Immune Activation, HIV Persistence, and the Cure

1. Immune Activation, HIV Persistence, and the Cure Daniel C. Douek, MD, PhDBethesda, Maryland

2. What We Talk About When We Talk About Immune Activation Immune activation occurs early in infection Virus load Cytokine A.R. Stacey et al JV 2009 • Normal innate response to viral infection in the acute phase of the infection

3. What We Talk About When We Talk About Immune Activation As viral load decreases, immune activation persists Innate • Cells: activated phenotype of Macrophages and Dendritic Cells • Cytokines, chemokines: TNF, IL-1, IL-6, IL-8, IL-15, IL-10 • Acute phase proteins: Serum Amyloid A, C-Reactive Protein • Coagulation: D-dimers, Tissue Factor • Fibrosis: Matrix Metalloprotease activation, collagen deposition • Microbial sensors: Lipopolysaccharide Binding Protein, soluble CD14 Adaptive • T cells: increased turnover, exhaustion, low thymic output, virus reservoir • B cells: increased turnover, altered phenotypic profile, hyper-Ig-emia • Frequency of activated T cells is a strong predictor of disease progression

4. Causes Of Chronic Immune Activation • Raised cytokine and chemokine levels are a consequence of immune activation • HIV-induced activation of innate immune system (N. Bhardwaj) • When virus load decreases after acute phase, immune activation remains elevated • Virus load alone is a poor predictor of disease progression (Rodriguez JAMA 2006) • Measures of immune activation predict disease progression independent of viral load (Giorgi, Deeks...) • Elite controllers who progress have increased activated CD38+ T cells (Hunt JID 2008) • When virus load is suppressed with ART immune activation still persists and predicts progression • Increased antigen load, bacterial overgrowth, herpes viruses (S. Deeks, P. Hunt) • Translocation of proinflammatory mediators across mucosae

5. Consequences of HIV Infection in GI Tract Loss of tight junctions Mucus CD4 T cell loss Microbial products Enterocyte apoptosis • HIV-Infected Gut • Massive loss of CD4 T cells • Enteropathy • 2-10x increased permeability • Translocation of microbial products • Systemic immune activation • Healthy Gut • Tight epithelial junctions, mucus • Anti-microbial peptides, Abs, cells • Majority of CD4 T cells in body • Cross-talk between microbes and epithelial cells and immune cells

6. microbial translocation Tem Tem Tem Tcm immune activation Tem Tcm gut gut CD4 depletion enteropathy Immune deficiency HIV target cells

7. microbial translocation Tem Tcm immune activation Tem immune deficiency gut poor pathogen control CD4 depletion enteropathy Immune deficiency HIV CMV ??? target cells low thymic output LT fibrosis T/B cell dysfunction non-AIDS morbidity and mortality inflammation tissue damage coagulopathy

8. Tem Tcm immune deficiency gut poor pathogen control microbial translocation CD4 depletion enteropathy Immune deficiency ART HIV Tem CMV immune activation Tcm Tem ??? target cells low thymic output LT fibrosis T/B cell dysfunction non-AIDS morbidity and mortality inflammation tissue damage coagulopathy

9. ART and T Cell Immune Activation 80 P<0.001 P<0.001 60 % CD38+DR+ CD8 T cells 40 20 0 HIV + Untreated (n=82) HIV + HAART (n=65) HIV – (n=132) Hunt, et al. J Infect Dis. 2003, 2008 and unpublished observations T cell activation declines during long-term ART, but remains elevated, even after many years of viral suppression

10. Markers of Inflammation and GI Dysfunction Predict Mortality Hunt, CROI 2012 SOCA/SCOPE cohorts Odds of Mortality (4thvs 1st Quartile) Markers of inflammation and gut barrier dysfunction predict mortality independently of CD4 count and virus load

11. ART, Immune Activation and CD4 T Cell Recovery Hunt, et al. J Infect Dis. 2003 and unpublished observations Reduced CD4 T cell recovery associated with immune activation

12. When Immune Activation Turns To The Dark Side Bad • Target cell generation • HIV replication • Thymic dysfunction • T and B cell exhaustion • Macrophage/DC activation • Cytokine/Chemokine secretion • Lymph node fibrosis • Generalized tissue fibrosis • Coagulation cascade activation • … … … Good • Anti-viral innate immune response • Restoration of memory CD4 T cells

13. Raltegravir Intensification Intensified Control P < 0.0001 P = 0.060 %CD38+ memory CD8 T cells P = 0.266 P < 0.0001 P = 0.010 Llibre, Buzón, Massanella et al. AntivTher 2011 Raltegravir intensification reduces immune activation significantly more than conventional therapy

14. Raltegravir Intensification Raltegravir intensification in 9 subjects resulted in decrease in IUPM and CD8 T cell activation

15. Raltegravir Intensification No association between plasma measures of viral persistence and T cell activation in blood

16. Virus and Immune Activation in Tissues r = 0.65 P = 0.012 Hunt, Yukl and Wong Sheth, MucImm 2012 Stronger association between cell-based measures of viral persistence and T cell activation in gut tissues

17. Slide 17 of 36 Virus and Immune Activation in Tissues Raltegravir intensification reduces immune activation and HIV RNA levels in gut tissue sites

18. Ongoing HIV Replication During ART? Although complete inhibition of viral replication is unlikely to be curative, all cure strategies are based on first having achieved complete suppression • Evidence against ongoing HIV replication on ART • Increasing evidence in favor of ongoing replication • Evidence it is associated with immune activation • The source of the sample is key (blood vs tissues) • The assay used to measure virus is critical

19. VISCONTI — Activation and Reservoir 14 subjects who started therapy very early after infection They remained on cART for many years and then therapy was stopped 6 Saez-Cirion et al, in press 5 4 HIV-DNA (log10 copies/106 PBMC) 3 2 1 Acute Chronic cART Elite Controllers Post-Rx Controllers PTC did not rebound when cART was stopped Like elite controllers they had low cell-associated HIV DNA But, in contrast, they had very low T cell activation

20. HIV-Specific Immunity and HIV Persistence CD8 CD4 r = - 0.56, P = 0.01 r = - 0.37, P = 0.12 Hatano JID 2011 On suppressive ART, strong HIV specific T cell responses in the gut mucosa are associated with lower levels of PBMC viral DNA

21. Tem Tcm immune deficiency gut poor pathogen control microbial translocation Immune deficiency ART Tem CMV Tem immune activation Tcm Tem ??? low thymic output LT fibrosis T/B cell dysfunction non-AIDS morbidity and mortality inflammation tissue damage coagulopathy

22. poor immune control of HIV poor pathogen control microbial products target cell generation infected cell proliferation virus transcription virus production new infection events low thymic output lymphoid fibrosis poor CD4 T cell renewal T/B cell dysfunction mucosal damage immune activation HIV effects of HIV infection

23. Chemokine receptor inhibitors: maraviroc, TB-652 Anti-infective therapy: CMV, EBV, HSV, HCV/HBV Microbial translocation: sevelamer, colostrum, rifaximin Enhance T cell renewal: Growth Hormone, IL-7 Anti-fibrotic drugs: pirfenidone, ACEi, ARBs, KGF Anti-aging: caloric restriction, sirtuin activators, vitamin D, omega-3 fatty acids, rapamycin, diet, exercise Therapeutic Interventions in Development • Anti-inflammatory drugs: • Chloroquine, HCQ • Minocycline • NSAIDs (COX-2i, aspirin) • Statins • Methotrexate • Thalidomide, lenalidomide, pentoxyfylline (weak TNF inhibitors) • Biologics (e.g., TNF inhibitors, IL-6 inhibitors, anti-IFNa, anti-PD1 • Anti-coagulants: • low dose warfarin, dabigatran, aspirin, clopidogrel Combination therapy may be necessary

24. In The Context of The Cure • Multiple mechanisms account for HIV persistence, all of which are being addressed therapeutically • The unifying theme is to reduce HIV reservoir size • Reduce inflammation • Increase immune function • Early ART and ART intensification • Gene therapy to reduce reservoir size • Stem cell transplants can reduce reservoir size • Drugs with biologic activity against latent virus exist • Vaccines may enhance host-clearance mechanisms Combination therapy may be necessary