Genomic monitoring unveil the early detection of the SARS-CoV-2 B.1.351 lineage (20H/501Y.V2) in Brazil

Sao Paulo State, the most populous area in Brazil, currently experiences a second wave of the COVID-19 pandemic which overwhelmed the healthcare system. Recently, due to the paucity of SARS-CoV-2 complete genome sequences, we established a Network for Pandemic Alert of Emerging SARS-CoV-2 Variants to rapidly understand the spread of SARS-CoV-2 and monitor in nearly real-time the circulating SARS-CoV-2 variants into the state. Through full genome analysis of 217 SARS-CoV-2 complete genome sequences obtained from the largest regional health departments we were able to identify the co-circulation of multiple SARS-CoV-2 lineages such as i) B.1.1 (0.92%), ii) B.1.1.1 (0.46%), iii) B.1.1.28 (25.34%), iv) B.1.1.7 (5.99%), v) B.1.566 (1.84%), vi) P.1 (64.05%), and P.2 (0.92%). Further our analysis allowed the detection, for the first time in Brazil of the South African variant of concern (VOC), the B.1.351 (501Y.V2) (0.46%). The identified lineage was characterized by the presence of the following mutations: ORF1ab: T265I, R724K, S1612L, K1655N, K3353R, SGF 3675_F3677del, P4715L, E5585D; Spike: D80A, D215G, L242_L244del, A262D, K417N, E484K, N501Y, D614G, A701V, C1247F; ORF3a: Q57H, S171L, E: P71L; ORF7b: Y10F, N: T205I; ORF14: L52F. Origin of the most recent common ancestor of this genomic variant was inferred to be between middle October to late December 2020. Analysis of generated sequences demonstrated the predominance of the P.1 lineage and allowed the early detection of the South African strain for the first time in Brazil. Our findings highlight the importance to increase active monitoring to ensure the rapid detection of new SARS-CoV-2 variants with a potential impact in pandemic control and vaccination strategies.

Complement C3 vs C5 inhibition in severe COVID-19: early clinical findings reveal differential biological efficacy

Growing clinical evidence has implicated complement as a pivotal driver of COVID-19 immunopathology. Deregulated complement activation may fuel cytokine-driven hyper-inflammation, thrombotic microangiopathy and NET-driven immunothrombosis, thereby leading to multi-organ failure. Complement therapeutics have gained traction as candidate drugs for countering the detrimental consequences of SARS-CoV-2 infection. Whether blockade of terminal complement effectors (C5, C5a, or C5aR1) can elicit similar outcomes to upstream intervention at the level of C3 remains debated. Here we have compared the clinical efficacy of the C5-targeting mAb eculizumab with that of the compstatin-based C3-targeted drug candidate AMY-101 in small independent cohorts of severe, mainly non-intubated COVID-19 patients. Our exploratory study indicates that therapeutic complement inhibition abrogates COVID-19 hyper-inflammation. Both C3 and C5 inhibitors elicit a robust anti-inflammatory response, reflected by a steep decline in CRP and IL-6 levels, associated with marked lung function improvement and resolution of SARS-CoV-2-associated ARDS. C3 inhibition afforded broader therapeutic control in COVID19 patients by attenuating both C3a and sC5b-9 generation and preventing FB consumption. This broader inhibitory profile of anti-C3 treatment was associated with a more robust decline of neutrophil counts, a greater decline of median LDH levels and more prominent lymphocyte recovery within the first 7 days of treatment. These early clinical results offer important insight into the differential mechanistic basis and underlying biology of C3 and C5 inhibition in COVID-19. They point to a broader pathogenic involvement of C3-mediated pathways and set the stage for larger prospective trials that will benchmark these complement-targeting agents in COVID-19.

Infection of human lymphomononuclear cells by SARS-CoV-2

Although SARS-CoV-2 severe infection is associated with a hyperinflammatory state, lymphopenia is an immunological hallmark, and correlates with poor prognosis in COVID-19. However, it remains unknown if circulating human lymphocytes and monocytes are susceptible to SARS-CoV-2 infection. In this study, SARS-CoV-2 infection of human peripheral blood mononuclear cells (PBMCs) was investigated both in vitro and in vivo. We found that in vitro infection of whole PBMCs from healthy donors was productive of virus progeny. Results revealed that monocytes, as well as B and T lymphocytes, are susceptible to SARS-CoV-2 active infection and viral replication was indicated by detection of double-stranded RNA. Moreover, flow cytometry and immunofluorescence analysis revealed that SARS-CoV-2 was frequently detected in monocytes and B lymphocytes from COVID-19 patients, and less frequently in CD4+T lymphocytes. The rates of SARS-CoV-2-infected monocytes in PBMCs from COVID-19 patients increased over time from symptom onset. Additionally, SARS-CoV-2-positive monocytes and B and CD4+T lymphocytes were detected by immunohistochemistry in post mortem lung tissue. SARS-CoV-2 infection of blood circulating leukocytes in COVID-19 patients may have important implications for disease pathogenesis, immune dysfunction, and virus spread within the host.