Virulence Profiles of Wild-Type, P.1 and Delta SARS-CoV-2 Variants in K18-hACE2 Transgenic Mice.

Since December 2019, the world has been experiencing the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and we now face the emergence of several variants. We aimed to assess the differences between the wild-type (Wt) (Wuhan) strain and the P.1 (Gamma) and Delta variants using infected K18-hACE2 mice. The clinical manifestations, behavior, virus load, pulmonary capacity, and histopathological alterations were analyzed. The P.1-infected mice showed weight loss and more severe clinical manifestations of COVID-19 than the Wt and Delta-infected mice. The respiratory capacity was reduced in the P.1-infected mice compared to the other groups. Pulmonary histological findings demonstrated that a more aggressive disease was generated by the P.1 and Delta variants compared to the Wt strain of the virus. The quantification of the SARS-CoV-2 viral copies varied greatly among the infected mice although it was higher in P.1-infected mice on the day of death. Our data revealed that K18-hACE2 mice infected with the P.1 variant develop a more severe infectious disease than those infected with the other variants, despite the significant heterogeneity among the mice.

Dermatological Manifestations in COVID-19: A Case Study of SARS-CoV-2 Infection in a Genetic Thrombophilic Patient with Mthfr Mutation.

The present case study describes the dermatological manifestations of COVID-19 in a patient with genetic thrombophilia (MTHFR-C677T mutation) and the identification of a SARS-CoV-2 variant of interest (VOI). A female patient, 47 years old, unvaccinated, with thrombophilia, was diagnosed with COVID-19. She presented with urticarial and maculopapular eruptions from the seventh day of symptoms, which progressed to multiple lesions with dark centers (D-dimer value > 1450 ng/mL). The dermatological manifestations disappeared after 30 days, corroborating the reduction in D-dimer levels. Viral genome sequencing revealed infection by the VOI Zeta (P.2). Antibody testing, performed 30 days after the onset of symptoms, detected only IgG. The virus neutralization test showed the highest neutralizing titer for a P.2 strain, validating the genotypic identification. Lesions were suggested to be due to infection in skin cells causing a direct cytopathic effect or release of pro-inflammatory cytokines triggering erythematous and urticarial eruptions. In addition, vascular complications are also proposed to be due to the MTHFR mutation and increased D-dimer values. This case report is an alert about COVID-19 in patients with pre-existing vascular diseases, especially in unvaccinated patients, by VOI.

Anti-SARS-CoV-2 equine F (Ab')2 immunoglobulin as a possible therapy for COVID-19.

The new outbreak of coronavirus disease 2019 (COVID-19) has infected and caused the death of millions of people worldwide. Intensive efforts are underway around the world to establish effective treatments. Immunoglobulin from immunized animals or plasma from convalescent patients might constitute a specific treatment to guarantee the neutralization of the virus in the early stages of infection, especially in patients with risk factors and a high probability of progressing to severe disease. Worldwide, a few clinical trials using anti-SARS-CoV-2 immunoglobulins from horses immunized with the entire spike protein or fragments of it in the treatment of patients with COVID-19 are underway. Here, we describe the development of an anti-SARS-CoV-2 equine F(ab')2 immunoglobulin using a newly developed SARS-CoV-2 viral antigen that was purified and inactivated by radiation. Cell-based and preclinical assays showed that the F(ab')2 immunoglobulin successfully neutralizes the virus, is safe in animal models, and reduces the severity of the disease in a hamster model of SARS-CoV-2 infection and disease.

In Nasal Mucosal Secretions, Distinct IFN and IgA Responses Are Found in Severe and Mild SARS-CoV-2 Infection.

Likely as in other viral respiratory diseases, SARS-CoV-2 elicit a local immune response, which includes production and releasing of both cytokines and secretory immunoglobulin (SIgA). Therefore, in this study, we investigated the levels of specific-SIgA for SARS-CoV-2 and cytokines in the airways mucosa 37 patients who were suspected of COVID-19. According to the RT-PCR results, the patients were separated into three groups: negative for COVID-19 and other viruses (NEGS, n = 5); negative for COVID-19 but positive for the presence of other viruses (OTHERS, n = 5); and the positive for COVID-19 (COVID-19, n = 27). Higher specific-SIgA for SARS-CoV-2, IFN-ß, and IFN-γ were found in the COVID-19 group than in the other groups. Increased IL-12p70 levels were observed in OTHERS group as compared to COVID-19 group. When the COVID-19 group was sub stratified according to the illness severity, significant differences and correlations were found for the same parameters described above comparing severe COVID-19 to the mild COVID-19 group and other non-COVID-19 groups. For the first time, significant differences are shown in the airway's mucosa immune responses in different groups of patients with or without respiratory SARS-CoV-2 infection.