Standardized immune monitoring for the prediction of infections after cardiopulmonary bypass surgery in risk patients

Abstract

Background: Infections are the most common cause of late complications in cardiopulmonary bypass (CPB) surgery patients, and are difficult to predict. Here we studied the diagnostic value of a standardized immune monitoring program based on recent advances in flow cytometry (exact quantification of surfacemarker expression) and cytokine determination (semiautomatic systems).Methods: CPB patients (56) at risk for complications (age >70 years and/or preoperative left-ventricular ejection fraction < 25 %) were classified into three groups: without (33), with suspected (14), and with confirmed (9) infection. Applying the Quantibrite™-system, we daily quantified the expression of CD11b, CD64, CD71, CD86, and HLA-DR on monocytes/granulocytes. Furthermore, the ex vivo secretion of tumor necrosis factor (TNF)-␣ as well as the plasma interleukin (IL)-10 levels were determined by a semiautomatic system. Ex vivo elastase release was measured by enzyme-linked immunosorbent assay (ELISA).Results: All patients showed signs of granulocyte activation and monocyte deactivation. Monocytic HLA-DR and plasma IL-10 were the best markers to discriminate patients with infection from those without as early as day 1. Using a cutoff of 5792 HLA-DR molecules per cell, both sensitivity and negative predictive value for patients who developed microbiologically confirmed infection was 1.0, and the area under the curve (AUC) was 0.85.Conclusions: Our data suggest that a standardized immune monitoring at day 1 might be useful for early discrimination of patients at elevated risk for infections. Cytometry Part B (Clin. Cytometry) 53B:54 -62, 2003.

Cellular Immunodepression Preceding Infectious Complications after Acute Ischemic Stroke in Humans

“…Plasma concentrations of cytokines – human tumor necrosis factor (TNF) α, interleukin (IL) 6, IL-10 – and cortisol were determined as described earlier [24]. The detection limit was >2 pg/ml for IL-6, >4 pg/ml for TNF-α, >5 pg/ml for IL-10 and >5.5 nmol/l for cortisol.…”

How to Improve Quality Assurance in Fluorometry: Fluorescence-Inherent Sources of Error and Suited Fluorescence Standards

“…the number of specific antibodies on the cell surface (antibody binding capacity, ABC) or the number of proteins within the cell, would possibly allow to improve medical diagnosis. For example, standardized immune monitoring, which includes the determination of ABC for different antibodies, has been recently applied [78] to derive criteria for the prediction of infections in risk patients after cardiopulmonary bypass surgery. For monocytes, the expression of HLA-DR (human leukocyte antigen) epitopes correlates with their activation and can be applied to monitor patients with septic shock [79].…”

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“…The possibility that this may occur can account for an increase in post surgery complications and in mortality [2].…”