BACKGROUND: The emerging infection of the 2019 novel coronavirus (2019-nCoV) in late December, 2019 in Wuhan, China, has caused an extreme health concern, with many patients having progressed to acute respiratory disease or other complications in a short period. Meanwhile, the risk factors associated with the disease progression still remain elusive. METHODS: A cohort of 17 patients with laboratory-confirmed 2019-nCoV infections who were admitted to the Ninth Hospital of Nanchang between January 28 and February 6, 2020, were enrolled in this study. All the patients received standardized treatment. The disease progression was evaluated every 7 days after admission. The clinical, radiologic, and laboratory characteristics were retrospectively analyzed, and the factors associated with the disease progression were screened by binary logistic regression analysis. RESULTS: The cohort comprised 11 women (64.7%) and 6 men (35.3%) between the ages of 18 to 70 years old. All patients had a reported history of contact with infection-confirmed patients. Fever (11/64.7%) and cough (8/47.1%) were the most common symptoms, whereas dyspnea (2/11.8%) and fatigue (3/17.6%) were rare, and there was no patient with diarrhea symptoms. There were 5 patients with aggravated disease at the first disease progression evaluation, and no patient received mechanical ventilation, transferred to the intensive care unit (ICU), or progressed to acute respiratory distress syndrome, septic shock, refractory metabolic acidosis, coagulation dysfunction, or death. Based on the disease progression, patients were divided into the non-aggravation group (12 cases) and the aggravation group (5 cases). There were no significant differences between the 2 groups with respect to their clinical characteristics. Chest computed tomography (CT) on admission revealed there were 8 patients (47.1%) with invasive lesions found bilaterally on the lungs on multiple lobes, 4 patients (23.5%) with invasive lesions on 1 lobe, and 5 patients (29.4%) with normal chest CT. The aggravation group had1 patient (20.0%) with invasive lesions on one lobe, 3 (60.0%) with invasive lesions on multiple lobes, bilaterally, and 1 (20.0%) with normal chest CT; meanwhile, the nonaggravation group had 3 patients (25.0%) with invasive lesions on one lobe, 5 (41.7%) with invasive lesions on multiple lobes, bilaterally, and 4 (33.3%) with normal chest CT. No significant difference was found between the 2 groups. In the aggravation group, the total lymphocyte counts significantly decreased in comparison to that in the non-aggravation group. Further analysis showed that the CD4+ T cell count but not the CD8+ T cell count of the aggravation group was significantly lower than that of the non-aggravation group. Correlation analysis indicated total lymphocyte count was positively correlated with CD4+ T cell count, and no significant differences were found between the 2 groups in other laboratory measurements, including those of white blood cell (WBC) count, C-reactive protein (CRP), albumin, lactate dehydrogenase (LDH), and D-dimer. Finally, a binary logistic regression model was used to identify the factors associated with the disease progression. It was found that total lymphocyte count was a risk factor associated with disease progression in patients infected with 2019-nCoV. CONCLUSIONS: A higher cell count of total lymphocytes may indicate a better outcome of the disease, and immune response may be a vital factor for directing disease progression in the early stage of 2019-nCoV infection.