Application of Flow Cytometry in the Early Diagnosis of Neonatal Sepsis

GOALS: To raise awareness of the utility of flow cytometric detection of inflammatory markers in the early diagnosis of neonatal sepsis. PROCEDURES: In accordance with the Tollner scoring system, cases with ≥10 points are accepted as having "clinical sepsis" and cases with 0-4 points as having "no sepsis". The study group consisted of 50 newborns with clinical sepsis as well as a control group of 50 newborns without sepsis. In all cases, blood counts, C-reactive protein (CRP) levels, and procalcitonin (PCT) levels were recorded. Additionally, the "cluster of differentiation" (CD)64, CD11b, and CD62L adhesion molecules and the presence of the human leukocyte antigen HLA-DR on monocyte and neutrophil surfaces were examined by flow cytometry. RESULTS: The levels of acute-phase reactants CRP and PCT were significantly higher in the study group than in the control group (p 0.05). Furthermore, receiver operating characteristic analysis indicated that neutrophil CD11b (nCD11b) is a diagnostic marker for neonatal sepsis (area under the curve [AUC]: 0.72, 95% confidence interval [CI]: 0.62-0.82, p<0.001). The sensitivity, specificity, and positive predictive value (PPV) for nCD11b were 72%, 68%, and 58.4%, respectively. Similarly, monocyte CD11b (mCD11b) positivity was found to be diagnostic (AUC 0.77, 95% CI: 0.68-0.87, p<0.001). The sensitivity and specificity for mCD11b were 72% and 68%, respectively. In addition, the sensitivity, specificity, and PPV for nHLA-DR were 62%, 60%, and 60.8%, respectively. CONCLUSION: In addition to acute-phase proteins, cell surface antigens such as CD11b, CD64, and HLA-DR should be used in routine investigations for the early diagnosis of neonatal sepsis. Such usage in combination with acute-phase reactants may enhance diagnostic accuracy.