Long-Term Reduction in Peripheral Blood HIV-1 Reservoirs Following Reduced- Intensity Allogeneic Stem Cell Transplantation in Two HIV-Infected Individuals Timothy J. Henrich 1,2, Gaia Sciaranghella 3, Jonathan Z. Li 1,2, Sebastien Gallien 4, Vincent Ho 5,2, Ann S. LaCasce 5,2, and Daniel R. Kuritzkes 1,2 1 Brigham and Women's Hospital, Boston, MA; 2 Harvard Medical School, Boston, MA; 3 Ragon Institute of MGH, MIT, and Harvard, Boston, MA; 4 Hopital Saint-Louis, Paris, France; 5 Dana-Farber Cancer Institute, Boston, MA. Your logo

Background One reported “functional cure” of HIV-1 infection: myeloablative allogeneic HSCT from a homozygous ccr5Δ32 donor 1,2 Several factors may have contributed to functional cure including pre-transplant myeloablative chemotherapy, GVHD, full engraftment of CCR5- donor cells Cytotoxic chemotherapy alone insufficient to eliminate reservoirs as HIV-1 DNA persists after autologous HSCT 3,4 The long-term effects of allogeneic HSCT using CCR5+ stem cells have not been studied in detail 1 Hutter et al. 2009; 2 Allers et al. 2010; 3 Simonelli et al. 2010; 4 Cillo et al. 2011;

Study Aims Study Aims:  Examine long-term changes in the peripheral HIV-1 reservoir following allogeneic HSCT in the setting of cART  Explore HIV-1 coreceptor usage, PBMC coreceptor expression and HIV-specific antibody responses pre- and post-HSCT Patients: 2 HIV-1 infected patients on combination ART who underwent reduced-intensity conditioning (RIC) allogeneic HSCT RIC = non-myeloablative chemotherapy, no total body irradiation or anti-thymocyte globulin

Methods Studied stored blood samples collected pre- and post-HSCT and prospectively collected samples (5 time points) 1)Quantified proviral HIV-1 DNA from peripheral blood mononuclear cells (PBMCs) and purified CD4 + T cells by real-time PCR 2)Quantified 2-LTR circles from PBMC episomal DNA 3)Quantified plasma viremia by a single-copy assay 4)Viral outgrowth assays using ~10 7 patient-derived CD4 + T cells and CD8 T cell-depleted lymphoblasts from an HIV-negative donor 5)CCR5 genotyping/flow cytometric quantification of CCR5 expression on CD3+ T lymphocytes 6)Genotypic and phenotypic determination of HIV-1 coreceptor usage 7)Quantified HIV-1-specific Ab levels & avidity

Study Patients Patient A: Male with perinatally acquired HIV-1 on long-term ART 2006: Stage IV Hodgkin disease  standard treatment Disease recurrence  salvage therapy 2007: Autologous HSCT 2008: Relapse  RIC partially mismatched unrelated-donor HSCT cART: TDF/FTC/EFV 3-4 years pre-HSCT with undetectable VL Clinical course post-allogeneic HSCT

Study Patients Patient B: Male with sexually acquired HIV-1 in mid-1980’s 2003: Large B-cell lymphoma  chemotherapy and cART started 2006: New stage IV Hodgkin lymphoma Disease recurrence  salvage therapy 2007: Autologous HSCT 2010: MDS (Tx-related)  RIC matched related-donor HSCT cART: TDF/FTC/RAL peri-transplant with undetectable VL Clinical course post-allogeneic HSCT

Patient A Viral outgrowth assay negative day No 2-LTRs detected

Patient B DLI= donor lymphocyte infusion Viral outgrowth assay negative day +652 No 2-LTRs detected

CCR5 / Coreceptor Usage Both patients heterozygous for ccr5Δ32 mutation PBMC homozygous wild-type for CCR5 after engraftment Percentage of CCR5-expressing lymphocytes nearly doubled after full donor engraftment in Patient A (sufficient sample) Full-length HIV-1 env amplified from proviral DNA at pre- and 1 st post-HSCT PBMC samples (later timepoints negative) V3-loop genotyping predicted CCR5 usage pre- and post-HSCT R5 phenotype confirmed by tropism assay of pseudotyped viruses expressing PBMC-derived env

Anti-HIV Ab Quantification HIV-specific Ab detected by VITROS assay pre- & post-HSCT Decrease in Ab levels post-HSCT from diluted and undiluted plasma Similar decrease in antigen avidity by limiting-antigen assay Limited Sensitivity VITROS AssayLimiting-Antigen Avidiy Assay Patient A Patient B

Summary & Conclusions Allogeneic HSCT with RIC in the setting of suppressive ART led to a substantial and sustained reduction in the HIV-1 reservoir in PBMC - Reduction in proviral HIV-1 DNA correlated temporally with full donor engraftment Engraftment of susceptible donor cells without infection adds supportive evidence that HIV-1 replication is fully suppressed by effective cART Declining HIV-specific Ab levels/avidity provide further evidence for minimal persistence of HIV-1 antigen Tissue sampling and analytic treatment interruption are necessary to fully assess the extent of HIV-1 reservoir reduction after allogeneic HSCT

Acknowledgements BWH:Funding Sources: Members of the Kuritzkes Lab:NIH/NIAID 1K23AI A1 to TJH Zixin HuUM1 AI to DRK; P30 AI Nina LinU19 AI to SGD Françoise Giguel Laura Lavoie Athe Tsibris Members of the ID Division Blood Systems Research Institute/UCSF: Michael Busch Sheala Keeting Mila Lebedeva UCSF: Steven Deeks Harvard School of Public Health: Ronald Bosch (SDAC)

Viral DNA Diversity Pre-HSCT Post-HSCT Patient A Single genome sequencing of full-length HIV-1 Env from PBMC DNA from pre- and 1 st post-HSCT samples No major evolutionary changes observed following HSCT