RÉSUMÉ
<p><b>OBJECTIVE</b>Neonatal sepsis is a common disease and the sepsis-related mortality rate is still high. Until now, there has no ideal diagnostic marker to early identify neonatal sepsis. Expression of neutrophil adhesion molecule CD(11b) was showed as the earlier reaction to the infection/inflammation, and may be applied as an early diagnostic marker for sepsis. This study was to investigate this antigen for early diagnosis of neonatal sepsis related to bacterial infection.</p><p><b>METHODS</b>According to clinical symptoms, signs and four indices (WBC, PLT, plasma CRP and ratio of I/T), fifty-one neonates with established or suspected sepsis were allocated retrospectively into two groups of sepsis [n = 23, gestational age of (38.3 +/- 2.4) weeks, postnatal age of (12.7 +/- 8.8) days, body weight: (3.1 +/- 0.8) kg] and suspected sepsis [n = 28, gestational age of (38.8 +/- 1.6) weeks, postnatal age of (11.7 +/- 7.3) days, body weight: (3.3 +/- 0.6) kg]. Fifteen healthy neonates were served as controls [gestational age: (38.5 +/- 1.4) weeks, postnatal age: (8.2 +/- 5.5) days, body weight: (3.3 +/- 0.3) kg]. CD(11b) was quantified with the whole blood flow cytometry and direct immunofluorescence technique.</p><p><b>RESULTS</b>The expressions of neutrophil CD(11b) in neonates with sepsis and suspected sepsis were (320 +/- 189) MFI and (456 +/- 213) MFI, respectively, which was lower than that of controls [(1,090 +/- 338) MFI, t = -9.01 and -7.56, respectively; P < 0.001]. The expression of CD(11b) was lower in neonates with sepsis than that with suspected sepsis (t = -2.39, P < 0.05). The expression of CD(11b) in neonates with CRP >or= 30 mg/L was (211 +/- 164) MFI, which was lower than those with CRP < 30 mg/L [(505 +/- 265) MFI, t = 2.64, P < 0.05]. The detection of CD(11b) (<or= 600 MFI) for suspected sepsis showed a sensitivity of 86.3%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 68.2%. The positive rate of CD(11b) detection was 86.3%, which was higher than the blood culture test (17.6%, chi(m)(2) = 31.2, P < 0.05).</p><p><b>CONCLUSION</b>The expression of CD(11b) in neonatal sepsis presented with a down-regulation and, the decreased CD(11b) expression might be related to the severity of infections. For the neonatal sepsis the serial measurements of neutrophil CD(11b) expression with the whole blood flow cytometry seemed feasible and reliable in the early diagnosis, evaluation of infection severity and observation of therapy reactions.</p>