Lack of viral control and development of cART escape mutations in macaques after bone marrow transplantation

Objective— We have previously demonstrated robust control of simian/human immunodeficiency virus (SHIV1157-ipd3N4) viremia following administration of combination antiretroviral therapy (cART) in pigtailed macaques. Here, we sought to determine the safety of hematopoietic stem cell transplantation (HSCT) in cART-suppressed and unsuppressed animals. Design— We compared disease progression in animals challenged with SHIV 100 days post-transplant (PT), to controls that underwent transplant following SHIV challenge and stable, cART-dependent viral suppression. Methods— SHIV viral load, combination antiretroviral therapy (cART) levels, and anti-SHIV antibodies were measured longitudinally from plasma/serum from each animal. Flow cytometry the principal investigator of the study. CWP and KGH designed, conducted, and coordinated the experiments. CWP and PP coordinated the animal experiments. MLH conducted the SHIV DNA measurements. CS, JIM, and AK designed and conducted the cART measurement experiments. WMO, ACR, and SCD conducted the flow cytometry experiments. RB and JIM designed and conducted the viral sequencing experiments. AEW, KRJ, JIM, and SLH contributed substantially to the study conception and design, and critically reviewed the manuscript. We thank Helen Crawford for help in preparing this manuscript, and Lisa Frenkel for helpful discussions. We also thank Veronica Nelson, Erica Curry, and Kelvin Sze for excellent support in our pigtailed macaque studies, Larry Stensland for total SHIV DNA measurements, Michael Watling for conducting sequencing assays, Baoping Tian and Heather Mack for technical assistance with T-cell phenotyping experiments, and Leon Flannery and Joel Ahrens for conducting GI biopsy procedures. The SHIV1157-ipd3N4 inoculum used in these studies was kindly provided by Ruth Ruprecht. Tenofovir and Emtricitabine were kindly provided by Gilead Sciences. Raltegravir was kindly provided by Merck. H. -P. Kiem is a Markey Molecular Medicine Investigator and received support as the inaugural recipient of the José Carreras/E. Donnall Thomas Endowed Chair for Cancer Research. was used to assess T-cell subset frequencies in peripheral blood and gastrointestinal tract (GI). Deep sequencing was used to identify cART resistance mutations. Results— In control animals, virus challenge induced transient peak viremia, viral set point, and durable suppression by cART. Subsequent HSCT was not associated with adverse events in these animals. PT animals were challenged during acute recovery following HSCT, and displayed sustained peak viremia and cART resistance. Although PT animals had comparable plasma levels of antiretroviral drugs and showed no evidence of enhanced infection of myeloid subsets in the periphery, they exhibited a drastic reduction in virus-specific antibody production and decreased T-cell counts. Conclusions— These results suggest that virus challenge prior to complete transplant recovery impairs viral control and may promote drug resistance. These findings may also have implications for scheduled treatment interruption (STI) studies in patients on cART during post-HSCT recovery: premature STI could similarly result in lack of viral control and cART resistance.