Slide 1 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA. IAS–USA
Daniel C. Douek, MD, PhDBethesda, Maryland
Immune Activation, HIV Persistence, and the Cure
Slide 2 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
What We Talk About When We Talk About Immune Activation
Normal innate response to viral infection in the acute phase of the infection
A.R. Stacey et al JV 2009
Virus loadCytokine
Immune activation occurs early in infection
Slide 3 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
• 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
Innate
As viral load decreases, immune activation persists
• 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
Adaptive
What We Talk About When We Talk About Immune Activation
Slide 4 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
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
Slide 5 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Consequences of HIV Infection in GI Tract
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
Mucus
HIV-Infected Gut
•Massive loss of CD4 T cells
•Enteropathy
•2-10x increased permeability
•Translocation of microbial products
•Systemic immune activation
CD4 T cell loss
Loss of tight junctions
Enterocyte apoptosisMicrobial products
Slide 6 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
HIV
immune activation
gut
CD4 depletionenteropathy
Tcm
Tcm
TemTem
Tem
Tem
gut
Slide 7 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
HIV
immune activation
gut
CD4 depletionenteropathy
Tcm
Tem
Tem
CMV
low thymic outputLT fibrosis
T/B cell dysfunction
inflammationtissue damagecoagulopathy
non-AIDS morbidity and mortality
immune deficiency
???
Slide 8 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Tcm
Tem
gut
Tcm
Tem
Tem
low thymic outputLT fibrosis
T/B cell dysfunction
inflammationtissue damagecoagulopathy
non-AIDS morbidity and mortality
immune deficiency
CMV
???
HIV
CD4 depletionenteropathy
ARTimmune
activation
Slide 9 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
T cell activation declines during long-term ART, but remains elevated, even after many years of viral suppression
Hunt, et al. J Infect Dis. 2003, 2008 and unpublished observations
ART and T Cell Immune Activation
HIV –(n=132)
HIV +HAART(n=65)
HIV +Untreated
(n=82)
0
20
40
60
80
% C
D38
+D
R+ C
D8
T c
ells
P<0.001
P<0.001
Slide 10 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Hunt, CROI 2012SOCA/SCOPE cohorts
Markers of Inflammation and GI Dysfunction Predict Mortality
Odds of Mortality (4th vs 1st Quartile)
Markers of inflammation and gut barrier dysfunction predict mortality independently of CD4 count and virus load
Slide 11 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
ART, Immune Activation and CD4 T Cell Recovery
Reduced CD4 T cell recovery associated with immune activation
Hunt, et al. J Infect Dis. 2003 and unpublished observations
Slide 12 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
When Immune Activation Turns To The Dark Side
Good
• Anti-viral 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
• … … …
Slide 13 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
P < 0.0001
P = 0.060
P < 0.0001
P = 0.266
P = 0.010
Llibre, Buzón, Massanella et al. Antiv Ther 2011
%C
D38
+ m
emor
y C
D8
T c
ells
ControlIntensified
Raltegravir intensification reduces immune activation significantly more than conventional therapy
Raltegravir Intensification
Slide 14 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Raltegravir Intensification
Raltegravir intensification in 9 subjects resulted in decrease in IUPM and CD8 T cell activation
Slide 15 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
No association between plasma measures of viral persistence and T cell activation in blood
Raltegravir Intensification
Slide 16 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Hunt, Yukl and Wong
Virus and Immune Activation in Tissues
Stronger association between cell-based measures of viral persistence and T cell activation in gut tissues
r = 0.65 P = 0.012
Sheth, Muc Imm 2012
Raltegravir intensification reduces immune activation and HIV RNA levels in gut tissue sites
Virus and Immune Activation in TissuesSlide 17 of 36
Slide 18 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
• 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
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
Slide 19 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Saez-Cirion et al, in press
14 subjects who started therapy very early after infectionThey remained on cART for many years and then therapy was stopped
HIV
-DN
A (
log 1
0 co
pies
/106
PB
MC
)
Acute Chronic cART EliteControllers
Post-Rx Controllers
1
2
3
4
5
6
VISCONTI — Activation and Reservoir
PTC did not rebound when cART was stopped Like elite controllers they had low cell-associated HIV DNABut, in contrast, they had very low T cell activation
Slide 20 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
On suppressive ART, strong HIV specific T cell responses in the gut mucosa are associated with lower levels of PBMC viral DNA
0 1 2
0.0
0.5
1.0
log10 Proviral DNA(per mil PBMC)
% G
ag-s
pec
ific
IF
Ng
+ I
L2+
CD
8+ T
cel
ls (
GA
LT
)
r = - 0.56, P = 0.01
CD4CD8
r = - 0.37, P = 0.12
Hatano JID 2011
HIV-Specific Immunity and HIV Persistence
Slide 21 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Tcm
Tem
gut
Tcm
Tem
Tem
low thymic outputLT fibrosis
T/B cell dysfunction
inflammationtissue damagecoagulopathy
non-AIDS morbidity and mortality
immune deficiency
CMV
???
ARTTem
immune activation
Slide 22 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
immune activation
low thymic output
lymphoid fibrosis
poor CD4 T cell renewal
T/B cell dysfunction
mucosal damage
target cell generation
infected cell proliferation
virus transcription
virus production
new infection events
Slide 23 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
• 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
• 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
Therapeutic Interventions in Development
Slide 24 of 24
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
• 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
In The Context of The Cure
Combination therapy may be necessary