CD27 and COVID-19: Instead, the number of effector T4 cells and PD1+ depleted T8 cells in critical COVID-19 patients, and effector T4 cells, CD28− differentiated T4 cells, CD57+ differentiated T4 cells, effector memory T8 cells, effector T8 cells, CD27− differentiated T8 cells, CD28− differentiated T8 cells, and CD57+ differentiated T8 cell subsets in severe patients were enlarged compared to mild cases, possibly indicating an active anti-inflammatory response.