Tamar Mardi

The erythrocyte adhesiveness/aggregation test (EAAT): A new biomarker to reveal the presence of low grade subclinical smoldering inflammation in individuals with atherosclerotic risk factors

BACKGROUND Multiple acute phase proteins and atherosclerotic risk factors increase the aggregability of erythrocytes. METHODS AND RESULTS We used a simple slide test and image analysis to determine the degree of erythrocyte adhesiveness/aggregation in the peripheral blood of 222 women and 221 men with no, one, two or more atherosclerotic risk factors. The degree of erythrocyte adhesiveness/aggregation correlated significantly with the concentration of commonly used variables of the acute phase response. We also showed that individuals with low erythrocyte adhesiveness/aggregation tend to be younger and to have fewer risk factors for atherosclerosis, including diabetes mellitus, hypertension, hyperlipidemia and smoking. CONCLUSIONS The association between increased erythrocyte adhesiveness/aggregation, higher concentrations of acute phase proteins, and increased atherosclerotic risk factors points to a possible clinical applicability of the erythrocyte adhesiveness/aggregation test (EAAT) to reveal the presence of both low-grade subclinical smoldering inflammation and morbid biology in individuals with risk factors for atherosclerosis.

Gender difference in C-reactive protein concentrations in individuals with atherothrombotic risk factors and apparently healthy ones

Recent studies have shown that C-reactive proteins have a pathogenetic role in atherothrombosis and concentrations of these substances could be used as a marker for future vascular events. The objective of this study was to determine gender differences in highly sensitive C-reactive protein (hs-CRP) in individuals with atherothrombotic risk factors and apparently healthy ones. We have presently matched 469 females and 469 males having the same age and body mass index (BMI). Of these, 210 men and 210 women had no atherothrombotic risk factors. In this group the hs-CRP concentrations were 1.6±3.4 mg l−1 in women and 1.0±2.7 mg l−1 in men (p<0.0005). These values were 2.1±3.4 mg l−1 and 1.5±2.8 mg l−1, respectively, in the entire cohort (p<0.0005), which included also individuals with atherothrombotic risk factors. We conclude that significant gender differences exist in hs-CRP concentrations despite perfect matching for age and BMI. These differences should be reflected in guidelines that suggest hs-CRP cut-off points for the stratification of vascular risk.

Flow-resistant red blood cell aggregation in morbid obesity

OBJECTIVE: Enhanced red blood cell (RBC) aggregation has an adverse effect on microcirculatory blood flow and tissue oxygenation. It has been previously shown that obesity is associated with increased RBC aggregation. The objectives of the present study were to further characterize obesity-related RBC aggregation and to examine whether the enhanced aggregation is a plasma- or cellular-dependent process.METHODS: Obese (body mass index (BMI)=40±6.3 kg/m2, n=22) and nonobese (BMI=24±3.4 kg/m2, n=18) individuals were evaluated for inflammation markers and aggregation parameters. Aggregation parameters were derived from the distribution of RBC population into aggregate sizes, and from the variation of the distribution as a function of flow-derived shear stress, using a cell flow properties analyzer. To differentiate plasmatic from cellular factors, we determined the aggregation in the presence of autologous plasma or dextran-500kDa and calculated the plasma factor (PF) in the obese group. PF ranges from 0 to 1. When the PF=1, the aggregation is all due to plasmatic factors, when PF=0, the altered aggregation depends entirely on cellular factors, whereas 0<PF<1 reflects the joint contribution of cellular and plasmatic factors.RESULTS: Obese subjects had relatively larger aggregates that were more resistant to dispersion by flow. The calculated PF in the obese group was 0.9, indicating a pronounced contribution of plasma to RBC aggregation in obesity.DISCUSSION: Our results suggest that obese individuals present pathological plasma-dependent RBC aggregation, which is probably triggered by plasma macromolecules associated with the inflammatory response. These findings impact the future attempts to develop strategies aimed at attenuation of the enhanced RBC aggregation in obese individuals.

Iodide‐induced sialadenitis complicating coronary angiography

Sialadenitis is an uncommon complication of intravenous administration of iodinated contrast medium. We present two cases of iodide‐induced sialadenitis following coronary angiography. Clinical features and clues to differentiation from suppurative sialadenitis are discussed. The mechanism for aseptic iodide‐induced sialadenitis remains unclear, but prognosis with conservative treatment is apparently good. Sialadenitis may recur with subsequent administration of contrast medium. Cathet Cardiovasc Intervent 2002;57:50–53.

A simple biomarker to exclude the presence of low grade inflammation in apparently healthy individuals

Background Atherosclerosis is accompanied by a low grade inflammatory response. Hypothesis To use erythrocyte aggregability as a biomarker to exclude the presence of low grade inflammatory response in apparently healthy individuals. Methods The adhesiveness/aggregation of red blood cells was quantitated by using a simple slide test and image analysis. Results We included 121 apparently healthy individuals and found a significant correlation between the degree of erythrocyte adhesiveness/aggregation and either the concentration of high sensitive CRP (r = 0.6, P < 0.001), erythrocyte sedimentation rate (r = 0.5, P < 0.0001) or fibrinogen (r = 0.5, P < 0.0001). By using certain cutoff points for the erythrocyte adhesiveness/aggregation test we could define individuals with a very low grade inflammatory response. Conclusions By using this inexpensive and rapid assessment, we could clearly discriminate between individuals with a very low inflammatory response and those with a more intense one. This biomarker should be further evaluated as a possible screening test for use in large populations of apparently healthy individuals in whom the detection of low grade inflammation might contribute to guiding appropriate lifestyle modifications and therapeutic interventions.

Automatic 3-Dimensional Visualization of Peripheral Blood Slides: A New Approach for the Detection of Infection/Inflammation at the Point of Care

CONTEXT The identification and quantitation of the intensity of the acute-phase response at the point of care might be of clinical relevance. OBJECTIVE To report the possibility of automatic screening of unstained peripheral blood slides by using a 3-dimensional image analysis system. DESIGN Peripheral venous blood was obtained from children with acute inflammation/infection and examined by an automatic 3-dimensional image analyzer to detect the number of white blood cells as well as to reveal the degree of erythrocyte aggregation, a marker of the humoral phase response. RESULTS We included 66 children with acute bacterial infections and 59 with nonbacterial inflammation/infection; mean ages of the 2 groups were 4.3 +/- 3.9 years and 4.2 +/- 3.7 years, respectively (P = .91). The percentages of correct classifications based on discriminant analysis in predicting between bacterial and nonbacterial inflammation/infection were 61.3% by using the white blood cell count, 64.5% by using the percentage of granulocytes, 61.6% by using the degree of erythrocyte aggregation, and 59.2% by using the number of leukocytes counted on the unstained slides. The results of the receiver-operated characteristic curve analysis yielded an area under the curve of 0.714 (P < .001) for the number of granulocytes, 0.699 (P < .001) for the white blood cell count, 0.685 (P < .001) for the number of leukocytes on the slides, and 0.685 (P = .001) for the degree of erythrocyte aggregation. The correlation between the number of leukocytes by the electronic cell analyzer and the number of cells counted on the slides was highly significant (r = 0.85, P < .001). CONCLUSIONS It is feasible to use an automatic 3-dimensional image analyzer to reveal the different intensities of the acute-phase response between a group of children with an acute bacterial infection and another with nonbacterial inflammation/infection. These findings might be relevant for potential application at the point of care.

The appearance of aggregated erythrocytes in the peripheral blood of individuals with insulin resistance

Insulin resistance is associated with low‐grade inflammatory response. The probability that the acute‐phase response is associated with enhanced erythrocyte adhesiveness/aggregation was not explored.

Capillary and venous leukocyte adhesiveness/aggregation to differentiate between viral and bacterial infection.

Abstract.Background: A simple capilary leukocyte adhesiveness/aggregation test (CAPLAAT) might be helpful in determining the intensity of inflammation in acute viral and bacterial infections. Patientsand Methods: We included 30 patients with acute bacterial infections, 14 with viral infectiona as well as 48 healthy controls. The leukocyte adhesiveness/aggregation test (LAAT) test was performed using a simple slide test and image analysis. Results: The CAPLAAT had a similar discrimination power between bacterial and viral infections as both the white blood cell count (WBC) and the erythrocyte sedimentation rate (ESR). It was more sensitive than the WBC and the ESR (77%, 68% and 66%, respectively) for the detection of bacterial infections and had a comparable negative predictive value. By analyzing the size distribution of the aggregated leukocytes, we found that a venous leukocyte adhesiveness/aggregation test (VLAAT) of four cells and more had the best positive predictive value (94%) and specificity (95%) for diagnosis of an acute bacterial infection (from all the acute phase response variables examined). Conclusion: The CAPLAAT might be attractive for the detection of inflammation and for the assessment of its severity at points of care where the services of a clinical laboratory are not available around the clock.

Leukocyte aggregation-related pseudoleukopenia in pediatrics: a sporadic event or a systematic error?

Objective: To determine whether electronic counter-related pseudoleukopenia is a rare phenomenon or a systematic underestimation in children with acute infection/inflammation. Methods: We have used a simple slide test and image analysis to reveal the number of white blood cells and their degree of aggregation. The number of leukocytes counted by an electronic cell analyzer was divided by the number of cells counted on the slides creating an electronic cell-to-slide leukocyte count ratio. Results: A significant (P < 0.0005) negative (r = −0.314) correlation between the above mentioned ratios and the percent of aggregated leukocytes in the peripheral blood was found in a group of 239 children with various acute infections. Thus elevated leukocyte aggregation is associated with a relatively lower electronic analyzer cell count. Conclusions: The appearance of aggregated leukocytes in the peripheral blood during acute infections might be associated with pseudoleukopenia. This phenomenon has been extensively described in the adult population and seems to exist in children as well.

Telemedicine-based Application for the Detection of Inflammation in Pediatrics

To assess the feasibility of using telemedicine for the diagnosis of inflammation in a pediatric population. The degree of erythrocyte adhesiveness/aggregation and the number of white blood cells on peripheral blood slides were evaluated using an image analysis system and transferred to an operator in a remote location. A highly significant correlation was found between the degrees of erythrocyte adhesiveness/aggregation as well as estimated white blood cell count determined by a remote operator and the objective measurements of both erythrocyte sedimentation rate and white blood cell count. A reasonable estimate of both erythrocyte sedimentation rate and white blood cell count can be obtained by using telemedicine in a group of children with acute infection/inflammation.