Clinical and Immune Features of Hospitalized Pediatric Patients With Coronavirus Disease 2019 (COVID-19) in Wuhan, China.

Question What are the immunologic features of pediatric patients with pneumonia caused by coronavirus disease 2019 (COVID-19)? Findings In this single-center case series involving 157 pediatric patients with COVID-19, systemic inflammation rarely occurred. Patients with moderate disease had higher interleukin 10 levels and lower neutrophil levels than patients with mild disease. Meaning The results of this study suggest that dysregulation of immune response may be involved in the pathologic process of COVID-19; gaining a deeper understanding of the role of neutrophils, CD4(+) T cells, and B cells in the pathogenesis of severe acute respiratory syndrome coronavirus 2 infection could be important for the clinical management of COVID-19. This case series delineates and compares the immunologic features of mild and moderate coronavirus disease 2019 (COVID-19) in pediatric patients. Importance The epidemiologic and clinical characteristics of pediatric patients with coronavirus disease 2019 (COVID-19) have been reported, but information on immune features associated with disease severity is scarce. Objective To delineate and compare the immunologic features of mild and moderate COVID-19 in pediatric patients. Design, Setting, and Participants This single-center case series included 157 pediatric patients admitted to Wuhan Children's Hospital with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Data were collected from January 25 to April 18, 2020. Exposures Documented SARS-CoV-2 infection. Main Outcomes and Measures Clinical and immunologic characteristics were collected and analyzed. Outcomes were observed until April 18, 2020. Results Of the 157 pediatric patients with COVID-19, 60 (38.2%) had mild clinical type with pneumonia, 88 (56.1%) had moderate cases, 6 (3.8%) had severe cases, and 3 (1.9%) were critically ill. The 148 children with mild or moderate disease had a median (interquartile range [IQR]) age of 84 (18-123) months, and 88 (59.5%) were girls. The most common laboratory abnormalities were increased levels of alanine aminotransferase (ALT) (median [IQR], 16.0 [12.0-26.0] U/L), aspartate aminotransferase (AST) (median [IQR], 30.0 [23.0-41.8] U/L), creatine kinase MB (CK-MB) activity (median [IQR], 24.0 [18.0-34.0] U/L), and lactate dehydrogenase (LDH) (median [IQR], 243.0 [203.0-297.0] U/L), which are associated with liver and myocardial injury. Compared with mild cases, levels of inflammatory cytokines including interleukin 6, tumor necrosis factor alpha, and interferon gamma were unchanged, whereas the level of immune suppressive interleukin 10 was markedly increased in moderate cases compared with mild cases (median [IQR], 3.96 [3.34-5.29] pg/mL vs 3.58 [3.10-4.36] pg/mL; P = .048). There was no statistically significant difference in absolute number of lymphocytes (including T cells and B cells) between mild and moderate cases, but moderate cases were associated with a decrease in neutrophil levels compared with mild cases (median [IQR], 2310/mu L [1680/mu L-3510/mu L] vs 3120/mu L [2040/mu L-4170/mu L]; P = .01). Immunoglobin G and the neutrophil to lymphocyte ratio were negatively associated with biochemical indices related to liver and myocardial injury (immunoglobulin G, ALT: r, -0.3579; AST: r, -0.5280; CK-MB activity: r, -0.4786; LDH: r, -0.4984; and neutrophil to lymphocyte ratio, ALT: r, -0.1893; AST: r, -0.3912; CK-MB activity: r, -0.3428; LDH: r, -0.3234), while counts of lymphocytes, CD4(+) T cells, and interleukin 10 showed positive associations (lymphocytes, ALT: r, 0.2055; AST: r, 0.3615; CK-MB activity: r, 0.338; LDH: r, 0.3309; CD4(+) T cells, AST: r, 0.4701; CK-MB activity: r, 0.4151; LDH: r, 0.4418; interleukin 10, ALT: r, 0.2595; AST: r, 0.3386; CK-MB activity: r, 0.3948; LDH: r, 0.3794). Conclusions and Relevance In this case series, systemic inflammation rarely occurred in pediatric patients with COVID-19, in contrast with the lymphopenia and aggravated inflammatory responses frequently observed in adults with COVID-19. Gaining a deeper understanding of the role of neutrophils, CD4(+) T cells, and B cells in the pathogenesis of SARS-CoV-2 infection could be important for the clinical management of COVID-19.