SARS-CoV-2 vaccines: A double-edged sword throughout rapid evolution of COVID-19.

After more than 2 years of the coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2, several questions have remained unanswered that affected our daily lives. Although substantial vaccine development could resist this challenge, emerging new variants in different countries could be considered as potent concerns regarding the adverse effects of reinfection or postvaccination. Precisely, these concerns address some significant and probable outcomes in vaccinated or reinfected models, followed by some virus challenges, such as antibody-dependent enhancement and cytokine storm. Therefore, the importance of evaluating the effectiveness of neutralizing antibodies (nAbs) elicited by vaccination and the rise of new variants must be addressed.

Serum levels of vitamin D and immune system function in patients with COVID-19 admitted to intensive care unit.

OBJECTIVE: Vitamin D is believed to affect the functionality of the immune system for the prevention of coronavirus disease. To investigate the role of this vitamin against the Coronavirus, this study analyzed the serum levels of vitamin D, the transcription pattern of inflammatory cytokines, and the frequency of total lymphocytes, TCD4+, TCD8+, and NK cells in 50 COVID-19-affected subjects in comparison to 50 healthy participants. MATERIALS AND METHODS: This study diagnosed and evaluated 100 patients. Frequency of lymphocytes was determined using flow cytometry. Cytokine expression levels were measured using Real-Time PCR. Serum levels of vitamin D and cytokines levels in cultured cell supernatant were measured by ELISA. RESULTS: Patients with COVID-19 exhibited decreased serum levels of vitamin D versus the healthy participants (p = 0.0024). The total number of lymphocytes, TCD4+, TCD8+, and NK cells was significantly reduced in patients with COVID-19 (p < 0.0001). Considerable upregulation of IL-12, IFN-γ, and TNF-α was seen in COVID-19 patients compared to the control group, whereas IFN-α was downregulated in COVID-19 patients. ELISA results also had increased levels of IL-12, TNF-α, and IFN-γ (p = 0.0014, 0.0012, and p < 0.0001, respectively), and decreased level of IFN-α (p = 0.0021) in patients with COVID-19 compared to the control group. CONCLUSION: These findings suggest a probable association among vitamin D concentrations, immune system function, and risk of COVID-19 infection. As a result, it is recommended that vitamin D be considered as a candidate for handling and controlling COVID-19 because of its ability to target the cytokine storm and its antiviral effects.

Different T cell related immunological profiles in COVID-19 patients compared to healthy controls.

In various pathological conditions, cellular immunity plays an important role in immune responses. Amongimmunecells, T lymphocytes pdomotecellular and humoralresponses as well as innate immunity. Therefore, careful investigation of these cells has a significant impact on accurate knowledge in COVID-19diseasepathogenesis. In current research, the frequency and function of various T lymphocytes involved in immune responses examined in SARS-CoV-2 patients with various disease severity compared to normal subjects. In order to make an accurate comparison among patients with various disease severity, this study was performed on asymptomatic recovered cases (n = 20), ICU hospitalized patients (n = 30), non-ICU hospitalized patients (n = 30), and normal subjects (n = 20). To precisely evaluate T cells activity following purification, their cytokine secretion activity was examined. Similarly, immediately after purification of Treg cells, their inhibitory activity on T cells was investigated. The results showed that COVID-19 patients with severe disease (ICU hospitalized patients) not only had a remarkable increase in Th1 and Th17 but also a considerable decrease in Th2 and Treg cells. More importantly, as the IL-17 and IFN-γ secretion was sharply increased in severe disease, the secretion of IL-10 and IL-4 was decreased. Furthermore, the inhibitory activity of Treg cells was reduced in severe disease patients in comparison to other groups. In severe COVID-19 disease, current findings indicate when the inflammatory arm of cellular immunity is significantly increased, a considerable reduction in anti-inflammatory and regulatory arm occurred.