Sensitivity of Capillary Electrophoresis to Detect Monoclonal Immunoglobulins: a Report of Two Cases and a Systematic Review.

BACKGROUND: The detection of monoclonal immunoglobulins (MIg) is a key element in the diagnosis of monoclonal gammopathies. METHODS: Here we report two cases of high concentration serum IgM-kappa MIgs (6.4 g/L and 6.8 g/L) not detected with capillary electrophoresis (CE). A systematic literature search was conducted to assess the sensitivity of CE to detect MIgs. RESULTS: The CE sensitivity to detect MIgs did not exceed 0.9 to 0.95 compared to immunofixation as standard. On the one hand, MIgs with blood concentrations below 1 g/L may be hidden by other serum proteins. On the other hand, some MIgs of high concentrations are not detected due to their insolubility in the electrophoresis buffer. CONCLUSIONS: Performing a second SPE with agarose gel electrophoresis method or modifying buffer properties may reveal some MIgs not detected by a first SPE alone.

Factors associated with poor fetal outcome in placental abruption.

OBJECTIVES: We aimed at describing placental abruption in our county and at evaluating factors associated with poor fetal outcome. STUDY DESIGN: In this case-control study, women with placental abruption were identified from two databases of Brest University Hospital between January 2013 and December 2018. MAIN OUTCOME MEASURES: Placental histological findings, course of pregnancies, maternal and fetal characteristics were described and compared between cases (placental abruption with stillbirth or neonatal death) and controls. RESULTS: We identified 135 placental abruption, of whom 24.4% were complicated with stillbirth and 6.5% with neonatal death. Forty percent of women were smokers and 14.1% had a history of vasculoplacental disorder. Pregnancies were complicated with 42.2% of pre-eclampsia and 43% of intrauterine growth restriction. Cases were associated with more autoimmune diseases in mother (20.0% versus 3.2%, P = 0.003), more aspirin or heparin use during pregnancy (20.0% versus 6.3%, P = 0.03), less pre-eclampsia (25.0% versus 49.5%, P = 0.01) and more deliveries ≤ 34 weeks of gestation (80.0% versus 43.2%, P = 0.0001) than controls. Placentas from cases showed more placental indentation ≥ 30% (42.5% versus 5.3%, P < 0.0001) and less histological chronic inflammation, especially less chronic chorioamniotitis (2.5% versus 24.2%, P = 0.002) than controls. In multivariate analysis, factors negatively associated with poor fetal outcome were placental histological chronic inflammation (P = 0.01) and macroscopic infarcts (P = 0.01). CONCLUSIONS: Poor fetal outcome is negatively associated with certain placental histological chronic lesions, but not with pre-eclampsia, what suggests various pathophysiological processes among placental abruption.

Correlation of biological parameters with placental parameters and pregnancy outcomes in pre-eclamptic women.

INTRODUCTION: Pre-eclampsia is characterized by maternal vascular malperfusion and chronic inflammation in placenta. Our purpose was to investigate the potential correlation of biological parameters with placental parameters and pregnancy outcomes in pre-eclamptic women. METHODS: Pre-eclamptic women were identified by interrogation of the Medical Registry Department in six French maternities between April 2013 and June 2018. Histological parameters in placentas (weight, macroscopic and microscopic lesions), baseline maternal characteristics and pregnancy outcomes (course of pregnancy, newborns' characteristics) were collected. Biological parameters were blood cell ratios (Platelet-to-Lymphocyte Ratio (PLR), Neutrophil-to-Lymphocyte Ratio (NLR)) collected at delivery and Placental growth factor (PlGF) measured in women with an available first trimester serum sample. Correlations of blood cell ratios and PlGF levels with placental parameters and pregnancy outcomes were assessed by Pearson's correlation test for quantitative parameters and by logistic regression analysis for qualitative parameters. RESULTS: 202 pregnancies were included, among which 68 had a first trimester PlGF quantification. No correlation was found between biological parameters and placental lesions. Low PLR was correlated with low placental weight (r = 0.156, p = 0.036) and with low birth weight (r = 0.179, p = 0.015). Low PlGF was correlated with long time from pre-eclampsia diagnosis to delivery (r = -0.250, p = 0.048). CONCLUSIONS: There is no correlation between biological parameters and placental lesions in pre-eclamptic women. Yet, low PLR at delivery is correlated with low placental and birth weights. Moreover, low first trimester PlGF is correlated with long time from pre-eclampsia diagnosis to delivery.

Comparison of the New, Rapid, and Fully Automated Kryptor TSH receptor Antibodies Assay (B.R.A.H.M.S.) with the Radioimmunological Assay (B.R.A.H.M.S.).

BACKGROUND: Radioimmunoassays, which are often not automated and time-consuming, are gradually being re-placed in medical laboratories by non-radioactive methods that need to be evaluated. The purpose was to compare the measurement of thyroid-stimulating hormone receptor antibodies (TRAb) by the new Brahms' kit using Kryptor TRACE technology and the Brahms' radioimmunoassay. METHODS: We prospectively collected all samples from patients who received thyroid-stimulating hormone receptor antibodies testing in July 2018 at the University Hospital of Brest. The radioimmunoassay used was the Dynotest TRAK human by BRAHMS Diagnostica (Berlin, Germany). The Kryptor method used the BRAHMS TRAK human Kryptor kit performed with the Kryptor Compact Plus system. RESULTS: The inter-assay coefficient variations for the radioimmunological and Kryptor methods were 11.07% and 8.36%, respectively, with the low level quality control and 8.36% and 4.38%, respectively, with the high level quality control. Forty-four patients were included in the study including thirty-two Graves' disease patients in follow-up. The sensitivity of the radioimmunological method for the detection of Graves' disease was 0.94 and the specificity was 0.73. The sensitivity of the Kryptor method was 0.91 and the specificity was 0.91. A non-proportional systematic bias in favor of higher values of TRAb concentrations with the radioimmunological method was observed: slope of 0.93 (0.74 - 1.07, 95% confidence interval) and an intercept of -0.69 IU/L (-1.58 to -0.30, 95% confidence interval). Compared to the Kryptor method, the radioimmunological method tends to overestimate TRAb concentrations by up to 120%. CONCLUSIONS: The fully automated Brahms Kryptor kit using TRACE technology to measure TRAb reduces sampling time and intra- as well as inter-assay variations. The Kryptor kit underestimates the results of TRAb leading to a lower sensitivity and higher specificity compared to the radioimmunoassay. Thus, the new Brahms Kryptor kit has good laboratory performances but the interpretation of the results must still be performed with caution.

Systematic overestimation of human serum albumin by capillary zone electrophoresis method due to monoclonal immunoglobulin interferences.

BACKGROUND: The capillary zone electrophoresis method of albumin measurement is frequently used in monoclonal gammopathy patients but some studies suggest poor performances of the method in this population. The aim of this study was to analyse the impact of serum monoclonal immunoglobulins on human serum albumin determination by capillary zone electrophoresis method compared to other available methods. METHOD: We prospectively measured albumin in 100 freshly collected non-frozen serum samples in a monoclonal gammopathy patients population, by using four different methods: the capillary zone electrophoresis method, the bromocresol purple dye method, the nephelometric method and the turbidimetric method. Differences in albumin values between the different methods were analysed with respect to serum monoclonal immunoglobulin concentration. These differences were further investigated by measuring albumin levels in human serum samples spiked with exogenous monoclonal immunoglobulins. RESULTS: Human serum albumin difference values between capillary zone electrophoresis compared to immunonephelometry method are significantly correlated with increasing monoclonal immunoglobulins concentrations: regression analyses revealed a correlation coefficient r2 = 0.60 and a slope of 0.14 (0.12-0.17, 95% confidence interval). The capillary zone electrophoresis method overestimated serum albumin levels by up to 67% (12 g/L) when monoclonal immunoglobulin level was 63 g/L. The determination of albumin levels in human serum samples spiked with exogenous monoclonal immunoglobulins showed an overestimation of human serum albumin measurement by the capillary zone electrophoresis method proportional to the amount of monoclonal immunoglobulin added in the serum with a slope of 0.19 (0.18-0.20, 95% confidence interval). CONCLUSION: Monoclonal immunoglobulins directly interfere with serum albumin measurement by the capillary zone electrophoresis method leading to a systematic overestimation of serum albumin concentrations proportional to the serum monoclonal immunoglobulin level.

Is capillary zone electrophoresis a suitable method for estimating serum albumin: A comparison of four methods.

BACKGROUND: The capillary zone electrophoresis method of albumin measurement is frequently used for oncologic and haematologic patients but few data exist about the agreement between the albumin measurements performed by capillary zone electrophoresis and other methods. The aim of this study was to analyse the agreement between human serum albumin measurements by capillary zone electrophoresis and by the nephelometry, bromocresol purple and turbidimetry methods. METHOD: We prospectively measured 100 freshly collected non-frozen patient serum samples, by using four different methods: the capillary zone electrophoresis method performed with a CAPILLARYS 2 instrument, the bromocresol purple dye method performed with an Advia XPT analyser, the nephelometric method performed with a BN ProSpec analyser and the turbidimetric method with reagents from DiAgam and performed with the Advia XPT analyser. RESULTS: A bias towards higher values in the lower range of albumin concentrations was observed with capillary zone electrophoresis compared to immunonephelometry: correlation coefficient r2 = 0.925; slope of 0.86 (0.82-0.89, 95% confidence interval), which is significantly different from 1; and an intercept of 4.94 g/L (3.67-6.16, 95% confidence interval). Similar results were observed when comparing capillary zone electrophoresis to the bromocresol purple and immunoturbidimetry methods. The capillary electrophoresis method overestimated low albumin levels by up to 25% (5 g/L). CONCLUSION: Compared to the nephelometry, turbidimetry and bromocresol purple methods, the capillary zone electrophoresis method tends to overestimate human serum albumin concentrations for levels below 30 g/L. This discrepancy could lead to an overestimation of the nutritional status, an inappropriate scoring of the disease and a delay in nutritional treatment.

Toxofilin upregulates the host cortical actin cytoskeleton dynamics, facilitating Toxoplasma invasion.

Toxoplasma gondii, a human pathogen and a model apicomplexan parasite, actively and rapidly invades host cells. To initiate invasion, the parasite induces the formation of a parasite-cell junction, and progressively propels itself through the junction, inside a newly formed vacuole that encloses the entering parasite. Little is known about how a parasite that is a few microns in diameter overcomes the host cell cortical actin barrier to achieve the remarkably rapid process of internalization (less than a few seconds). Using correlative light and electron microscopy in conjunction with electron tomography and three-dimensional image analysis we identified that toxofilin, an actin-binding protein, secreted by invading parasites correlates with localized sites of disassembly of the host cell actin meshwork. Moreover, quantitative fluorescence speckle microscopy of cells expressing toxofilin showed that toxofilin regulates actin filament disassembly and turnover. Furthermore, Toxoplasma tachyzoites lacking toxofilin, were found to be impaired in cortical actin disassembly and exhibited delayed invasion kinetics. We propose that toxofilin locally upregulates actin turnover thus increasing depolymerization events at the site of entry that in turn loosens the local host cell actin meshwork, facilitating parasite internalization and vacuole folding.