Clinical biochemistry最新文献

A rapidly expanding repertoire of neural antibody biomarkers exists for autoimmune central nervous system (CNS) disorders. Following clinical recognition of an autoimmune CNS disorder, the detection of a neural antibody facilitates diagnosis and informs prognosis and management. This review considers the phenotypes, diagnostic assay methodologies, and clinical utility of neural antibodies in autoimmune CNS disorders. Autoimmune CNS disorders may present with a diverse range of clinical features. Clinical phenotype should inform the neural antibodies selected for testing via the use of phenotype-specific panels. Both serum and cerebrospinal fluid (CSF) are preferred in the vast majority of cases but for some analytes either CSF (e.g. N-methyl-D-aspartate receptor [NMDA-R] IgG) or serum (e.g. aquaporin-4 [AQP4] IgG) specimens may be preferred. Screening using 2 methods is recommended for most analytes, particularly paraneoplastic antibodies. We utilize murine tissue-based indirect immunofluorescence assay (TIFA) with subsequent confirmatory protein-specific testing. The cellular location of the target antigen informs choice of confirmatory diagnostic assay (e.g. blot for intracellular antigens such as Hu; cell-based assay for cell surface targets such as leucine-rich glioma inactivated 1 [LGI1]). Titers of positive results have limited diagnostic utility with the exception of glutamic acid decarboxylase (GAD) 65 IgG autoimmunity, which is associated with neurological disease at higher values. While novel antibodies are typically discovered using established techniques such as TIFA and immunoprecipitation-mass spectrometry, more recent high-throughput molecular technologies (such as protein microarray and phage-display immunoprecipitation sequencing) may expedite the process of antibody discovery. Individual neural antibodies inform the clinician regarding the clinical associations, oncological risk stratification and tumor histology, the likely prognosis, and immunotherapy choice. In the era of neural antibody biomarkers for autoimmune CNS disorders, access to appropriate laboratory assays for neural antibodies is of critical importance in the diagnosis and management of these disorders.

Introduction

2,3-dinor 11β-Prostaglandin F2α (BPG) is an arachidonic acid derivative and the most abundant metabolic byproduct of prostaglandin D2, which is released during mast cell activation. Therefore, measurements of BPG in urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) provide a noninvasive method for evaluation and management of mast cell disorders. Measurements obtained by LC-MS/MS exhibit a high prevalence of chromatographic interferences resulting in challenges with optimal determination of BGP. In this investigation, differential mobility spectrometry (DMS) is utilized to overcome the limitations of current testing.

Methods

Urine samples were extracted using an automated solid-phase extraction method. Samples were then analyzed with and without DMS devices installed on two commercially available mass spectrometry platforms to assess the benefits of DMS. Following promising results from a preliminary analytical evaluation, LC-DMS-MS/MS measurements of BPG in urine were fully validated to assess the analytical implications of using this technology.

Results and discussion

The addition of DMS devices to the LC-MS/MS systems evaluated in this investigation significantly reduced interferences observed in the chromatograms. Concomitantly, DMS reduced the number of discordant quantifier/qualifier fragment ion results that significantly exceeded the ± 20 % limits, suggesting greater analytical specificity. The validation studies yielded low interday imprecision, with %CVs less than 6.5 % across 20 replicate measurements. Validation studies assessing other aspects of analytical performance also met acceptance criteria.

Conclusions

Incorporating DMS devices greatly improved the specificity of BPG measurements by LC-MS/MS, as evidenced by the comparison of chromatograms and fragment ion results. Validation studies showed exceptional performance for established analytical metrics, indicating that this technology can be used to minimize the impact of interferences without adversely impacting other aspects of analytical or clinical performance.

Introduction

Compared to normal PiMM, individuals with severe α1-antitrypsin (AAT) PiZZ (Glu342Lys) genotype deficiency are at higher risk of developing early-onset chronic obstructive pulmonary disease (COPD)/emphysema associated with Z-AAT polymers and neutrophilic inflammation. We aimed to investigate putative differences in plasma levels of acute phase proteins (APP) between PiMM and PiZZ subjects and to determine plasma Z-AAT polymer levels in PiZZ subjects.

Materials and methods

Nephelometric analysis of seven plasma APPs was performed in 67 PiMM and 44 PiZZ subjects, of whom 43 and 42, respectively, had stable COPD. Of the PiZZ-COPD patients, 21 received and 23 did not receive intravenous therapy with human AAT preparations (IV-AAT). Plasma levels of Z-AAT polymers were determined by Western blotting using specific mouse monoclonal antibodies (2C1 and LG96).

Results

In addition to lower plasma AAT, PiZZ patients had higher α2-macroglobulin (A2MG) levels than PiMM patients. In contrast, PiZZ who received IV-AAT had higher AAT values but lower A2MG values than PiZZ without IV-AAT. Regardless of the AAT genotype, AAT levels were inversely correlated with A2MG, and the AAT/A2MG ratio was correlated with lung diffusion capacity (DCLO%). All PiZZ patients had circulating Z-AAT polymer levels that correlated directly with A2MG. In PiZZ without IV-AAT therapy polymer levels correlated inversely with the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC).

Conclusion

Combined measurement of plasma AAT and A2MG levels may be of clinical value in assessing the progression of COPD and requires further attention.

Background

Multiple Acyl-CoA Dehydrogenase Deficiency (MADD), also known as Glutaric Aciduria Type II, is an exceptionally rare autosomal recessive genetic disorder that disrupts the metabolism of fatty acids, amino acids, and choline. It presents with a wide range of clinical manifestations, from severe neonatal-onset forms to milder late-onset cases, with symptoms including metabolic disturbances and muscle weakness. Jordan's anomaly is a distinctive morphological feature found in peripheral blood white cells and is typically associated with Neutral Lipid Storage Disease (NLSD).

Case report

In our case report, the patient initially presented with symptoms of vomiting, abdominal pain, and altered consciousness. The presence of white cell Jordan's anomaly was detected in the blood smear. Subsequent serum tests revealed elevated levels of transaminases, creatine kinase, uric acid, and multiple acylcarnitines, while blood glucose and free carnitine levels were notably reduced. High-throughput sequencing confirmed heterozygous pathogenic variants in the electron-transferring flavoprotein dehydrogenase (ETFDH) gene, leading to the conclusive diagnosis of MADD. Following a three-month treatment regimen involving high-dose vitamin B2, coenzyme Q10, and other supportive interventions, the patient exhibited significant clinical improvement, ultimately resulting in discharge.

Conclusion

The identification of Jordan's anomaly in a pediatric patient with late-onset MADD sheds light on its broader implications within the realm of lipid storage myopathies. The significance of this finding extends beyond its conventional association with NLSD, challenging the notion of its exclusivity. This novel observation serves as a compelling reminder of the diagnostic significance this morphological abnormality holds, potentially revolutionizing diagnostic practices within the field.

Objectives

Our objective was to shorten the screen for multiple myeloma (MM), through reflex testing.

Design and Methods

The clinical laboratory in the public University Hospital of San Juan (Alicante, Spain), serves 234,551 inhabitants. Through an intervention agreed with general practitioners, the Laboratory Information System (LIS) automatically registered serum immunoglobulins (Ig) when serum total proteins (STP) > 80 g/L for the first time in primary care patients. When concomitantly one Ig presented a value above and one below its reference interval, the LIS automatically registered a serum protein electrophoresis (SPEP). When a monoclonal peak in SPEP, immunofixation electrophoresis (IFE) for the typification of monoclonal bands (MB) was performed. If MB were present, a comment in the report explained the intervention. The number of additionally registered Ig, SPEP, IFE, and new diagnosis of MM were counted. The number of days elapsed from the report of elevated STP result to the final MM diagnosis was also counted as median and interquartile range (IQR), and compared to a pre intervention period.

Results

2071 cases of hyperproteinemia were identified, and had 91 a monoclonal peak, confirmed by IFE. In 35 patients it was a new finding, and 9 were diagnosed with MM, 3 Waldestrom macroglobulinemia, 2 lymphoplasmacytic lymphoma and 21 monoclonal gammopathy of undetermined significance. The number of days elapsed from hyperproteinemia to diagnosis was lower in the intervention period (21.5 vs 119.4) (P < 0.01). As our results show, in addition to shortening the time to diagnosis, an increased rate of detection of plasma cell disorders was observed when using our algorithm.

Conclusions

The above laboratory interventions agreed with clinicians, making use of laboratory technology resulted in early identification of MM.

Objectives

Growing evidence suggests that systemic lupus erythematosus (SLE), an organ-damaging systemic autoimmune illness, may be influenced by long-noncoding RNAs (lncRNAs). This study aimed to assess the relative expression of lncRNAs (MIR31HG, NKILA, and PACER) in patients with SLE to evaluate their role in the disease.

Design and Methods

This study involved 70 patients with SLE and 70 apparently healthy control subjects. The expression levels of lnc-MIR31HG, NKILA, and PACER were quantified using real-time PCR.

Results

Lnc-MIR31HG, NKILA, and PACER were significantly upregulated in SLE cases compared to controls (P < 0.001). ROC curve analysis revealed a 91.43 % sensitivity of PACER for the diagnosis of SLE at a cutoff point of > 1.46, followed by NKILA with 90 % sensitivity at a cutoff point of > 1.16, and MIR31HG with 85.71 % sensitivity at a cutoff point of > 1.43. MIR31HG had the highest sensitivity for the diagnosis of lupus nephritis (86.67 %) at a cutoff point of > 7.19, then NKILA with 80 % sensitivity at a cutoff point of > 8.12, and finally PACER expression with 73.33 % sensitivity at a cutoff point of > 18.19. Moreover, MIR31HG and NKILA revealed a significant correlation with albumin/creatinine ratio, estimated glomerular filtration rate, and the SLEDAI score. Regression analysis revealed the potential roles of MIR31HG, NKILA, and PACER expression as predictors for SLE.

Conclusion

An upregulated lncRNA panel (MIR31HG, NKILA, and PACER) could play a role in the pathogenesis and, hence, the predisposition to SLE. MIR31HG and NKILA can serve as prognostic markers significantly linked with disease activity.

Background

Recently acquired data suggests that sodium-glucose cotransporter-2 (SGLT2) may be a therapeutic target for cerebral ischemia. The specific impact of SGLT2 in acute ischemic stroke (AIS) remains unknown. We aimed to explore the levels of SGLT2 in AIS patients and its association with functional prognosis.

Methods

In this study, 132 AIS patients and 44 healthy controls were recruited prospectively to determine serum SGLT2 levels. Logistic regression analysis was employed to assess the association between serum SGLT2 level and stroke risk as well as 3-month outcome. Receiver operating characteristic (ROC) curves were utilized to evaluate predictive values for blood biomarkers.

Results

Serum SGLT2 levels were significantly higher (P =.000) in AIS patients (47.1 (interquartile range [IQR]: 42.4–50.9) ng/mL) than healthy controls (35.7 (IQR: 28.6–39.5) ng/mL). The optimal SGLT2 cutoff point for diagnosing AIS was 39.55 ng/mL, with a sensitivity of 90.2 % and specificity of 77.3 %. Serum levels of SGLT2 were negatively correlated with the onset time of AIS (linear fit R² = 0.056, P =.006), but were not associated with National Institutes of Health Stroke Scale (NIHSS) scores (r = 0.007, P >.05) and lesion volume (r = -0.151, P >.05). SGLT2 was not remarkably different between patients with unfavorable and favorable outcomes (46.7 (IQR: 41.9–49.6) ng/mL vs 47.6 (IQR: 42.5–51.9) ng/mL; P =.321).

Conclusions

The serum SGLT2 concentration may be a potential biomarker for the diagnosis of AIS. However, it does not exhibit any association with disease severity or functional prognosis.

Introduction

Multiple studies have investigated the role of cardiac troponin (cTn) in the risk stratification of patients with COVID-19. Most of these investigations are based on cTn values at presentation and do not consider the prognostic significance of cTn changes over time. This study aimed to investigate the prognostic role of serial cTn measurements in patients hospitalized with COVID-19 with samples that were not obtained for clinical indications.

Methods

Patients hospitalized between April 2020 and March 2021 with PCR-confirmed SARS-CoV-2 infection were evaluated. Blood samples collected for any reason were stored for subsequent analysis. If clinical high sensitivity hs-cTnT (Roche) was not measured, samples were tested separately in batches. Hs-cTnI (Abbott) was also evaluated.

Results

There were 228 unique patients. There were 21 (9.2 %) deaths. No patient with a low hs-cTnT (<6 ng/L) died and 1 patient with low hs-cTnI (<5 ng/L) died. Myocardial injury was associated with higher odds of death, when defined by hs-cTnT (OR: 7.88, 95 % CI: 2.04–30.40, p = 0.003) or hs-cTnI (OR: 7.46, 95 % CI: 2.68–20.77, p < 0.001). This association remained after propensity weighting. An increasing pattern was associated with higher odds of death compared to a stable pattern for hs-cTnT (OR: 5.45, 95 % CI: 1.81–16.40, p = 0.003) and hs-cTnI (OR: 4.49, 95 % CI: 1.02–19.81, p = 0.048). Among patients with myocardial injury defined by hs-cTnT, an increasing pattern was associated with higher odds of death compared to a decreasing pattern (OR: 4.80, 95 % CI: 1.16–19.97, p = 0.031).

Conclusions

Patients hospitalized with COVID-19 with myocardial injury have higher odds of death. Serial hs-cTn testing provides additional risk stratification in these patients.

Background

An analytical benchmark for high-sensitivity cardiac troponin (hs-cTn) assays is to achieve a coefficient of variation (CV) of ≤ 10.0 % at the 99th percentile upper reference limit (URL) used for the diagnosis of myocardial infarction. Few prospective multicenter studies have evaluated assay imprecision and none have determined precision at the female URL which is lower than the male URL for all cardiac troponin assays.

Methods

Human serum and plasma matrix samples were constructed to yield hs-cTn concentrations near the female URLs for the Abbott, Beckman, Roche, and Siemens hs-cTn assays. These materials were sent (on dry ice) to 35 Canadian hospital laboratories (n = 64 instruments evaluated) participating in a larger clinical trial, with instructions for storage, handling, and monthly testing over one year. The mean concentration, standard deviation, and CV for each instrument type and an overall pooled CV for each manufacturer were calculated.

Results

The CVs for all individual instruments and overall were ≤ 10.0 % for two manufacturers (Abbott CV_pooled = 6.3 % and Beckman CV_pooled = 7.0 %). One of four Siemens Atellica instruments yielded a CV > 10.0 % (CV_pooled = 7.7 %), whereas 15 of 41 Roche instruments yielded CVs > 10.0 % at the female URL of 9 ng/L used worldwide (6 cobas e411, 1 cobas e601, 4 cobas e602, and 4 cobas e801) (CV_pooled = 11.7 %). Four Roche instruments also yielded CVs > 10.0 % near the female URL of 14 ng/L used in the United States (CV_pooled = 8.5 %).

Conclusions

The number of instruments achieving a CV ≤ 10.0 % at the female 99th-percentile URL varies by manufacturer and by instrument. Monitoring assay precision at the female URL is necessary for some assays to ensure optimal use of this threshold in clinical practice.

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK-9) is a circulating protein that plays an important role in lipid metabolism and is linked to inflammation, which has implications for atherosclerosis and its severe cardiac effects. We studied the potential association of the PCSK-9 gene single nucleotide polymorphism (SNP), Oxidized low-density lipoprotein receptor 1- (OLR-1), and caspase-3 serum levels with the risk and severity of premature coronary artery disease (PCAD). The potential contribution of PCSK-9 serum level to the severity of PCAD patients was also assessed.

Method

This case-control study included 120 PCAD patients (age < 45), and 60 age matched healthy controls. Serum PCSK-9 and caspase-3 levels and clinical characteristics were recorded. SYNTAX score was calculated to estimate the severity of the coronary artery lesions. The SNP rs2483205 of the PCSK-9 gene and the rs11053646 of the OLR-1gene were genotyped in all participants.

Results

Serum PCSK-9 levels were higher in PCAD patients and were significantly different among the three SYNTAX score groups (SS ≤ 12, 12 < SS ≤ 21.5, and SS > 21.5). The diagnostic cutoff values of PCSK-9 and caspase-3 levels for PCAD were > 3.2 ng/mL for both, yielding an area under the curve (AUC) of 0.98 and 0.92, sensitivity of 85 %, 98 %, and specificity of 99.5 %, 93 % for PCSK-9 and caspase-3, respectively. The genotypes TT + CT vs. CC of PCSK-9′s rs2483205 SNP presented a higher risk for PCAD and higher SYNTAX scores. Furthermore, the rs11053646 SNP of OLR-1 presented the CG genotype as more risky and having higher SYNTAX scores.

Conclusion

Circulating PCSK9 and caspase-3 concentrations were higher in PCAD patients and were associated with CAD severity. The SNPs of PCSK-9 (rs2483205) and OLR-1 (rs11053646) were associated with PCAD and its severity.