Flow Cytometry in the Detection of Neonatal Sepsis

Abstract

Neonatal sepsis remains a burden problem by showing minimal initial symptoms of subtle character, nonspecific manifestation, and diagnostic pitfalls. The clinical course can be fulminant and fatal if treatment is not commenced promptly. It is therefore crucial to establish early diagnosis and initiate adequate therapy. Besides clinical symptoms, the most reliable laboratory markers in establishing diagnosis is currently the combined measurement of CRP and a cytokine (IL-6 and IL-8). Due to their different kinetics, a diagnostic gap might occur and thus withholding antimicrobial therapy in clinical suspicion of infection is not acceptable. We therefore need parameters which unerringly differentiate between infants in need for antimicrobial therapy and those who are not. Flow cytometry promises to be a useful tool in this field, allowing the determination of different cellular, dissolved, and functional pathophysiological components of sepsis. Despite technical and methodical advances in flow cytometry, its use in clinical routine is still limited. Advantages and disadvantages of promising new parameters in diagnosis of sepsis performed by flow cytometry, particularly CD64, HLA-DR, and apoptosis, are reviewed here. The necessity of tests to be used as an “ideal” parameter is presented.

Diagnostic Utility of Neutrophil CD64 as a Marker for Early-Onset Sepsis in Preterm Neonates

“…Signs and symptoms suggestive of clinical sepsis have been described in detail in the previous studies [8], [11], [12]. As part of the evaluation, two or more of the following previously validated hematologic criteria were used as indicators for sepsis: (1) absolute neutrophil count of >12×10 3 cells/mm 3 , (2) white blood cell count of >20×10 3 cells/mm 3 , (3) immature/total neutrophil ratio of >20%, (4) platelet count of <150×10 3 cells/mm 3 , (5) CRP of >3.0 mg/L.…”

Ratios of CD64 expressed on neutrophils, monocytes, and lymphocytes may be a novel method for diagnosis of neonatal sepsis

“…Also, it can be incorporated as a valuable marker to exclude neonatal sepsis (NS) [9][10][11][12][13][14]. Studies have showed that the expression of CD64 on neutrophils has high sensitivity and accuracy in identifying sepsis [14][15][16]. However, diversities of CD64 expression descriptions and various cut-off values exist in different laboratories [9,16].…”

Effect of early-onset infections on expression of CD11a, CD11b, CD11c, CD18, CD54 and CD62L molecules on surface of neutrophils and monocytes from peripheral venous blood in preterm infants

“…It is believed, that in the early phase of inflammation, cytokine-induced leukocyte activation changes the expression of many adhesion molecules on the surface of granulocytes and monocytes. The best known adhesion molecules are CD11b, CD54, CD62L and CD64 [14,15,16]. Differences in assessment of the quantitative expression of adhesion molecules in healthy and infected neonates with varying degrees of gestational maturity have prompted us to carry out a study in a population of preterm infants.…”

“…Uważa się, że we wczesnej fazie zapalenia następuje aktywacja leukocytów indukowana cytokinami, co powoduje zmiany ekspresji wielu molekuł adhezyjnych na powierzchni granulocytów i monocytów. Do najlepiej poznanych należą CD11b, CD54, CD62L i CD64 [14,15,16]. Rozbieżności w ocenie ilościowej ekspresji molekuł adhezyjnych u zdrowych i chorych noworodków o różnym stopniu dojrzałości płodowej, skłoniły nas do przeprowadzenia badań własnych u wcześniaków.…”