To the Editor
The decline of T lymphocytes in peripheral blood is a typical laboratory
characteristic of patients with COVID-19, especially in severe
patients1,2. T-lymphocytes play a critical role in
antiviral immunity. CD4+T lymphocyte subsets secretes
high level of effector cytokines, especially interferon-γ (IFN-γ), which
are essential for virus clearance3. However, there is
no research concerning whether CD4+T predicted
outcomes of COVID-19 patients.