CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

SARS-CoV-2 RNA by in situ hybridization and immunodetection visualized by confocal microscopy. Spike and serotonin were quantified in plasma. Results: The frequency of CD41+ MKs in peripheral blood mononucleated cells (PBMCs) was significantly higher than healthy donors (0.28±0.05 versus 0.03±0.02) as a sign of MK infection, as we previously shown in acutely infected individuals with SARS-CoV-2 in platelets. Accordingly, in all samples analyzed, circulating MK in Long COVID sheltered both Spike and SARS-CoV-2 ssRNA, but also dsRNA suggestive of viral replication. These infected MKs produced blood platelets that contain also P Spike and SARS-CoV-2 ssRNA. Platelets microclots were detected in all tested Long COVID patients. Spike protein was detected at the pg level in 30 % of analyzed plasma from Long COVID but not CR individuals. The level of serotonin in platelet and of tryptophan hydroxylase-1 (TPH-1), the enzyme that regulates serotonin synthesis decreased significantly (p<0.0001) in blood of Long COVID patients compared to CR individuals. Conclusion: In patients developing Long COVID, SARS-CoV-2 persists and replicates in MKs producing virus-containing platelets. The presence of spike in plasma might be an additional sign of viral persistence that could be used as a Long COVID biomarker. The presence of the virus could lead to abnormal platelet activation and the formation of microclots, which would contribute to the various symptoms and to deregulation of serotonin uptake, contributing to the neurocognitive symptoms observed in long-onset COVID. Low-Level HIV Viremia Affects T-Cell Activation and Senescence in InSTI Era Violeta Lara Aguilar 1 , Manuel Llamas-Adán 1 , Oscar Brochado-Kith 1 , Celia Crespo-Bermejo 1 , Sergio Grande-García 1 , Sonia Arca-Lafuente 1 , Ignacio De los Santos 2 , María Carmen Prado 1 , Mario Alía 1 , Coral Sainz-Pinós 1 , Amanda Fernández-Rodíguez 1 , Luz Martín-Carbonero 3 , Ricardo Madrid 4 , Verónica Briz 1 1 Institute of Health Carlos III, Madrid, Spain, 2 Hospital Universitario de La Princesa, Madrid, Spain, 3 La Paz University Hospital, Madrid, Spain, 4 Complutense University of Madrid, Madrid, Spain Background: 10% of people with HIV (PWH) show low-level viremia (LLV) under antiretroviral therapy (ART). We evaluated the influence of this poor virological response on the immune system in comparison to individuals with suppressed viremia (SV). Methods: Prospective observational study in 54 subjects matched by clinical and epidemiological characteristics: i) n=27 PWH with persistent LLV (50-200 copies/mL) and ii) n=27 PWH with SV (<50 copies/mL) as controls. 45 soluble biomarkers of systemic inflammation were evaluated by multiplex immunoassays. Activation (CD25, HLADR and CD38) and senescence (CD57, PD1 and TIM-3) levels in peripheral T-cell subsets were characterized by spectral flow cytometry. Differences in plasma biomarkers and cell frequencies were evaluated by generalized linear models, adjusted by age, gender, and ART. Results: The median age was 53 years and 77.8% were male. 74% of PWH with LLV were on integrase inhibitors compared to 48% in SV group. LLV group showed no significant differences in the maturation of CD4+ T cells, which were more activated (CD38+) and exhausted (PD1+, TIM3+ and PD1+TIM3+) compared to SV, especially the more immature stages of development (Figure 1A). A decrease in PD1+ subpopulations in effector memory (EM) (Th0-1 and TEMRA pE1) and a trend in central memory (CM) were also observed in LLV group, as well as an increase in TIM3+ expression. Significant differences were observed in the most senescent phenotype (PD1+TIM3+) in EM Th0-1 and TEMRA E populations in the LLV group. In addition, LLV group showed a trend towards a lower CD8+ naïve and EM1 T cell count and a higher frequency of CM and TEMRA E cells (HLADR+), as well as a higher up-regulation of TIM3+ in CD8+ compartment (Figure 1B). We also observed a lower frequency of CD8+ EM PD1+ subpopulations (EM1, EM2, EM4, TEMRA pE1 and TEMRA pE2) and an increase of these same subpopulations expressing TIM-3+. Overall, LLV group showed a highly senescent EM response (EM3 PD1+TIM3+ and TEMRA E PD1+TIM3+) compared to controls. No significant differences were found in inflammatory markers between groups. Conclusion: The persistence of LLV (50-200 copies/mL) leads to a decrease of CD8+ EM1 population and an increase in activation mainly in EM subpopulations that are functionally exhausted. This could partially explain the absence of significant differences in the inflammatory profile between both groups, suggesting an aberrant immune function in LLV individuals unable to control and eliminate infected cells.

348

349

Ultra-Low Level HIV p24 Production as a Driver of Immune Activation in Individuals Treated with ART Enrico Richter 1 , Theresa Bechtel 1 , Antonia Büning 1 , Marek Korencak 1 , Trevor A. Crowell 2 , Heiko Jessen 3 , Juergen K. Rockstroh 1 , Stefan Esser 4 , Christoph Boesecke 1 , Hendrik Streeck 1 1 University of Bonn, Bonn, Germany, 2 Henry M Jackson Foundation, Bethesda, MD, USA, 3 Praxis Jessen 2 + Kollegen, Berlin, Germany, 4 University Hospital Essen, Essen, Germany Background: Similar to the persistent presence of HIV, residual immune activation has been observed despite antiretroviral therapy (ART). It was shown that in treated people with HIV, T cells remain activated even when the virus is undetectable. The causes of this chronic inflammation and immune activation in treated HIV are not fully understood. Methods: Here, we have developed an ultrasensitive p24 single-molecule array to detect p24 in plasma at a 1000-fold lower concentration (fg/ml) compared to previous assays. This advancement allowed us to analyze people with chronic HIV who are undergoing treatment (with undetectable viral load) and compared it to immune correlates measured by a multicolor immune assay. Results: We first investigated whether plasma p24 is detectable at ultra-low concentrations in a cohort of 172 individuals with chronic and ART-treated HIV infection, who have maintained HIV RNA levels below the detection limit (<50 HIV RNA copies/ml) for >4 years. Ultra-low level HIV p24 [range 4.5 fg/ ml – 330 fg/ml] was detectable in 48 out of 172 individuals (28%). There was no significant correlation between age, gender, ART regimen and the average duration of therapy was identical between groups with or without detectable HIV p24 (p24+: 8.4 years [4.3 – 17]; p24-: 8.4 years [4 – 30]; p>0.05). Next, we hypothesized that ongoing p24 production is responsible for low level immune activation. Indeed, CD8 and CD4 T cells from individuals with detectable HIV p24 showed significantly increased expression of the activation marker CD38 compared to individuals without detectable p24 (p < 0.05). Interestingly, individuals with detectable HIV p24 had significantly higher HIV-specific CD8 T cell responses (p<0.05) despite ongoing treatment, indicating that they are still able to recognize HIV infected cells. We also determined HIV p24 concentration behavior before and after ART initiation as well as from acute to chronic infection. Therefore, we studied 43 people who initiated suppressive ART during acute HIV and remained virally suppressed over a 2-year period. Despite HIV-1 RNA that declined to undetectable levels (<30 copies/mL), p24 levels remained detectable in 25% of individuals one year and 19% of individuals two years after ART start. Conclusion: Despite continuous ART, we were able to detect ultra-low level of p24 production, suggesting either ongoing viral replication or active transcriptional HIV integration sites can be the primary driver of HIV immune activation. The figure, table, or graphic for this abstract has been removed.

Poster Abstracts

78

CROI 2024