Serial determinations of neutrophil CD64 expression for the diagnosis and monitoring of sepsis in critically ill patients.

BACKGROUND: Early identification of sepsis is important to be able to initiate timely therapy and optimize survival. Neutrophil CD64 (nCD64) expression has been proposed as a potential marker of sepsis. METHODS: In this prospective observational study, adult patients admitted to our 34-bed medico-surgical department of intensive care over a 3.5-month period were included. Neutrophil CD64 expression was measured by flow cytometry at admission and daily until discharge or death. Blood C-reactive protein (CRP) level was measured routinely. Diagnosis of sepsis was recorded and appropriateness of empirical antibiotic treatment was established post hoc. RESULTS: Of the 548 patients included, 468 had flow cytometry measurements within 24 hours after admission, of whom 103 had sepsis. Septic patients had higher admission nCD64 expression than did nonseptic patients (P < .001). A cutoff admission nCD64 expression of 230 median fluorescence intensity (MFI) identified sepsis with a sensitivity of 89% (81%-94%) and specificity of 87% (83%-90%). When combining CRP and nCD64 expression, an abnormal result for both was associated with a 92% probability of sepsis, whereas sepsis was ruled out with a probability of 99% if both were normal. Septic patients receiving inappropriate empirical antibiotics had persistently elevated nCD64 expression, whereas expression decreased over time in patients receiving appropriate antibiotics. In nonseptic patients, an increase in nCD64 expression ≥40 MFI predicted intensive care unit (ICU)-acquired infection (n = 29) with a sensitivity of 88% and specificity of 65%. CONCLUSIONS: Measurement of nCD64 expression at ICU admission, especially when combined with CRP concentrations, is useful in diagnosing sepsis. Serial determinations of nCD64 could be used for monitoring purposes.

Validation of the cantharidin-induced skin blister as an in vivo model of inflammation.

AIM: Pharmacological profiling techniques, such as the cantharidin-induced skin blister, may be used to assess the anti-inflammatory properties of novel drugs. However, no data are available on the reproducibility of this technique or on the blocking effect of anti-inflammatory drugs, such as anti-TNF and corticosteroids. METHODS: A group of 30 healthy subjects were randomized into three parallel groups treated with placebo, oral methylprednisolone 20 mg day(-1) for 7 days or anti-tumour necrosis factor (TNF) (adalimumab, Humira®, Abbott) 40 mg s.c. single dose. A first blister was induced at baseline and collected, immediately before the start of treatment and a second blister was obtained 7 days after the start of treatment. The total number of cells, the cell viability and the differential cell count were evaluated by two independent observers, who were blind to treatment. anova was used to compare change from baseline among the three groups before pairwise comparisons. RESULTS: Among the placebo group, there was no significant difference in the total cell count, neutrophils, eosinophils and monocytes between day 1 and day 7. Methylprednisolone inhibited the eosinophil influx in mean % (95% CI) (-1.0 (-1.7, -0.3); P < 0.02) and absolute (P < 0.02) values, while anti-TNF inhibited the neutrophil influx in mean % (95% CI) (-19.3 (-29.5, -9.1); P < 0.01) and absolute (P < 0.05) values. CONCLUSIONS: The cantharidin-induced skin blister is a safe, well tolerated and reproducible procedure. Pre-treatment with anti-TNF or methylprednisolone inhibited the neutrophilic or eosinophilic trafficking, respectively. It could be useful in profiling anti-inflammatory drugs regarding their effects on the cellular inflammatory response.

Time course of endotoxin-induced airways' inflammation in healthy subjects.

Few data are available on the kinetic of the airways' inflammation induced by inhaled endotoxin in a given subject. The purpose of this study was to evaluate in healthy subjects the time-related endotoxin-induced airways' inflammation. The cells counts from the induced-sputum were evaluated before, 6 and 24 h, and 7 days after an exposure to 20 mcg inhaled endotoxin, in eight pre-selected volunteers. To avoid interference of the induced-sputum procedure on the response to endotoxin, each time-point was evaluated in randomized order at 2-weeks interval after three separate inhalations of endotoxin. A significant rise of the relative number of lymphocytes (p<0.05) and polymorphonuclear neutrophils (PMN; p<0.02) and of the absolute number of PMN (p<0.05) occurring at 6 h, followed by an increase of the absolute number of the total viable cells (p<0.01), macrophages (p<0.001), neutrophils (p<0.01), and lymphocytes (p<0.05) at 24 h after endotoxin inhalation. The inflammatory response recovered totally after 7 days. In human beings, the inhalation of endotoxin induced a transient airway inflammation after 6 h, peaked at 24 h and recovered after 7 days. When repeated endotoxin inhalations are used as a model of inflammation, a wash-out period of at least 7 days should be applied between each exposure in each subject.