Background SARS-CoV-2 pre-existing T-cell immune reactivity can be present in some people. A general perturbation of the main peripheral lymphocyte subsets has been described in severe COVID-19 patients, but very few studies assessed the general memory T-cell homeostasis in the acute phase of COVID-19. Here, we performed a general analysis of the main memory T cell populations in the peripheral blood of patients admitted to the hospital for a confirmed or probable COVID-19 diagnosis. Methods In this cross-sectional study, adult patients (aged ≥ 18 years) needing hospital admission for respiratory disease due to confirmed or probable COVID-19, were recruited before starting the therapeutic protocol for this disease. In addition to the assessment of the general lymphocyte subpopulations in the early phase of COVID-19, central memory T cells (Tmcentr cells: CD45RO+CCR7+) and effector memory T cells (Tmeff cells: CD45RO+CCR7−) were assessed by multi-color flow cytometry, in comparison to a control group. Results During the study period, 148 study participants were recruited. Among them, 58 patients turned out positive for SARS-CoV-2 PCR (including both patients with interstitial pneumonia [PCR+Pn+] and without this complication [PCR+Pn−]), whereas the remaining 90 patients resulted to be SARS-CoV-2 PCR negative, even though all were affected with interstitial pneumonia [PCR−Pn+]. Additionally, 28 control patients without any ongoing respiratory disease were recruited. A clear unbalance in the T memory compartment emerged from this analysis on the whole pool of T cells (CD3+ cells), showing a significant increase in Tmcentr cells and, conversely, a significant decrease in Tmeff cells in both pneumonia groups (PCR+Pn+ and PCR−Pn+) compared to the controls; PCR+Pn− group showed trends comprised between patients with pneumonia (from one side) and the control group (from the other side). This perturbation inside the memory T cell compartment was also observed in the individual analysis of the four main T cell subpopulations, based upon the differential expression of CD4 and/or CD8 markers. Conclusion Overall, we observed both absolute and relative increases of Tmcentr cells and decrease of Tmeff cells in patients affected with interstitial pneumonia (regardless of the positive or negative results of SARS-CoV-2 PCR), compared to controls. These results need confirmation from additional research, in order to consider this finding as a potential biological marker of interstitial lung involvement in patients affected with viral respiratory infections.

Background. Long COVID-19 symptoms appeared in many COVID-19 survivors. However, the prevalence and symptoms associated with long COVID-19 and its comorbidities have not been established. Methods. In total, 312 patients with long COVID-19 from 21 primary care centers were included in the study. At the six-month follow-up, their lung function was assessed by computerized tomography (CT) and spirometry, whereas cardiac function was assessed by electrocardiogram (ECG), Holter ECG, echocardiography, 24 h blood pressure monitoring, and a six-minute walk test (6MWT). Results. Of the 312 persons investigated, significantly higher systolic and diastolic blood pressure, left ventricular hypertrophy, and elevated NT-proBNP were revealed in participants with hypertension or type 2 diabetes. Left ventricular diastolic dysfunction was more frequently present in patients with hypertension. The most common registered CT abnormalities were fibrotic changes (83, 36.6%) and mediastinal lymphadenopathy (23, 10.1%). Among the tested biochemical parameters, three associations were found in long COVID-19 patients with hypertension but not diabetes: increased hemoglobin, fibrinogen, and ferritin. Nine patients had persisting IgM antibodies to SARS-CoV-2. Conclusions. We demonstrated a strong association between signs of cardiac dysfunction and lung fibrotic changes with comorbidities in a cohort of long COVID-19 subjects.

Background. Long COVID-19 symptoms appeared in many COVID-19 survivors. However, the prevalence and symptoms associated with long COVID and its comorbidities have not been established. Methods. Between May and September 2020 we included 312 patients with post-COVID-19 from 21 primary care centers if they had any persistent symptoms for at least three months from the first onset of the disease. On the 6 months follow up, their lung function was assessed by CT and spirometry, whereas cardiac function was assessed by electrocardiogram (ECG), Holter ECG, Echocardiography, and 24-hour blood pressure monitoring. A six-minute test (6MWT) was conducted on 308 participants during the follow-up visit. All participants were given a questionnaire with items on demographic information, current complaints, comorbidities, and medications, and Chalder Fatigue Scale (CFS) questionnaire. Statistical analysis was done using R vs. 4.1.2. Two-group comparison of continuous variables was performed using a T-test for normally distributed data, and the Mann-Whitney Wilcoxon test, ANOVA, and Kruskal-Wallis tests were applied for multiple comparisons following with Tukey and Dunn tests as post-hoc methods. Hochberg p-value adjustment was used to reduce the false discovery rate during multiple comparisons. Categorical variables were analyzed with Fishers Exact test. Results. Of 312 persons investigated, there was no significant gender difference between post-COVID-19 clinical manifestations except for memory dysfunction and anxiety, more prevalent among female participants. Chalder Fatigue Score was predominant in female participants (243, 78%). 39 (12.5%) participants reported having type 2 diabetes mellitus, and 158 (50.64%) had hypertension. Among the tested parameters, those positively correlated with comorbid conditions include age, BMI, D-dimers, NT-proBNP, C-reactive protein, neutrophils, fasting glucose, and HbA1c; hypertension also shows three associations that were not found in patients when examining the role of diabetes: increased hemoglobin, fibrinogen, and ferritin. 24-hour blood pressure monitoring revealed significantly higher systolic and diastolic blood pressure, left ventricular hypertrophy, and elevated NT-proBNP in participants with hypertension and subjects with type 2 diabetes. Left ventricular diastolic dysfunction is more frequently present in patients with hypertension. Chest CT was conducted on 227 (72.8%) participants 5.8+/-0.9 months after the onset of COVID-19. The most common registered CT abnormality was chronic bronchitis (198, 87.2%), followed by fibrotic changes in (83, 36.6%) and mediastinal lymphadenopathy (23, 10.1%). Immunological test results showed that SARS-CoV19 IgG antibodies were present in 241 subjects (77.2%), and SARS-CoV19 IgM antibodies were present in 9 subjects (2.88%). Conclusions. Our study provides valuable clues for long-term post-sequelae in a cohort of the Long COVID-19 subjects. We demonstrated a strong association of signs of cardiac dysfunction, lung fibrotic changes, increased hemoglobin, fibrinogen, and ferritin with hypertension but not with other comorbidities. Our results are of importance for understanding the Long Covid-19 syndrome.