Immune responses and residual SARS-CoV-2 in two critically ill COVID-19 patients before and after lung transplantation. Issue 4 (April 2021) - Yan, Yan; Jiang, Xiufeng; Fu, Juanjuan; Huang, Jiehui; Qiu, Yuanwang; Ding, Difei; Ge, Lina; Zhang, Hao; Huang, Lihua; Lu, Xiaojie; Hu, Qinxue