TABLE 4.
Observed fluctuation in T cell subsets in adult COVID-19 patients.
| T cell subsets | Observation | Analyzed patients | Compared group(s) | References |
| Total CD3+CD19– T lymphocyte | Reduction (%) | Deceased | Survivors | Cui et al., 2020 |
| Reduction (#) | Deceased | Survivors | Cui et al., 2020; Belaid et al., 2021 | |
| Reduction (%) | Cases | Recovered | Mathew et al., 2020 | |
| Reduction (%) | Cases | HD | Mathew et al., 2020 | |
| Reduction (#) | Severeη | Mildζ /moderateθ | Song et al., 2020; Belaid et al., 2021 | |
| No change (%) | Severeη | Mildζ | Song et al., 2020 | |
| CD3+CD4+ Helper T lymphocyte | Reduction (%) | Deceased | Survivors | Cui et al., 2020 |
| Reduction (#) | Deceased | Survivors | Cui et al., 2020 | |
| Reduction (#) | Pneumonia patients | HD | Wang F. et al., 2020 | |
| Reduction (#) | Severeη | Mildζ /moderateθ | Song et al., 2020; Wang F. et al., 2020; Belaid et al., 2021; Taghiloo et al., 2021 | |
| No change (%) | Severeη | HD | De Biasi et al., 2020 | |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| Reduction (%) | Cases | Recovered | Mathew et al., 2020 | |
| Reduction (%) | Cases | HD | Mathew et al., 2020 | |
| No change (%) | Severeη | Mildζ | Song et al., 2020 | |
| CD3+CD8+ Cytotoxic T lymphocyte | Reduction (%) | Deceased | Survivors | Cui et al., 2020 |
| Reduction (#) | Deceased | Survivors | Cui et al., 2020; Belaid et al., 2021 | |
| Reduction (#) | Pneumonia patients | HD | Wang F. et al., 2020 | |
| Reduction (#) | Severeη | Mildζ /moderateθ | Song et al., 2020; Wang F. et al., 2020; Belaid et al., 2021; Taghiloo et al., 2021 | |
| No change (%) | Severeη | HD | De Biasi et al., 2020 | |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| Reduction (%) | Cases | Recovered | Mathew et al., 2020 | |
| Reduction (%) | Cases | HD | Mathew et al., 2020 | |
| No change (%) | Severeη | Mild | Song et al., 2020 | |
| CCR7+CD45RA+CD28+CD27+ CD4+ naïve | No change (%) | Severeη | HD | De Biasi et al., 2020 |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA+CD28+CD27+/- CD4+ central memory | No change (%) | Severeη | HD | De Biasi et al., 2020 |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| No change (%) | Severeη | HD | De Biasi et al., 2020 | |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA+CD28-CD27+/- CD4+ terminal effector | Increase (%) | Severeη | HD | De Biasi et al., 2020 |
| No change (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA+CD27- CD4+ naïve terminal effector | Increase (%) | Cases | Recovered | Mathew et al., 2020 |
| Increase (%) | Cases | HD | Mathew et al., 2020 | |
| CD38+HLA-DR+ CD4+ activated | No change (#) | Severeη | HD | De Biasi et al., 2020 |
| Increase (%) | Severeη | HD | De Biasi et al., 2020 | |
| Increase (%) | Mildζ | HD | Song et al., 2020 | |
| Increase (%) | Severeη | HD | Song et al., 2020 | |
| Increase (%) | Deceased | Survivors | Belaid et al., 2021 | |
| Increase (%) | Cases | Recovered | Mathew et al., 2020 | |
| Increase (%) | Cases | HD | Mathew et al., 2020 | |
| No change (%) | Severeη | Mildζ /moderateθ | Song et al., 2020; Belaid et al., 2021 | |
| PD-1+CD57+ CD4+ exhausted/senescent | Increase (%) | Severeη | HD | De Biasi et al., 2020 |
| No change (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7+CD45RA+CD28+CD27+ CD8+ naïve | Reduction (%) | Severeη | HD | De Biasi et al., 2020 |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7+CD45RA+ CD8+ naïve | Reduction (%) | Severeη | Mildζ /moderateθ | Belaid et al., 2021 |
| Reduction (%) | Deceased | Survivors | Belaid et al., 2021 | |
| CCR7-CD45RA+CD28+CD27+/- CD8+ central memory | Reduction (%) | Severeη | HD | De Biasi et al., 2020 |
| Reduction (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA-CD28+/-CD27+/- CD8+ effector memory | No change (%) | Severeη | HD | De Biasi et al., 2020 |
| No change (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA-CD8+ effector memory | Increase (%) | Deceased | Survivors | Belaid et al., 2021 |
| CCR7-CD45RA+CD28-CD27+/- CD8+ terminal effector | Increase (%) | Severeη | HD | De Biasi et al., 2020 |
| No change (#) | Severeη | HD | De Biasi et al., 2020 | |
| CCR7-CD45RA+CD27- CD8+ naïve terminal effector | Increase (%) | Cases | Recovered | Mathew et al., 2020 |
| Increase (%) | Cases | HD | Mathew et al., 2020 | |
| CD38+HLA-DR+ CD8+ activated | Increase (%) | Severeη | HD | De Biasi et al., 2020 |
| Increase (#) | Severeη | HD | De Biasi et al., 2020 | |
| Increase (%) | Mildζ | HD | Song et al., 2020 | |
| Increase (%) | Severeη | HD | Song et al., 2020 | |
| Increase (%) | Deceased | Survivors | Belaid et al., 2021 | |
| Increase (%) | Severeη | Mildζ | Song et al., 2020 | |
| Increase (%) | Cases | Recovered | Mathew et al., 2020 | |
| Increase (%) | Cases | HD | Mathew et al., 2020 | |
| No change (%) | Severeη | Mildζ /moderateθ | Belaid et al., 2021 | |
| PD-1+CD57+ CD8+ exhausted/senescent | Increase (%) | Severeη | HD | De Biasi et al., 2020 |
| No change (#) | Severeη | HD | De Biasi et al., 2020 | |
| BAL T cells | Reduction (%) | Severeη /Criticalι | Moderateθ | Liao et al., 2020 |
| Increase (%) | Moderateθ | HD | Liao et al., 2020 |
T cell subset, peripheral blood T cell subset analyzed in the reported studies; (%), as frequency values; (#), as absolute number; Cases, COVID-19 patients (irrespective of severity); HD, healthy donors; Recovered, non-hospitalized subjects who had recovered from SARS-CoV-2 infection.
ζPatients with or without pneumonia admitted to general wards not requiring intensive care.
ηPatients experiencing the following: respiratory failure, respiratory rate > 30 bpm, oxygen saturation < 93% at rest, arterial partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) (PaO2/FiO2) ratio < 300 mmHg.
θFever, respiratory symptoms, and pneumonia evidenced by computed tomography.
ιAny of the following: requirement for mechanical ventilation, shock, or concomitant organ failure.