|
| Study groups (number of patients) | Change in Treg levels | Cell phenotype | Notes | Reference no. |
|
Xie et al. | Asymptomatic disease | Decrease | NA | In asymptomatic patients, IL-2 was associated with faster viral clearance and early immune responses. | [54] |
Kratzer et al. | Convalescent patients (109) vs. healthy (98) | Decrease | CD25+FoxP3+ | Acute SARS-CoV-2 infection is beneficial by activation of T cells or harmful by reduction of neutrophils. | [51] |
Chen et al. | Mild (80)/severe (22) vs. healthy (67) | Increase | CD4+CD25+CD127low | CD4+ T cells, B cells, IL-6, and IL-10 are indicators of COVID-19 severity. | [47] |
Sadeghi et al. | Critical (40) vs. healthy (40) | Decrease | CD4+CD25+CD127− | Imbalanced ratios of Th17/Tregs could play an important role in inflammatory responses and the pathogenesis of the disease. | [52] |
Jiménez-Cortegana et al. | Hospitalized (20) vs. healthy (20) | Decrease | CD4+CD25highCD127− | M-MDSCs, but not Tregs, could play a role in the immunosuppression shown in COVID-19 patients. | [8] |
Patterson et al. | Different severity (224) | Decrease | NA | Decreased Tregs in COVID-19 compared with healthy controls. | [53] |
Mohebbi et al. | Different severity (30) | Decrease | CD4+FoxP3+CD25+ | Decreased Tregs in COVID-19 patients compared with healthy controls. | [57] |
Galván-Peña et al. | Different severity (57) | Increase | CD25+FoxP3+ | Increased Tregs in severe patients is associated with worse outcome. | [43] |
Kalfaoglu et al. | Severe | Decrease | NA | In the lung, T cells highly expressed immune-regulatory receptors and CD25, while suppressing expression of FoxP3. | [63] |
Qin et al. | Severe (286) vs. non-severe (166) | Decrease | CD4+CD25+CD127low | | [59] |
Neumann et al. | Severe (20) vs. mild/moderate (23) | Increase | IL-10-secreting Tregs | | [45] |
Wang et al. | Extremely severe (15) vs. severe (20) vs. mild (30) | Decrease | CD45RA+ cells | The percentage of natural Tregs was decreased in extremely severe patients. | [61] |
Wang et al. | Critical (3) vs. severe (5) vs. mild (4) | Decrease | CD4+CD25+CD127− | Tregs increase during progression from mild to severe then decreased through the progression to critical disease. | [62] |
Meckiff et al. | Hospitalized (critical) vs. non hospitalized (mild) | Decrease | NA | | [55] |
Chen et al. | Severe (11) vs. moderate (10) | Decrease | CD4+CD25+CD127low and CD45RA+ | | [60] |
Rezaei et al. | Critical (8) vs. severe (27) vs. Moderate (17) | No change | CD4+CD25+FOXP3+ | | [50] |
Rutkowska et al. | Critical (18) vs. severe (23) | Decrease | NA | Percentage of CD45RO+CD95+ Tregs, among other Treg subsets, was higher in critical compared to severe. | [56] |
Ronit et al. | Mechanically ventilated patients (4) with moderate-to-severe COVID-19 ARDS | Increase | FoxP3+CTLA-4+ Tregs | Increased Tregs with activation markers in the lung. | [46] |
Vicket et al. | SARS-CoV-2 (24) vs. RSV (10) vs. Flu (9) vs. Healthy donors (23) | Immune landscape in SARS cov-2 similar to flu or RSV patients | CD25+ CD127−Foxp3+ | Only in critical patients, the levels of CD25+CD127− FoxP3+ cells were increased. | [44] |
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