We have deeply investigated T cell compartment, plasma cytokines and cells producing cytokines in patients affected by Covid-19. At admission, patients were lymphopenic; in all of them SARS-CoV-2 was detected in a nasopharyngeal swab specimen by real-time RT-PCR, and pneumonia was subsequently confirmed by X-rays.Detailed 18-parameter flow cytometry was performed in 21 patients and 13 controls. Coupling polychromatic cytometry with unsupervised data analysis, we found that patients show an increased amount of CD4+ T lymphocytes that were activated, exhausted, stem memory or Treg. Similar results concerning activation and exhaustion were found in the CD8+ T cell compartment, within which the differences were even greater.Measuring plasma level of 31 cytokines linked to inflammation revealed that Covid-19 showed a dramatic increase of several molecules, such as TH1 and TH2 cytokines, chemokines, galectins, pro- and anti-inflammatory mediators, confirming the importance of a massive immune activation causing the cytokine storm. Then, intracellular staining detecting the simultaneous production of different cytokines after a para-physiologic stimulus given by anti-CD3/CD28 mAbs revealed not only a high capacity to produce a variety of molecules, including TNF-a, IFN-g and IL-2, but also a significant skewing of CD4+ T cells towards the TH17 phenotype.A therapeutic approach now exists based on the administration of drugs that block IL-6 pathway, and is now consistently improving the course of the disease. IL-17 is crucial in recruiting and activating neutrophils, cells that can migrate to the lung and are heavily involved in the pathogenesis of Covid-19. We show here that a significant skewing of activated T cells towards TH17 functional phenotype exists in Covid-19 patients. Thus, we suggest that blocking IL-17 pathway by already available biological drugs that are used to treat different pathologies could be a novel, additional strategy to improve the health of patients infected by SARS-CoV-2.
Background: Monocyte Distribution Width (MDW), a new cytometric parameter correlating with cytomorphologic changes occurring during massive monocyte activation, has recently been described as promising early biomarker of sepsis. Similar to sepsis, in SARS-CoV-2-associated disease (COVID-19) monocyte/macrophage subsets are considered key mediators of the life-threatening hyper-inflammatory disorder –commonly defined as ‘cytokine storm’– which is part of the complex infection-associated immune dysregulation observed in severe COVID-19 cases (possibly constituting a kind of viral sepsis). Therefore, in this work, we aimed at investigating, for the first time, possible roles of MDW testing in the monitoring of COVID-19 patients.Methods: We longitudinally measured MDW values (readily available along with automated blood cell count) in a cohort of 87 patients with COVID-19 diagnosis, consecutively admitted to our clinics in early 2020, due to aggravation of their clinical status. Statistical analyses were then applied to correlate MDW values with inflammatory markers, disease severity, clinical trajectories and final outcome.Results: We initially found significant direct correlations between MDW and different inflammatory markers routinely assessed during hospitalization, namely CRP (p<0.001), fibrinogen (p<0.001) and ferritin (p<0.01). Moreover, high MDW values resulted remarkably associated with fatal outcome of severe COVID-19 patients (AUC=0.76, 95% CI: 0.66-0.87, sensitivity 0.75, specificity 0.70, MDW threshold 26.4; RR=4.91, 95% CI: 1.73-13.96; OR=7.14, 95% CI: 2.06-24.71). Furthermore, when evaluating MDW dynamics in COVID-19 cases with longer follow-up, we frequently observed progressive MDW increment in patients with worsening inflammation, while clinical recovery was consistently associated with MDW decrease. Of note, MDW evaluation may also help to assess the response to immunomodulatory treatments, such as tocilizumab. Conclusions: Our pilot study shows that MDW can be useful in the monitoring of COVID-19 patients, as this innovative hematologic biomarker is (i) easy and rapid to obtain, (ii) directly related to the activation state of a fundamental inflammatory cell subset (i.e. monocytes, pivotal in both cytokine storm and sepsis immunopathogenesis), (iii) well correlated with clinical severity of COVID-19-associated inflammatory disorder, and, in turn, (iv) endowed with relevant prognostic significance. Additional studies are needed to define further the clinical impact of MDW testing in the management of COVID-19 patients.
Monocyte Distribution Width (MDW), a new cytometric parameter correlating with cytomorphologic changes occurring upon massive monocyte activation, has recently emerged as promising early biomarker of sepsis. Similar to sepsis, monocyte/macrophage subsets are considered key mediators of the life-threatening hyper-inflammatory disorder characterizing severe COVID-19. In this study, we longitudinally analyzed MDW values in a cohort of 87 COVID-19 patients consecutively admitted to our hospital, showing significant correlations between MDW and common inflammatory markers, namely CRP (p<0.001), fibrinogen (p<0.001) and ferritin (p<0.01). Moreover, high MDW values resulted to be prognostically associated with fatal outcome in COVID-19 patients (AUC=0.76, 95% CI: 0.66-0.87, sensitivity 0.75, specificity 0.70, MDW threshold 26.4; RR=4.91, 95% CI: 1.73-13.96; OR=7.14, 95% CI: 2.06-24.71). This pilot study shows that MDW can be useful in the monitoring of COVID-19 patients, as this innovative hematologic biomarker is: (i) easy to obtain, (ii) directly related to the activation state of a fundamental inflammatory cell subset (i.e. monocytes, pivotal in both cytokine storm and sepsis immunopathogenesis), (iii) well correlated with clinical severity of COVID-19-associated inflammatory disorder, and, in turn, (iv) endowed with relevant prognostic significance. Additional studies are needed to define further the clinical impact of MDW testing in the management of COVID-19 patients.
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