Peripheral T cell lymphopenia in COVID-19: potential mechanisms and impact

In this review, we demonstrate that CD4+ and CD8+ T cell lymphopenia is a feature of severe COVID-19 compared with moderate disease in hospitalised patients. Pathology data indicate T cell infiltration into infected organs, particularly the lung. Potential mechanisms affecting T cells in severe disease due to SARS-CoV-2 infection include T cell redistribution and sequestration, pyroptosis, and apoptosis.