Volume 49, Issue 1

Chronic liver diseases (CLDs) represent a major cause of morbidity and mortality worldwide. In all etiologies of CLDs, staging of liver fibrosis is essential for both prognosis and management. Until a few years ago, liver biopsy was the only tool for the diagnosis of liver fibrosis in patients with CLDs. However, liver biopsy is an invasive and costly procedure. More recently, various serum biomarkers and laboratory tests have been proposed as surrogates of liver histology. Due to inadequate diagnostic accuracy or to lack of sufficient validation, guidelines still do not recommend them as a substitute for liver biopsy that is still considered the gold standard for the diagnosis of liver fibrosis. Notably, non-invasive serum biomarkers, when combined, may reduce by 50%–80% the number of liver biopsies needed for correctly classifying hepatic fibrosis. However, liver biopsy cannot be avoided completely, but should be used in those cases in which non-invasive methods show poor accuracy. In this view, serum biomarkers and liver biopsy represent a union between laboratory medicine and hepatology.

Current screening for fetal aneuploidies relies on biochemical and ultrasound measurements, and the sensitivity and specificity needs to be improved to reduce the number of pregnant women subjected to invasive diagnostic procedures, such as amniocentesis. Proteomic technologies enable new strategies for discovering biomarkers from complex biological fluids in a high-throughput and sensitive manner. Since mass spectrometry-based techniques allow for both qualitative and quantitative analysis of a given proteome, they have been widely used to resolve and compare the proteome of maternal plasma, serum, urine, cervical-vaginal fluid, and amniotic fluid. Comparisons of proteomes of normal fluids with those from aneuploidy pregnancies have revealed a host of candidate markers that still need to be verified. In parallel with proteomics, there is interest in other emerging techniques, such as RNA-SNP analysis or quantitation of fetal DNA by shotgun sequencing. Although these genomic techniques hold much promise, discovery of additional markers via quantitative proteomic comparisons could drastically improve current conventional screening at reasonable cost. Proteomics-based biomarker discovery is applicable to detection of not just aneuploidies, but also other pregnancy-related diseases.

The aim of in vitro testing of thyroid function is to accurately reflect the in vivo activity of key analytes, such as thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4). For these key laboratory parameters, it is highly desirable that assay results are interpretable in relation to consensus reference intervals, which should not vary depending on the choice of method used for measurement. The IFCC Working Group for Standardization of Thyroid Function Tests has recently published three reports on standardization of thyroid function tests in order to resolve the issues concerning method performance and quality specifications, as well as to meet clinical requirements. The aim of the present article is to discuss the relevant contribution of the IFCC Working Group study towards the standardization of free triiodothyronine (FT3) and free thyroxine (FT4) assays. The most important result obtained by this study is the establishment of a reliable candidate reference procedure and some commutable reference materials. These reference materials, including sera collected from blood donors, were measured by the gold standard method, and by several immunoassay methods and two equilibrium dialysis procedures in order to obtain a recalibration of test results. The recalibration on average eliminated assay-specific biases with respect to reference method values. However, sample-related effects remained among the immunoassay methods tested. Although these findings are clearly important, they should only be considered a start towards harmonization of patients test results. In conclusion, further studies are necessary to answer the question of whether standardization and harmonization of the FT3 and FT4 test is an impossible mission (or not).

Background: The identification of cystic fibrosis (CF) patients who are at greater risk of lung damage could be clinically valuable. Thus, we attempted to replicate previous findings and verify the possible association between three single nucleotide polymorphisms (SNPs c.–52G>A, c.–44C>G and c.–20G>A) in the 5’ untranslated region (5′ UTR) of the β defensin 1 ( DEFB1 ) gene and the CF pulmonary phenotype. Methods: Genomic DNA from 92 Italian CF patients enrolled in different regional CF centres was extracted from peripheral blood and genotyped for DEFB1 SNPs using TaqMan ® allele specific probes. In order to avoid genetic confounding causes that can account for CF phenotype variability, all patients were homozygous for the F508del CFTR mutation, and were then classified on the basis of clinical and functional data as mild lung phenotype (Mp, n=50) or severe lung phenotype patients (Sp, n=42). Results: For the c.–20G>A SNP, the frequency of the A allele, as well as the AA genotype, were significantly more frequent in Mp than in Sp patients, and thus this was associated with a protective effect against severe pulmonary disease (OR=0.48 and 0.28, respectively). The effect of the c.–20G>A A allele is consistent with a recessive model, and the protective effect against Sp is exerted only when it is present in homozygosis. For the other two SNPs, no differences were observed as allelic and genotypic frequency in the two subgroups of CF patients. Conclusions: Our results, although necessary to be confirmed in larger and multiethnic populations, reinforce DEFB1 as a candidate modifier gene of the CF pulmonary phenotype.

Background: Coronary artery disease (CAD) is a complex multifactorial and polygenic disorder where multiple environmental and genetic factors are involved simultaneously. The purpose of this study was to explore the relationship between the interaction of cyclooxygenase-2 (COX-2) gene polymorphism and smoking and CAD in a Uighur population. Methods: Using a case-control study of Chinese Uighur CAD patients (n=430) and healthy controls (n=470), we investigated the roles of G-765C polymorphism in the COX-2 gene ( PTGS2 ) by the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Results: The PTGS2 GG genotype was significantly more prevalent in CAD patients (84.6% vs. 78.3%; p=0.014). Multiple logistic regression analysis showed two independent risk factors: smoking (OR 1.89, 95% CI 1.01–5.24; p=0.008) and hypertension (OR 2.73, 95% CI 1.59–7.21; p=0.001). Moreover, there was a synergistic effect between smoking and the PTGS2 polymorphism and the occurrence of CAD (interaction p=0.009). The odds ratio (OR) estimated by the combined analysis of the PTGS2 GG genotype and smoking history (OR 4.09, 95% CI 2.7–9.3) was markedly higher than that estimated separately from the PTGS2 GG genotype (OR 1.28, 95% CI 0.8–1.9) or smoking (OR 2.51, 95% CI 1.5–5.7) alone. Plasma 6-keto-PGF1α, a stable metabolite of PGI 2 , was lower in individuals with the PTGS2 GG genotype (p<0.05). Smoking could further lower plasma 6-keto-PGF1α concentrations in GG genotype carriers than non-smokers, especially in patients with CAD. Conclusions : The PTGS2 polymorphism and smoking were synergistically and significantly associated in Chinese Uighur patients with CAD.

Background: The mechanism of paraoxonase 1 (PON1) atheroprotective remains elusive. The lactonizing/lactonase activity of PON1 is gaining favor as the most significant in physiology. Methods: We studied 42 end-stage renal disease (ESRD) patients undergoing hemodialysis (HD) and 49 control subjects. We measured PON1 lactonase, arylesterase and triesterase activities by kinetic methods. Results: Serum lactonase activity was 11% lower in ESRD patients (p<0.0001) and did not correlate with high-density lipoprotein (HDL) cholesterol when controlling for confounders. Lactonase activity was significantly higher after dialysis. Using a repeated measure-ANOVA adjusted for the confounders (age, gender, total cholesterol, triglyceride and HDL cholesterol) we show that the changes in lactonase after dialysis were significant (p<0.0001). HD increases lactonase activity to levels indistinguishable from those of control subjects. In simple linear regression analyses we showed a significant inverse correlation between changes in lactonase and those of creatinine by dialysis (r=–0.339, p=0.028). Conclusions: ESRD patients maybe more susceptible to lipid peroxidation and to protein homocysteinylation than healthy subjects due to the decreased activity of lactonase. A lower serum lactonase activity would be coupled with delayed catabolism of oxidized phospholipids in low-density lipoprotein and oxidized macrophages, and with greater protein homocysteinylation, accelerating atherogenesis. One mechanism for lower lactonase activity in ESRD patients may be inhibition by uremic toxins and oxidative stress. The pathophysiology of reduced lactonase activity in uremia and the beneficial effects of HD need further investigation.

Background: Daptomycin is a recently developed cyclic lipopeptide antibiotic active against most Gram-positive pathogens including vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus . To optimize treatment efficacy and safety, especially in patients undergoing multiple drug regimens and/or co-morbidities, a specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of daptomycin in plasma. Methods: A C18 column was used for separation, with a mobile phase initially consisting of 0.1% formic acid, water, and acetonitrile (ACN) in a linear gradient from 20% to 70%. After protein precipitation with ACN, the clear upper layer was diluted in water:ACN (50:50, v/v) before injection. Detection was performed using an electrospray ionization technique. MS/MS transitions, monitored in the positive ion mode were m/z 811.1 → m/z 313.1 for daptomycin, and m/z 609.4 → m/z 194.9 for reserpine, used as internal standard. Results: Elution of daptomycin and reserpine occurred at 4.5 and 3.9 min, respectively. The method was validated over a range of concentrations from 1 mg/L to 120 mg/L. The assay met recommended acceptance criteria: coefficients of variation were <6.3% and <7.4%, and accuracies were between –5.9% and +11.2% and between –3.5% and +3.7%, for intra- and inter-day validations, respectively. Conclusions: This method appears well-adapted to routine hospital practice for therapeutic drug monitoring of daptomycin considering its time of analysis, range of concentrations measured, precision and accuracy.

Background : Chagas disease is endemic in Latin America, affecting 16–18 million people with more than 100 million exposed to risk of infection. Its etiological agent is Trypanosoma cruzi . To date, benznidazole is the only treatment of Chagas disease available in Europe. Methods: A high-performance reversed-phase isocratic liquid chromatographic method for benznidazole analysis in human plasma is described. The mobile phase consists of 60% ultrafiltered water and 40% acetonitrile. Samples were precipitated with trichloroacetic acid (0.3 M) (1/1, v/v). The injection volume was 100 μL. Benzocaine was used as internal standard. Results: The assay was linear over a benznidazole concentration range of 1.6–100 μg/mL. The method showed good agreement of results (n=15): inaccuracy (5.6%), intra- and inter-day variability (1.1% and 3.9%, respectively), recovery (94.9%), limit of detection (0.8 μg/mL), lower limit of quantitation (1.6 μg/mL) and acceptable stability over 24 h in the auto-sampler. Only 25 samples (58%) showed values within the therapeutic range. Three samples were subtherapeutic and 15 were in the toxic range. Conclusions: The method offers a fast and simple approach to determining benznidazole in human plasma which could be of use in pharmacokinetic and safety studies.

Background: Serum free light chain (FLC) analysis is used in the prognostic assessment and monitoring of patients with monoclonal gammopathies (MG). Its use in detection of MG is less widespread despite good sensitivity for diseases poorly detected by serum protein electrophoresis (SPE), e.g., FLC disease and AL amyloidosis. FLC analysis may facilitate earlier diagnosis in these diseases. However, if replacing urine protein electrophoresis (UPE) in an initial screening algorithm, this must be balanced against any loss of detection of Bence Jones proteinuria (BJP). Methods: We assessed the effect of replacing UPE with FLC. Sensitivity of FLC for BJP was assessed in 126 clinical cases where UPE and FLC analyses were performed. Impact on disease detection was assessed from 753 patient sera tested by SPE and FLC and 128 patients matched associated urine samples. Results: Sensitivity of FLC for BJP was 98%. Use of FLC in routine testing increased the number of MG detected by 7%. Conclusions: Using FLC alongside or in place of UPE can give clinical benefit through earlier diagnosis and hence treatment earlier in the patients' disease.

Background: Quantification of monoclonal immunoglobulin free light chains (FLCs) in serum is used increasingly in clinical practice for the diagnosis, prognostic assessment, and treatment monitoring of monoclonal gammopathies. It is used as an adjunct to standard serum protein electrophoresis and immunofixation. However, methods for FLC quantification need further standardization and validation. Methods: The Czech Myeloma Group and the Czech Society of Clinical Biochemistry have initiated an interlaboratory study where six laboratories collaborating with the primary myeloma treatment centres measured FLC concentrations in 12 serum samples from patients with monoclonal gammopathies. Results: Repeatability of the measurements in five laboratories was calculated based on differences between the results of duplicate measurements. We found that repeatability depended more on the laboratory than on the device used for measurement. Conclusions: The study revealed several weak points in the methodology, including the need for a uniform sample dilution procedure. Interlaboratory reproducibility was comparable with values achieved in the NEQAS programme. Because the κ/λ ratio cannot be measured with high precision, κ and λ FLC concentrations should be used where possible. Due to its impact on the clinical management of patients with gammopathy, FLC quantification needs to become a part of the regular quality control cycle in myeloma centres.

Background: Evidence suggests that zinc-α 2 -glycoprotein (ZAG) might serve as a biomarker for human metabolic alterations. We measured serum ZAG in patients with non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of the metabolic syndrome, and examined its association with clinical, biochemical, and histological phenotypes. Methods: Serum ZAG was determined using ELISA in 90 patients with biopsy-proven NAFLD and 81 controls. Results: Serum ZAG concentrations did not differ in patients with NAFLD (median 61 μg/mL; interquartile range: 56–73 μg/mL) compared with healthy controls (median 66 μg/mL; interquartile range: 56–78 μg/mL, Mann-Whitney U-test, p=NS). However, among patients with NAFLD serum ZAG concentrations were significantly higher in males and in those with the metabolic syndrome. After stepwise linear regression analysis, serum ZAG concentrations were the only independent predictor of the number of metabolic syndrome components in patients with NAFLD (β=0.22; t=2.001, p<0.05). Conclusions: In summary, the hypothesis of an association between NAFLD and serum ZAG concentrations is not supported by the present results. However, ZAG remains an interesting molecule for further research in the field of human metabolic disorders.

Background: Although many reports have elucidated pathophysiological characteristics of abnormal bone metabolism in patients with type 2 diabetes mellitus (DT2), determinants of bone mineral density (BMD) in patients with DT2 are still controversial. Methods: We examined 168 Belarussian men 45–60 years of age. Plasma total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, triglycerides, hemoglobin A 1c (HbA 1c ), immunoreactive insulin, and C-reactive protein concentrations were assessed. BMD was measured using dual energy X-ray densitometry of the lumbar spine (L 1 –L 4 ). Total testosterone (TT) and sex hormone-binding globulin were measured, and free testosterone (FT) was calculated. Results: Using univariate linear regression analysis, BMD of the lumbar spine was significantly correlated with FT (r=0.32, p<0.01) and TT (r=0.36, p<0.01). Using multiple linear regression analysis adjusted for confounding factors, BMD was significantly correlated with TT (β=0.23, p<0.001) and TC (β=–0.029, p=0.005). Age (β=0.005, p=0.071), body mass index (β=0.005, p=0.053), HbA 1c (β=–0.002, p=0.72) and duration of diabetes (β=0.001, p=0.62) were not significantly correlated with BMD. Conclusions: Our data indicate that androgens are independent determinants of BMD in male patients with DT2.

Background: Plasma vitamin B12 [cobalamin (Cbl)] concentrations are usually measured as a screening marker for vitamin B12 deficiency. Siemens Healthcare Diagnostics has introduced Cbl assays for various platforms, i.e., the immulite (IML) 2000 and 2500. In our laboratories, regular validation studies for the IML 2500 were conducted and showed acceptable quality specifications. After the introduction of the IML 2500 Cbl assay, clinicians in the department of internal medicine reported an increased frequency of patients with Cbl-concentrations less than 148 pmol/L. Methods: In order to investigate this claim from the clinicians, we retrospectively analyzed the internal and external quality control (QC) of the Cbl assay. In addition, the monthly patient means for the Cbl assay were analyzed both before and after the introduction of the new Cbl assay. Results: No abnormalities were found in the internal and external QCs. However, the monthly patient means for the Cbl assay showed a statistically significant decrease in cobalamin concentrations. Siemens acknowledged the problems and formulated a new Cbl assay, which was subsequently validated in our laboratories and showed equivocal Cbl results when compared to the IML 2000 Cbl assay. Conclusions: We report a flawed validation study conducted by the manufacturer that resulted in an undetected analytical problem in the IML 2500 Cbl assay, its subsequent introduction on the market, the final recognition of the poor performance of the assay by our clinicians, and the eventual resolution by the manufacturer. Hence, it emphasizes the utmost importance for thorough comparison between assays over the entire measurement range, even when both assays are produced by the same manufacturer.

Background: The prevalence and course of pseudothrombocytopenia in outpatients is uncertain. Methods: In a cohort study of 687,955 members of a health maintenance organization, we extracted 36,780 consecutive automated complete blood count test results and determined the point prevalence of pseudothrombocytopenia during a one-month period. We also calculated a retrospective cumulative prevalence over the past 5 years. Results: There were 1105 (2.7%) patients with platelet counts of 100–149×10 9 /L and 304 (0.8%) with counts <100×10 9 /L, of whom 12.8% (n=39) had pseudothrombocytopenia newly discovered or in the past. There were 40 additional patients with a history of pseudothrombocytopenia, but now showing platelet counts of 150×10 9 /L or more, and another 21 with platelet counts of 100–149×10 9 /L. The total cumulative prevalence of pseudothrombocytopenia was 0.27% (100/36,780), 2.5-fold higher than the point prevalence of 0.11% (39/36,780). Platelet counts were extremely variable in these patients during the 5-year follow-up period. Conclusions: Physicians should be aware of the variability of platelet counts in patients with pseudothrombocytopenia in order to reduce unnecessary retesting. Since pseudothrombocytopenia can result in platelet counts between 100 and 149×10 9 /L, peripheral smears should be done in all patients with such values, or the reference limit value should be lowered to 100×10 9 /L.

Background: Detection of absolute and relative lymphocytosis in otherwise asymptomatic elderly patients is very common in the primary care setting and frequently results in referral for screening of lymphoproliferative disorders. Since many B-cell chronic lymphoproliferative disorders (B-CLPD) are indeed asymptomatic at diagnosis in most patients with lymphocytosis, no sign of such a disorder is usually detected. Currently, specific guidelines for screening of patients with lymphocytosis are lacking. We investigated the practicability and clinical value of a single colour CD19 count performed by a primary care laboratory in order to improve the diagnostic follow-up of patients with lymphocytosis in a primary care laboratory. Methods: The capability of detecting monoclonal B-cell lymphocytosis and B-CLPD by CD19, was first confirmed in patient samples with known B-CLPD. Next, in a previously defined geographic area, a CD19 count was performed on all samples for patients aged ≥40 years with relative or absolute lymphocytosis but without neutropenia. Clinical follow-up, with a median of 4 years, was performed using both a survey among the requesting general practitioners and by analysis of the records of the referral hospitals within the borders of the defined area. Results: A total of 520 cases with asymptomatic lymphocytosis were identified. In all cases, the CD19 count was performed; 207 (40%) showed increased values and 313 (60%) showed normal values. An increase in CD19 proved highly sensitive for detection of B-CLPD (98%, 95% CI; 94%–100%) with a high positive predictive value (57%, 95% CI; 50%–63%). The area under curve, the receiver-operating characteristic curve of the CD19 count (0.93, 95% CI; 0.91–0.96), was significantly higher compared to the absolute lymphocyte count (0.86, 95% CI; 0.83–0.89), especially in patients with moderate lymphocytosis. Conclusions: This study indicates that the CD19 count, performed by a primary care laboratory, is feasible and a promising tool for initial screening of lymphocytosis to discriminate B-CLPD from benign causes of lymphocytosis.

Background: In this study, the effect of gender and physio-logical ageing on circulating concentrations of plasma sulfated glycosaminoglycans (sGAG) as well as molecules involved in pro- (tumor necrosis factor-α; TNF-α) and anti-inflammatory responses (soluble tumor necrosis factor receptor-1, sTNF-RI) were assessed. The relationships between sGAG and molecules involved in age-dependent extracellular matrix (ECM) remodeling during physiological ageing were also investigated. Methods: Circulating TNF-α and sTNF-RI were measured in 91 healthy volunteers using enzyme-linked immunosorbent assays. sGAG were quantified using an Alcian blue-binding assay. Results: A linear age-related decline in plasma sGAG was found during the first five decades of life (r=–0.61, p<0.05), followed by an increase occurring only in females (r=0.46, p<0.05). Circulating TNF-α concentrations were inversely correlated with age (r=–0.24, p<0.05) over the lifetime. For TNF-α, the observed changes were gender specific. Serum sTNF-RI concentrations were not affected by age in either men or women. A significant positive correlation was found between the concentrations of TNF-α and both sGAG (r=0.22, p<0.05) and sTNF-RI (r=0.21, p<0.05). Conclusions: Our data demonstrate that physiological ageing is associated with ECM remodeling, reflected by plasma sGAGs concentrations. Changes in the ECM metabolism during the ageing process were influenced by circulating TNF-α. Furthermore, serum concentrations of biomolecules involved in pro- and anti-inflammatory responses are not increased in healthy elderly subjects.

Background: Hyperuricemia has been implicated in the pathogenesis of obesity and related metabolic abnormalities. Studies on the association between serum uric acid (sUA) and metabolic syndrome (MetS) in juvenile obesity are scant. The effect of gender has not been evaluated. Methods: sUA (uricase method), anthropometric and biochemical indices were measured in gender-stratified children/adolescents consisting of 113 overweight/obese and 71 lean individuals. Results: In males, sUA was significantly elevated in overweight as well as obese patients. sUA was strongly associated with obesity indices and reflected sexual development, decreases in high density lipoprotein-cholesterol, and moderately, the number of MetS components. Waist circumference (WC) and Tanner stage explained 40% of sUA variability. Controlling for body mass index (BMI) and other MetS components, sUA was associated with abdominal obesity, explaining 30% of variability in WC. In females, sUA was significantly increased in obesity, high blood pressure (BP), and MetS and corresponded with the number of MetS components, indices of glucose metabolism, triglycerides (TG), and the atherogenecity index. Insulin-resistance (IR) (homeostasis model assessment; HOMA) and high BP explained 29% of sUA variability, whereas sUA, while controlling for BMI, age, and other MetS components, was associated with hypertriglyceridemia, hyperglycemia, high BP, and abdominal obesity. IR mediated the associations with high TG and glucose. Conclusions: The association between sUA and MetS components in juvenile obesity is gender-specific, with females being related more closely and to more metabolic abnormalities. It may explain why, despite its lower concentrations, sUA is an independent predictor of mortality from all causes and from vascular diseases exclusively in females. Our findings may help in identifying metabolic abnormalities which may possibly be targeted by reducing sUA in males and females.

Background: The aim of this study was to investigate the possible correlation between smoking status and biomarkers of exposure (BoE) and biological effect (BoBE) in monozygotic twins discordant for smoking status (smoker and non-smoker pairs). By eliminating potential genetic variability in this manner, a clearer pattern of the effects of lifestyle and environmental exposures should become apparent. Methods: This was a cross-sectional study on monozygotic healthy twins (44 subjects, 26 males and 18 females) with a mean age 31.5 years. BoE to cigarette smoke and BoBE were measured in body fluids (24 h urine and blood) after medical pre-screening. Results: All BoE were significantly higher in the smoker twins. Among BoBE, 11-dehydrothromboxane B 2 (11-dehydro TBX), 2,3-dinorthromboxane B 2 (2,3-dinor TBX), 8-epi-prostaglandin F2α (8-epiPGF), hydroxyproline (OH-P), fibrinogen, white blood cell (WBC), neutrophil and lymphocyte counts and heart rate were statistically significantly increased in the smoker compared to the non-smoker twins. Moreover, statistically significant correlations between neutrophil count and 11-dehydro TBX (r=0.32), WBC and 8-epiPGF (r=0.33), OH-P and 8-epiPGF (r=0.49) and heart rate and fibrinogen (r=0.46) were observed. Conclusions: The study results confirmed the reliability of the BoE for the evaluation of smoking status. Moreover, a subset of the BoBE, reported as being associated with inflammatory conditions and early stages of vascular disorders, has emerged as showing a consistent relationship with smoking status from the present and the previous studies. By using monozygotic twin pairs, genetic variability has been excluded as a possible source of variability in this study. These results should assist in the interpretation of other population studies using these biomarkers.

Background: Mesothelioma and ovarian cancer have been reported to have a similar pathogenesis, and for this reason it was hypothesized that there may be biomarkers in common and possibly associated with benign pleural diseases caused by asbestos exposure. Methods: Serum biomarkers including insulin-like growth factor-II (IGF-II), leptin, prolactin and vascular endothelial growth factor (VEGF) were measured in an observational study of subjects with benign asbestos-related pleural diseases (BARPD) (n=24) and healthy subjects with an asbestos exposure history (n=12). Results: Mean serum IGF-II and VEGF concentration in healthy subjects with a history of asbestos exposure were higher than those with BARPD. Mean serum concentrations of leptin and prolactin showed opposite trends when compared to IGF-II and VEGF concentrations among these groups. Conclusions: The results suggest that IGF-II and VEGF concentrations are lower in BARPD, similar to studies of ovarian cancer. This finding warrants further investigation with malignant asbestos-related diseases.

Background: Serum cystatin B (CSTB) concentrations have been reported to be increased in patients with hepatocellular carcinoma compared to concentrations seen in normal subjects. In this study, we developed a “fluorescent microsphere immunoassay” (FMI) capable of specifically detecting CSTB in serum. Methods: The FMI used a microparticle conjugated polyclonal antibody to CSTB and biotinylated monoclonal antibody as capture protein and probe protein, respectively. The results were obtained using the Bio-Plex 200 system. Results: The dose-response relationship between CSTB and fluorescent intensity showed linearity in the range 0–1000 pg/mL and 7 pg/mL, sensitivity lower than 11.2 pg/mL. This result revealed that the FMI system was more sensitive than enzyme-linked immunoassay (ELISA). Additionally, the FMI system used smaller sample volumes compared to ELISA. Conclusions: We measured CSTB with both the FMI and an ELISA procedure and compared the two methods. The CSTB concentrations in serum specimens as measured with the FMI assay system were similar to those measured with ELISA. Thus, the new FMI using the Bio-Plex system may be useful for detection of CSTB in human serum.