Rationale: Changes in anti-SARS-CoV-2 defense immune subsets in patients treated with dexamethasone (DXM) for severe COVID-19 and their relation to disease outcomes are poorly understood. Methods: Blood-lymphocyte subsets of 110 hospitalized COVID-19 patients were prospectively examined. A first sample was taken at enrollment and a second one 7–10 days later. Total B-, T-lymphocytes, CD4+, CD8+, T-regulatory (Treg), Natural-Killer (NK) and NK T-cells were counted using flow cytometry. Results: At enrollment, patients with respiratory failure, characterized by DXM failure (intubation/death) or DXM success (hospital discharge) exhibited significantly fewer CD3+, CD4+ and CD8+ cells and B-lymphocytes compared to the control group (no respiratory failure/no DXM). At the time of treatment completion, the DXM-failure group exhibited significantly fewer CD3+, CD4+ and CD8+ cells, memory CD4+ and CD8+ T-lymphocytes, compared to the control and the DXM-success groups and fewer activated CD4+ T-lymphocytes, Tregs and NK cells compared to the control group. At the time of treatment completion, the number of all investigated lymphocyte subsets increased in the DXM-success group and was similar to those of the control group. NK cells significantly decreased over time in the DXM-failure group. Conclusion: The lymphocyte kinetics differ between DXM-treated and control COVID-19 patients and are associated with clinical outcomes.

INTRODUCTIONResearch suggests that racial minorities are overrepresented in the number of COVID-19 related deaths compared to people of White origin. This is the first study to assess racial differences in the clinical characteristics and outcomes of COVID-19 positive patients, hospitalized in Greece. METHODS This retrospective, cross-sectional study included 628 COVID-19 hospitalized patients, from 10 September to 31 December 2020. We compared data concerning gender, age, comorbidities and outcome, between patients of European and non-European origin. Moreover, we applied logistic regression in which the outcome, in our case in-hospital death, was assessed with race, age, sex, and Charlson Comorbidity Index (CCI) score. RESULTS In the first and unadjusted race-only logistic regression model, non-Europeans (OR=0.057; 95% CI: 0.008-0.411, p=0.005) were less likely than European patients to die in the hospital. However, controlling for sex, age and CCI score resulted in non-significant differences. CONCLUSIONS There are a lot of statistically significant differences between European and non-European COVID-19 hospitalized patients regarding their clinical characteristics, with the second presenting a lower hospital mortality rate, but after adjusting for age, sex and CCI score, race seems to be not significant.