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Objectives Evaluate associations between ACE inhibitors (ACEis) and angiotensin receptor blockers (ARBs) and clinical outcomes in acute viral respiratory illness (AVRI). Design Retrospective cohort analysis of claims data. Setting The USA; 2018–2019 influenza season. Participants Main cohort: people with hypertension (HTN) taking an ACEi, ARB or other HTN medications, and experiencing AVRI. Falsification cohort: parallel cohort receiving elective knee or hip replacement. Main outcome measures Main cohort: hospital admission, intensive care unit, acute respiratory distress (ARD), ARD syndrome and all-cause mortality. Falsification cohort: complications after surgery and all-cause mortality. Results The main cohort included 236 843 episodes of AVRI contributed by 202 629 unique individuals. Most episodes were in women (58.9%), 81.4% in people with Medicare Advantage and 40.3% in people aged 75+ years. Odds of mortality were lower in the ACEi (0.78 (0.74 to 0.83)) and ARB (0.64 (0.61 to 0.68)) cohorts compared with other HTN medications. On all other outcomes, people taking ARBs (but not ACEis) had a >10% reduction in odds of inpatient stays compared with other HTN medications. In the falsification analysis (N=103 353), both ACEis (0.89 (0.80 to 0.98)) and ARBs (0.82 (0.74 to 0.91)) were associated with decreased odds of complications compared with other HTN medications; ARBs (0.64 (0.47 to 0.87)) but not ACEis (0.79 (0.60 to 1.05)) were associated with lower odds of death compared with other HTN medications. Conclusions Outpatient use of ARBs was associated with better outcomes with AVRI compared with other medications for HTN. ACEis were associated with reduced risk of death, but with minimal or no reduction in risk of other complications. A falsification analysis conducted to provide context on the possible causal implications of these findings did not provide a clear answer. Further analysis using observational data will benefit from additional approaches to assess causal relationships between these drugs and outcomes in AVRI.

Abstract Background Human Immunodeficiency Virus (HIV) outcomes have significantly improved at the expense of other age-related diseases including chronic kidney disease. Early reports of people living with HIV (PLWH) undergoing deceased-donor kidney transplantation (DDKT) showed poor outcomes, but these have notably improved after introduction of antiretrovirals. Despite years of experience, the optimal induction immunosuppression (IIS) in PLWH remains subject of debate. Large-scale studies describing the current ISS practices in PLWH undergoing DDKT are lacking. Here, we describe the U.S. national trends of IIS used in PLWH undergoing DDKT from 2000 to 2018 using the United Network of Organ Sharing (UNOS) database. Methods We analyzed the UNOS database to determine the selection of IIS in PLWH undergoing first-time DDKT between 1/1/2000 and 12/31/2018. Cases with unknown HIV status at the time of transplant were excluded. Age, sex and demographics were analyzed. The regimen used for IIS was compared based on HIV serostatus and the change in induction regimen was trended over time. Results A total of 139,650 cases underwent DDKT during the study period. Among these, 1,384 were identified as HIV-positive. PLWH were significantly younger than HIV-negative (49±10 years vs. 51.6 ± 15.3 years; p< 0.001) (Table 1). A greater proportion of men was seen in the PLWH group compared to HIV-negative persons (76.2% vs. 60.4%; p< 0.0001). In the HIV-negative group, 12.1% undergoing DDKT did not receive IIS compared to 16.4% in PLWH (p< 0.0001). Medications that have significantly increased in use with years in PLWH included rabbit anti-thymocyte globulin (rATG), steroids, and basiliximab (3.54, 3.25, 2.28, respectively; p< 0.001). On our trend analysis (Figure 1), the percentage of PLWH receiving any IIS is increasing by 4.04% each year (p< 0.001). Table 1 Figure 1 Conclusion Our study suggests that IIS is an increasing practice in PLWH undergoing DDKT, predominantly using rATG, steroids, and basiliximab. Understanding the current practices might lead to further studies to determine the long-term outcomes after different induction regimens in PLWH. Disclosures All Authors: No reported disclosures

Abstract Purpose: TNF-related apoptosis inducing ligand (TRAIL) expression by immune cells contributes to antitumor immunity. A naturally occurring splice variant of TRAIL, called TRAILshort, antagonizes TRAIL-dependent cell killing. It is unknown whether tumor cells express TRAILshort and if it impacts antitumor immunity. Experimental Design: We used an unbiased informatics approach to identify TRAILshort expression in primary human cancers, and validated those results with IHC and ISH. TRAILshort-specific mAbs were used to determine the effect of TRAILshort on tumor cell sensitivity to TRAIL, and to immune effector cell dependent killing of autologous primary tumors. Results: As many as 40% of primary human tumors express TRAILshort by both RNA sequencing and IHC analysis. By ISH, TRAILshort expression is present in tumor cells and not bystander cells. TRAILshort inhibition enhances cancer cell lines sensitivity to TRAIL-dependent killing both in vitro and in immunodeficient xenograft mouse models. Immune effector cells isolated from patients with B-cell malignancies killed more autologous tumor cells in the presence compared with the absence of TRAILshort antibody (P < 0.05). Conclusions: These results identify TRAILshort in primary human malignancies, and suggest that TRAILshort blockade can augment the effector function of autologous immune effector cells. See related commentary by de Miguel and Pardo, p. 5546

Advances in HIV-1 therapy have transformed the once fatal infection into a manageable, chronic condition, yet the search for a widely applicable approach to cure remains elusive. The ineffectiveness of antiretroviral therapy (ART) in reducing the size of the HIV-1 latent reservoir has prompted investigation into the mechanisms of HIV-1 latency and immune escape.

Abstract CD4 T cells from HIV-1 infected patients die at excessive rates compared to those from uninfected patients, causing immunodeficiency. We previously identified a dominant negative ligand that antagonizes the TRAIL-dependent pathway of cell death, which we called TRAILshort. Because the TRAIL pathway has been implicated in CD4 T cell death occurring during HIV-1 infection, we used short hairpin RNA knockdown, CRISPR deletion, or Abs specific for TRAILshort to determine the effect of inhibiting TRAILshort on the outcome of experimental acute HIV infection in vitro. Strikingly, all three approaches to TRAILshort deletion/inhibition enhanced HIV-induced death of both infected and uninfected human CD4 T cells. Thus, TRAILshort impacts T cell dynamics during HIV infection, and inhibiting TRAILshort causes more HIV-infected and uninfected bystander cells to die. TRAILshort is, therefore, a host-derived, host-adaptive mechanism to limit the effects of TRAIL-induced cell death. Further studies on the effects of TRAILshort in other disease states are warranted.

ABSTRACT HIV protease is known to cause cell death, which is dependent upon cleavage of procaspase 8. HIV protease cleavage of procaspase 8 generates Casp8p41, which directly binds Bak with nanomolar affinity, causing Bak activation and consequent cell death. Casp8p41 can also bind Bcl2 with nanomolar affinity, in which case cell death is averted. Central memory CD4 T cells express high levels of Bcl2, possibly explaining why those cells do not die when they reactivate HIV. Here, we determine that the Casp8p41-Bcl2 complex is polyubiquitinated and degraded by the proteasome. Ixazomib, a proteasome inhibitor in clinical use, blocks this pathway, increasing the abundance of Casp8p41 and causing more cells to die in a Casp8p41-dependent manner. IMPORTANCE The Casp8p41 pathway of cell death is unique to HIV-infected cells yet is blocked by Bcl2. Once bound by Bcl2, Casp8p41 is polyubiquitinated and degraded by the proteasome. Proteasome inhibition blocks degradation of Casp8p41, increasing Casp8p41 levels and causing more HIV-infected cells to die.