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The pathogenesis of persistent HIV-associated inflammation during long-term antiretroviral therapy. Steven G. Deeks Professor of Medicine University of California, San Francisco.
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The pathogenesis of persistent HIV-associated inflammation during long-term antiretroviral therapy Steven G. DeeksProfessor of MedicineUniversity of California, San Francisco
Untreated and to a lesser degree treated HIV infection is associated with increased frequency of “activated” (CD38+ HLA-DR+) T cells
Activated CD38+ HLA-DR+ T cells are rapidly turning over in untreated disease Srinivasula et al., Blood 2011
Pre-treatment activation “set-point” strongly predicts extent of activation during suppressive HAARART Hunt et al, CROI 2010, Poster #306, and submitted
UARTO: High CD8+ T aell activation at month 6 of HAART predicts mortality in Ugandans with VL<400 In Cox Proportional Hazards models, each 10% increase in the frequency of activated (%CD38+ HLA-DR+) CD8+ T cells was associated with an increased hazard of death even after adjustment for baseline CD4 count (HR: 1.62, P=0.048) or month 6 CD4 count (HR: 1.61, P=0.042). Hunt et al, CROI 2010, Poster #306, and submitted
Why are “activated” T cells elevated in antiretroviral-treated disease? Residual HIV replication CMV (and other prevalent co-infections) Microbial translocation Lack of immunoregutory responses Thymic dysfunction and residual defects in adaptive immune responses Lymphoid fibrosis Co-morbid conditions (metabolic syndrome, central adiposity)
Does residual replication during HAART contribute to chronic inflammation?
Raltegravir intensification had no effect on CD8+ T cell activation (blood and GALT) suggesting that active viral replication is not a causes of persistent inflammation 30 20 % CD38+HLA-DR+ CD8+ T cells (blood) 10 PBO RGV 0 0 4 8 12 16 20 24 Weeks Hatano et al., JID 11
The size of HIV reservoir (as defined by RNA/DNA ratio) is associated with frequency of activated CD4+ T cells in rectal tissues Hatano, Hunt, Yukl and Wong (IAS 2011)
Most (but not all) studies have shown that HIV infection results in mucosal damage, microbial translocation and inflammation; this effect persists during HAART Brenchley JM Nature Medicine 2006
Levels of sCD14 (a marker of LPS and/or monocyte/macrophage activation) predicts mortality in HIV disease independent of other factors (SMART study) Sandler JID 2011
CMV elicits massive immune responses even in asymptomatic young HIV uninfected adults Sylwester/Picker, JEM, 2005
CMV-specific T cell responses are approximately five fold higher in treated HIV infected adults Naeger et al, PLoS ONE 2009
Higher CMV-specific CD8 IFN-γ production associated with atherosclerosis in several studies Hsue et al, AIDS, 2006
Loss of T cell regenerative capacity and altered immunoregulatory responses
HIV-associated inflammation → T reg response → TGF-β→ Collagen deposition → Fibrosis → Reduced IL-7 → Reduced T cell regeneration → Inflammation CD3+ Collagen 1 + Desmin +
Inflammation increases IDO production which in turn causes Th17 depletion, microbial translocation and more inflammation T Cell Proliferative Defect ↓Tryptophan IDO Induction in DC/MØ IFN-γ LPS ↑HAA Microbial Translocation Th17 Depletion Favre/McCune Science Translationa Med 2010 Hunt et al, IAS, 2011, #MOAA0105
Telomerase (a reverse transcriptase) is inhibited by certain NRTIs (ZDV, d4T, TDF), and treated HIV disease is associated with shorter telomeres Strahl and Blackburn. Nuc Acid Res 1994:22:893–900 Leeansyah et al. 6th IAS on Pathogenesis, Clinical Research and Prevention, Rome, July 2011; Poster TUPE127
Conclusions T cell activation as defined by CD38 and HLA-DR expression remains elevated during HAART Functional characteristics of cells not fully defined T cell activation associated with disease Multiple mechanisms cause activation during HAART Residual HIV replication (controversial) Microbial translocation (controversial) CMV and other co-pathogens (needs confirmation) Loss of T regulatory cells and other immunoregulatory responses Lymphoid fibrosis (may be central to preceding causes) Homeostatic proliferation (not “activation”) Telomerase inhibition (indirect effect) Metabolic syndrome, abdominal obesity
Acknowledgements SCOPE Cohort / UCSF Peter Hunt Hiroyu Hatano Jeff Martin David Naeger Rebecca Hoh Rick Hecht Vivek Jain Elizabeth Sinclair Lorrie Epling Mike McCune Elsewhere Netanya Sander Danny Douek Michael Lederman Alan Landay Russell Tracy April Ferre Barbara Shacklett Tim Shacker Ashley Haase Larry Corey Robert Kaplan Sharon Lewin NIAID RO1 AI087145, K24AI069994, CNICS (5R24AI067039), CLIC