Abstract: [Abstract] Objective Investigating the value of the peripheral blood neutrophil adhesion molecule CD11b and CD64 expression in the early diagnosis of neonatal bacterial infection and evaluating its efficacy. Methods Sixty-three suspected neonatal bacterial infection cases who were hospitalized from May 2005 ~ May 2008 were recruited into the study. Recorded their clinical manifestations, blood culture, cerebrospinal fluid culture results and five non-specific indices were measured for each patient. The patients were divided into sepsis group (n = 33) and non-septisemic infection group (n =30).Fifteen hospitalized neonates with noninfectious diseases were enrolled as controls (n = 15). 1ml peripheral blood would be taken from each group patients within 24～48h after they hospitalized. The levels of peripheral blood neutrophil CD11b and CD64 were measured by flow cytometry. During the recovery period (treatment 1 week later) for sepsis group measured again. Results The levels of peripheral blood neutrophil CD11b in sepsis group were higher than those of non-septisemic infection group and control group (P <0.05 ). There were no difference between non-septisemic infection group and control group (P = 1.000). The expressions of neutrophil CD64 in sepsis group were significantly higher than those of non-sepsis infection group and the control group (P <0.05), non-septisemic infection group were higher than those of control group (P <0.05). The levels of CD11b and CD64 of the cases with septicemia significantly decreased on the restoration stage (P<0.05). Positive critical value of sepsis group were CD11b≥320MFI, CD64≥20MFI , which for diagnosis sepsis showed sensitivity and specificity were 72.73% and 75%, 94.74% and 80.49%，respectively. The expressions of neutrophil CD11b and CD64 have no statistics significance between Gram-positive bacteria and gram-negative bacteria infection. Conclusion The expression of peripheral blood neutrophil adhesion molecule CD11b and CD64 measured by the whole blood flow cytometry can be used as one of the laboratory index for early diagnosis neonatal sepsis. For the neonatal sepsis, the serial measurements of CD11b and CD64 expression have a high value on evaluated infection severity and observaed therapy reactions.Observed on the infection to determine the extent of the evaluation of treatment with a more a high clinical value.

Key words: neonate, sepsis, CD11b, CD64, flow cytometry