Proposal of a new method to avoid misinterpretations in the evaluation of the leukergy test

Increased adhesiveness of white blood cells in patients with unstable angina: additional evidence for an involvement of the immune-inflammatory system

BACKGROUND

Data are being accumulated on the presence of inflammatory response in patients with acute coronary syndromes.

HYPOTHESIS

The study was undertaken to confirm that the adhesive state of the peripheral blood leukocytes can provide information on an inflammatory process in patients with unstable angina pectoris.

METHODS

The study included 21 patients with unstable angina, 32 patients with stable angina, and 13 patients with chest pain and no evidence of coronary artery disease.

RESULTS

The percentage of aggregated leukocytes in patients with unstable angina (5.8 +/- 3.2%) was significantly (p < 0.02) increased compared with that of patients with no evidence of active coronary disease (3.2 +/- 2.6%).

CONCLUSION

Additional evidence for an existing smoldering inflammatory process in unstable angina pectoris can be provided by testing the percentage of aggregated leukocytes in peripheral blood.

Value of cerebrospinal fluid leukocyte aggregation in distinguishing the causes of meningitis in children

BACKGROUND

Current laboratory tests often cannot distinguish between bacterial and aseptic meningitis rapidly and accurately. The ability to make a prompt diagnosis has important implications for the management and outcome of children with meningitis. The observation that leukocytes aggregate in the cerebrospinal fluid (CSF) has been previously reported, and it has been advocated as a reliable method to distinguish the causes of meningitis in children.

OBJECTIVE

To investigate the utility of CSF leukocyte aggregation as a screening test to distinguish between bacterial and aseptic meningitis.

METHODS

We compared the clinical and laboratory indices of 109 prospectively enrolled patients with meningitis (67 bacterial, 23 viral, 19 undefined etiology) and evaluated the validity of the CSF leukocyte aggregation test. The predefined leukocyte aggregation scores (LAS) were compared among the types of meningitis, and correlations with other markers of inflammation were calculated.

RESULTS

The median LAS was significantly higher (P < 0.001) in the bacterial (32.1%; range, 0 to 84.1%) than in the viral (0%; range, 0 to 16.6%) or undefined (0%; range, 0 to 20.7%) groups. The optimal sensitivity of the leukocyte aggregation test, 98.5 to 92.5%, was demonstrated with LAS values of 0 to 3%. The corresponding specificity was 64.3 to 88.1%. The peripheral white blood cell (WBC) count, serum C-reactive protein, CSF WBC count, blood culture, CSF Gram stain and CSF culture were inferior to the LAS as screening tests when compared individually. The LAS was as effective as CSF protein, TNF-alpha, IL-1-beta, IL-6 and IL-8 to predict bacterial meningitis. In a logistic regression model that included routine laboratory tests, the best predictor of bacterial meningitis was the LAS (odds ratio, 1.6 to 3.7). Significant correlations were demonstrated between the LAS and CSF protein, CSF WBC count, IL-1-beta, IL-6 and IL-8. Duration of symptoms before diagnosis, pretreatment with antibiotics, HIV-1 infection status and CSF red blood cell count did not significantly alter the LAS.

CONCLUSIONS

There is no single test to diagnose the etiology of meningitis in children promptly and accurately. The finding of leukocyte aggregation in CSF might be of value as a sensitive adjunctive screening tool for the timely diagnosis of bacterial meningitis, recognizing that it has low specificity and potential practical limitations.

The leukocyte adhesiveness/aggregation test as an inflammation-related, plasma-dependent agglutination phenomenon

The leukocyte adhesiveness/aggregation test (LAAT) is a non-specific marker of inflammation. In the present study, we examined the expression of the CD11b/CD18 as well as the CD62L antigens on the surface of peripheral blood leukocytes in 84 patients with various inflammatory conditions and 60 controls by using whole blood flow cytometry. We also conducted several in vitro experiments in order to explain the mechanism of the leukocyte adhesiveness/aggregation. A significant (r= -0.36, p<0.001) negative correlation was found between the expression of CD62L on the surface of peripheral blood polymorphonuclears and the state of LAA. There was no correlation between the availability of the CD11b/CD18 antigen and the adhesive state of these cells. In a series of in vitro experiments, we could show that it is possible to significantly reduce the number of aggregated leukocytes in the peripheral blood by using dilutions with buffer but not with plasma. There is no change in the degree of aggregation following incubation at low temperature in the presence of an aerobic metabolism blocker or following incubation with a divalent ion chelator. Additionally, white blood cells could be seen to adhere to protein-rich areas in the peripheral slides. We assume that the state of LAA in the peripheral blood as revealed by the LAA test is more a plasma factor-dependent agglutination than a firm aggregation phenomenon. Factors other than the leukocyte integrins or selectins should be sought as being responsible for this LAA phenomenon.

Increased leukocyte adhesiveness/aggregation in patients with inflammatory bowel disease during remission. Further evidence for subclinical inflammation

PURPOSE

We have used a novel leukocyte adhesiveness/aggregation test (LAAT) to show that many patients with inflammatory bowel disease (IBD) in clinical remission have a subclinical low grade inflammation.

METHODS

Included in the study are 500 controls, 96 patients with IBD in remission, and 106 patients in relapse.

RESULTS

The percent of aggregated white blood cells detected in the peripheral blood was 5.9 +/- 3.9, 9.1 +/- 5.9, and 18.8 +/- 9.4, respectively. The difference between each group and any other was significant at P < 0.0001. Similar results were obtained when other acute phase reactants like the erythrocyte sedimentation rate, white blood cell count, differential count, and C-reactive protein level were examined. However, in a linear regression analysis, LAAT was the only significant (P < 0.0006) variable that could classify correctly each subject to the appropriate category of control and IBD in remission or relapse.

CONCLUSIONS

Identification of patients with IBD in clinical remission who have ongoing inflammation may be of clinical-therapeutic relevance. The LAAT is a simple, rapid, and convenient test. The present study indicates that it is also very sensitive.

Increased leucocyte adhesiveness/aggregation is a most useful indicator of disease activity in patients with inflammatory bowel disease

The aim of the study was to determine the comparative usefulness of inflammatory markers, in evaluating disease activity in patients with inflammatory bowel disease. Disease activity was assessed by the Mayo Clinic score for ulcerative colitis, and Harvey-Bradshaw score for Crohn's disease. Five hundred normal blood donors who had no underlying inflammatory condition served as controls. The erythrocyte sedimentation rate, platelet and white blood cell count, C reactive protein, and the leucocyte adhesiveness/aggregation test (LAAT) were determined in each patient. One hundred and twenty four patients with inflammatory bowel disease were tested while in remission and 128 in relapse. Their mean (SD) per cent of aggregated white blood cells in the peripheral blood was 8 (5) and 17 (10) respectively compared with controls 6 (4) (p < 0.0001). Moreover, the LAAT could effectively discriminate between various grades of disease activity, the values in patients with active disease being 13 (6)% in mild, 17 (10)% in moderate, and 26 (10)% in severe disease (p < 0.0001). Other acute phase reactants including the erythrocyte sedimentation rate, the white blood cell count, the platelet count, neutrophil count, as well as, the C reactive protein concentration did not differentiate as well between the various groups. Using logistic regression analysis to differentiate between inflammatory bowel disease patients in remission or relapse, the LAAT was the single best indicator. The addition of any other test did not contribute to the discrimination. Among the different laboratory variables tested only the LAAT significantly discriminated between the five different subgroups of controls, remission and mild, moderate or severe disease activity.

Leukocyte aggregation in patients with a previous cerebral ischemic event

BACKGROUND AND PURPOSE

The role of leukocyte aggregation in ischemic stroke is controversial. In this study we investigated this hemorheologic alteration in patients at risk for stroke.

METHODS

Leukocyte aggregation was evaluated with the leukergy test in 61 patients with a recent cerebral ischemic event and in 61 control subjects.

RESULTS

In patients leukocyte aggregation was significantly higher than in control subjects (3.8 +/- 3.4% versus 2.5 +/- 2.2%; P = .01). In control subjects, the presence of vascular risk factors was associated with values of aggregation similar to those observed in patients.

CONCLUSIONS

These findings suggest an association between altered leukocyte aggregation and cerebrovascular disease. Further investigations are needed to evaluate whether this hemorheologic alteration can be considered a marker of increased risk for stroke.

Effects of opiates on blood rheology

To evaluate the possible effect of opiates on blood rheology, the plasma fibrinogen, prothrombin time and leukocyte aggregation were measured in 75 heroin addicts categorized by the time of abstention from heroin and the administration of naltrexone (25 active heroin abusers, 25 abstaining for 1 week, 11 abstaining for at least 5 months and 14 abstaining for 1 month and taking naltrexone during this period). No difference was detected in prothrombin time, but the leukocyte aggregation and fibrinogen were significantly different among the four groups (p = 0.028 and p = 0.0001, respectively). In particular, fibrinogen was 318 +/- 10.9 mg/dL in heroin abusers, significantly higher than that of the remaining three groups; the percentage of aggregated leukocytes was 5.01 +/- 0.77 in heroin users, significantly higher than that of subjects abstaining for at least 5 months. The fibrinogen levels declined sharply with abstention and an additive effect was noted with the administration of naltrexone, but leukocyte aggregation changed more slowly, and the effect of naltrexone (if any) was weaker. These data indicate an adverse effect of opiates on blood rheology and suggest that further studies should be performed to evaluate whether naltrexone may be useful in the prevention of major ischemic syndromes in patients with hyperfibrinogenemia and, perhaps, in those with high levels of leukocyte aggregation.

Serial determinations of leukocyte aggregation in patients with ischemic stroke

The pattern of leukocyte aggregation and its possible relationship with the clinical outcome were evaluated in 35 untreated patients with acute cerebrovascular disease during each of the first three days of hospitalization. Although statistically significant differences were found when comparing patients and age and sex matched controls during any of the 3 days, a large overlapping of values was noted in each comparison. The overlapping was strongly reduced when the average 3-day value was compared. Similarly, when comparing subgroups of patients classified on the basis of their clinical status, the overlap of values observed during any of the 3 days dropped from 70% to 30% when considering the average 3-day levels of leukocyte aggregation. Furthermore, the level of correlation between leukocyte aggregation and size of cerebral infarction was better when considering the average 3-day value (p = .005) than the best single-day correlation (p = .01). These data suggest that the association between acute cerebrovascular ischemia and leukocyte rheology is better discovered when repeated evaluation of the latter are performed.