A series of novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) since the end of 2019 is ongoing and triggering a global public health crisis.The estimated case fatality rate is approximately 3.4% in China.However, some patients experience dyspnea within 1 week and develop rapidly to organ injury and even death within 2 weeks after dyspnea. 1 In addition, early organ injury could lead to higher risks of mortality.Thus, early identification of patients at risk of organ injury and death is crucial, which saves the patients from classified and invasive treatment, improving clinical outcome and prognosis.The human immune system plays significant roles in the resistance of foreign pathogens and the progress of pneumonia.Recent studies have mentioned that T cells were decreased in COVID-19 patients, excessive activated immune response was caused by pathogenic Th1 cells, and inflammatory CD14 + CD16 + monocytes may connect to pulmonary immunopathology, leading to deleterious clinical manifestations and even acute mortality after SARS-CoV-2 infections. 2 SARS-CoV-2 might damage lymphocytes, especially T lymphocytes, and the immune system was impaired during the period of disease to cause tissue injury. 2,3 Therefore, immune dysfunction is very likely to be a risk factor for patients with COVID-19, and immunological profiling may assist in the prediction of organ injury and prognosis in COVID-19 patients.However, few studies have systematically reported immunological characteristics and their relationship with organ injury and mortality in patients with COVID-19.In this multicenter retrospective cohort study, we analyzed data from the Early Risk Stratification of Novel Coronavirus Pneumonia (ERS-COVID-19) study.The study was registered at www.chictr.org.cn(Identifier: ChiCTR2000030494).The study complied with the Declaration of Helsinki, and the Human Ethical Committee of West China Hospital of Sichuan University approved the study protocol.From January 31, 2020 to February 18, 2020, 509 patients retrospectively enrolled in the ERS-COVID-19 study.The COVID-19 was confirmed according to the National Health Commission of the People's Republic of China and the National Administration of Traditional Chinese Medicine. 4The inclusion criteria were age >18 years old and first diagnosis of COVID-19.The exclusion criteria were examination without immune-related indicators before treatment, pregnancy, taking immunosuppressive drugs or corticosteroids, a history of chronic organ dysfunction or immunological disease, operation history within 3 months, and simultaneous infection with other diseases.Finally, a total of 163