CD71(+) Erythroid Cell Expansion in Adult Sepsis: Potential Causes and Role in Prognosis and Nosocomial Infection Prediction

BACKGROUND: Immune suppression contributes to nosocomial infections (NIs) and poor prognosis in sepsis. Recent studies revealed that CD71(+) erythroid cells had unappreciated immunosuppressive functions. This study aimed to investigate the values of CD71(+) erythroid cells (CECs) in predicting NIs and prognosis among adult septic patients. The potential factors associated with the expansion of CECs were also explored. METHODS: In total, 112 septic patients and 32 critically ill controls were enrolled. The frequencies of CD71(+) cells, CD71(+)CD235a(+) cells, and CD45(+) CECs were measured by flow cytometry. The associations between CECs and NIs and 30-day mortality were assessed by ROC curve analysis and Cox and competing-risk regression models. Factors associated with the frequency of CECs were identified by linear regression analysis. RESULTS: The percentage of CD71(+) cells, CECs, and CD45(+) CECs were higher in septic patients than critically ill controls. In septic patients, the percentages of CD71(+) cells, CECs, and CD45(+) CECs were associated with NI development, while CD71(+) cells and CECs were independently associated with 30-day mortality. Linear regression analysis showed that the levels of interleukin (IL)-6 and interferon (IFN)-γ were positively associated with the frequencies of CD71(+) cells, CECs, and CD45(+) CECs, while IL-10 was negatively associated with them. Additionally, the levels of red blood cells (RBCs) were negatively associated with the percentage of CD45(+) CECs. CONCLUSIONS: CECs were expanded in sepsis and can serve as independent predictors of the development of NI and 30-day mortality. Low levels of RBCs and high levels of IL-6 and IFN-γ may contribute to the expansion of CECs in sepsis. TRIAL REGISTRATION: ChiCTR, ChiCTR1900024887. Registered 2 August 2019, http://www.chictr.org.cn/showproj.aspx?proj=38645