Composition and Variation Analysis of the T Cell Receptor β-Chain Complementarity Determining Region 3 Repertoire in Neonatal Sepsis.

T cell receptor (TCR) diversity is clearly related to protection from infection. However, the characteristics of TCR diversity in neonates are not clear. In this study, we investigated the TCR diversity of neonates with sepsis. Twenty neonates with severe sepsis and eight matched neonates without infection were enrolled in the study. For the neonates with sepsis, EDTA-anticoagulated blood was collected on day 1 after the diagnosis of sepsis and on day 7 of treatment. For the neonates without infection, blood was collected one time. DNA was extracted from peripheral blood mononuclear cells. The complementarity determining region 3 (CDR3) gene was analysed by multiplex PCR and high-throughput sequencing. The CDR3 types and lengths were similar in patients and healthy controls. There was a significant difference in VJ gene usage among the three groups. Compared to the healthy neonates, the neonates with sepsis had different VJ pairs and generated different clonotypes. Although the TCR β-chain diversity was generally lower in the neonates with sepsis, there was no significant difference in TCR β-chain diversity between the patients and the healthy controls. Our data showed the characteristics of the TCR repertoire in neonates with sepsis, which represents a potentially valuable data set. This result is useful for understanding neonatal susceptibility to infection.