CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

Conclusions: The presence of oncogenic HIV-1 proteins and several other cancer-related proteins from the host carried by exosomes in people living with both HIV and NADCs implies that HIV infection might be a significant factor in the dysregulation of “onco-proteins” influencing a poorer prognosis in those patients with NADCs. Validation of Quantification of Lesional KSHV DNA Content for Diagnosis of Kaposi Sarcoma in Africa Aggrey Semeere 1 , Jeffrey Martin 2 , Racheal A. Ayanga 1 , Andrea Gardner 3 , Juan Boza 4 , Miranda McGaskey 3 , Jason Manning 4 , Megan Wenger 2 , Charles Kasozi 5 , Robert Lukande 6 , Tim McCalmont 2 , Phil LeBoit 2 , Toby Maurer 7 , Ethel Cesarman 3 , David Erickson 4 1 Infectious Diseases Institute, Kampala, Uganda, 2 University of California San Francisco, San Francisco, CA, USA, 3 Weill Cornell Medicine, New York, NY, USA, 4 Cornell University, Ithaca, NY, USA, 5 Masaka Regional Referral Hospital, Masaka, Uganda, 6 Makerere University College of Health Sciences, Kampala, Uganda, 7 Indiana University Health, Indianapolis, IN, USA Background: Inaccessibility and inaccuracies limit histopathologic diagnosis of Kaposi sarcoma (KS) in Africa. We hypothesized that quantification of KSHV DNA from suspicious skin lesions could distinguish KS from non-KS lesions, thus eventually enabling creation of a diagnostic test that would limit need for histopathologic interpretation. In our earlier training population, quantification of lesional KSHV DNA by qPCR (using sub-optimally transportable Ct values) had high sensitivity and specificity for the diagnosis of KS. We now assess diagnostic accuracy of qPCR in an external validation population and using a more transportable KSHV copy number readout. Methods: Using identical processes for both the training (N=506 participants) and validation populations, we performed skin punch biopsies among consecutive patients referred for suspected KS in Uganda. One-half of the biopsy had histopathology performed, and the other half was stored in RNAlater and later underwent DNA purification in the U.S. and testing for KSHV ORF 26 DNA in two replicates by qPCR. With histopathology as gold standard and ROC curves, we assessed the performance characteristics of the mean of the replicates for the diagnosis of KS. An optimal KSHV DNA copy number cutoff that was earlier derived in the training population was assessed in the validation population. Results: The validation population consisted of 427 participants with skin biopsies; 34% were women, and 91% were HIV-infected. Histopathology revealed that 338 biopsies were KS and 89 were not. Using the previously derived threshold of 161 copies of KSHV DNA per 5 µl input into the reaction, which in our training population yielded 91% sensitivity and 91% specificity for KS diagnosis (accuracy=91% and area under the curve (AUC) = 0.96), qPCR in the validation population yielded 93% sensitivity, 93% specificity, 93% accuracy and an AUC of 0.93 (Figure). Conclusions: In an external validation population in Uganda, qPCR of lesional KSHV DNA had high sensitivity and specificity for diagnosis of KS, performing similarly to our training population. Because of ambient endemic KSHV infection, mere qualitative detection of KSHV DNA in skin lesions is non-specific for KS diagnosis. Instead, precise quantification of KSHV DNA is needed, and a KSHV DNA copy number threshold that balances sensitivity and specificity is now established. This validation of qPCR performance motivates a point-of-care nucleic acid-based diagnostic test for KS, which we are currently developing.

imaging mass cytometry was employed with 40 immune cell markers for TME characterization. Linear mixed effects model, AI-based pageRank mathematical algorithm based on spectral graph theory, and neighborhood enrichment analysis were employed. Results: NSCLC from PWH demonstrated differential distribution of tumor infiltrating CD8+ T cell clusters defined by marker expression patterns, enriched for the expression of PD-1 and Lag-3, as well as activation and proliferation markers, compared to tumors from PWOH. Several clusters of T cells were significantly elevated in tumors from PWH, with the strikingly the finding of significant increased proportion of “Exhausted burned out CD8+ T cells” that have high levels of PD-1, Lag-3, Tbet and Ki67 (Fold change increase of 4.21 in PWH, p<0.0001). We also demonstrate higher expression of immunoregulatory molecules (PD-L1, PD-L2, B7-H3, B7-H4, IDO1 and VISTA), among tumor associated macrophages, confirmed by the expansion of three unique TAM clusters comprising 58.8% of TAMs vs. 17.8% in tumors from PWH vs PWOH respectively (p<0.0001). An unsupervised and cell segmentation-independent signature associated using spectral graph theory methodology discriminated cells between HIV-associated and non-HIV tumors with 84.6% accuracy, with confirmation of the cell segmentation approach. Furthermore, we noted differences in spatial orientation of immune cells within the TME of PWH compared to PWOH, with evidence of increased Euclidean distance between each immune cell subtype (CD8 and CD4 T cells, and TAM) and CK+ tumor cells among PWH (p<0.0001 for each pair of cell types). Conclusions: Our study demonstrates that the TME of PWH is characterized by a unique immune landscape with evidence of expansion of immune cells with enhanced immunoregulatory phenotypes, associated impaired anti-tumor responses, and altered spatial distribution of immune cells compared to PWOH. These findings have significant implications for response to immune checkpoint blocker therapies. Viral and Host Proteins Carried by Exosomes From PLWH Could Play a Role as Triggers of NADCs Asier Ureta 1 , Clara Restrepo 1 , Manuel Pedregal 2 , Héctor Callata 2 , Sara Nistal 3 , Hector Peinado 4 , Alberto Alcázar 5 , Emma Martínez-Alonso 5 , María L. García-Gil 6 , Alfonso Cabello 2 , Vicente Estrada 7 , Miguel Górgolas 2 , Jesús García-Foncillas 8 , Jose M. Benito 1 , Norma Rallón 1 1 Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, Spain, 2 Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain, 3 Hospital Universitario Rey Juan Carlos, Madrid, Spain, 4 Spanish National Cancer Research Centre (CNIO), Madrid, Spain, 5 Hospital Universitario Ramon y Cajal, Madrid, Spain, 6 Universidad Complutense de Madrid, Madrid, Spain, 7 Hospital Universitario Clínico San Carlos, Madrid, Spain, 8 Universidad Autónoma de Madrid, Madrid, Spain Background: A higher incidence and more rapid progression of several types of non-AIDS-defining cancer (NADC) have been reported in people living with HIV (PLWH). However, the exact mechanism linking HIV-1 infection to the development of NADCs is not yet fully understood. In vitro studies have suggested that viral molecules carried by exosomes derived from HIV-1-infected cells can promote and exacerbate cancer. Herein, we analysed the proteomic (viral and host) profile of exosomes from patients with active NADC, stratified according to the presence or absence of HIV infection. Methods: 4 study groups were included: 15 PLWH on ART with NADC (HIV + NADC + group), 15 people with NADC without HIV-1 (NADC + group), 15 PLWH on cART without NADC (HIV + group) and 15 healthy volunteers (HC group). A non-targeted label-free quantitative proteomic by LC-MS/MS, parallel reaction monitoring, and western blot analyses were performed in purified exosomes from plasma of all study subjects. Results: gp120, RT and IN HIV-1 proteins were detected in the exosomes of HIV + NADC + group and HIV + group. Interestingly, gp120 protein was increased in HIV + NADC + group compared to HIV + group (p<0.05), the IN protein was decreased in HIV + NADC + group compared to HIV + group (p<0.05) while the RT protein did not show differences between both groups. Of note both gp120 and RT proteins, have been previously associated with cancer events. Additionality, 40 human proteins were found differentially expressed (DE) in the exosomes of HIV + NADC + group compared to NADC + group. Remarkably, among these proteins, five pro-oncogenic (QSOX1, COMP, FTL, OIT3, KRT6B) were upregulated and three anti-oncogenic (HGFAC, GPX3, and SPARCL1) were downregulated in HIV + NADC + . Moreover, six of these eight proteins were also DE in HIV+ group compared to the NADC + in the same direction as the HIV + NADC + versus NADC + groups.

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Poster Abstracts

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