The role of the lectin pathway (LP) of complement has not been explored in the thrombotic microangiopathies (TMA). We examined levels of MASP2, the effector enzyme of the LP, in three major forms of TMA and assessed the effect of the anti‐MASP2 human monoclonal antibody narsoplimab on TMA plasma‐induced activation of caspase 8 in microvascular endothelial cells. MASP2 levels were highly elevated in all TMA patients versus controls. Caspase 8 activation was suppressed by clinically relevant levels of narsoplimab. In conclusion, we found that the LP of complement is activated in TMAs of diverse etiology and LP inhibition may be of therapeutic benefit in these disorders.

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Lost to follow-up (n = 0) Lost to follow-up (n = 1) Lost to follow-up (n = 2) Moved out of the study area (n = 1) Due to a SAE (n = 1) Lost to follow-up (n = 0) Analyses were performed as indicated above and as detailed in the comprehensive CONSORT flow diagram presented in Extended Data Fig. 1. Enrollment Allocation Follow-up Analysis HIV-1 mRNA + and/or p24 + cells (FISH-flow)HIV-1-specific immunity (AIM)

Efforts to cure HIV have focused on reactivating latent proviruses to enable elimination by CD8+ cytotoxic T-cells. Clinical studies of latency reversing agents (LRA) in antiretroviral therapy (ART)-treated individuals have shown increases in HIV transcription, but without reductions in virologic measures, or evidence that HIV-specific CD8+ T-cells were productively engaged. Here, we show that the SARS-CoV-2 mRNA vaccine BNT162b2 activates the RIG-I/TLR – TNF – NFκb axis, resulting in transcription of HIV proviruses with minimal perturbations of T-cell activation and host transcription. T-cells specific for the early gene-product HIV-Nef uniquely increased in frequency and acquired effector function (granzyme-B) in ART-treated individuals following SARS-CoV-2 mRNA vaccination. These parameters of CD8+ T-cell induction correlated with significant decreases in cell-associated HIV mRNA, suggesting killing or suppression of cells transcribing HIV. Thus, we report the observation of an intervention-induced reduction in a measure of HIV persistence, accompanied by precise immune correlates, in ART-suppressed individuals. However, we did not observe significant depletions of intact proviruses, underscoring challenges to achieving (or measuring) HIV reservoir reductions. Overall, our results support prioritizing the measurement of granzyme-B-producing Nef-specific responses in latency reversal studies and add impetus to developing HIV-targeted mRNA therapeutic vaccines that leverage built-in LRA activity.

Viruses employ a variety of strategies to escape or counteract immune responses, including depletion of cell surface major histocompatibility complex class I (MHC-I), that would ordinarily present viral peptides to CD8 + cytotoxic T cells. As part of a screen to elucidate biological activities associated with individual severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral proteins, we found that ORF7a reduced cell surface MHC-I levels by approximately fivefold. Nevertheless, in cells infected with SARS-CoV-2, surface MHC-I levels were reduced even in the absence of ORF7a, suggesting additional mechanisms of MHC-I down-regulation. ORF7a proteins from a sample of sarbecoviruses varied in their ability to induce MHC-I down-regulation and, unlike SARS-CoV-2, the ORF7a protein from SARS-CoV lacked MHC-I downregulating activity. A single amino acid at position 59 (T/F) that is variable among sarbecovirus ORF7a proteins governed the difference in MHC-I downregulating activity. SARS-CoV-2 ORF7a physically associated with the MHC-I heavy chain and inhibited the presentation of expressed antigen to CD8 + T cells. Specifically, ORF7a prevented the assembly of the MHC-I peptide loading complex and caused retention of MHC-I in the endoplasmic reticulum. The differential ability of ORF7a proteins to function in this way might affect sarbecovirus dissemination and persistence in human populations, particularly those with infection- or vaccine-elicited immunity.

In simian-human immunodeficiency virus (SHIV)-infected non-human primates, broadly neutralizing antibodies (bNAbs) against the virus appear to stimulate T cell immunity. To determine whether this phenomenon also occurs in humans we measured HIV-1-specific cellular immunity longitudinally in individuals with HIV-1 starting antiviral therapy (ART) with or without adjunctive bNAb 3BNC117 treatment. Using the activation-induced marker (AIM) assay and interferon-γ release, we observe that frequencies of Pol- and Gag-specific CD8+ T cells, as well as Gag-induced interferon-γ responses, are significantly higher among individuals that received adjunctive 3BNC117 compared to ART-alone at 3 and 12 months after starting ART. The observed changes in cellular immunity were directly correlated to pre-treatment 3BNC117-sensitivity. Notably, increased HIV-1-specific immunity is associated with partial or complete ART-free virologic control during treatment interruption for up to 4 years. Our findings suggest that bNAb treatment at the time of ART initiation maintains HIV-1-specific CD8+ T cell responses that are associated with ART-free virologic control.

Background Vaccination programs have been launched worldwide to halt the spread of COVID-19. However, the identification of existing, safe compounds with combined treatment and prophylactic properties would be beneficial to individuals who are waiting to be vaccinated, particularly in less economically developed countries, where vaccine availability may be initially limited. Methods We used a data-driven approach, combining results from the screening of a large transcriptomic database (L1000) and molecular docking analyses, with in vitro tests using a lung organoid model of SARS-CoV-2 entry, to identify drugs with putative multimodal properties against COVID-19. Results Out of thousands of FDA-approved drugs considered, we observed that atorvastatin was the most promising candidate, as its effects negatively correlated with the transcriptional changes associated with infection. Atorvastatin was further predicted to bind to SARS-CoV-2’s main protease and RNA-dependent RNA polymerase, and was shown to inhibit viral entry in our lung organoid model. Conclusions Small clinical studies reported that general statin use, and specifically, atorvastatin use, are associated with protective effects against COVID-19. Our study corroborrates these findings and supports the investigation of atorvastatin in larger clinical studies. Ultimately, our framework demonstrates one promising way to fast-track the identification of compounds for COVID-19, which could similarly be applied when tackling future pandemics.

Before the modern era of HIV/AIDS therapeutics, which enabled a cascade of early recognition of infection, prompt initiation of effective antiretroviral therapies, and close follow-up, severe forms of microvascular clotting disorders known as thrombotic microangiopathies (TMAs) were frequent in the setting of advanced HIV disease. Their incidence was as high as 7% in the period 1984-1999, but fell dramatically, to <0.5%, by 2002. This profound change was predicated on one critical development: availability of new classes of anti-HIV drugs, enabling reduction and maintenance of HIV viral loads to undetectable levels. Another development in the period 1999-2002 related to TMA therapy: with recognition of autoantibodies against the von Willebrand factor cleaving protease ADAMTS13 as the etiology of most cases of one major form of TMA, thrombotic thrombocytopenic purpura, it permitted appropriate use of life-saving interventions based on plasma exchange and immune suppression. A more recent factor in TMA therapeutics was the 2011 approval by the US FDA and European EMA of eculizumab, a humanized monoclonal antibody against complement component C5, for the treatment of atypical hemolytic uremic syndrome, another major form of TMA. Despite these milestones, life- and organ-threatening TMAs still occur in untreated HIV disease and, to a much lesser extent, in those patients with suppressed viral loads. Confusion in terms of the differential diagnosis of these TMAs also impedes use of directed treatments. This report utilizes a case study of a young woman with advanced AIDS who presented with a severe TMA, characterized by coma and renal failure, to highlight the diagnostic and therapeutic challenges raised by complex hematologic conditions occurring in the setting of HIV.