Prognostic value of phagocytic activity of neutrophils and monocytes in sepsis. Correlation to CD64 and CD14 antigen expression

Abstract

The role of the phagocytic function of monocytes and neutrophils in sepsis has been poorly investigated. The present study evaluated the impact of the phagocytic activity of neutrophils and monocytes on the outcome of patients with severe sepsis. Thirty-one patients and 30 healthy individuals were enrolled in the study. The phagocytic activity of monocytes and neutrophils was evaluated during 24 h after admission and the results were correlated to the expression of CD64 on neutrophils and monocytes, CD14 antigen on monocytes, the Simplified Acute Physiology Score II and the patients' survival. A reduced phagocytic activity of neutrophils during the first 24 h after admission was a negative predictor for survival. Increased expression of CD64 antigen on polymorphonuclear cells (PMNs) and monocytes was favourably correlated to the patients' survival. In multivariate analysis the phagocytic activity of PMNs was the only independent predictor factor for survival. Patients with PMN phagocytic activity <37% had lower expression of CD64 on monocytes and PMNs and worse outcome, while those with phagocytic activity >37% had higher expression of CD64 on monocytes and PMNs and better outcome. Reduced phagocytic activity of neutrophils may represent a state of neutrophil inactivation similar to that previously described for monocytes during the compensatory anti-inflammatory response.

Fig. 1

A representative fluorescence activated cell sorter experiment showing histograms comparing isotype controls with the expression of CD14 and CD64 antigens in monocytes (a–d) and the expression of CD64 in PMNs (e, f) in a survivor patient at the day of admission. MIF, mean intense fluorencence.

Fig. 2

A representative fluorescence activated cell sorter experiment showing the phagocytic activity of PMNs (R1) and monocytes (R2) in a survivor patient (middle), a non-survivor patient (bottom) on the day of admission and a control (top), following incubation for 10 min at 37°C in the presence of flouroscein-labelled E. coli.

Fig. 3

Correlation between phagocytic activity of PMNs and expression of CD64 on monocytes (a) and PMN (b) on the day of admission. Variables were evaluated by Pearson's correlation coefficient value. The horizontal dotted line represents the mean percentages of expression of CD64 on monocytes and PMN in the control group respectively.

Fig. 4

Correlation between expression of CD64 on monocytes and PMNs on the day of admission. Variables were evaluated by Pearson's correlation coefficient value.