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Comparison Evaluation of Automated Nucleated Red Blood Cell Enumeration by Sysmex XN 1000 in Comparison With Microscopic Reference in Children Under 1 Year.

Clinical Laboratory

In newborns, elevated nucleated red blood cell (NRBC) levels can be associated with enhanced erythropoietic stress and might be predictive for adverse outcome. Also, the presence of NRBC in peripheral blood might lead to erroneous enumeration results of white blood cells in automated hematology analyzers. We aimed to assess the comparability of the Sysmex XN 1000 to manual slide reviews and correlation of NRBC with inflammation markers.

Specimens of 3397 children under 1 year were compared by automated and microscopic NRBC enumeration. Additionally, potential correlations between NRBC and age and inflammation markers were examined.

Overall, there was good correlation (r = 0.97) between automated (range: 0%-3883%) and microscopic enumeration (range: 0%-3694%) of NRBC with high comparability up to a NRBC value of 200% and an increase in the variation between the two methods with increasing NRBC numbers. When 94 samples with ≤ 200% NRBC and ≥ 30% divergence between methods were separately reanalyzed with respect to overlapping cell populations in their scattergrams, Sysmex would have generated unrecognized incorrect automated results in 47 samples, corresponding to 1.4% of total study samples. NRBC counts were negatively correlated to age, but not to inflammation markers.

Sysmex XN 1000 is highly precise in the enumeration of NRBC in children under 1 year up to counts of 200% and might replace time-intense manual counting in routine diagnostics. In the setting of neonatal and intensive care diagnostics, microscopic control and supervision of scattergrams are highly recommended for any automated NRBC enumeration processes.

Reliability of a Screening Method Using Antibiotic Disks to Detect Carbapenemases in Glucose-Nonfermenting Gram-Negative Microorganisms From Clinical Samples of a Regional Hospital in Southeastern Spain.

Clinical Laboratory

Infections by glucose-nonfermenting gram-negative bacilli (NFGNB) pose a major public health problem due to multiresistance to beta-lactam antibiotics, especially plasmid-borne carbapenemases. Their detection by microbiology laboratories is challenging, and there is a need for easy-to-use and reliable diagnostic techniques. Our objective was to evaluate an in-house screening method to presumptively detect carbapenemases in NFGNB in a simple and clinically useful manner.

The study included 175 NFGNB isolates from urinary, respiratory, and rectal samples. In a triple assay, isolates were incubated at 37°C for 24 h on three solid-culture media: MacConkey II Agar, 5% Sheep Blood Columbia Agar and Mueller Hinton II Agar; meropenem (MEM) and cefepime (FEP) disks were employed for screening. Studies were then performed on the inhibition halo diameter, scanning effects, and the appearance of mutant colonies, which were compared with those observed using the colorimetric Neo-Rapid CARB Kit and immunochromatography (NG5-Test Carba and K-Set for OXA-23). Receiver operating characteristic curves were constructed for these data.

Carbapenemases were expressed by 79/175 (45.1%): 19 Pseudomonas aeruginosa and 60 Acinetobacter baumannii. Optimal inhibition halo diameter cutoffs to detect this resistance on 5% sheep blood agar were as follows: 6 mm (MEM) and 6.5 mm (FEP) for P. aeruginosa (in the absence of scanning effects and mutations) and 10.5 mm (MEM) and 16 mm (FEP) for A. baumannii (even in the presence of scanning effects).

The combined utilization of MEM and FEP antibiotic disks in 5% sheep blood agar, measuring their inhibition haloes, offers an effective method to predict the presence of carbapenemases as resistance mechanism in P. aeruginosa and A. baumannii.

The dilution evaluation as a corrective measure for interference in the white blood cell scattergram in Beckman Coulter DxH 900.

Clinical Laboratory

The Beckman Coulter DxH 900 is a haematological analyser capable of counting and sizing blood cells, and obtaining a complete blood cell count (CBC). This analyses different parameters of red blood cells (RBC), platelets and white blood cells/leukocytes. Some automated CBC counters present limitations due to specimen characteristics, abnormal cells or both factors. In the presence of abnormalities, the DxH 900 has a flagging system, warning the laboratory technician that something needs to be verified. In the present work, we evaluated samples from oncologic patients, presenting a population erroneously perceived as being lymphocytes. The most common explanations for this situation are RBC resistant to lysis or serum hyperbilirubinaemia.

In an attempt to solve and understand what the cause of this problem might be, we diluted our samples (1:3) and analysed the serum total bilirubin. To identify cells' abnormalities, the samples were also analysed by manual DLC counts. During the study, we also checked the different flags presented by the equipment.

The results evidenced that the major interference was due to RBC lysis resistance, corresponding to 94.7% of the cases, while hyperbilirubinaemia was only present in 73.4%. Besides, we determined that some samples with normal bilirubin levels also presented interference, suggesting that hyperbilirubinaemia was not the main cause of the error. The most recurrent flag observed was "High event rate".

The dilution solved all of the observed interferences. The results between diluted and manual counts showed a strong correlation, leading us to introduce dilution in our laboratory routine.

A Multiplex Recombinase-Aided qPCR Assay for Highly Sensitive and Rapid Detection of khe, blaKPC -2, and blaNDM -1 Genes in Klebsiella pneumoniae.

Clinical Laboratory

This study aimed to establish a highly sensitive and rapid single-tube, two-stage, multiplex recombinase-aided qPCR (mRAP) assay to specifically detect the khe, blaKPC-2, and blaNDM-1 genes in Klebsiella pneumoniae.

mRAP was carried out in a qPCR instrument within 1 h. The analytical sensitivities of mRAP for khe, blaKPC-2, and blaNDM-1 genes were tested using recombinant plasmids and dilutions of reference strains. A total of 137 clinical isolates and 86 sputum samples were used to validate the clinical performance of mRAP.

mRAP achieved the sensitivities of 10, 8, and 14 copies/reaction for khe, blaKPC-2, and blaNDM-1 genes, respectively, superior to qPCR. The Kappa value of qPCR and mRAP for detecting khe, blaKPC-2, and blaNDM-1 genes was 1, 0.855, and 1, respectively (p < 0.05).

mRAP is a rapid and highly sensitive assay for potential clinical identification of khe, blaKPC-2, and blaNDM-1 genes in K. pneumoniae.

Effect of a Declined Plasma Concentration of Valproic Acid Induced by Meropenem on the Antiepileptic Efficacy of Valproic Acid.

Clinical Laboratory

This study aimed to indicate whether a declined plasma concentration of valproic acid (VPA) induced by co-administration of meropenem (MEPM) could affect the antiepileptic efficacy of VPA.

We retrospectively reviewed data of hospitalized patients who were diagnosed with status epilepticus or epilepsy between 2010 and 2019. Patients co-administered VPA and MEPM during hospitalization were screened and assigned to the exposure group, while those co-administerd VPA and other broad-spectrum antibiotics were allocated to the control group.

The exposure group and control group included 50 and 11 patients, respectively. With a similar dosage of VPA, the plasma concentration of VPA significantly decreased during co-administration (24.6 ± 4.3 μg/mL) compared with that before co-administration (88.8 ± 13.6 μg/mL, p < 0.0001), and it was partly recovered with the termination of co-administration (39.8 ± 13.2 μg/mL, p = 0.163) in the exposure group. The inverse probability of treatment weighting estimated the treatment efficacy via changes in seizure frequency, seizure duration, and concomitant use of antiepileptic drugs, which were not significantly different between the exposure and control groups. In the exposure group, there was no significant differences in seizure frequency between the periods of before-during and before-after (p = 0.074 and 0.153, respectively). Seizure duration during VPA-MEPM co-administration was not significantly different from that before co-administration (p = 0.291).

In this study, the reduced plasma concentration of VPA induced by the co-administration of MEPM did not affect the antiepileptic efficacy of VPA. This conclusion should be interpreted with caution, and more research is warranted.

Chinese Clinical Trial Registry: ChiCTR2000034567. Registered on 10 July 2020.

Clinical Performance of Immunonephelometric Assay and Chemiluminescent Immunoassay for Detection of IgG Subclasses in Chinese.

Clinical Laboratory

Detection of IgG subclasses (IgGSc) is vital for the diagnosis and management of disease, especially IgG4-related diseases (IgG4-RD). This study aimed to evaluate the performances of the chemiluminescent immunoassay (CLIA) for detecting IgGSc and diagnosing IgG4-RD by IgGSc.

A total of 40 individuals with IgG4-RD, 40 with primary Sjogren's syndrome (pSS), and 40 healthy controls (HCs) were enrolled. Serum samples were collected for the simultaneous detection of IgG1, IgG2, IgG3, and IgG4 by the Siemens immunonephelometric assay and the CLIA. The correlation analysis was performed, and diagnostic value was analyzed by the receiver operating characteristic (ROC) curve.

Patients with IgG4-RD had higher IgG4 (p < 0.001) and lower IgG1 (p < 0.001) than those with pSS, and HC. The results by the Siemens immunonephelometric assay and the CLIA showed a strong correlation in detecting IgG1, IgG2, IgG3, and IgG4 (r = 0.937, r = 0.847, r = 0.871, r = 0.990, all p < 0.001, respectively). The sum of IgG1, IgG2, IgG3, and IgG4 using two assays strongly correlated with total IgG by the IMMAGE 800 (r = 0.866, r = 0.811, both p < 0.001, respectively). For discriminating IgG4-RD from pSS and HC, no significant differences were observed in CLIA IgG4 and Siemens immunonephelometric assay IgG4 (z = 0.138, p = 0.891), which provided the area under the curves (AUCs) of 0.951 (p < 0.001) and 0.950 (p < 0.001), respectively. The AUCs of CLIA IgG1 and Siemens immunonephelometric assay IgG1 in distinguishing pSS from IgG4-RD and HC were 0.761 (p < 0.001) and 0.765 (p < 0.001), respectively, with no significant differences (z = 0.228, p = 0.820).

The CLIA and the Siemens immunonephelometric assay appeared to have good consistency with comparable diagnostic value in detecting IgGSc, especially IgG4, and IgG1 that can accurately identify IgG4-RD or pSS in clinical practice.

Assessment of Faecal Microbiota Transplant Stability in Deep-Freeze Conditions: A 12-Month Ex Vivo Viability Analysis.

Clinical Laboratory

Faecal microbiota transplantation (FMT) is an established treatment for Clostridioides difficile infection and is under investigation for other conditions. The availability of suitable donors and the logistics of fresh stool preparation present challenges, making frozen, biobanked stools an attractive alternative.

This study aimed to evaluate the long-term viability of bacterial populations in faecal samples stored at -80°C for up to 12 months, supporting the feasibility of using frozen grafts for FMT.

Fifteen faecal samples from nine healthy donors were processed, mixed with cryoprotectants and stored at -80°C. Samples were assessed at baseline and after 3, 6 and 12 months using quantitative culturing methods to determine the concentration of live bacteria.

Quantitative analysis showed no significant decrease in bacterial viability over the 12-month period for both aerobic and anaerobic cultures (p = 0.09). At all timepoints, the coefficients of variability in colony-forming unit (CFU) counts were greater between samples (102 ± 21% and 100 ± 13% for aerobic and anaerobic cultures, respectively) than the variability between measurements of the same sample (30 ± 22% and 30 ± 19%).

The study confirmed that faecal microbiota can be preserved with high viability in deep-freeze storage for up to a year, making allogenic FMT from biobanked samples a viable and safer option for patients. However, a multidonor approach may be beneficial to mitigate the risk of viability loss in any single donor sample.

Dynein Light Intermediate Chains Exhibit Different Arginine Methylation Patterns.

Clinical Laboratory

The motor protein dynein is integral to retrograde transport along microtubules and interacts with numerous cargoes through the recruitment of cargo-specific adaptor proteins. This interaction is mediated by dynein light intermediate chain subunits LIC1 (DYNC1LI1) and LIC2 (DYNC1LI2), which govern the adaptor binding and are present in distinct dynein complexes with overlapping and unique functions.

Using bioinformatics, we analyzed the C-terminal domains (CTDs) of LIC1 and LIC2, revealing similar structural features but diverse post-translational modifications (PTMs). The methylation status of LIC2 and the proteins involved in this modification were examined through immunoprecipitation and immunoblotting analyses. The specific methylation sites on LIC2 were identified through a site-directed mutagenesis analysis, contributing to a deeper understanding of the regulatory mechanisms of the dynein complex.

We found that LIC2 is specifically methylated at the arginine 397 residue, a reaction that is catalyzed by protein arginine methyltransferase 1 (PRMT1).

The distinct PTMs of the LIC subunits offer a versatile mechanism for dynein to transport diverse cargoes efficiently. Understanding how these PTMs influence the functions of LIC2, and how they differ from LIC1, is crucial for elucidating the role of dynein-related transport pathways in a range of diseases. The discovery of the arginine 397 methylation site on LIC2 enhances our insight into the regulatory PTMs of dynein functions.

Analytical Performance Evaluation of a Digital Real-Time PCR for Quantifying Major BCR::ABL1 Transcripts.

Clinical Laboratory

Accurate quantification of the BCR::ABL1 transcripts is essential for measurable residual disease (MRD) monitoring in chronic myeloid leukemia (CML) after tyrosine kinase inhibitor (TKI) treatment. This study evaluated the newly developed digital real-time PCR method, Dr. PCR, as an alternative reverse transcription-PCR (qRT-PCR) for MRD detection.

The performance of Dr. PCR was assessed using reference and clinical materials. Precision, linearity, and correlation with qRT-PCR were evaluated. MRD levels detected by Dr. PCR were compared with qRT-PCR, and practical advantages were investigated.

Dr. PCR detected MRD up to 0.0032%IS (MR4.5) with excellent precision and linearity and showed a strong correlation with qRT-PCR results. Notably, Dr. PCR identified higher levels of MRD in 12.7% (29/229) of patients than qRT-PCR, including six cases of MR4, which is a critical level for TKI discontinuation. Dr. PCR also allowed for sufficient ABL1 copies in all cases, while qRT-PCR necessitated multiple repeat tests in 3.5% (8/229) of cases.

Our study provides a body of evidence supporting the clinical application of Dr. PCR as a rapid and efficient method for assessing MRD in patients with CML under the current treatment regimen.

A Systematic Literature Review on the Use of Dried Biofluid Microsampling in Patients With Kidney Disease.

Clinical Laboratory

Kidney disease is fairly unique due to the lack of symptoms associated with disease activity, and it is therefore dependent on biological monitoring. Dried biofluids, particularly dried capillary blood spots, are an accessible, easy-to-use technology that have seen increased utility in basic science research over the past decade. However, their use is yet to reach the kidney patient population clinically or in large-scale discovery science initiatives. The aim of this study was to systematically evaluate the existing literature surrounding the use of dried biofluids in kidney research.

A systematic literature review was conducted using three search engines and a predefined search term strategy. Results were summarised according to the collection method, type of biofluid, application to kidney disease, cost, sample stability and patient acceptability.

In total, 404 studies were identified and 67 were eligible. In total, 34,739 patients were recruited to these studies with a skew towards male participants (> 73%). The majority of samples were blood, which was used either for monitoring anti-rejection immunosuppressive drug concentrations or for kidney function. Dried biofluids offered significant cost savings to the patient and healthcare service. The majority of patients preferred home microsampling when compared to conventional monitoring.

There is an unmet need in bringing dried microsampling technology to advance kidney disease despite its advantages. This technology provides an opportunity to upscale patient recruitment and longitudinal sampling, enhance vein preservation and overcome participation bias in research.

INPP5E Regulates the Distribution of Phospholipids on Cilia in RPE1 Cells.

Clinical Laboratory

Primary cilia are static microtubule-based structures protruding from the cell surface and present on most vertebrate cells. The appropriate localization of phospholipids is essential for cilia formation and stability. INPP5E is a cilia-localized inositol 5-phosphatase; its deletion alters the phosphoinositide composition in the ciliary membrane, disrupting ciliary function.

The EGFP-2xP4MSidM, PHPLCδ1-EGFP, and SMO-tRFP plasmids were constructed by the Gateway system to establish a stable RPE1 cell line. The INPP5E KO RPE1 cell line was constructed with the CRISPR/Cas9 system. The localization of INPP5E and the distribution of PI(4,5)P2 and PI4P were examined by immunofluorescence microscopy. The fluorescence intensity co-localized with cilia was quantified by ImageJ.

In RPE1 cells, PI4P is localized at the ciliary membrane, whereas PI(4,5)P2 is localized at the base of cilia. Knocking down or knocking out INPP5E alters this distribution, resulting in the distribution of PI(4,5)P2 along the ciliary membrane and the disappearance of PI4P from the cilia. Meanwhile, PI(4,5)P2 is located in the ciliary membrane labeled by SMO-tRFP.

INPP5E regulates the distribution of phosphoinositide on cilia. PI(4,5)P2 localizes at the ciliary membrane labeled with SMO-tRFP, indicating that ciliary pocket membrane contains PI(4,5)P2, and phosphoinositide composition in early membrane structures may differ from that in mature ciliary membrane.

Molecular Characterization of α- and β-Thalassemia Among Children Less Than 18 Years Old in Guizhou, China.

Clinical Laboratory

Thalassemia is an inherited hemolytic disease, the complications and sequelae of which have posed a huge impact on both patients and society. But limited studies have investigated the molecular characterization of α- and β-thalassemia in children from Guizhou, China.

Between January 2019 and December 2022, a total of 3301 children, aged 6 months to 18 years, suspected of having thalassemia underwent molecular analysis.

Out of the total sample, 824 (25%) children were found to carry thalassemia mutations. The carrier rates of α-thalassemia, β-thalassemia, and α + β-thalassemia were determined as 8.1%, 15.6%, and 1.3%, respectively. Approximately 96.5% of the α-thalassemia gene mutations were --SEA (51%), ααCS (20.9%), -α3.7 (19.6%), and -α4.2 (5.0%). The most prevalent mutations of β-thalassemia were βCD17(A>T) (41.5%), βCD41-42(-TTCT) (37.7%), and βIVS-II-654(C>T) (11.3%). Additionally, we identified rare cases, including one case with ααHb Nunobiki /αα, two cases with triplicated α-thalassemia (one case with ααα/ααα and βCD41-42 /βN and the other with ααα-3.7 /αα and βE CD26 /βN ), and also one case with α Q-Thailand α/-α4.2 and βCD41-42 /βN .

Our study findings provide important insights into the heterogeneity of thalassemia carrier rates and molecular profiles among children in the Guizhou region. The findings support the development of prevention strategies to reduce the incidence of severe thalassemia in the future.