BACKGROUND: As a major cause of mortality in neonates, neonatal sepsis is often accompanied by immune dysfunctions, which are frequently caused by dysregulated T cell sub-populations. The role of regulatory B cells in neonatal sepsis, however, remains unknown. Therefore, this study investigated the percentage and functional variation of CD19+CD24hiCD38hi regulatory B cells in peripheral blood of neonatal sepsis patients in an attempt to elucidate the role of these regulatory B cells in pathogenesis of sepsis.

MATERIAL AND METHODS: Flow cytometry was used to quantify the percentage of CD19+CD24hiCD38hi regulatory B cells from peripheral blood samples. The correlation between B cell percentage and C reactive protein (CRP) level was analyzed. Secretion level of interleukin-10 (IL-10) and effects on the proliferation of naïve CD4+ T cells were further analyzed.

RESULTS: The percentage of CD19+CD24hiCD38hi regulatory B cells in neonatal sepsis patients was significantly higher compared to healthy controls (p<0.05), and was positively correlated with serum CRP level. The percentage of IL-10+ CD19+CD24hiCD38hi regulatory B cells was also higher in sepsis patients, and also had more potent inhibition on naïve CD4+ T cells (p<0.01).

CONCLUSIONS: The elevation of CD19+CD24hiCD38hi regulatory B cells in neonatal sepsis can inhibit body immune function and thus may participate in the pathogenesis of sepsis.

Keywords: Antigens, CD24 - blood, Antigens, CD19 - blood, Antigens, CD38 - blood, B-Lymphocytes, Regulatory - pathology, C-Reactive Protein - metabolism, Infant, Newborn, Interleukin-10 - blood, Membrane Glycoproteins - blood, Neonatal Sepsis - pathology, Staphylococcal Infections - pathology, Thrombocytopenia - pathology