How Does the Immune System Recover After a Stem Cell Transplant?
By Jeffrey Laurence, M.D.
Despite effective antiretroviral therapy, people living with HIV (PWH) are at increased risk of developing certain types of cancer that require a stem cell transplant for their cure. Such transplants were behind the cures of the Berlin and London patients. Preliminary data suggest that PWH are at heightened risk for infectious complications due to the way their immune systems recover post-transplant, compared to those without HIV. The mechanism by which this occurs is unknown.
Six PWH on antiretroviral therapy and 21 HIV-negative individuals underwent stem cell transplants. No difference was seen in the recovery of CD4+ T cells after the transplant, even though PWH had lower CD4 cell counts before the procedure. In contrast, much higher numbers of CD8+ killer T cells were found in the HIV-positive group post-transplant. These higher T cell numbers occurred between nine and 12 months post-transplant, and persisted for several years. The researchers found no consistent patterns in the number or function of these cells in the PWH that they assessed.
The authors concluded that this study, based on a small number of patients, “highlights how little we know about the clinical course post-transplant for HIV-positive persons,” arguing for more research focused on this population.
amfAR was a funder of this study.
Dr. Laurence is amfAR’s senior scientific consultant.