Slide 1 of 24
Immune Activation, HIV
Persistence, and the Cure
Daniel C. Douek, MD, PhD
Bethesda, Maryland
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
IAS–USA
Slide 2 of 24
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 3 of 24
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 4 of 24
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 5 of 24
Consequences of HIV Infection in GI Tract
Loss of tight junctions
Mucus
CD4 T cell loss
Microbial products
Enterocyte apoptosis
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
HIV-Infected Gut
•Massive loss of CD4 T cells
•Enteropathy
•2-10x increased permeability
•Translocation of microbial products
•Systemic immune activation
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 6 of 24
gut
CD4 depletion
enteropathy
HIV
Tem Tem
Tem
Tcm
Tem Tcm
immune
activation
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 7 of 24
immune deficiency
gut
CD4 depletion
enteropathy
HIV
Tem
immune
activation
Tcm
Tem
low thymic output
LT fibrosis
T/B cell dysfunction
inflammation
non-AIDS morbidity
tissue damage
mortality
From DCand
Douek,
MD, at San Francisco, CA: March
24, 2013, IAS-USA.
coagulopathy
CMV
???
Slide 8 of 24
immune deficiency
gut
CD4 depletion
enteropathy
ART
HIV
Tem Tem
immune
activation
Tcm
Tem Tcm
low thymic output
LT fibrosis
T/B cell dysfunction
inflammation
non-AIDS morbidity
tissue damage
mortality
From DCand
Douek,
MD, at San Francisco, CA: March
24, 2013, IAS-USA.
coagulopathy
CMV
???
Slide 9 of 24
% CD38+DR+ CD8 T cells
ART and T Cell Immune Activation
80
P<0.001
P<0.001
60
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 10 of 24
Markers of Inflammation and GI Dysfunction Predict
Mortality
Odds of Mortality (4th vs 1st Quartile)
Hunt, CROI 2012
SOCA/SCOPE cohorts
Markers of inflammation and gut barrier dysfunction predict
mortality independently of CD4 count and virus load
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 11 of 24
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 12 of 24
When Immune Activation Turns To The Dark Side
Good
Bad
• Anti-viral innate immune response
• Target cell generation
• Restoration of memory CD4 T cells
• HIV replication
• Thymic dysfunction
• T and B cell exhaustion
• Macrophage/DC activation
• Cytokine/Chemokine secretion
• Lymph node fibrosis
• Generalized tissue fibrosis
• Coagulation cascade activation
• ………
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
%CD38+ memory CD8 T cells
Raltegravir Intensification
P < 0.0001
P = 0.266
Slide 13 of 24
Intensified
Control
P = 0.060
P = 0.010
P < 0.0001
Llibre, Buzón, Massanella et al. Antiv Ther 2011
Raltegravir intensification reduces immune activation
significantly more than conventional therapy
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Raltegravir Intensification
Slide 14 of 24
Raltegravir intensification in 9 subjects resulted in decrease in
IUPM and CD8 T cell activation
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Raltegravir Intensification
Slide 15 of 24
No association between plasma measures of viral persistence and
T cell activation in blood
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 16 of 24
Virus and Immune Activation in Tissues
r = 0.65 P = 0.012
Hunt, Yukl and Wong
Sheth, Muc Imm 2012
Stronger association between cell-based measures of viral
persistence and T cell activation in gut tissues
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 17 of 36
Virus and Immune Activation in Tissues
Raltegravir intensification reduces immune activation
and HIV RNA levels in gut tissue sites
Slide 18 of 24
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 19 of 24
VISCONTI — Activation and Reservoir
HIV-DNA (log10 copies/106 PBMC)
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
3
2
1
Acute Chronic cART
Elite
Post-Rx
Controllers 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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 20 of 24
CD8
1.0
r = - 0.56, P = 0.01
0.5
0.0
0
1
2
% Gag-specific IFNg+ IL2+
CD4+ T cells (GALT)
% Gag-specific IFNg+ IL2+
CD8+ T cells (GALT)
HIV-Specific Immunity and HIV Persistence
CD4
6
r = - 0.37, P = 0.12
5
4
3
2
1
0
0
log10 Proviral DNA
(per mil PBMC)
1
2
log10 Proviral DNA
(per mil PBMC)
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
immune deficiency
Slide 21 of 24
gut
ART
Tem
Tem Tem
immune
activation
Tcm
Tem Tcm
low thymic output
LT fibrosis
T/B cell dysfunction
inflammation
non-AIDS morbidity
tissue damage
mortality
From DCand
Douek,
MD, at San Francisco, CA: March
24, 2013, IAS-USA.
coagulopathy
CMV
???
Slide 22 of 24
target cell generation
infected cell proliferation
virus transcription
virus production
low thymic output
immune
activation
new infection events
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
lymphoid fibrosis
poor CD4 T cell renewal
T/B cell dysfunction
mucosal damage
Slide 23 of 24
Therapeutic Interventions in Development
• Chemokine receptor inhibitors: • Anti-inflammatory drugs:
– 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
–
–
–
–
–
–
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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.
Slide 24 of 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
From DC Douek, MD, at San Francisco, CA: March 24, 2013, IAS-USA.