IL6 and lymphopenia: The mean (SD) duration of fever was 5 (2.4) days (eTables 3 and 4 in the Supplement), and all patients had laboratory evidence of inflammation, including lymphopenia and/or significantly elevated inflammatory markers, such as C-reactive protein, erythrocyte sedimentation rate, D-dimer, ferritin, fibrinogen, and IL-6 (eTable 5 in the Supplement).