Lupus anticoagulant laboratory diagnosis by applying the 2020 ISTH-SSC guidelines

BACKGROUND

The ISTH-SSC guidelines for lupus anticoagulant (LA) testing recommend using in-house determined cut-off values, pooled normal plasma (PNP) for ratio normalization, and a ratio for the mixing test interpretation. They strongly support the mixing step role in the diagnostic process.

OBJECTIVES

To investigate and compare the LA testing results and interpretations obtained following the ISTH-SSC guidelines or the available alternatives.

PATIENTS/METHODS

Blood samples for LA testing from 462 consecutive patients were evaluated for screening, mixing and confirmatory tests. The analysis focused on the interpretation differences between using (1) the in-house cut-off values versus the manufacturer's cut-off values, (2) a normalized ratio calculated using PNP at each run versus the mean of the reference interval, (3) a normalized ratio versus the index of circulating anticoagulant to interpret the mixing step, and (4) a two-step versus three-step procedure.

RESULTS

LA testing outcomes were comparable when using the in-house and manufacturer's cut-off values. More positive dilute Russell's viper venom (DRVV) time results were obtained with the normalized ratio based on PNP than with the mean of the reference interval. Overall, the mixing test results obtained with the normalized ratio and the index of circulating anticoagulant showed a good agreement. Among the 97 DRVV Screen test-positive samples, 33 and 89 were classified as LA-positive with the 3-step and the 2-step procedure, respectively.

CONCLUSIONS

The cut-off value used and the way to normalize ratios had a limited impact. Conversely, it is important to understand the mixing test characteristics to maximize its diagnostic potential.

Management of rare inherited bleeding disorders: Proposals of the French Reference Centre on Haemophilia and Rare Coagulation Disorders

INTRODUCTION

The rare coagulation disorders may present significant difficulties in diagnosis and management. In addition, considerable inter-individual variation in bleeding phenotype is observed amongst affected individuals, making the bleeding risk difficult to assess in affected individuals. The last international recommendations on rare inherited bleeding disorders (RIBDs) were published by the United Kingdom Haemophilia Centre Doctors' Organisation in 2014. Since then, new drugs have been marketed, news studies on surgery management in patients with RIBD have been published, and new orphan diseases have been described.

AIM

Therefore, the two main objectives of this review, based on the recent recommendations published by the French Reference Centre on Haemophilia and Rare Bleeding Disorders, are: (i) to briefly describe RIBD (clinical presentation and diagnostic work-up) to help physicians in patient screening for the early detection of such disorders; and (ii) to focus on the current management of acute haemorrhages and long term prophylaxis, surgical interventions, and pregnancy/delivery in patients with RIBD.

[Fatal intracerebral hemorrhage in a patient with chronic neutrophilic leukemia: About one case and literature review]

INTRODUCTION

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative syndrome characterized by a significant increase in mature neutrophils. One of the most serious complications is the occurrence of bleeding events, which may sometimes lead to death.

CASE REPORT

A 75-year-old patient presented with CNL, complicated by a severe bleeding phenotype. Biological investigations revealed platelet function defect and increase in neutrophil elastase. The follow-up was marked by an intracranial hemorrhage leading to the patient's death 7 months after diagnosis.

CONCLUSION

This bleeding phenotype has been reported several times in patients with CNL. However, the pathophysiological mechanisms that cause bleeding are not yet fully understood.

Giant optical nonlinearity interferences in quantum structures

Second-order optical nonlinearities can be greatly enhanced by orders of magnitude in resonantly excited nanostructures. These resonant nonlinearities continually attract attention, particularly in newly discovered materials. However, they are frequently not as heightened as currently predicted, limiting their exploitation in nanostructured nonlinear optics. Here, we present a clear-cut theoretical and experimental demonstration that the second-order nonlinear susceptibility can vary by orders of magnitude as a result of giant destructive, as well as constructive, interference effects in complex systems. Using terahertz quantum cascade lasers as a model source to investigate interband and intersubband nonlinearities, we show that these giant interferences are a result of an unexpected interplay of the second-order nonlinear contributions of multiple light and heavy hole states. As well as of importance to understand and engineer the resonant optical properties of nanostructures, this advanced framework can be used as a novel, sensitive tool to elucidate the band structure properties of complex materials.

Applying FAIR Principles to Plant Phenotypic Data Management in GnpIS

GnpIS is a data repository for plant phenomics that stores whole field and greenhouse experimental data including environment measures. It allows long-term access to datasets following the FAIR principles: Findable, Accessible, Interoperable, and Reusable, by using a flexible and original approach. It is based on a generic and ontology driven data model and an innovative software architecture that uncouples data integration, storage, and querying. It takes advantage of international standards including the Crop Ontology, MIAPPE, and the Breeding API. GnpIS allows handling data for a wide range of species and experiment types, including multiannual perennial plants experimental network or annual plant trials with either raw data, i.e., direct measures, or computed traits. It also ensures the integration and the interoperability among phenotyping datasets and with genotyping data. This is achieved through a careful curation and annotation of the key resources conducted in close collaboration with the communities providing data. Our repository follows the Open Science data publication principles by ensuring citability of each dataset. Finally, GnpIS compliance with international standards enables its interoperability with other data repositories hence allowing data links between phenotype and other data types. GnpIS can therefore contribute to emerging international federations of information systems.

Increased factor VIII plays a significant role in plasma hypercoagulability phenotype of patients with cirrhosis

Essentials The role of increased factor VIII in cirrhosis-induced hypercoagulability has never been demonstrated. Factor VIII and protein C effects were characterized by thrombin generation with thrombomodulin. Factor VIII elevation plays a significant role in cirrhosis-induced plasma hypercoagulability. Only protein C and factor VIII normalization led to thrombin generation similar to controls.

SUMMARY

Background In cirrhosis, thrombin generation (TG) studied in the presence of thrombomodulin (TM) indicates plasma hypercoagulability. Although the role of protein C (PC) deficiency has been investigated, the influence of an increase in the factor VIII level has never been addressed. Objectives We investigated the roles of high FVIII and low PC levels in increased TG in the presence of TM. Methods Blood samples were prospectively collected from 35 healthy controls and 93 patients with cirrhosis (Child-Turcotte-Pugh [CTP]-A, n = 61; CTP-B, n = 19; and CTP-C, n = 13) and FVIII levels > 150% (n = 48) and/or PC levels < 70% (n = 88). TG was performed with tissue factor (5 pm), phospholipids, and TM (4 nm). FVIII and PC levels were normalized by adding an inhibitory anti-FVIII antibody and exogenous PC, respectively. Results The endogenous thrombin potential (ETP) in the presence of TM was higher in patients than in controls. After FVIII normalization, the ETP (median) decreased from 929 nm min to 621 nm min (CTP-A), 1122 nm min to 1082 nm min (CTP-B), and 1221 nm min to 1143 nm min (CTP-C); after PC normalization, it decreased from 776 nm min to 566 nm min (CTP-A), 1120 nm min to 790 nm min (CTP-B), and 995 nm min to 790 nm min (CTP-C). The ETP was reduced by 17% and 30%, respectively, but normal TG was not restored. When both FVIII and PC levels were normalized, the ETP decreased from 929 nm min to 340 nm min (CTP-A), 1122 nm min to 506 nm min (CTP-B), and 1226 nm min to 586 nm min (CTP-C), becoming similar to control levels. Conclusion Cirrhosis-induced plasma hypercoagulability, as demonstrated in these experimental conditions, can be partly explained by opposite changes in two factors: PC level (decrease) and FVIII level (increase).

Development of a Simple Hydroponic Assay to Study Vertical and Horizontal Resistance of Soybean and Pathotypes of Phytophthora sojae

Phytophthora root rot, caused by Phytophthora sojae, is one of the most damaging diseases of soybean and the introgression of Rps (Resistance to P. sojae) genes into elite soybean lines is arguably the best way to manage this disease. Current bioassays to phenotype the gene-for-gene relationship are hampered with respect to reproducibility and long-term stability of isolates, and do not accurately predict horizontal resistance individually. The aim of our study was to investigate a new way of phenotyping P. sojae isolates and vertical and horizontal resistance in soybean that relies on zoospores inoculated directly into a hydroponic system. Inoculation of P. sojae isolates against a set of eight differentials accurately and reproducibly identified pathotypes over a period of two years. When applied to test vertical resistance of soybean lines with known and unknown Rps genes, the bioassay relied on plant dry weight to correctly identify all genes. In addition, simultaneous inoculations of three P. sojae isolates, collectively carrying eight major virulence factors against 64 soybean lines with known and unknown levels of horizontal resistance, separated the plants into five distinct groups of root rot, allowing the discrimination of lines with various degrees of partial resistance. Based on those results, this bioassay offers several advantages in facilitating efforts in breeding soybean for P. sojae resistance and in identifying virulence factors in P. sojae.

Are all heparins safe for on-pump heart surgery?

BACKGROUND

Intravenous Panpharma heparin(®) was used in all on-pump cardiac surgery in our heart-surgery department for a short period. This brand of heparin replaced the previous Choay heparin(®) heparin supplied by the Sanofi-Aventis Laboratory. Unusual postoperative bleedings over this period prompted us to evaluate postoperative hemostasis by comparing these two heparins.

METHODS

We compared data from patients who had undergone on-pump cardiac surgery during Panpharma heparin(®) period (group P, 257 patients) to those how received Choay heparin(®) (group C, 194 patients).

RESULTS

Despite group P receiving a significantly lower dose of heparin (mean dose 21,000 IU/CEC) compared to group C (mean dose 22,000 IU/CEC) (p = 0.05), the number of surgical re-explorations needed to perfect postoperative hemostasis was significantly higher for group P (3.5% vs. 0) (p = 0.01). Heparin anti-Xa activity after surgery was higher in group P at postoperative h1 and h12 compared to group C, which explained reoperations for hemostasis.

CONCLUSION

Despite standardization, variations remain regarding anticoagulant activity between different manufacturing processes and heparin preparations. Surgical teams need to be aware that the biological effects of different brands of heparin may not be as expected and could endanger a usually safe procedure, such as cardiac surgery.

Optical sideband generation up to room temperature with mid-infrared quantum cascade lasers

Mid-infrared (MIR) sideband generation on a near infrared (NIR) optical carrier is demonstrated within a quantum cascade laser (QCL). By employing an externally injected NIR beam, E(NIR), that is resonant with the interband transitions of the quantum wells in the QCL, the nonlinear susceptibility is enhanced, leading to both frequency mixing and sideband generation. A GaAs-based MIR QCL (E(QCL) = 135 meV) with an aluminum-reinforced waveguide was utilized to overlap the NIR and MIR modes with the optical nonlinearity of the active region. The resulting difference sideband (E(NIR) - E(QCL)) shows a resonant behavior as a function of NIR pump wavelength and a maximum second order nonlinear susceptibility, χ((2)), of ~1 nm/V was obtained. Further, the sideband intensity showed little dependence with the operating temperature of the QCL, allowing sideband generation to be realized at room temperature.

Computer-predicted peptides that mimic discontinuous epitopes on the A2 domain of factor VIII

Development of antibodies (Abs) against factor VIII (FVIII) is a severe complication of haemophilia A treatment. Recent publications suggest that domain specificity of anti-FVIII antibodies, particularly during immune tolerance induction (ITI), might be related to the outcome of the treatment. Obtaining suitable tools for a fine mapping of discontinuous epitopes could thus be helpful. The aim of this study was to map discontinuous epitopes on FVIII A2 domain using a new epitope prediction functionality of the PEPOP bioinformatics tool and a peptide inhibition assay based on the Luminex technology. We predicted, selected and synthesized 40 peptides mimicking discontinuous epitopes on the A2 domain of FVIII. A new inhibition assays using Luminex technology was performed to identify peptides able to inhibit the binding of anti-A2 Abs to A2 domain. We identified two peptides (IFKKLYHVWTKEVG and LYSRRLPKGVKHFD) able to block the binding of anti-A2 allo-antibodies to this domain. The three-dimensional representation of these two peptides on the A2 domain revealed that they are localized on a limited region of A2. We also confirmed that residues 484-508 of the A2 domain define an antigenic site. We suggest that dissection of the antibody response during ITI using synthetic peptide epitopes could provide important information for the management of patients with inhibitors.

Unequivocal differentiation of coherent and chaotic light through interferometric photon correlation measurements

We present a novel experimental technique that can differentiate unequivocally between chaotic light and coherent light with amplitude fluctuations, and thus permits us to characterize unambiguously the output of a laser. This technique consists of measuring the second-order intensity cross correlation at the outputs of an unbalanced Michelson interferometer. It is applied to a chaotic light source and to the output of a semiconductor nanolaser whose "standard" intensity correlation function above threshold displays values compatible with a mixture of coherent and chaotic light. Our experimental results demonstrate that the output of such lasers is not partially chaotic but is indeed a coherent state with amplitude fluctuations.

Identification of urinary oligosaccharides by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

A new method of urinary oligosaccharides identification by matrix-assisted laser desorption time-of-flight mass spectrometry is presented. The method involves three steps: coupling of the urinary oligosaccharides with 8-aminonaphthalene-1,3,6-trisulfonic acid; fast purification over a porous graphite carbon extraction column; and mass spectrometric analysis. Identification of urinary oligosaccharides is based on the patterns and values of the pseudomolecular ions observed. We report here the patterns in urines from patients with Pompe disease, alpha and beta mannosidoses, galacto-sialidosis, and GM1 gangliosidosis. The protocols described here allowed facile and sensitive identification of the pathognomonic oligosacchariduria present in lysosomal diseases and can be extended to any pathological oligosacchariduria.