Diagnostic and prognostic evaluation of soluble CD14 subtype for sepsis in critically ill patients: a preliminary study

Introduction

Sepsis, a leading cause of death in critical care patients, is the result of complex interactions between the infecting microorganisms and the host responses that influence clinical outcomes [1]. Reliable biochemical markers that enable early diagnosis are still needed. A new marker, presepsin (soluble CD14 subtype, sCD14-ST) is a circulating fragment of 13 kDa of soluble CD14 that originates from the cleavage of the CD14 expressed on the surface membranes of monocytes/macrophages. sCD14-ST has been shown to increase significantly in patients with sepsis [2]. In our study we compare diagnostic performance of presepsin, C-reactive protein (CRP) and procalcitonin (PCT).

Methods

Critical patients with suspected sepsis admitted to the Unit of Intensive Care of the University Hospital of Catanzaro (Italy) were recruited into this study; healthy volunteers were also included as controls. Plasma samples in EDTA from each patient were collected at multiple time points; samples were tested for CRP, PCT and presepsin. Blood cultures were also evaluated and processed by a BacT/Alert 3D system (bioMérieux, Italy); CRP was measured by immunonephelometry (Siemens Healthcare Diagnostic, Italy) and PCT was assayed by an enzyme-linked fluorescent assay (VIDAS BRAHMS PCT, bioMérieux, Italy); presepsin levels were measured by rapid automated PATHFAST immunoanalyzer (kindly provided by GEPA SRL, Italy), based on chemiluminescent enzyme immunoassay. A statistical analysis was carried out by Mann-Whitney test.

Results

Presepsin and PCT levels were significantly higher in culture-positive subjects versus negative controls; such difference was found even at the admission time. The presepsin values in worsening/dead patients exhibited a significantly higher level at admission time. On the contrary, in the same group of patients, PCT exhibited a decrease of its level. In poor prognosis patients CRP showed a quite irregular kinetic, although in such a group the admission value was higher than the same marker in live subjects.

Conclusion

In this preliminary study, presepsin and PCT levels exhibited substantial higher values in culture-positive patients. The kinetic curves of presepsin, obtained from both survival and worsening/dead subjects, revealed the optimal performance of this biomarker, particularly in severely ill patients, as also shown in other studies. During sepsis, increase of presepsin levels may be a more reliable marker, indicating an unfavorable outcome [3, 4]. Furthermore, high presepsin levels could alert clinicians not to suspend antibiotic treatments even after clinical symptoms have improved and PCT levels have returned to normal.