Prognostic Value of CD64 Marker for Patients in Intensive Care Unit

Some local or systemic biological markers, using highly specialized techniques, have an interest that remains quite marginal in routine.

Markers of inflammation generally have elevated concentrations in circulating blood, but these increases are not specific for prognosis. This is the case of pro-inflammatory cytokines (TNF, IL-1, IL-6...)[1, 2] and especially, so-called'acute phase' proteins such as C-reactive protein (CRP) and procalcitonin. It is now well established that the rise in the CRP is totally non-specific. With regard to procalcitonin, the published data are far from univocal[3-4], in particular because of the heterogeneity of the populations studied (emergency services, medical services, intensive care).

These conventional biological assays are therefore not very informative and less efficient than the clinical-biological scores used in routine (SAPSII and SOFA).

An alternative diagnostic approach relies on molecular changes in the cellular compartment of innate immunity. Activation of neutrophil polymorphils (PNN) is the result of the pro/anti-inflammatory cytokinic balance and hormonal cascades In other words, the degree of activation of NNPs can be considered as the barometer of the intensity of any acute inflammatory phenomenon. One of the most specific indicators of a systemic inflammatory response is the increased expression of CD64, a high affinity receptor to the immunoglobulin fragment Fcγ, on the surface of PNNs.

CD64 expression elevation is induced in 4-6 hours by numerous cytokines (G-CSF, IFN- γ[5-7]. Given the very low basal expression level of CD64 (less than 2000 sites per cell) and its rate of elevation in case of inflammation, its determination could prove interesting in demonstrating the inflammatory response and its intensity.