCU School of Medicine. "But, based on our data, we believe there is a case for early intervention with personalized antiviral treatments following stem cell transplantation in order to suppress hCMV reactivation."
The scientists found similarities in HLA-bound peptide sequences between human and hCMV genomes. The HLA (human leukocyte antigen) is a system of genes responsible for regulating immune responses, and peptides are short chains of amino acids that play key roles in regulating the activities of other molecules. It turns out that hCMV peptides are very similar to peptides expressed in GVHD-affected tissue.
"We developed a computer model that shows how the immune system can react to hCMV peptides to trigger a graft-versus-host response," explained Toor. "By sequencing the DNA of stem cell donors and recipients, we believe we can use computer modeling to further identify patients at risk and better personalize post-transplant care to decrease the potential for graft-versus-host disease."
Toor hopes to further explore the relationship between hCMV and GVHD. His team is currently working to secure funding to apply their model to larger patient data sets.