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The safety of casirivimab + imdevimab (CAS + IMD) (anti-severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] monoclonal antibodies [mAbs]) in pediatric outpatients with coronavirus disease 2019 (COVID-19) was evaluated in a randomized phase 1/2/3 trial. Consistent with adults, CAS + IMD was generally well tolerated with low drug-induced immunogenicity rates. The findings support the development of next-generation anti-SARS-CoV-2 mAbs for at-risk pediatric patients. [ABSTRACT FROM AUTHOR]

The development of an effective HIV vaccine to prevent and/or cure HIV remains a global health priority. Given their central role in the initiation of adaptive immune responses, dendritic cell (DC)-based vaccines are being increasingly explored as immunotherapeutic strategies to enhance HIV-specific T cells in infected individuals and, thus, promote immune responses that may help facilitate a functional cure. HIV-1-based lentiviral (LV) vectors have inherent advantages as DC vaccine vectors due to their ability to transduce non-dividing cells and integrate into the target cell genomic DNA, allowing for expression of encoded antigens over the lifespan of the cell. Moreover, LV vectors may express additional immunostimulatory and immunoregulatory proteins that enhance DC function and direct antigen-specific T cells responses. Recent basic and clinical research efforts have broadened our understanding of LV vectors as DC-based vaccines. In this review, we provide an overview of the pre-clinical and clinical LV vector vaccine studies for treating HIV to date. We also discuss advances in LV vector designs that have enhanced DC transduction efficiency, target cell specificity, and immunogenicity, and address potential safety concerns regarding LV vector-based vaccines. [ABSTRACT FROM AUTHOR]

Dendritic cells are professional antigen-presenting cells of the immune system and are major producers of type-I interferon. Their role in HIV-1 infection is not well understood. They express CD4 and CCR5 yet appear to be resistant to infection. In culture, infection of the cells with HIV-1 is inhibited by the host cell restriction factor SAMHD1. Lentiviruses such as HIV-2/SIVmac counteract the restriction by encoding Vpx, a virion-packaged accessory protein that induces the proteasomal degradation of SAMHD1. In this study we investigated SAMHD1-mediated restriction in the two major dendritic cell subsets: plasmacytoid dendritic cells (pDC) and myeloid dendritic cells (mDC). The cells were highly resistant to HIV-1 and expressed high levels of SAMHD1. SAMHD1 amino acid residue T592, a target of CDK1 phosphorylation, was unphosphorylated, corresponding to the antiviral form of the enzyme. The resistance to infection was not counteracted by Vpx and SAMHD1 was not degraded in these cells. Treatment of pDCs with a cocktail of antibodies that blocked type-I interferon signaling partially restored the ability of Vpx to induce SAMHD1 degradation and caused the cells to become partially permissive to infection. pDCs and mDCs responded to HIV-1 virions by inducing an innate immune response but did not appear to sense newly produced Gag protein. The findings suggest that in vivo, dendritic cells serve as sentinels to alert the immune system to the virus but do not themselves become infected by virtue of high levels of SAMHD1. [ABSTRACT FROM AUTHOR]

The deoxynucleoside triphosphohydrolase SAMHD1 restricts retroviral replication in myeloid cells. Human immunodeficiency virus type 2 (HIV-2) and a simian immunodeficiency virus from rhesus macaques (SIVmac) encode Vpx, a virion-packaged accessory protein that counteracts SAMHD1 by inducing its degradation. SAMHD1 is thought to work by depleting the pool of intracellular deoxynucleoside triphosphates but has also been reported to have exonuclease activity that could allow it to degrade the viral genomic RNA or viral reverse-transcribed DNA. To induce the degradation of SAMHD1, Vpx co-opts the cullin4a-based E3 ubiquitin ligase, CRL4. E3 ubiquitin ligases are regulated by the covalent attachment of the ubiquitin-like protein Nedd8 to the cullin subunit. Neddylation can be prevented by MLN4924, a drug that inhibits the nedd8-activating enzyme. We report that MLN4924 inhibits the neddylation of CRL4, blocking Vpx-induced degradation of SAMHD1 and maintaining the restriction. Removal of the drug several hours postinfection released the block. Similarly, Vpx-containing virus-like particles and deoxynucleosides added to the cells more than 24 h postinfection released the SAMHD1-mediated block. Taken together, these findings support deoxynucleoside triphosphate pool depletion as the primary mechanism of SAMHD1 restriction and argue against a nucleolytic mechanism, which would not be reversible. [ABSTRACT FROM AUTHOR]

A correction to the article "Recent Advances in Lentiviral Vaccines for HIV-1 Infection" is presented.

Objective: Pregnant women with COVID-19 are at elevated risk for severe outcomes, but clinical data on management of these patients are limited. Monoclonal antibodies, such as casirivimab plus imdevimab (CAS+IMD), have proven effective in treating non-pregnant adults with COVID-19, prompting further evaluation in pregnant women., Methods: A phase 3 portion of an adaptive, multicentre, randomised, double-blind, placebo-controlled trial evaluated the safety, clinical outcomes, pharmacokinetics and immunogenicity of CAS+IMD (1200 mg or 2400 mg) in the treatment of pregnant outpatients with COVID-19 (NCT04425629). Participants were enrolled between December 2020 and November 2021, prior to the emergence of Omicron-lineage variants against which CAS+IMD is not active. Safety was evaluated in randomised participants who received study drug (n=80); clinical outcomes were evaluated in all randomised participants (n=82). Only two pregnant participants received placebo, limiting conclusions regarding treatment effect. Infants born to pregnant participants were followed for developmental outcomes ≤1 year of age., Results: In pregnant participants, CAS+IMD was well tolerated, with no grade ≥2 hypersensitivity or infusion-related reactions reported. There were no participant deaths, and only one COVID-19-related medically attended visit. Although two pregnancies (3%) reported issues in the fetus/neonate, they were confounded by maternal history or considered to be due to an alternate aetiology. No adverse developmental outcomes in infants ≤1 year of age were considered related to in utero exposure to the study drug. CAS+IMD 1200 mg and 2400 mg rapidly and similarly reduced viral loads, with a dose-proportional increase in concentrations of CAS+IMD in serum. Pharmacokinetics were consistent with that reported in the general population. Immunogenicity incidence was low., Conclusion: CAS+IMD treatment of pregnant outpatients with COVID-19 showed similar safety, clinical outcomes and pharmacokinetic profiles to that observed in non-pregnant adults. There was no evidence of an impact on developmental outcomes in infants ≤1 year of age., Trial Registration Number: NCT04425629., Competing Interests: Competing interests: TDN, MT, SG, SA, JC, AW, JX, JDD, SCI, CP, DA, DS, BK, ATD, RB, GPG, EC, NB and PD are employees and stockholders at Regeneron Pharmaceuticals, Inc. ATH is a Regeneron employee/stockholder and former Pfizer employee and current stockholder. KCT, JDH and GAH are Regeneron employees and stockholders, and have a patent pending, which has been licensed and receiving royalties, with Regeneron. JAB is a site PI for Regeneron Pharmaceuticals, Inc. multicentred clinical trials, Enanta multicentred clinical trials and Pfizer multicentred clinical trials; a sub-investigator for Novavax multicentred clinical trials; and an advisory board/panel member for Avalere, Pfizer, Moderna, Sobi and Valneva., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: While immunotherapy has been highly successful for the treatment of some cancers, for others, the immune response to tumor antigens is weak leading to treatment failure. The resistance of tumors to checkpoint inhibitor therapy may be caused by T cell exhaustion resulting from checkpoint activation., Methods: In this study, lentiviral vectors that expressed T cell epitopes of an experimentally introduced tumor antigen, ovalbumin, or the endogenous tumor antigen, Trp1 were developed. The vectors coexpressed CD40 ligand (CD40L), which served to mature the dendritic cells (DCs), and a soluble programmed cell death protein 1 (PD-1) microbody to prevent checkpoint activation. Vaccination of mice bearing B16.OVA melanomas with vector-transduced DCs induced the proliferation and activation of functional, antigen-specific, cytolytic CD8 T cells., Results: Vaccination induced the expansion of CD8 T cells that infiltrated the tumors to suppress tumor growth. Vector-encoded CD40L and PD-1 microbody increased the extent of tumor growth suppression. Adoptive transfer demonstrated that the effect was mediated by CD8 T cells. Direct injection of the vector, without the need for ex vivo transduction of DCs, was also effective., Conclusions: This study suggests that therapeutic vaccination that induces tumor antigen-specific CD8 T cells coupled with a vector-expressed checkpoint inhibitor can be an effective means to suppress the growth of tumors that are resistant to conventional immunotherapy., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: There is limited qualitative research on patients' experiences with long COVID-19, and how specific symptoms impact their daily lives. The study aimed to understand patients' lived experiences of long COVID-19 and to develop a conceptual model representing the symptoms and their impact on overall quality of life., Setting: Qualitative study consisting of a comprehensive literature review, and in-depth clinician and patient semistructured interviews., Participants: Forty-one adult patients with long COVID-19, of whom 18 (44%) were recruited through Regeneron Pharmaceuticals's clinical trials and 23 (56%) through recruitment agencies; 85.4% were female and 73.2% were White. Five independent clinicians treating patients with long COVID-19 were interviewed. Concept saturation was also assessed., Primary and Secondary Outcomes: Interview transcripts were analysed thematically to identify concepts of interest spontaneously mentioned by patients, including symptoms and their impacts on daily life, to guide the development of the conceptual model., Results: Findings from the literature review and clinician and patient interviews resulted in the development of a conceptual model comprising two overarching domains: symptoms (upper respiratory tract, lower respiratory tract, smell and taste, systemic, gastrointestinal, neurocognitive and other) and impacts (activities of daily living, instrumental activities of daily living, physical impacts, emotional, social/leisure activities and professional impacts). Saturation was achieved for the reported impacts. The symptoms reported were heterogenic; neurocognitive symptoms, such as numbness, ringing in ears, haziness, confusion, forgetfulness/memory problems, brain fog, concentration, difficulties finding the right word and challenges with fine motor skills, were particularly pertinent for several months., Conclusion: The conceptual model, developed based on patient experience data of long COVID-19, highlighted numerous symptoms that impact patients' physical and mental well-being, and suggests humanistic unmet needs. Prospective real-world studies are warranted to understand the pattern of long COVID-19 experienced in larger samples over longer periods of time., Competing Interests: Competing interests: DR is a Regeneron Pharmaceuticals, Inc. employee/stockholder and former Roche employee, and current stockholder. SS-K, YZ, MH, TDN and GPG are employees/stockholders at Regeneron Pharmaceuticals, Inc. JYC and KP are employees of Modus Outcomes, and consulted for Regeneron Pharmaceuticals, Inc. AJP reported receiving personal fees from Regeneron Pharmaceuticals, Inc. during the conduct of the study, personal fees from Imvaria, Boehringer Ingelheim, EBSCO/Dynamed and Roche outside the submitted work. EM reports payments to his institution received from SciClone Pharmaceuticals, Regeneron Pharmaceuticals, Inc., Pfizer, Chemic Labs/KODA Therapeutics, Cidara and Leidos Biomedical Research/NCI; and reports Advisory board: Basilea and grants from NIH/NIAID, NIH/NIGMS and BARDA., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Lentiviral vector-based dendritic cell vaccines induce protective T cell responses against viral infection and cancer in animal models. In this study, we tested whether preventative and therapeutic vaccination could be achieved by direct injection of antigen-expressing lentiviral vector, obviating the need for ex vivo transduction of dendritic cells. Injected lentiviral vector preferentially transduced splenic dendritic cells and resulted in long-term expression. Injection of a lentiviral vector encoding an MHC class I-restricted T cell epitope of lymphocytic choriomeningitis virus (LCMV) and CD40 ligand induced an antigen-specific cytolytic CD8+ T lymphocyte response that protected the mice from infection. The injection of chronically infected mice with a lentiviral vector encoding LCMV MHC class I and II T cell epitopes and a soluble programmed cell death 1 microbody rapidly cleared the virus. Vaccination by direct injection of lentiviral vector was more effective in sterile alpha motif and HD-domain containing protein 1-knockout (SAMHD1-knockout) mice, suggesting that lentiviral vectors containing Vpx, a lentiviral protein that increases the efficiency of dendritic cell transduction by inducing the degradation of SAMHD1, would be an effective strategy for the treatment of chronic disease in humans.

Data that can be used to guide perioperative antibiotic prophylaxis in our era of emerging antibiotic resistance are limited. We reviewed orthopedic surgeries complicated by surgical site infections (SSIs). Eighty percent of 69 arthroplasty and 80 spine fusion SSIs were infected with Gram-positive bacteria; most were staphylococcal species; and more than 25% of Staphylococcus aureus and more than 65% of coagulase-negative staphylococci were methicillin-resistant. Gram-negative bacteria were isolated from 30% of arthroplasty SSIs and 25% of spine fusion SSIs. Resistance to cefazolin was higher than 40%. A significant proportion of SSIs were caused by resistant organisms, and antibiotic guidelines were altered to provide more adequate surgical prophylaxis.

Vanishing bile duct syndrome (VBDS) is a group of rare disorders characterized by ductopenia, the progressive destruction and disappearance of intrahepatic bile ducts leading to cholestasis. Described in association with medications, autoimmune disorders, cancer, transplantation, and infections, the specific mechanisms of disease are not known. To date, only 4 cases of VBDS have been reported in human immunodeficiency virus (HIV) infected patients. We report 2 additional cases of HIV-associated VBDS and review the features common to the HIV-associated cases. Presentation includes hyperbilirubinemia, normal liver imaging, and negative viral and autoimmune hepatitis studies. In HIV-infected subjects, VBDS occurred at a range of CD4+ T-cell counts, in some cases following initiation or change in antiretroviral therapy. Lymphoma was associated with two cases; nevirapine, antibiotics, and viral co-infection were suggested as etiologies in the other cases. In HIV-positive patients with progressive cholestasis, early identification of VBDS and referral for transplantation may improve outcomes.