HIV Disease Pathogenesis

Slide Presentation HIV Disease Pathogenesis Bethesda, MD What Do We Mean by Pathogenesis Today? 1 Survival from Age 25 Years (N = 3,990) Probability of Survival 0.75 0.5 0.25 0 25 30 35 40 45 50 55 60 65 70 Age Increased life expectancy in the era of HAART Late HAART (2000 2005) Early HAART (1997 1999) Pre-HAART (1995 1996) Lohse N. Ann Intern Med. 2007; ART-CC, Lancet, 2008; Lewden, JAIDS, 2007; van Sighem, AIDS, 2010 What Do We Mean by Pathogenesis Today? 1 Survival from Age 25 Years (N = 3,990) Probability of Survival 0.75 0.5 0.25 0 25 30 35 40 45 50 55 60 65 70 Age Population controls Late HAART (2000 2005) Early HAART (1997 1999) Pre-HAART (1995 1996) Life span of ART-treated patients is 10 years less than that of uninfected people, esp. if therapy is started late. Lohse N. Ann Intern Med. 2007; ART-CC, Lancet, 2008; Lewden, JAIDS, 2007; van Sighem, AIDS, 2010

What Do We Mean by Pathogenesis Today? Cardiovascular disease 1-3 Cancer (non-aids) 4 Bone fractures/osteopenia 5,6 Liver failure 7 Kidney failure 8 Cognitive decline 9 Frailty 10 ART-CC. CID. 2010 50:1387-1396 1. Klein D. JAIDS. 2002 30:471-477 2.Hsue P. Circulation. 2004 109:316-319 3. Grinspoon SK. Circulation. 2008 118:198-210 4.Patel P. Ann Int Med, 2008;148:728-736 5.Triant V. JCEM. 2008 93:3499-3504 6. Arnsten JH. AIDS. 2007 21:617-623 7. Odden MC. Arch Int Med. 2007 167:2213-2219 8.Choi A. AIDS. 2009 23:2143-2149 9.McCutchan JA. AIDS. 2007 21:1109-1117 10.Desquilbet L. JGBSMSci. 2007 62:1279-1286 Almost two-thirds of deaths in the late ART era are non-aids associated. Non-AIDS events are greater in treated HIV disease than in uninfected people even after adjusting for age, ART, and traditional risk factors. 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 What We Talk About When We Talk About Immune Activation As virus load decreases, immune activation persists. Innate Cells: activation of macrophages and dendritic cells Cytokines, chemokines: IFNa, 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 metalloproteinase 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, exhaustion, hypergammaglobulinemia Frequency of activated T cells is a strong predictor of disease progression.

Causes of Chronic Immune Activation HIV-induced activation of innate immune system (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). Immune activation predicts disease progression independent of viral load (Giorgi, Deeks etc). Elite controllers who progress have increased activated CD38+ T cells (Hunt JID 2008). When virus load is suppressed with ART, activation persists and predicts progression. Increased antigen load, bacterial overgrowth, herpes viruses (Deeks) Defective tryptophan metabolism (McCune, Hunt) Immunologic and structural damage to gut, increased mucosal permeability, translocation of inflammatory microbial products into systemic circulation Consequences of HIV Infection in GI Tract Mucus Loss of tight junctions Microbial products Enterocyte apoptosis CD4 T cell loss Healthy Gut Tight epithelial junctions, mucus Antimicrobial peptides, Abs, cells Majority of CD4 T cells in body Cross talk between microbes and epithelial and immune cells HIV-Infected Gut Massive loss of CD4 T cells Enteropathy 2-10x increased permeability Translocation of microbial products Systemic immune activation gut CD4 depletion enteropathy HIV Tcm Tcm immune activation

immune deficiency gut CD4 depletion enteropathy HIV Tcm immune activation CMV??? non-aids morbidity and mortality low thymic output LT fibrosis T/B cell dysfunction inflammation tissue damage coagulopathy Tcm Tcm immune deficiency gut CD4 depletion enteropathy HIV ART immune activation CMV??? non-aids morbidity and mortality low thymic output LT fibrosis T/B cell dysfunction inflammation tissue damage coagulopathy Markers of Inflammation and GI Dysfunction Predict Mortality Microbial translocation Inflammation Coagulation Hunt, CROI 2012 T cells %CD38 + DR + %CD57 + DR + Odds of Mortality (4 th vs 1 st Quartile) (Independent of CD4 count and virus load) Markers of inflammation and gut barrier dysfunction predict mortality independently of CD4 count and virus load.

When Immune Activation Turns to the Dark Side Good Antiviral innate immune response Restoration of memory CD4 T cells 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 Immune Activation and HIV Persistence Does inflammation contribute to HIV persistence? Does HIV replication contribute to persistent inflammation? Can novel therapies reduce reservoir size? Anti-inflammatory drugs Enhanced HIV-specific immunity It is difficult to establish cause and effect. Immune Activation and HIV Persistence Slide 16 of 38 % activated memory CD4 T cells LAT24F_L_An_3p_4p_38pDRp 0 5 10 15 20 Correlation r=0.689, p=0.003 0 1000 2000 3000 Total HIV DNA (copies/million resting memory CD4 cells); digital PCR Frequency of HIV DNA-containing resting memory CD4 T cells correlates with frequency of activated CD4 T cells.

Immune Activation and HIV Persistence Katlama CROI 2013 IL-7 causes CD4 T-cell proliferation without virus production but with increased HIV-infected CD4 T-cell reservoir. Raltegravir Intensification No association between plasma measures of viral persistence and T-cell activation in blood. Raltegravir Intensification %CD38 + memory CD8 T cells P < 0.0001 Nat Med 2010 P = 0.266 P = 0.060 P = 0.010 P < 0.0001 Intensified Control Llibre, Buzón, Massanella et al. Antiv Ther 2011 Raltegravir intensification reduces immune activation and virus replication significantly more than conventional therapy.

Raltegravir Intensification Raltegravir intensification in nine subjects resulted in decrease in infectious virus and CD8 T-cell activation. Raltegravir Intensification JID 2013 Rapid increase in the level of 2-LTR circles and decrease in D-dimers in some subjects. Viral replication persists in some individuals even after long-term ART and is associated with inflammatory biomarkers. Virus and Immune Activation in Tissues Raltegravir intensification reduces immune activation and HIV RNA levels in gut tissue sites.

How Big Is the Reservoir? It was thought that <1% of HIV sequences in cells are replication competent. Cell 2013 88% of HIV sequences in cells have identifiable defects. 12% have intact genomes and may be replication competent. Size of the latent reservoir, and hence the barrier to cure, may be up to 60-fold greater than previously estimated. 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. Virus Persistence on cart: A5276 Virus persistence by single copy assay (SCA) of plasma virus SCA on patients at ~4, 7, and 11 years on suppressive ART (n=64) Yr 4: N (%) Yr 7: RNA > 1 c/ml Yr 10: RNA > 1 c/ml +/+ (persistent) 17 (27) 65% 56% +/- (intermittent) 25 (39) 32% 36% -/- (negative) 22 (34) 14% 9% Persistent viremia at year 4 often still positive at years 7 and 10 Absence of viremia at year 4 often still negative at years 7 and 10 No change in pvl over time if persistent viremia (median ~ 1.4 c/ml) Riddler SA, et al. CROI 2014, Abstract #420

Ongoing HIV Replication During ART? Day 0 Month 1 Month 3 Month 6 100% PNAS 2014 Median Percent Difference of LN from PBMC Concentrations #1 #2 #3 #4 n/a Median % Difference 50% 0% -50% -100% LN Ileum Rectum TFV-DP FTC-TP ATV DRV EFV Persistent virus replication in lymph nodes during ART is associated with lower levels of ARVs in tissues. Immune Activation and HIV Persistence A. What mechanisms associate immune activation with HIV persistence? B. How may they direct therapeutic interventions? immune deficiency gut Tcm Tcm ART immune activation CMV??? low thymic output LT fibrosis T/B cell dysfunction non-aids morbidity and mortality inflammation tissue damage coagulopathy

target cell generation infected cell proliferation virus transcription virus production new infection events immune activation low thymic output lymphoid fibrosis poor CD4 T-cell renewal T/B-cell dysfunction mucosal damage Therapeutic Interventions in Development 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 Antifibrotic drugs: pirfenidone, ACEi, ARBs, KGF Anti-aging: caloric restriction, sirtuin activators, vit. D, omega-3 fatty acids, rapamycin, diet, exercise (not recommended by me) Anti-inflammatory drugs: chloroquine, hydroxychloroquine minocycline NSAIDs (COX-2i, aspirin) statins methotrexate anakinra (IL-1Ra) thalidomide, lenalidomide, pentoxyfylline (weak TNF inhibitors) biologics (TNFi, IL-6i, anti-ifna, anti-pd1, anti-pdl1, JAKi, IDOi, Casp-1i) Anticoagulants: warfarin, dabigatran, aspirin, clopidogrel Combination therapy may be necessary. Therapeutic Interventions in Studies LPS fold increase Sevelamer: Pandrea, CROI 2013 Probiotics: Klatt et al. JCI 2013 DR + CD38 + CD4 T cells %CD4 T cells in colon ARV + Probiotic ARV Bovine colostrum: Asmuth, Douek et al. AIDS 2013 scd14 µg/ml 4 3 2 1 0 P=0.740 P=0.008 D0 D28 W12 % mucosal CD4 + T cells P <0.001 100 P=0.002 80 P=0.042 60 40 20 0 Baseline W12 HIV- IL-7: Sereti et al. PLoS Path 2014

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. Vaccines may enhance host-clearance mechanisms. Early ART and ART intensification. Drugs with biologic activity against latent virus exist. Gene therapy to reduce reservoir size. Stem cell transplants can reduce reservoir size. Combination therapy may be necessary. Berlin and Boston Patients HSCT/Patient Factor Berlin Patient Boston Patient A Boston Patient B Cancer AML Hodgkin s lymphoma Hodgkin s lymphoma Mode of acquisition Sexual (adult) Perinatal Sexual (adult) Favorable HLA alleles? No No No Type of HSCT HLA identical ( 10 of 10 match ) HLA C-mismatched, unrelated donor Matched related donor CCR5 genetics of graft 32 Homozygous 32 Heterozygous 32 Heterozygous HSCT conditioning Myeloablative Reduced intensity Reduced intensity GVHD Acute and chronic, no active disease Immunosuppression Cyclosporine A, methylprednisolone, mycophenolate mofetil Acute and chronic, no active disease Tacrolimus ART regimen pre-ati TDV/FTC/EFV TDF/FTC/EFV TDF/FTC/RAL Length of ART post-hsct None 4.5 years 2.8 years Acute and chronic, no active disease None (during ATI) Pre-HSCT HIV-1 DNA Unknown 144 copies/10 6 PBMC 96 copies/10 6 PBMC Time to recrudescence Cured 12 weeks 32 weeks Adapted from Heinrich CROI 2014 Patient A: Where Did the Virus Come From? Consensus B HIV-1 DNA pre-hsct Heinrich CROI 2014 Plasma RNA 5 days after rebound A single virus accounts for recrudescence

The Importance of Target Cell Availability HSCT/Patient Factor Berlin Patient Boston Patient A Boston Patient B Cancer AML Hodgkin s lymphoma Hodgkin s lymphoma Mode of acquisition Sexual (adult) Perinatal Sexual (adult) Favorable HLA alleles? No No No Type of HSCT HLA identical ( 10 of 10 HLA C-mismatched, Matched related donor match ) unrelated donor CCR5 genetics of graft 32 Homozygous 32 Heterozygous 32 Heterozygous HSCT conditioning Myeloablative Reduced intensity Reduced intensity GVHD Acute and chronic, no active disease Immunosuppression Cyclosporine A, methylprednisolone, mycophenolate mofetil Acute and chronic, no active disease Tacrolimus ART regimen pre-ati TDV/FTC/EFV TDF/FTC/EFV TDF/FTC/RAL Length of ART post-hsct None 4.5 years 2.8 years Acute and chronic, no active disease None (during ATI) Pre-HSCT HIV-1 DNA Unknown 144 copies/10 6 PBMC 96 copies/10 6 PBMC Time to recrudescence Cured 12 weeks 32 weeks Adapted from Heinrich CROI 2014 Thanks for the Memories Netanya Sander Jason Brenchley Tim Schacker Steve Deeks Peter Hunt Jake Estes Sarah Palmer Joe Wong Rick Hecht Nicolas Chomont Rafick Sekaly Michael Lederman and the BBC and loads of other wonderful people VRC NIAID Office of AIDS Research GATES