CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

403 Bone MarrowMacrophages Are a Potential Source of CNS Virus With SIV-Encephalitis Jaclyn C. Mallard 1 ; Brittany Rife 2 ; David J. Nolan 2 ; Graham Beck 1 ; Emily Papazian 1 ; Russell Simons 1 ;Tricia H. Burdo 1 ; Marco Salemi 2 ; Kenneth C.Williams 1 1 Boston Coll, Chestnut Hill, MA, USA; 2 Emerging Pathogens Inst, Univ of Florida, Gainesville, FL, USA Background: The origin of central nervous system (CNS) inflammatory macrophages and source of CNS virus in HIV-associated neurocognitive disorders (HAND) and SIV- encephalitis (SIVE) are not well defined. CD163+ perivascular macrophages are derived from bone marrow (BM) monocyte precursors, comprise SIVE lesions and are productively infected in the CNS. Monocyte expansion and increased plasma soluble CD163 (sCD163) are associated with HAND and SIVE. Blocking monocyte traffic to the CNS with SIV infection reduces the number of inflammatory and productively infected macrophages in the brain. We hypothesized that SIV-infected perivascular macrophage precursors in BM (Mo/MΦ) are a source of CNS virus in SIVE. Methods: Twenty-one rhesus macaques were infected with SIVmac251. Eleven were CD8+ lymphocyte-depleted to expedite AIDS progression and ten were non-depleted. We compared numbers of Mo/MΦ in BM, expansion of monocyte subsets and plasma sCD163 and virus from animals with AIDS and SIVE (n=6) to animals that developed AIDS without SIVE (SIVnoE, n=11), and animals sacrificed without AIDS (n=4). CD68+Mo/MΦ were extracted from BM using laser capture microdissection. SIV gp120 sequences from BM CD68+ Mo/MΦ were analyzed using intra-host Bayesian phylogeography and compared to SIV gp120 from BM tissue, sorted monocytes and CD3+ lymphocytes, plasma virus, dissected meninges and CNS tissues. Results: SIVE animals had higher numbers of Mo/MΦ in BM than SIVnoE animals. Numbers of BMMo/MΦ correlated with monocyte expansion, plasma sCD163 and virus at necropsy. SIVE animals had higher percentages of CD14+CD16+ pro-inflammatory monocytes from day 20 post-infection to necropsy than SIVnoE animals. We were able to amplify SIV gp120 cDNA from qPCR of 15 animals from BM. SIV gp120 from BMMo/MΦ of SIVE animals shared a most recent common ancestor (MRCA) with sequences from monocytes collected at necropsy. BM was the origin of the MRCA of CNS SIV gp120 sequences in late stage infection of SIVE animals. Conclusions: The correlation of BMMo/MΦ with monocyte expansion and plasma sCD163 that are markers of HAND and SIVE highlights the association between increased numbers of BMMo/MΦ and development of SIVE. The BM ancestry of SIV gp120 sequences sampled from the CNS suggests a viral migration occurred between BM and brain in late stage infection of SIVE animals. CNS virus seeding from BM and viral migration between BMMo/MΦ and monocytes in late stage infection underscore the importance of BMMo/ MΦ in neuropathogenesis. 404 Peripheral Immune Activation Modulates HIV RNA Entry to CSF in Early Acute Infection Alexandra Schuetz 1 ; Suteeraporn Pinyakorn 2 ; Leah Le 3 ;Yuwadee Phuang-Ngern 1 ; Eugène Kroon 4 ; Linda Jagodzinski 5 ;Thep Chalermchai 4 ;VictorValcour 6 ; Jintanat Ananworanich 5 ; Serena S. Spudich 3 ; for the RV254/SEARCH 010 Study Group 1 US AFRIMS, Bangkok, Thailand; 2 US Military HIV Rsr Prog, Walter Reed Army Inst of Rsr, Silver Spring, MD, USA; 3 Yale Univ Sch of Med, New Haven, CT, USA; 4 SEARCH, Bangkok, Thailand; 5 Military HIV Rsr Prog, Bethesda, MD, USA; 6 Univ of California San Francisco, San Francisco, CA, USA Background: The mechanisms determining the magnitude of initial HIV entry into the nervous system during acute HIV infection (AHI) are largely unknown. We examined whether peripheral blood and mucosal cellular immune activation were independently associated with the level of HIV RNA detected in cerebrospinal fluid (CSF) during the earliest stages of HIV infection (Fiebig I to III). Methods: Concurrent blood, CSF and sigmoid biopsy samples were obtained at the time of AHI diagnosis (8 Fiebig I, 11 Fiebig II and 19 Fiebig III) in the context of an observational study of AHI in Bangkok, Thailand (RV254/SEARCH 010). CSF and plasma HIV RNA levels were measured by Roche Amplicor HIV-1 Monitor and Roche COBAS TaqMan HIV-1 tests. Multiparameter flow cytometry was performed using frozen and fresh samples to determine systemic and mucosal immune activation (Ki67 + and CD38 + /HLA-DR + ), respectively. CSF chemokine levels (IP-10 and neopterin) were quantified by ELISA. Mann Whitney U test was used for comparisons and linear regression and Pearson’s Correlation to evaluate associations. Results: Among 38 early AHI subjects, 90%were MSM, the median age was 29 years, mean CD4 count was 438 cells/mm 3 , and estimated duration since exposure was 15 days. During early AHI, plasma (p<0.001) and CSF HIV RNA (p<0.001), CSF neopterin levels (p=0.003) and the frequency of activated CD8 + T cell in blood (p=0.002) and sigmoid mucosa (p<0.001) increased with progression from Fiebig I to Fiebig III. In univariate analyses of the overall group, CSF HIV RNA was associated with CSF IP-10 levels (r=0.37, p=0.04), CSF neopterin levels (r=0.61, p<0.001), the frequency of CD8 + Ki67 + T cells in the blood (r=0.56, p=0.001) and the frequency of CD8 + Ki67 + (r=0.48, p=0.008) and CD8 + CD38 + HLA-DR + (r=0.46, p=0.01) T cells in the mucosa. Moreover, when adjusting for levels of plasma HIV RNA, the frequency of peripheral CD8 + Ki67 + T cells remained a significant predictor of CSF HIV RNA (adjusted r=0.78, p<0.001; Figure 1). Conclusions: During early AHI, CSF inflammation and peripheral and mucosal immune activation are present and increase with progression of Fiebig stage from I to III. The correlation between CSF HIV RNA and frequency of activated CD8 + T cells in the blood independent from plasma HIV RNA supports the hypothesis that peripheral immune activation modulates the amount of HIV entering the CNS during this earliest stage of infection.

Poster Abstracts

153

CROI 2016