Correlation of Lymphocyte Subpopulations, Clinical Features and Inflammatory Markers during Severe COVID-19 Onset oleh Angelos Liontos, Alexandros-George Asimakopoulos, Georgios S. Markopoulos, Dimitrios Biros, Lazaros Athanasiou, Stavros Tsourlos, Leukothea Dova, Iro-Chrisavgi Rapti, Ilias Tsiakas, Evangelia Ntzani, Evangelos Evangelou, Ioanna Tzoulaki, Konstantinos Tsilidis, George Vartholomatos, Evangelia Dounousi, Haralampos Milionis, Eirini Christaki