April 24, 2013 | by Nicole White
Even as University of Minnesota physicians attempt the first cord blood transplant designed specifically to cure a pediatric patient of HIV and leukemia, City of Hope researchers have devised a program that could make such transplants more readily available.
The cord blood being used in the Minnesota transplant, which took place Tuesday, has a rare mutation shown to protect against HIV, and researchers at City of Hope have been working with cord blood banks and other institutions to identify blood with this mutation. Doing so could make the blood more readily available to those who could benefit.
The boy undergoing the treatment Tuesday was born with HIV, the virus that causes AIDS, and several months ago developed a rare form of leukemia, according to the Minneapolis Star Tribune.
To date, only one patient in the world has been cured of HIV/AIDS by transplantation. Timothy Brown, known as the Berlin patient, was treated with bone marrow from a donor with a specific mutation in a cell surface protein. This mutation protects against HIV by preventing the virus from entering the T cells, ultimately preventing it from destroying the immune system.
However, this procedure has been nearly impossible to replicate due to the difficulty in finding a marrow donor who both carries the rare variant and is a match for the human leukocyte antigens – protein molecules on bone marrow cells that can provoke the immune system. A donor and recipient’s human leukocyte antigens, or HLA, should match as closely as possible to prevent the recipient’s immune system from attacking the donated marrow.
That’s why in a paper published in the current issue of Biology of Blood and Marrow Transplantation, City of Hope scientists and their colleagues suggest using cord blood with the mutation as a viable alternative. Cord blood also requires significantly less stringent matching, as the immune cells of newborn babies are not as functional as those of adults.
Already, City of Hope researchers have developed a screening test to identify the mutation, tested tens of thousands of units of cord blood and found about 170 units that have the mutation.
“One of our goals with this study was to call attention to the fact that we have this available bank of HIV-1 resistant cord blood units that should be used for studies such as that in Minnesota,” said one of the study’s authors, John Zaia, M.D., the Aaron D. and Edith Miller Chair in Gene Therapy at City of Hope.
Other institutions also are working to identify cord blood units that carry the mutation. One of those, M.D. Anderson Cancer Center, provided the blood used in the University of Minnesota procedure. Researchers at the M.D. Anderson Cord Blood Bank also participated in the recent City of Hope study.
The patient received seven days of high dose chemotherapy and radiation before his transplant Tuesday. The next 100 days will be considered “high risk” for the patient, according to University of Minnesota officials. The treatment can damage organs, as well as wipe out the bone marrow and immune system in addition to the cancer. The patient will receive anti-retroviral drugs to suppress the HIV, and will be tested over the next weeks and months for evidence of the infection.
Collaborators on the study were StemCyte International Cord Blood Center in Covina; Midwestern Regional Medical Center in Zion, Ill.; David Geffen School of Medicine at UCLA in Los Angeles; St. Louis Cord Blood Bank at Cardinal Glennon Children’s Medical Center in St. Louis; the Carolinas Cord Blood Bank at Duke University Medical Center in Durham, N.C.; University of Texas M.D. Anderson Cancer Center in Houston; University of Colorado Hospital in Denver; Barcelona Cord Blood Bank in Barcelona, Spain; Sydney Cord Blood Bank in Sydney, Australia; National Bone Marrow Donor Program in Minneapolis; and HMD Consulting in Irvine, Calif.