Analysis of the positivity rate in IgE positive patients to inhalant allergens in Verona Hospital Laboratory during 2002-2003

BACKGROUND

At present test tube allergy diagnosis is becoming increasingly more comparable to skin prick tests and is therefore increasingly more reliable, not only from an analytical point of view but also from a clinical one. The cost of test tube allergens has decreased over the years and the specific IgE dosage can quickly give a good diagnostic indication.

OBJECTIVE

To study the percentage of positive subjects for each individual allergen in cases of suspected allergy, the laboratory can easily identify, also by age bracket, the positivity for those well known allergens that are more commonly responsible for allergic pathologies by using the skin prick test. Our laboratory has studied the test tube diagnostic activity of 2002 and 2003. The inhaled allergens used to identify the positivity percentage were selected from those in our Allergy Unit and which literature identifies as those more commonly positive at skin prick tests.

METHODS

The positivity rate of specific IgEs (UniCAP100- Phamarcia) were analyses for two age brackets before and after the age of 12. The younger than 12 group was then subdivided further into pre-school age (3-5 years) and school age (6-12).

RESULTS

It can be stated that in the grass group, the seasonal allergens, the most commonly positive were cereals and pellitory, the latter increasing in adult age (above 12 years). In the tree group of seasonal allergens, positivity was found to increase in adult age for olive and cypress trees. The more commonly positive perennial allergens in the adult age (above 12) are dermathophagoides and cat. Below 12, there is a strong positivity to alternaria.

CONCLUSIONS

Such test tube studies on IgE positivity are not only useful for better defining diagnostic patterns to give an initial idea of suspected allergy, but also to highlight any changes in the IgE antibody count within different age brackets, with the possibility of documenting the progress of the pathology which is characteristic of the allergy in question.

Analysis of the positivity rate in IgE positive patients to food allergens in Verona Hospital laboratory during 2003

BACKGROUND

It has been known for some time now that reactions to allergens, not only those inhaled but also those in food, varies with age in atopical patients.

OBJECTIVE

To evaluate the specific IgE positivity percentage in order to improve laboratory diagnosis in subjects with suspected food allergy.

METHODS

The positivity percentages of specific IgE were analysed (UniCAP100-Pharmacia) taking into consideration the two age brackets of below and above 12 years. The below 12 years age bracket was then further divided into pre-school age (3-5 years) and school age (6-12 years).

RESULTS

By measuring the simple positivity percentage for specific IgE to food allergens, there is a clear decrease as the child matures in reactions to milk and eggs and an increase towards food IgEs that cross-react with grass and tree pollens or other inhaled allergens like moulds and mites.

CONCLUSION

It will be necessary in the future to have the diagnostic means to identify this cross-reaction problem by using recombinant allergens that can demonstrate the combined reaction between inhaled and food allergens.

Immunoassay of anti-thyroid autoantibodies: high analytical variability in second generation methods

The use of highly sensitive immunometric methods in clinical laboratories to assay anti-thyroid antibodies has progressively expanded in recent years but it is not known whether the new techniques have improved the analytical variability connected with the preceding methodologies. The Italian Society of Laboratory Medicine Study Group on Autoimmune Diseases conducted a collaborative study with the biomedical industry to evaluate the degree of standardization of the new analytical procedures. Twelve companies agreed to participate in the study on the search for anti-thyroglobulin (anti-Tg) and anti-thyroperoxidase (anti-TPO) antibodies in nine sera from patients with autoimmune thyroiditis, and in six sera from patients with non-autoimmune thyroid disease; ten immunometric and three immunofluorescence methods were employed. Agreement of qualitative results was close to 90% for anti-Tg and 97% for anti-TPO, with no important differences between the methods; variability of the quantitative results, expressed as CV% of absolute (in lU/ml) and relative (in cut-off concentration multiples) values was 93.9% and 102.3%, respectively, for anti-Tg, and 75.5% and 62.9%, respectively, for anti-TPO. These findings show that despite the progressive improvement in the analytical techniques, the variability between methods for the assay of anti-Tg and anti-TPO is still unexpectedly high, and probably due to several factors such as uncertainty in defining the positive cutoff concentration, absence of adequate international reference preparations, modality of autoantigen purification, and analytical variability in the assay procedures.

Guidelines for the laboratory use of autoantibody tests in the diagnosis and monitoring of autoimmune rheumatic diseases

The Italian Society of Laboratory Medicine Study Group on the Diagnosis of Autoimmune Diseases has generated a series of guidelines for the laboratory diagnosis and monitoring of systemic autoimmune rheumatic diseases intendedfor the use of clinical pathologists and laboratory physicians. These guidelines are based on a systematic review of published works and expert panel discussion and consist of 13 recommendations for antinuclear antibodies, anti-double-stranded native DNA, and antinuclear specific antibodies. To improve analytic performances and help select the most appropriate test for specific autoantibodies, as well as provide education and guidance in the use of these tests, special emphasis is placed on laboratory methods.

Flow cytometric reticulocyte counting. Parallel evaluation of five fully automated analyzers: an NCCLS-ICSH approach

We performed a parallel evaluation of 5 automated reticulocyte analyzers. The guidelines were those proposed by the National Committee for Clinical Laboratory Standards and the International Council for Standardisation in Haematology. Duplicate analyses were performed for 225 healthy subjects and 115 patients affected by various diseases. The reference intervals were different for each method (ADVIA 120, 27-125 x 10(3)/microL [27-125 x 10(9)/L]; CELL DYN 4000, 25-108 x 10(3)/microL [25-108 x 10(9)/L]; GEN-S, 20-85 x 10(3)/microL [20-85 x 10(9)/L]; SE 9500 RET, 23-95 x 10(3)/microL [23-95 x 10(9)/L]; and VEGA RETIC, 30-130 x 10(3)/microL [30-130 x 10(9)/L]). The comparisons of percentage counts with the microscopic reference method were satisfactory for all automated methods. However, a tendency to overestimate at low counts was noted. This progressively increased from the SE 9500 RET to the VEGA RETIC. The imprecision was excellent for all the methods at normal and high concentrations. This was higher at low concentrations. When compared with the microscopic reference, the analyzers showed satisfactory sensitivity at low counts and excellent sensitivity at high counts. The overall agreement varied from 74.8% for the GEN-S to 86.1% for the SE 9500 RET.

Sensitivity and Specificity of Immunological Methods for the Detection of Anti-Topoisomerase I (Scl70) Autoantibodies: Results of a Multicenter Study

Background: The ability of immunometric methods to identify anti-topoisomerase I (Scl70) antibodies is controversial. We wished to quantify the performance of the currently available commercial systems for the assay of anti-topoisomerase I antibodies in a large multicenter study.

Methods: Fifty Italian clinical laboratories analyzed 36 serum samples: 27 from individuals with scleroderma/systemic sclerosis, and 9 from a control group. The scleroderma/systemic sclerosis samples were positive in our laboratories by both ELISA and immunoblot (IB), and the control samples were negative. The laboratories used 42 immunoenzymatic (ELISA), 21 IB, 3 counterimmunoelectrophoresis, and 2 dot-blot methods, produced by 23 different manufacturers.

Results: We obtained 2389 results. The ELISA methods showed 99.2% specificity and 97.2% sensitivity for detection of anti-Scl70 antibodies. For IB methods, specificity was 97.6% and sensitivity was 96.1%. The Western-blot method had poor analytical specificity (27% false positives for anti-extractable nuclear antigen antibodies other than anti-Scl70).

Conclusions: Excluding Western blots, commercial ELISA and IB reagents as used in clinical laboratories have a sensitivity and a specificity >95% for determination of anti-Scl70 antibodies.

Sensitivity and specificity of immunological methods for the detection of anti-topoisomerase I (Scl70) autoantibodies: results of a multicenter study. The Italian Society of Laboratory Medicine Study Group on the Diagnosis of Autoimmune diseases

BACKGROUND

The ability of immunometric methods to identify anti-topoisomerase I (Scl70) antibodies is controversial. We wished to quantify the performance of the currently available commercial systems for the assay of anti-topoisomerase I antibodies in a large multicenter study.

METHODS

Fifty Italian clinical laboratories analyzed 36 serum samples: 27 from individuals with scleroderma/systemic sclerosis, and 9 from a control group. The scleroderma/systemic sclerosis samples were positive in our laboratories by both ELISA and immunoblot (IB), and the control samples were negative. The laboratories used 42 immunoenzymatic (ELISA), 21 IB, 3 counterimmunoelectrophoresis, and 2 dot-blot methods, produced by 23 different manufacturers.

RESULTS

We obtained 2389 results. The ELISA methods showed 99.2% specificity and 97.2% sensitivity for detection of anti-Scl70 antibodies. For IB methods, specificity was 97.6% and sensitivity was 96.1%. The Western-blot method had poor analytical specificity (27% false positives for anti-extractable nuclear antigen antibodies other than anti-Scl70).

CONCLUSIONS

Excluding Western blots, commercial ELISA and IB reagents as used in clinical laboratories have a sensitivity and a specificity >95% for determination of anti-Scl70 antibodies.

[Importance of chemoprevention in oncology]

The therapeutic approach to cancer is generally limited to the advanced phases of disease. The preventive strategies aim at eliminating or reducing the exposition to known carcinogenes. We act with pharmacological and/or with an accurate dietary education to induce cellular differentiation phenomena, cytostasis and apoptosis. Chemoprevention acts both on the inductive phase (metabolic activation, DNA adducts), as well as on the promotion/proliferation of the long pre-clinical period of latency (antioxidants, anti-inflammatory, retinoids, carotenoids, vitamins and micronutrients, hormones and hormonal inhibitors, polyamine inhibitors, ditholetions, isothiocyanates, telomerase inhibitors, etc). Unanimous agreement has been reached on the preventive role of retinoids in head and neck tumors and of the cervical uterus, of hormonal inhibitors in breast and prostate cancer, and of anti-inflammatory in colorectal cancer. New and more accurate parameters for the evaluation of results and individual applications of chemopreventive strategies are linked to the biological research of high-risk subjects (genetic damage) or increased individual susceptibility. Caution, instead, should be applied in the clinical trial planning. An increased risk in developing and dying of lung tumor in smokers has been shown for the use vitamin A. Many clinical studies have been started in order to establish an efficient chemoprevention in oncology, and with the early diagnostic programs, and the evaluation of genotypic and phenotypic alterations, encouraging results will be reached for the next millennium.

Levels of C-telopeptide fragments of collagen type I enable the monitoring and early adjustment of clodronate therapy in patients with postmenopausal osteoporosis

We monitored the efficacy of therapy with clodronate, a bisphosphonate drug, in women with postmenopausal osteoporosis, using urinary immunoenzymatic assay of C-telopeptide of collagen type I, an eight amino acid fragment (collagen fragment) of the C-telopeptide of the alpha1-chain of collagen type I (EKAHDGGR). The analysis of the dynamics of collagen fragment concentrations (a marker of bone resorption) during treatment suggests the possibility of early modulation and customization of therapy based on the levels of this marker. This could enable improved control over secondary effects and side effects of clodronate therapy. Pharmacologic inhibition of bone resorption by osteoclasts could be indirectly responsible for the increase in parathyroid hormone found during treatment with clodronate. Increased levels of parathyroid hormone are probably necessary to stimulate residual osteoclast activity and are sufficient for the maintenance of calcium-phosphate homeostasis in a new pharmacologically-induced equilibrium. Outside this context the levels of parathyroid hormone of certain patients would be considered pathologic.

Modification of serum proteins in guinea pigs immunized and challenged with toluene diisocyanate

OBJECTIVES

Guinea pigs were used to determine whether immunization and challenge by toluene diisocyanate (TDI) induce changes in the serum protein concentrations of the "acute-phase response" and whether TDI can form adducts with serum proteins.

METHODS

Guinea pigs were immunized by weekly intradermal injections of TDI and challenged with TDI 7 days after the 3rd injection. The animals were killed 6 hours after the challenge, and serum was analyzed for protein characterization by gel electrophoresis and for specific antibodies to TDI by enzyme-linked immunosorbent assay (ELISA) and Western blotting.

RESULTS

The total serum protein concentration of the immunized TDI-challenged guinea pigs increased in comparison with that of nonimmunized animals [75 (SE 0.7) versus 47.4 (SE 2.3) mg/ml; ]. Albumin and alpha, and alpha2 globulins increased significantly [respectively: 65.8 (SE 0.2)%, 2.1 (SE 0.1)% and 7.2 (SE 0.1)% versus 59 (SE 1.3)%, 1.3 (SE 0.1)% and 3.7 (SE 0.1)%], whereas beta1 and beta2 globulins decreased in the immunized TDI-challenged guinea pigs [7.8 (SE 0.2)% and 0.8 (SE 0.2)% versus 15.8 (SE 0.7)% and 4.8 (SE 0.2)%]. The gamma globulin concentrations did not change significantly. In the immunized TDI-challenged animals, albumin was modified by TDI and ran faster on agarose gel electrophoresis than did albumin from nonimmunized guinea pigs. In the ELISA, only immunized animals had high titers of TDI-specific antibodies (IgG and IgG1); by blotting, the antibodies reacted against TDI, the TDI-BSA-conjugate and several TDI-conjugated guinea pig serum proteins, but they did not react against any native or denaturated serum protein when unconjugated with TDI.

CONCLUSIONS

These findings indicate that, in guinea pigs, immunization and challenge with TDI induces changes in serum proteins of the "acute phase response" and TDI is adducted to serum proteins with different molecular weights (eg, albumin).

Evaluation of diagnostic reliability of DCA 2000 for rapid and simple monitoring of HbA1c

The monitoring of diabetic patients by evaluating glycated protein levels is now widely accepted and performed. The microchromatographic version of the high performance liquid chromatography method is the technique most frequently used in clinical practice. The DCA 2000 instrument (Bayer Diagnostics, Milan, Italy), based on an immunochemical technique, has been proposed for the rapid and simple evaluation of HbAlc, using even capillary blood. We evaluated 171 subjects including 22 healthy volunteers, 78 type 2 diabetic patients with different degrees of metabolic control, 11 women affected by gestational diabetes mellitus (GDM), 6 patients with hyperlipemia, 38 patients with chronic renal failure, 13 diabetic patients with chronic renal failure, and 3 patients with hemoglobinopathies. The DCA 2000 model was compared with the Diamat HPLC system. Data from within-run imprecision studies showed excellent precision, for both DCA 2000 and the HPLC system. The correlation between the two different systems, as shown by other statistical evaluations, was good (y = 0.911x + 0.462, r = 0.923). Results from the control group and diabetic patients were used to compare the two methods. Values obtained using the DCA 2000 were significantly lower (p < 0.0001) than those obtained with the HPLC system, in both healthy subjects and diabetic patients. To detect possible interferences, selected samples were analyzed from patients with hyperlipemia, diabetes and chronic renal failure, and hemoglobinopathies. While in the case of hyperlipemia, an acceptable correlation coefficient between the two systems was confirmed (y = 1.047x - 1.236, r = 0.876), in the case of chronic renal failure the correlation turned out to be very low (y = 0.254x + 3.456, r = 0.203). Our results indicate that the DCA 2000 gives accurate and reliable results in the clinical field of interest.

[Detection of anti-ENA autoantibodies in patients with systemic connective tissue diseases. Analytical variability and diagnostic sensitivity of 4 methods]

This study was designed to assess the analytical sensitivity and rate of agreement between commercial methods and reagents, among the most used in Italy for the detection of autoantibodies to extractable nuclear antigens (ENA). Sixty-eight serum samples from patients with clinically diagnosed systemic rheumatic diseases were aliquoted and distributed to 4 hospital laboratories; three ELISA (Elias, Shield, Inova) and 1 immunoblot method (Euroimmun) were used. Overall agreement between the test reagents, for each anti-ENA specificity, was 69.1% for Ro/SSA, 83.3% for La/SSB, 70.6% for RNP, 73.5% for Sm, 91.1% for Jo1, and 82.3% for Scl70. Lack of specificity (i.e., false positive reactions) was the most important cause of low concordance. When the data were analysed according to the clinical diagnosis, total agreement and specificity improved. However, a significant difference in terms of sensitivity was observed in the SLE group (30 sera) for RNP (positivity ranged from 20% to 43%) and for Sm (from 7% to 37%), and in the Sjögren's syndrome group (13 sera) for anti-La/SSB (from 8% to 38%). Comparable data were obtained for anti-Ro/SSA (from 70% to 77%) both in the SLE and the Sjögren's syndrome group. Sensitivity of all 4 reagents was good in detecting anti-Scl70 autoantibodies in the 8 patients with diffuse systemic sclerosis, as well as anti-Jo1 autoantibody in the 5 polymyositis patients, with a 100% and a 95% agreement, respectively. These data suggest the need of a better standardization of commercial reagents and analytical procedures, and the opportunity that every laboratory should perform anti-ENA determination by at least two different methods, since none of the methods tested was completely reliable in detecting all anti-ENA autoantibody specificities.

Disability is associated with malnutrition in institutionalized elderly people. The I.R.A. Study. Istituto di Riposo per Anziani

Several factors, such as disability, malnutrition, weight loss, and the interactive effect of diseases and aging have been associated with morbidity and mortality in the elderly population. Nevertheless, the relationship between disability and biological parameters has not been extensively investigated as a primary focus. In a cross sectional survey, 344 institutionalized elderly subjects were evaluated. Disability was measured according to the Katz index, and patients were divided into three groups: low (0-1 lost ADL), mild (2-4 lost ADL), and severe (5-6 lost ADL). Anthropometric, metabolic, and nutritional parameters were assessed; age, gender, number of pathologies, and number of drugs were also recorded. Data were analyzed by multiple comparison of means according to Scheffé, and by multivariate logistic regression analysis. An impairment in functional status was associated with several modifications in biological parameters. Logistic regression analysis showed that severe disability (5-6 lost ADL) was associated with low waist/hip ratio (< 0.9 vs > 0.9, OR: 1.56, CI 95%: 1.08-2.25), high body resistance (> 625 vs < 575 omega, OR: 1.39, CI 95%: 1.38-1.39), low plasma albumin levels (< 3.5 vs > 4.0 g/dL, OR: 6.02, CI 95%: 5.18-6.85), and low plasma transferrin levels (< 200 vs > 250 mg/dL, OR: 5.47, CI 95%: 4.56-4.58) independently of age, gender, comorbidity, and other confounding factors. Our results indicate that severe disability in ADL is strongly associated with anthropometric and biohumoral parameters suggesting the presence of malnutrition. A careful evaluation of the nutritional state appears to be of primary importance, and efforts to improve nutritional status are needed in approaching disabled elderly patients.

[Malignant lymphoma. Epidemiologic review of 150 cases]

In the present paper the incidence of lymphomatous disease in Messina and its province, with growing urbanization and rural limiting areas, is discussed: by analysing 150 cases of malignant lymphoma observed at our Institute from 1990 to 1995. The method proposed, based on data obtained from the medical files of these patients, took into consideration various parameters such as age, sex, residence, profession, clinical and bioptic diagnosis, LDH and disease presentation. The final results showed an increase of the risk for NHL in the rural province where the main profession is agriculture or handicraft (ceramics, forged iron, glasswork, refinery), in subjects above 60 years of age; for the HL instead, over the years, a minor incidence of risk has been observed. The data obtained were partially similar to those reported in the international literature. The most present form in NHL was the lymphocytic and the centrocytic follicular form, while for HL it was the mixed cells form. The relationship between the two sexes was higher in males with HL and almost equal in NHL. The age range mostly affected by HL was between 25 and 65 years of age.

Variability between methods to determine ANA, anti-dsDNA and anti-ENA autoantibodies: a collaborative study with the biomedical industry

This study was performed by the Italian Society of Laboratory Medicine (SIMeL) in order to establish the variability between the different analytical systems currently used in clinical laboratories for the detection of autoantibodies diagnostic of systemic autoimmune disease. Sixteen industrial, and two university laboratories participated in this study which entailed the determination of anti-nuclear (ANA), anti-dsDNA and anti-ENA antibodies in 11 sera from patients with clinically diagnosed systemic rheumatic disease, using reagents produced by these companies and different methodologies (indirect immunofluorescence, immunoenzymatic assay, counterimmunolectrophoresis, immuno and western blotting). We found 93.5% agreement between the methods used for the detection of ANA, 85.2% for anti-dsDNA antibodies, and 86.9% for anti-ENA antibodies. Among the anti-ENA antibodies, regardless of the method used, detection percentages were excellent for anti-RNP and anti-SSB/La (100%), good for anti-SSA/Ro (93%), but unacceptable for the anti-Jo-1 (67%), anti-Scl70 and anti-Sm (47%) antibodies. This further stresses the need for rigorous standardisation of commercial reagents and analytical procedures, as well as the introduction of external quality assessment (EQA) programs, and a complete definition of operative protocols adjusted to the sensitivity and specificity of the various methods.

Isolated rectal relapse in non Hodgkin lymphoma patient

The authors report on case of isolated rectal relapse of non Hodgkin lymphoma after complete remission with chemotherapy. They analyse diagnostic and therapeutic aspects, on the grounds of literature data and personal experience.

Sysmex SE-9000 hematology analyzer: performance evaluation on leukocyte differential counts using an NCCLS H20-A protocol. National Committee for Clinical Laboratory Standards

We evaluated the performance (ie, imprecision, inaccuracy, and analytic sensitivity) of the Sysmex SE-9000 commercial hematology analyzer (TOA Medical Electronics, Kobe, Japan) on differential leukocyte counts according to the National Committee for Clinical Laboratory Standards H20-A protocol. The results obtained were compared with those from the Bayer H6000 and H3 (Bayer Diagnostic Division, Tarrytown, NY), the Coulter MAXM (Miami, Fla), and the microscopic method. Altogether, samples from 462 subjects were analyzed. The results show a substantial superimposition of reference intervals between the methods. The imprecision of the SE-9000 is low for all the leukocyte subpopulations, with the exception of basophils (coefficient of variation: neutrophils, 3.35%; lymphocytes, 4.25%; monocytes, 7.9%; eosinophils, 9.5%; and basophils, 44.2%) and is consistently lower than that of manual counts. The correlation with other methods is high, with the exception of basophils (r2: neutrophils, 0.94-0.95; lymphocytes, 0.93-0.97; monocytes, 0.76-0.85; eosinophils, 0.96-0.99; and basophils, 0.02-0.56). When compared with the microscopic method, an overestimation of neutrophils is seen mostly at low concentrations (mean difference, 2.63), and an underestimation of lymphocytes is seen at high concentrations (mean difference, -3.1). The clinical sensitivity was good, with an agreement of 75.7% on morphologic and 89.6% on distributional abnormalities. With a new analytical channel for immature cells (IMI), the analyzer shows high sensitivity in detecting immature cells of the granulocytic lineage (from 94.4% for immature granulocytes to 96% for myeloblasts).

Reticulocyte quantification by Coulter MAXM VCS (volume, conductivity, light scatter) technology

In this study the ability of the Coulter MAXM analyzer to quantify reticulocytes was evaluated. The results were compared with those obtained by a microscopic method according to NCCLS H44-P recommendations and with the results from the automated analyzer Sysmex R-1000. Duplicate samples from 330 patients were analyzed. The reference intervals obtained with the three methods were: MAXM 0.37-1.80%, median 0.83%; manual 0.40-2.30%, median 1.00%; R-1000 0.60-1.95%, median 1.06%. The imprecision (CV) at all concentrations is lower than the microscopic method (low 16.1% vs 67%; normal 16.9% vs 28.9%; high 9.5% vs 13.0%). The MAXM shows a good overall correlation with the microscopic method (intercept 0.01, slope 0.89, r2 = 0.87) despite evidence of a significant overestimation at low concentrations [difference (D) 0.30] and a moderate underestimation at normal (D -0.15) and high (D -1.04) concentrations; the same behavior is shown in comparison with results from the R-1000, with an overall underestimation by MAXM (D -0.26). When compared with the microscopic method, MAXM shows a modest sensitivity at low reticulocyte counts (54.8%) and satisfactory sensitivity for high counts (87.3%), with an overall agreement of 81.3%.

Reticulocyte quantification by Coulter MAXM VCS (volume, conductivity, light scatter) technology

In this study the ability of the Coulter MAXM analyzer to quantify reticulocytes was evaluated. The results were compared with those obtained by a microscopic method according to NCCLS H44-P recommendations and with the results from the automated analyzer Sysmex R-1000. Duplicate samples from 330 patients were analyzed. The reference intervals obtained with the three methods were: MAXM 0.37-1.80%, median 0.83%; manual 0.40-2.30%, median 1.00%; R-1000 0.60-1.95%, median 1.06%. The imprecision (CV) at all concentrations is lower than the microscopic method (low 16.1% vs 67%; normal 16.9% vs 28.9%; high 9.5% vs 13.0%). The MAXM shows a good overall correlation with the microscopic method (intercept 0.01, slope 0.89, r2 = 0.87) despite evidence of a significant overestimation at low concentrations [difference (D) 0.30] and a moderate underestimation at normal (D -0.15) and high (D -1.04) concentrations; the same behavior is shown in comparison with results from the R-1000, with an overall underestimation by MAXM (D -0.26). When compared with the microscopic method, MAXM shows a modest sensitivity at low reticulocyte counts (54.8%) and satisfactory sensitivity for high counts (87.3%), with an overall agreement of 81.3%.

Laboratory evaluation of the Miles H.3 automated reticulocyte counter. A comparative study with manual reference method and Sysmex R-1000

OBJECTIVE

To evaluate the performance of the new commercial Miles H.3 RTX analyzer in counting reticulocytes.

METHODS AND PATIENTS

The results from the counter were compared to those obtained from microscopic methods, following the National Committee for Clinical Laboratory Standards H44-P guidelines, and to the results from the Sysmex R-1000 counter. In total, 279 samples were analyzed in duplicate with each of the three methods. One hundred thirty-three samples were from healthy subjects, while 146 were from patients with various pathologies, 10 of whom presented with posttherapeutic aplasia of the bone marrow and 9 with iron-deficiency anemia.

RESULTS

The reference intervals for the normal controls are different for each of the three methods (manual: 0.35-2.35%, 16 to 116 x 10(9)/L; Miles H.3: 0.65-2.30%, 35.1 to 112.0 x 10(9)/L; Sysmex R-1000: 0.6-1.85%, 28.0 to 85.0 x 10(9)/L). The overall imprecision was lower for the instruments than for the microscopic method (Miles H.3: coefficient of variation, 11.6%; R-1000: coefficient of variation, 4.2%; microscopic method: coefficient of variation, 24.2%). The Miles H.3 shows a good correlation with the other methods, yet it overestimated the low values with respect to both the microscopic method (intercept, 0.55; slope, 0.70) and the R-1000 (intercept, 0.44; slope, 0.78). This became particularly pronounced in patients with marrow aplasia.

CONCLUSIONS

Miles H.3 can produce results with an acceptable degree of accuracy. The agreement with the dedicated fluorescence-based flow cytometer R-1000 at normal and high concentrations is also good. The possibility of providing reticulocyte indices as well as erythrocyte indices (mean volume, mean hemoglobin content, mean hemoglobin concentration) and the relative dispersion indices could be useful in understanding red cell pathophysiology in normal and iron deficient patients.

Evaluation of a specific immunoinhibition method for the determination of pancreatic alpha-amylase

Ten clinical centres in Italy participated in an evaluation of a pancreas-specific alpha-amylase assay using two monoclonal antibodies. Comparisons with electrophoretic methods showed good agreement in the reference range, but systematic deviations above it. The diagnostic information of the two methods appeared substantially different if the percentage values from electrophoresis were compared with activity units from the immunoinhibition method, but became similar if the two methods were compared on the basis of activity units. Reference intervals determined for serum/plasma corresponded to those previously published, but those determined for urine differed slightly from the published values. Clinical sensitivities for the assessment of acute pancreatitis (n = 134) were found as follows. Related to the upper limit of the control group (n = 141), the pancreatic alpha-amylase, total alpha-amylase and lipase showed sensitivities of 0.94, 0.87 and 0.93, respectively. When the cut-off point was set at the three-fold upper limit of the control group, sensitivities of 0.73, 0.53 and 0.70 were found, and the specificity was 1.00 for all three methods. Based on this commonly used higher cut-off point, the determination of lipase in addition to pancreatic alpha-amylase enhanced the sensitivity in the recognition of acute pancreatitis by 8%; conversely, the determination of pancreatic alpha-amylase in addition to lipase increased the number of true positive results by 13%. The high practicability and interlaboratory transferability documented in the results of the collaborative study show that the pancreatic alpha-amylase assay is very useful for recognizing pancreatic inflammations, especially in combination with lipase.

Effect of high-dose steroid therapy on T-cell subpopulations. A longitudinal study in MS patients

Lymphocyte subpopulations, T cell activation antigens, and serum levels of interleukin 2 (IL-2) and soluble IL-2 receptor (sIL2R), were studied in relapsing-remitting MS (RR-MS) patients before and after high-dose steroid therapy. Prior to therapy, a minority of patients showed increased HLA-DR antigen expression, and an increased number of CD16+ and CD19+ cells. Steroid treatment induced a significant increase in HLA-DR and CD19 expression, a significant reduction in CD16+, CD57+, and CD8+ CD57+ cells, and a slight, non-significant, decrease in IL-2 and sIL-2R levels and CD25 expression on CD4+ T lymphocytes.