Search

BACKGROUND. Coronavirus disease 19 (COVID-19) is an emerging infectious disease caused by SARS-CoV-2. Antiviral immune response is crucial to achieve pathogen clearance; however, in some patients an excessive and aberrant host immune response can lead to an acute respiratory distress syndrome. The comprehension of the mechanisms that regulate pathogen elimination, immunity, and pathology is essential to better characterize disease progression and widen the spectrum of therapeutic options. METHODS. We performed a flow cytometric characterization of immune cell subsets from 30 patients with COVID-19 and correlated these data with clinical outcomes. RESULTS. Patients with COVID-19 showed decreased numbers of circulating T, B, and NK cells and exhibited a skewing of [CD8.sup.+] T cells toward a terminally differentiated/senescent phenotype. In agreement, [CD4.sup.+] T and [CD8.sup.+] T, but also NK cells, displayed reduced antiviral cytokine production capability. Moreover, a reduced cytotoxic potential was identified in patients with COVID-19, particularly in those who required intensive care. The latter group of patients also showed increased serum IL-6 levels that inversely correlated to the frequency of granzyme A-expressing NK cells. Off-label treatment with tocilizumab restored the cytotoxic potential of NK cells. CONCLUSION. The association between IL-6 serum levels and the impairment of cytotoxic activity suggests the possibility that targeting this cytokine may restore antiviral mechanisms. FUNDING. This study was supported by funds from the Department of Experimental and Clinical Medicine of University of Florence (the ex-60% fund and the 'Excellence Departments 2018-2022 Project') derived from Ministero dell'Istruzione, dell'Universita e della Ricerca (Italy)., Introduction SARS-CoV-2 is the etiological agent of coronavirus disease 19 (COVID-19) and belongs to the same group of RNA viruses that caused SARS and Middle East respiratory syndrome (MERS) in [...]

BACKGROUND. Immunization against SARS-CoV-2, the causative agent of COVID-19, occurs via natural infection or vaccination. However, it is currently unknown how long infection- or vaccination-induced immunological memory will last. METHODS. We performed a longitudinal evaluation of immunological memory to SARS-CoV-2 up to 1 year after infection and following mRNA vaccination in naive individuals and individuals recovered from COVID-19 infection. RESULTS. We found that memory cells are still detectable 8 months after vaccination, while antibody levels decline significantly, especially in naive individuals. We also found that a booster injection is efficacious in reactivating immunological memory to spike protein in naive individuals, whereas it was ineffective in previously SARS-CoV-2-infected individuals. Finally, we observed a similar kinetics of decay of humoral and cellular immunity to SARS-CoV-2 up to 1 year following natural infection in a cohort of unvaccinated individuals. CONCLUSION. Short-term persistence of humoral immunity, together with the reduced neutralization capacity versus the currently prevailing SARS-CoV-2 variants, may account for reinfections and breakthrough infections. Long-lived memory B and CD4* T cells may protect from severe disease development. In naive individuals, a booster dose restored optimal antispike immunity, whereas the needs for vaccinated individuals who have recovered from COVID-19 have yet to be defined. FUNDING. This study was supported by funds to the Department of Experimental and Clinical Medicine, University of Florence (Project Excellence Departments 2018-2022), the University of Florence (project RICTD2122), the Italian Ministry of Health (COVID-2020-12371849), and the region of Tuscany (TagSARS CoV 2)., Introduction Immunization against SARS-CoV-2, the causative agent of COVID-19 occurs via natural infection or vaccination. As of December 20, 2021, more than 273 million people have been infected worldwide, with [...]

Background: Patients with B-cell lymphoma are a fragile category of subjects, particularly exposed to infections and characterized by an impaired vaccination response due to the disease itself and, even more, to the chemotherapy regimen. For this reason, extensive knowledge of the immune response status of these subjects is of fundamental importance to obtain possible indications for a tailored immunization strategy. Methods: We enrolled two cohorts of patients with B-cell lymphoma under rituximab treatment or 3-24 months after treatment. In all patients, we evaluated both humoral and cellular immunological memory toward SARS-CoV-2, after standard vaccination and upon one booster dose. Results: We observed no Spike-specific IgG production in patients (n = 25) under anti-CD20 treatment, whereas patients (n = 16) vaccinated after the completion of chemotherapy showed a higher humoral response. Evaluating SARS-CoV-2-specific T-cell response, we found that patients in both cohorts had developed robust cellular immunity after vaccination. Of the 21 patients (51%) that experienced a breakthrough SARS-CoV-2 infection, only six patients developed severe disease. Interestingly, these six patients had all been treated with rituximab plus bendamustine. Notably, we observed that Spike-specific IgG levels in patients treated with rituximab plus bendamustine were absent or lower compared with those in patients treated with rituximab plus other chemotherapy, whereas Spike-specific T-cell response was not different based on chemotherapy regiment. Discussion: Our results show that, in patients with B-cell lymphoma under rituximab therapy, anti-SARS-CoV-2 mRNA vaccination induces a weak or absent humoral response but a consistent T-cell response. In addition, chemotherapy regimens with bendamustine further reduce patients' ability to mount a Spike-specific humoral response even after a long time period from chemotherapy discontinuation. These results provide evidence that different chemotherapeutics display different immunosuppressive properties that could be taken in to account in the choice of the right drug regimen for the right patient. Moreover, they question whether immunocompromised patients, particularly those treated with bendamustine, need interventions to improve vaccine-induced immune response. [ABSTRACT FROM AUTHOR]

The characterization of the adaptive immune response to COVID-19 vaccination in individuals who recovered from SARS-CoV- 2 infection may define current and future clinical practice. To determine the effect of the 2-dose BNT162b2 mRNA COVID-19 vaccination schedule in individuals who recovered from COVID-19 (COVID- 19-recovered subjects) compared with naive subjects, we evaluated SARS-CoV-2 Spike-specific T and B cell responses, as well as specific IgA, IgG, IgM, and neutralizing antibodies titers in 22 individuals who received the BNT162b2 mRNA COVID-19 vaccine, 11 of whom had a previous history of SARS-CoV-2 infection. Evaluations were performed before vaccination and then weekly until 7 days after second injection. Data obtained clearly showed that one vaccine dose is sufficient to increase both cellular and humoral immune response in COVID-19-recovered subjects without any additional improvement after the second dose. On the contrary, the second dose proved mandatory in naive subjects to further enhance the immune response. These findings were further confirmed at the serological level in a larger cohort of naive (n = 68) and COVID-19-recovered (n = 29) subjects, tested up to 50 days after vaccination. These results question whether a second vaccine injection in COVID-19-recovered subjects is required, and indicate that millions of vaccine doses may be redirected to naive individuals, thus shortening the time to reach herd immunity., Introduction As of April 4, 2021, more than 130.4 million people have been diagnosed with COVID-19 worldwide, with more than 2.8 million confirmed deaths (1). COVID-19 is associated with high [...]