CROI 2019 Abstract eBook

Abstract eBook

Oral Abstracts

data suggest that two types of KS exist, based on loss or overexpression of WT1. In KS cases that overexpress this protein, WT1 may be a promising target as a biomarker and immunotherapy.

in point-of-care format, and ultimately greatly increase access to timely and accurate KS diagnosis.

Oral Abstracts

20LB QUANTIFICATION OF KSHV DNA AS A DIAGNOSTIC TEST FOR KAPOSI SARCOMA IN AFRICA Aggrey Semeere 1 , Andrea Gardner 2 , Megan Wenger 3 , Priscilla Namaganda 1 , Ryan Snodgrass 4 , Varun Kopparthy 4 , Esther Freeman 5 , John Ssali 6 , Mwebesa Bwana 7 , Toby Maurer 3 , Robert Lukande 8 , Miriam Laker-Oketta 1 , David Erickson 4 , Ethel Cesarman 2 , Jeffrey Martin 3 1 Infectious Disease Institute, Kampala, Uganda, 2 Weill Cornell Medicine, New York, NY, USA, 3 University of California San Francisco, San Francisco, CA, USA, 4 Cornell University, Ithaca, NY, USA, 5 Massachusetts General Hospital, Boston, MA, USA, 6 AIDS Healthcare Foundation Uganda, Kampala, Uganda, 7 Mbarara University of Science and Technology, Mbarara, Uganda, 8 Makerere University College of Health Sciences, Kampala, Uganda Background: Histopathologic evaluation, the gold standard for diagnosis of Kaposi sarcoma (KS), has long been limited in sub-Saharan Africa by lack of personnel and materials. Even where pathology is available, accuracy of KS diagnosis is often sub-optimal. This has led to widespread delays and inaccuracies in KS diagnosis, often resulting in late or improper treatment (e.g., unwarranted chemotherapy). As an alternative to histopathology, we hypothesized that quantification of KSHV DNA in skin lesions can diagnose KS. Methods: We evaluated consecutive patients with skin lesions, suspected by their primary care providers to be KS, who were referred for a skin biopsy at 3 HIV care centers in Uganda. Traditional histopathologic evaluation of the 5 mm skin punch biopsies, including anti-LANA staining, was performed in Africa and by up to 3 pathologists in the US. Quantitative PCR (qPCR) for KSHV ORF 26 was performed on extracted DNA from the biopsy. Using the consensus of the US pathologists as the gold standard, we determined the sensitivity & specificity of PCR (both qualitative and quantitative) for KS diagnosis. A receiver operating characteristics curve was used to assess quantitative cutpoints and area under the curve (AUC). Results: We tested 506 participants with skin lesions. Median age was 33 years, 38%were women, and 94%were HIV-infected; 22% of lesions were macules, 64% plaques, and 14% nodules. Consensus US pathologic testing revealed that 330 biopsies were KS, 149 not KS and 27 were indeterminate. Using US pathology as gold standard, the sensitivity of African pathology was 95% and specificity was 70%. Sensitivity of qualitative detection (presence or absence) of KSHV DNA for KS diagnosis was 99% but specificity was only 78%. Evaluation of quantitative KSHV DNA content found an AUC of 0.96; at the optimal cutpoint (1412 KSHV copies per 5 µl specimen), sensitivity was 98% and specificity was 90%, with 96% of subjects correctly classified. Conclusion: In the context of sub-Saharan Africa, where KSHV is endemic, quantification of KSHV DNA content in skin lesions by PCR has both high sensitivity and specificity for the diagnosis of KS when compared to gold standard pathology. In contrast, qualitative detection of KSHV DNA is non- specific. The findings suggest that a nucleic acid amplification-based diagnostic test for KS could largely replace the need for histopathology, be implemented

21 TWO NOVEL POTENTIAL THERAPEUTIC TARGETS IN THE KSHV LIFE CYCLE Thomas Schulz , Medizinische Hochschule Hannover, Hannover, Germany Twenty-five years after the discovery of KSHV our understanding of the molecular mechanisms governing its replication, persistence and pathogenicity has advanced to the point where it may become possible to identify novel therapeutic targets for pharmacological intervention. In our recent work, we have focused on the KSHV thymidine kinase and a non-structural membrane protein encoded by open reading frame (ORF) K15. Work by Gill and colleagues (EMBO J. 2014) had suggested that the KSHV thymidine kinase (TK) homologue, encoded by ORF 21, has tyrosine kinase properties. We therefore explored if tyrosine kinase inhibitors already approved for cancer chemotherapy would show activity against KSHV TK. We found that several compounds potently inhibit KSHV TK in in vitro and ex cellulo kinase assays, and also strongly inhibit KSHV productive (lytic) replication in tissue culture, as well as KSHV-dependent tumorigenesis in a xenograft model. Regarding the viral non-structural membrane protein encoded by ORF K15 (pK15), we have previously shown that is expressed in Kaposi Sarcoma tissue and that, in primary endothelial cells, it is required for KSHV-dependent angiogenic and proliferative effects, as well as for the ability of KSHV to reactivate from latency; pK15 recruits, and promotes the activation of, the cellular lipase PLC ϒ 1 to achieve these biological properties (Bala et al., PLoS Path. 2012; Gramolelli et al., PLoS Path 2015; Abere et al. PLoS Path. 2017; Abere et al. J. Virol. 2018). We have now studied the interaction of pK15 with PLC ϒ 1 at the molecular and structural level and identified first small molecule inhibitors that potently interfere with the activation of PLC ϒ 1 by pK15 and KSHV lytic replication. Ongoing work aims to optimize these ‹hits› to reach a starting point for hit-to-lead development. 22 TARGETING THE NONCANONICAL NF- κ B PATHWAY REVERSES SIV LATENCY Maud Mavigner 1 , Richard M. Dunham 2 , Alyssa Brooks 1 , Cristin Galardi 3 , Gavin C. Sampey 4 , Steven E. Bosinger 5 , Thomas Vanderford 5 , David M. Margolis 4 , Guido Silvestri 5 , Ann Chahroudi 1 1 Emory University, Atlanta, GA, USA, 2 GlaxoSmithKline, Research Triangle Park, NC, USA, 3 ViiV Healthcare, Research Triangle Park, NC, USA, 4 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 5 Yerkes National Primate Research Center, Atlanta, GA, USA Background: The leading approach to eradicate HIV consists of the induction of latency reversal and subsequent clearance of cells reactivating the virus. Here, we tested a novel latency reversing agent (LRA) strategy that selectively activates the non-canonical NF-κB pathway (ncNF-κB) using a mimetic of the second mitochondrial-derived activator of caspases (SMACm). Methods: We evaluated the SMACm AZD5582 in 12 SIV-infected ART- suppressed rhesus macaques (RM) compared to 9 controls. After over a year of ART, RM received 3-10 weekly doses of AZD5582 intravenously at 100 μg/ kg. Plasma viral loads (PVL) were measured longitudinally and levels of cell- associated SIV-RNA and -DNA were quantified in resting CD4+ T-cells isolated from peripheral blood, lymph nodes (LN), spleen and bone marrow (BM).

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CROI 2019