Pooled Serum Research Articles

Effect of Roasting on the Conformational Structure and IgE Binding of Sesame Allergens.

Sesame can trigger a systemic allergic reaction. In the present study, we investigated the responses of the structure and IgE binding of sesame allergens to different roasting treatments (120, 150, and 180 °C for 5 to 30 min). We analyzed the tryptic digestion peptides using a label-free mass spectrometry method. The total amount of soluble proteins in sesame was significantly reduced by roasting at 180 °C, followed by 150 °C. Ses i 1 was the most stable protein during processing as it still possessed a higher protein abundance compared to other allergens after roasting under 180 °C. The most unstable allergens were Ses i 4 and Ses i 7, which suffered severe protein degradation at 180 °C. Roasting at 180 °C remarkably increased the secondary structure content of α-helices but decreased that of β-sheets, whereas roasting at 120 and 150 °C had a limited effect on the secondary structure of sesame proteins. Moreover, serum pool Western blot analysis showed that the main allergens were oleosin of Ses i 4 and Ses i 5. The IgE-binding ability of sesame allergens was significantly decreased under 180 °C roasting, as well as the solubility of sesame proteins, which showed remarkable congruence in changes. Relative quantification results indicate that individual sesame allergens respond differently to the roasting process. In general, sesame allergens are unstable under roasting treatment. Therefore, the allergenic potential of sesame allergens may be minimized by selecting appropriate parameters during processing.

The Comparison of the Point-of-Care Serum Procalcitonin Assay Method with the BRAHMS Certified Method

Background and Aims: As a method for the diagnosis and management of sepsis, the serum procalcitonin assay is routinely used, especially in the emergency department (ED) and intensive care units (ICU). Procalcitonin has reasonable diagnostic accuracy for bacteremia in hospitalized patients of all age groups with suspected infection or sepsis. This study aimed to compare the Getein Biotech procalcitonin point of care method with the ADVIA Centaur® BRAHMS serum procalcitonin method.
 Materials and Methods: Linearity,recovery, accuracy, and imprecision studies were carried out to evaluate the analytical performance. Bland-Altman plots and Passing-Bablok regression analysis were used to compare patient results. The Kappa test assessed the concordance between the results at cut-off levels of 0.5ng/mL and 2.0ng/mL.
 Results: In the linearity study performed by obtaining serial dilutions from high and low-level serum pools, the regression equations were "y=-0.03(-0.07 to 0.05)+1.01(0.7 to 1.08)x" and "y=0.463(-1.16 to 2.01)+0.912(0.72 to 1.04)x" respectively. There is no deviation from linearity with the Cusum test (p=0.99 and 0.57). Average recovery value:86%. The CV% values of Control Level-1,2 were 3.75% and 4.2%. 0.1-50.0ng/ml range shows deviation from linearity determined by Cusum test (p=0.01). There was no deviation from linearity in the range of 0.1-2.0ng/ml (p=0.42). Kappa values were calculated as 0.864 and 0.800 (p<0.001).
 Conclusions: Getein1600 Procalcitonin test should be used for triage or screening purposes. However, a high constant error and deviation from linearity detected at high concentrations indicate that this test should not be used to initiate an antibiotic therapy or alter the current therapy course.

Harmonization Status of Serum Ferritin Measurements and Implications for Use as Marker of Iron-Related Disorders.

Serum ferritin is considered a suitable biomarker of iron-related disorders. However, data about the comparability of results among commercial measuring systems (MSs) are contradictory. We performed an intercomparison study aimed at verifying the current interassay variability and its impact on clinical application of the test. Obtaining this information is vital because manufacturers continue to claim calibration alignment to different WHO preparations, which are not related to each other in terms of traceability. Four widely used MSs were evaluated. The interassay agreement was verified using 39 human serum pools. The recovery of WHO International Standard (IS) 94/572 (the only reference material available at the time of the study) was evaluated, after assessing the material commutability. Finally, an approach for harmonizing ferritin results was proposed. Highly significant differences (P < 0.00001) among ferritin concentrations assayed by different MSs were detected and the interassay CV (median 22.9%; interquartile range 21.8-25.5) overlapped the desirable intermethod bias (24.6%). IS 94/572 was commutable for use only with Access and Centaur, with Access being the only MS correctly recovering its assigned value. Accordingly, we used regression data against Access to recalibrate MSs, indirectly aligning them to IS 94/572, with a substantial improvement in degree of harmonization and traceability to higher-order reference. The harmonization among evaluated ferritin MSs is far from optimal, with the implementation of traceability to different WHO ISs being a factor of confusion. A recalibration approach, however, would permit measurement harmonization, allowing the use of common decision thresholds.

Virus-like particles displaying conserved toxin epitopes stimulate polyspecific, murine antibody responses capable of snake venom recognition

Antivenom is currently the first-choice treatment for snakebite envenoming. However, only a low proportion of antivenom immunoglobulins are specific to venom toxins, resulting in poor dose efficacy and potency. We sought to investigate whether linear venom epitopes displayed on virus like particles can stimulate an antibody response capable of recognising venom toxins from diverse medically important species. Bioinformatically-designed epitopes, corresponding to predicted conserved regions of group I phospholipase A2 and three finger toxins, were engineered for display on the surface of hepatitis B core antigen virus like particles and used to immunise female CD1 mice over a 14 weeks. Antibody responses to all venom epitope virus like particles were detectable by ELISA by the end of the immunisation period, although total antibody and epitope specific antibody titres were variable against the different epitope immunogens. Immunoblots using pooled sera demonstrated recognition of various venom components in a diverse panel of six elapid venoms, representing three continents and four genera. Insufficient antibody yields precluded a thorough assessment of the neutralising ability of the generated antibodies, however we were able to test polyclonal anti-PLA2 IgG from three animals against the PLA2 activity of Naja nigricollis venom, all of which showed no neutralising ability. This study demonstrates proof-of-principle that virus like particles engineered to display conserved toxin linear epitopes can elicit specific antibody responses in mice which are able to recognise a geographically broad range of elapid venoms.

Establishment and clinical application of an assay for the activity of circulating immune complexes using human O-erythrocytes as an indicator system

ObjectiveTo develop a suitable clinical laboratory assay for detecting the activity of circulating immune complexes (CICs) that activate complement (ACIC). MethodsCICs measured in serum were initially used to activate complement, and the remaining complement was activated through sensitized human O-erythrocytes. ACIC was quantified by the degree of hemolysis. Each serum sample was tested for ten consecutive days to determine its stability. Reference ranges are suggested. ACIC was measured in both healthy individuals and patients with autoimmune diseases as well. ResultsThe OD values of the hemolysis degree index were inversely proportional to ACIC (r = -0.986, P = 0.002). A pooled serum was used to eliminate interference and optimize the experiment. The hemolysis degree (HD) was used to indicate the detection result. HD = (detection value OD/negative value OD)*100. Both the intra-batch and the inter-batch results showed good stability with a CV of 6.5% and 8.1%, respectively. HD differences between males and females were significant (P = 0.015) while the normal distribution for both genders was conformed. The HD recommended reference range for men is 56–88 while for women is 51–86. Serum HD of healthy subjects and autoimmune disease patients showed a significant difference (P = 0.001). Autoimmune disease patients have lower HD which was a result of having stronger ACIC. ConclusionThe ACIC assay while utilizing human O-erythrocytes as an indicator system is sensitive and accurate, and has potential in clinical applications.

Maternal and child biomonitoring strategies and levels of exposure in western Canada during the past seventeen years: The Alberta Biomonitoring Program: 2005-2021.

The Alberta Biomonitoring Program (ABP) was created in 2005 with the initial goal of establishing baseline levels of exposure to environmental chemicals in specific populations in the province of Alberta, Canada, and was later expanded to include multiple phases. The first two phases focused on evaluating exposure in pregnant women (Phase One, 2005) and children (Phase Two, 2004-2006) by analyzing residual serum specimens. Phase Three (2013-2016) employed active recruitment techniques to evaluate environmental exposures using a revised list of chemicals in paired serum pools from pregnant women and umbilical cord blood. These three phases of the program monitored a total of 226 chemicals in 285 pooled serum samples representing 31,529 individuals. Phase Four (2017-2020) of the ABP has taken a more targeted approach, focusing on the impact of the federal legalization of cannabis on the exposure of pregnant women in Alberta to cannabis, as well as tobacco and alcohol using residual prenatal screening serum specimens. Chemicals monitored in the first three phases include herbicides, neutral pesticides, metals, metalloids, and micronutrients, methylmercury, organochlorine pesticides, organophosphate pesticides, parabens, phthalate metabolites, perfluoroalkyl substances (PFAS), phenols, phytoestrogens, polybrominated compounds, polychlorinated biphenyls (PCBs), dioxins and furans, polycyclic aromatic hydrocarbons (PAHs), and tobacco biomarkers. Phase Four monitored six biomarkers of tobacco, alcohol, and cannabis. All serum samples were pooled. Mean concentrations and 95% confidence intervals (CIs) were calculated for the chemicals detected in ≥25% of the sample pools. cross the first three phases, the data from the ABP has provided baseline exposure levels for the chemicals in pregnant women, children, and newborns across the province. Comparison within and among the phases has highlighted differences in exposure levels with age, geography, seasonality, sample type, and time. The strategies employed throughout the program phases have been demonstrated to provide effective models for population biomonitoring.

Current Status of Serum Insulin and C-Peptide Measurement in Clinical Laboratories: Experience from 94 Laboratories in China.

BackgroundAccurate measurements of serum insulin and C-peptide are needed for the therapy and classification of diabetes. This study investigated the status of serum insulin and C-peptide measurements in China by analyzing the results of five pooled serum samples measured in 94 laboratories.MethodsPatient serum samples were pooled into five groups according to insulin and C-peptide concentrations and measured in 94 laboratories using different measurement systems. The inter- and intra-laboratory %CV as well as inter- and intra-measurement system %CV were calculated to assess the status of insulin and C-peptide measurements. To verify whether the disagreement between laboratories was due to different calibrators, as reported in previous studies, one low-level and one high-level sample extracted from the five pooled serum samples were used to recalibrate clinical measurement systems.ResultsThe mean intra-laboratory, intra-measurement system, inter-laboratory, and inter-measurement system %CVs were 2.7%, 4.8%, 21.8%, and 22.4%, respectively, for insulin and 2.3%, 6.7%, 16.4%, and 24.5%, respectively, for C-peptide. The inter- and intra-laboratory %CVs for insulin decreased with increasing concentration. After recalibration with low- and high-level samples, the mean inter-measurement %CV decreased from 22.4% to 17.2% for insulin and from 24.5% to 5.7% for C-peptide.ConclusionsThe intra-laboratory and intra-measurement system imprecision values are satisfactory for serum insulin and C-peptide measurements. However, the results from laboratories using different measurement systems were not comparable, and there is still much work needed to achieve the standardization or harmonization of serum insulin and C-peptide measurements.

Commutability Assessment of Frozen Human Serum Pools for External Quality Assessment of Tumor Markers

Eun-jung Cho, Sun Hyun Kim, Jinyoung Hong, Hyeyoung Lee, Jungwon Hyun, Sung Eun Cho, Woochang Lee, Hyun Soo Kim, Eun-Jee Oh, Sail Chun, and Won-Ki Min. Lab Med Qual Assur 2022;44:111-20. https://doi.org/10.15263/jlmqa.2022.44.2.111

An unusually long Rift valley fever inter-epizootic period in Zambia: Evidence for enzootic virus circulation and risk for disease outbreak.

Rift valley fever (RVF) is a mosquito-borne disease of animals and humans. Although RVF outbreaks are usually reported at 5-15-year intervals in sub-Saharan Africa, Zambia has experienced an unusually long inter-epizootic/-epidemic period of more than three decades. However, serological evidence of RVF virus (RVFV) infection in domestic ruminants during this period underscores the need for comprehensive investigation of the mechanisms of virus perpetuation and disease emergence. Mosquitoes (n = 16,778) captured from eight of the ten provinces of Zambia between April 2014 and May 2019 were pooled (n = 961) and screened for RVFV genome by a pan-phlebo RT-PCR assay. Aedes mosquito pools (n = 85) were further screened by nested RT-PCR assay. Sera from sheep (n = 13), goats (n = 259) and wild ungulates (n = 285) were screened for RVFV antibodies by ELISA while genome detection in pooled sera (n = 276) from domestic (n = 248) and wild ungulates (n = 37) was performed by real-time RT-PCR assay. To examine the association between the long inter-epizootic period and climatic variables, we examined El Niño-Southern Oscillation indices, precipitation anomalies, and normalized difference vegetation index. We then derived RVF risk maps by exploring climatic variables that would favor emergence of primary RVFV vectors. While no RVFV genome could be detected in pooled mosquito and serum samples, seroprevalence was significantly high (OR = 8.13, 95% CI [4.63–14.25]) in wild ungulates (33.7%; 96/285) compared to domestic ruminants (5.6%; 16/272). Retrospective analysis of RVF epizootics in Zambia showed a positive correlation between anomalous precipitation (La Niña) and disease emergence. On risk mapping, whilst northern and eastern parts of the country were at high risk, domestic ruminant population density was low (< 21 animals/km2) in these areas compared to low risk areas (>21 animals/km2). Besides evidence of silent circulation of RVFV and the risk of disease emergence in some areas, wildlife may play a role in the maintenance of RVFV in Zambia.

The Prevalence and Genetic Diversity of PCV3 and PCV2 in Colombia and PCV4 Survey during 2015-2016 and 2018-2019.

Four genotypes of circovirus have been recognized in swine, with PCV2 and PCV3 being the most associated with clinical manifestations, while PCV4 does not have a defined disease. In addition, PCV2 is associated with different syndromes grouped as diseases associated with porcine circovirus (PCVAD), while PCV3 causes systemic and reproductive diseases. In the present study, we retrospectively detected PCV2, PCV3, and PCV4 in Colombia during two periods: A (2015–2016) and B (2018–2019). During period A, we evaluated stool pools from the 32 Colombian provinces, finding a higher prevalence of PCV3 compared to PCV2 as well as PCV2/PCV3 co-infection. Furthermore, we determined that PCV3 had been circulating since 2015 in Colombia. Regarding period B, we evaluated sera pools and tissues from abortions and stillborn piglets from the five provinces with the highest pig production. The highest prevalence found was for PCV3 in tissues followed by sera pools, while PCV2 was lower and only in sera pools. In addition, PCV2/PCV3 co-infection in sera pools was also found for this period. The complete genome sequences of PCV3 and PCV3-ORF2 placed the Colombian isolates within clade 1 as the majority in the world. For PCV2, the predominant genotype currently in Colombia is PCV2d. Likewise, in some PCV3-ORF2 sequences, a mutation (A24V) was found at the level of the Cap protein, which could be involved in PCV3 immunogenic recognition. Regarding PCV4, retrospective surveillance showed that there is no evidence of the presence of this virus in Colombia.

Immunization of Rabbits with a Quadrivalent Shigella Bioconjugate Vaccine Induces Functional Antibodies Reactive with Shigella Isolates from Kenya.

ABSTRACTDiarrheal diseases are a leading cause of global morbidity and mortality, disproportionately affecting children in resource-limited settings. Although improvements in hygiene and access to clean water are helpful, vaccines are considered essential due to the low infectious dose of Shigella species and increasing antibiotic resistance. Building on achievements with conjugate vaccines, a safe and immunogenic novel bioconjugate vaccine linking Shigella O-antigen to Pseudomonas aeruginosa exoprotein A has been developed to induce immunity against Shigella flexneri 2a, 3a, and 6 and S. sonnei. This study evaluated the breadth of reactivity and functionality of pooled serum from rabbits immunized with monovalent and quadrivalent Shigella bioconjugates formulated with or without an adjuvant against Shigella serotypes isolated in Kenya. Rabbit sera were assayed by colony blot for reactivity with 67 isolates of Shigella serotypes targeted by the vaccine, S. flexneri (2a, 3a, and 6) and S. sonnei, and 42 isolates of Shigella serotypes not targeted by the vaccine, S. flexneri (1b, 2b, 4a, and 4b), S. boydii, and S. dysenteriae. Shigella isolates testing positive in the colony blot assay were then used to assess functional activity using a bactericidal assay. Of the 41 Shigella isolates targeted by the vaccine, 22 were reactive with the adjuvanted quadrivalent and the respective monovalent rabbit sera. The S. flexneri 2a and 3a monovalent rabbit serum cross-reacted with S. flexneri 3a, 2b, and 2a, respectively. Immunization with the adjuvanted quadrivalent vaccine also induced cross-reactivity with isolates of S. flexneri 2b, 4a, and 4b. Collectively, these results suggest that the Shigella quadrivalent vaccine may be more broadly protective than designed, offering a promising solution to Shigella infections.IMPORTANCE Diarrheal diseases are the third leading cause of death globally, disproportionally affecting low- to middle-income countries like Kenya, with Shigella species being the leading cause of bacterial diarrhea, especially in children. The low infectious dose and high antibiotic resistance levels complicate treatment, leading to long-term sequelae that necessitate control measures such as vaccines to reduce morbidity and mortality rates, especially among children under 5 years of age. A quadrivalent bioconjugate Shigella vaccine was recently developed to safely and effectively induce immunity against four important Shigella spp. This study demonstrates the breadth of reactivity and functionality of the parenterally administered bioconjugate vaccine by evaluating the ability of rabbit sera to bind and kill Shigella isolates recently collected in Kenya. These results suggest that the Shigella quadrivalent vaccine may be more broadly protective than designed and may offer a promising solution to the morbidity and mortality associated with Shigella infections.

P302 ENDOTHELIALITIS AS A POSSIBLE CAUSE OF MYOCARDIAL INJURY DURING COVID–19 INFECTION

A 53–year–old woman was admitted for chest pain for over two weeks, fever, dry cough, fatigue and myalgia. Chest pain increased in supine position and inspiration. Nasopharyngeal swab was positive for SARS–CoV–2 RT–PCR assay. Admission ECG displayed mild ST–segment elevation (0,5 mm) in inferolateral leads and echocardiogram showed normal left ventricular volume, mildly decreased left ventricular EF (52%) and no regional wall motion abnormalities. Blood tests exhibited elevated values of high–sensitivity troponin I (818 pg/mL), proBNP (19.190 pg/mL), CRP (42 mg/dL), D–Dimer test (1090 ng/mL) and WBC (13000/uL, N 89%, L 7%). IL–6 resulted slightly increased (18 ng/mL). ECG after 24 hours showed T wave inversion in inferolateral leads. Coronary CT angiography revealed normal epicardial arteries. A new echocardiogram, after five days, showed infero–basal hypokinesia, improved global EF (57%) and minimal pericardial effusion. Aspirin and fondaparinoux were started. Myopericarditis was suspected and high dose steroids were administered. After a few days, symptoms improved and ECG, echocardiographic abnormalities and troponin levels were normalized. At 6 weeks follow–up the patient was asymptomatic, ECG and echocardiogram were both normal. Instead cardiac MRI showed signs of endothelial injury: presence of interstitial oedema in the inferoapical and anteroseptal wall (STIR–T2–weighted), without late gadolinium enhancement. We measured blood levels of endothelial dysfunction markers: soluble ICAM–1, VCAM–1 and von Willebrand factor (vWF). They all resulted elevated as compared to a laboratory pool of normal serum (535 ng/ml, 265 ng/ml, and 1659 ng/ml, respectively). Our case was suggestive of myopericarditis related to Sars–Cov–2, but echocardiogram and MRI did not show signs of myocarditis permanent damage. However MRI showed interstitial oedema and hyperemia, typical signs of endothelial injury. Moreover we found high levels of soluble endothelial adhesion molecules, vWF, ICAM–1 and VCAM–1, likely expression of the microcirculatory endothelial dysfunction due to myocardial endothelialitis.In conclusion, our case report suggests that, in COVID–19, acute myocardial injury associated with clinical and investigational signs of myocarditis can be due to myocardial endothelialitis rather than true myocarditis and that an early management with anti–inflammatory drugs (steroids) can be particularly beneficial in patients with unexplained elevated cardiac troponin.

The Identification and Characterization of Immunoreactive Fungal Proteins Recognized by Sera from Zimbabweans Sensitized to Fungi

Background: Exposure to fungal allergens poses a serious threat to human health, especially to mould-allergic individuals. The prevalence of fungal allergic disease is increasing globally but is poorly studied in Africa. Here, we aimed to identify and characterize fungal proteins that were immunoreactive against serum samples from fungal-sensitized Zimbabweans from Shamva district to inform the development of diagnostics and therapeutics. Methods: Crude protein extracts of the Ascomycota Aspergillus fumigatus, Alternaria alternata, Cladosporium herbarum, Epicoccum nigrum, Penicillium chrysogenum, and Saccharomyces cerevisiae as well as mucoromycota Rhizopus nigricans were individually separated by one-dimensional gel electrophoresis for protein staining and immunoblotting. A pool of eight sera from fungi-sensitive Zimbabwean children aged 3–5 years was used to screen the crude extracts to determine their immunoreactivity. Protein bands recognized by the sera were subjected to mass spectrometry to identify the individual proteins reactive with the sera. Results: The pooled serum sample reacted with 20 bands, which resolved to 34 distinct proteins, most of which were novel immunogens. The pool was most reactive to A. alternata. The proteins identified included peptidases (8/34), hydrolases (6/34), oxidoreductases (5/34), and glucosidases (4/34), while 11/34 were unknown. Eight of the proteins were predicted to be allergens using the Structural Database of Allergenic Proteins (SDAP). Conclusions: We identified novel immunogens from fungi expanding the number of known fungal allergens. These form a potential basis for diagnostics specific for the Zimbabwean population. Validation assays will now need to be carried out to further evaluate the cross-reactivity of the identified allergen candidates as well as investigate their potential recognition in a larger cohort of patients. Furthermore, there is now a need to conduct studies relating sensitization to these immunogens and clinical diseases in the population.

MO454: Increased Senescent Cell Burden and Alterations in NRF2 Pathway Drive Uraemic Vascular Calcification in Humans

Abstract BACKGROUND AND AIMS Vascular calcification is a clinical sequelae of chronic kidney disease (CKD) that is associated with high cardiovascular-related mortality in end-stage kidney failure (ESKF) patients. Increased senescent cell burden and dysregulation of the NRF2 pathway, the master regulator of antioxidant genes, have been suggested to play an important role in the onset of multiple non-communicable burden-of-lifestyle diseases, including but not limited to diabetes, obesity and CKD. Thus, we investigated if senescence and NRF2 pathways may serve as drivers of uraemia-induced vascular calcification in human arteries. METHOD ESKF patients without epigastric artery calcification and coronary artery calcification (CAC) (n = 8) were matched with patients with severely calcified epigastric arteries and the presence of CAC (n = 8). In all subjects, samples of epigastric arteries were obtained during living donor kidney transplantation surgery. Gene (qPCR) and protein expression (immunohistochemistry) of cellular senescence markers (p16, p21), NRF2 pathway candidates (NRF2, NQO1, CAT, SOD1) and calcification markers (RUNX2, ALPL) were assessed. In addition, four groups of aortic vascular smooth muscle cells (VSMCs) were treated as follows: i) control media; ii) osteogenic media (Pi = 2.5mM); iii) osteogenic media + pooled serum from non-ESKD subjects; or iv) osteogenic media + pooled uraemic serum from ESKF patients that had severely calcified epigastric arteries (n = 8). Calcification in cell culture experiments was assessed using BoneTag Optical Probe and normalized for protein content, while gene expression analysis for a selection of calcification, senescence and NRF2-related markers, and SA-beta-GAL staining, were performed (n = 4 each). RESULTS At the gene expression level, severely calcified epigastric arteries as assessed by von Kossa staining (Figure 1a) had preserved ALPL expression but significantly increased RUNX2 expression (P &amp;lt; 0.01; Figure 1b) when compared with non-calcified vessels. Gene expression of p16, but not p21, was increased in the calcified compared with non-calcified group (P &amp;lt; 0.001, Figure 1c), while both p16 and p21 protein expressions were elevated in the media layer of calcified vessels (Figure 1c). NRF2 and downstream target gene expressions remained similar between the two groups, however, NRF2 protein expression was increased in the non-calcified group. In cell culture studies, uraemic serum-induced VSMC calcification was increased when compared to non-uraemic serum and osteogenic controls (P &amp;lt; 0.0001, Figure 2a). This was further accompanied by increased ALPL gene expression (P &amp;lt; 0.0001, Figure 2b) and reduced NRF2, SOD1 and NQO1 gene expression (all P &amp;lt; 0.01, Figure 2c). SA-beta-gal staining and p16/p21 gene expression analysis revealed that uraemic serum-induced calcification was not associated with increased senescent cell burden. CONCLUSION Established calcification in ESKF patients is associated with increased senescent cell burden, but preserved NRF2 pathway markers, in epigastric arteries. In contrast, induced calcification was accompanied by the diminished activity of the NRF2 pathway, but not senescence pattern, using an in vitro approach in VSMCs. Our translational data indicate that established and induced calcification may reflect different pathophysiological processes, supporting data from a parallel study using 5/6 rats (Laget, Hobson et al., unpublished data). Future studies should consider the timing of initiation of NRF2 agonist/senolytic treatment when targeting calcification in ESKF patients.

MO241: Nets and Terminal Complement Pathway as Potential Biomarkers for Complement Overactivation Assessment in Anca-Associated Vasculitis

Abstract BACKGROUND AND AIMS Clinical, in vitro, and animal model-derived evidence has demonstrated a critical involvement of the alternative complement pathway (aCP) in the pathogenesis of ANCA-associated vasculitis (AAV). In this regard, neutrophil extracellular traps (NETs) have been suggested to be a key element between ANCA-induced neutrophil activation and aCP [1]. However, the role of the terminal complement pathway (tCP) is less well studied [2]. METHOD A prospective, observational, multicenter study analyzing first episodes and relapses of patients with AAV, with a minimum follow-up of 6 months, was performed. Blood samples were collected at diagnosis (AAV-t1) and at remission (AAV-t2). Control population consisted of age and sex-matched individuals. Complement activation was assessed by analyzing the complement membrane attack complex (C5b-9) deposition on cultured endothelial cells (HMEC-1), by immunofluorescence, after exposing them to activated plasma (a-plasma: obtained by mixing patient's citrated plasma with healthy subjects’ sera pool, 1:1). C5b-9 deposits induced by patients’ a-plasma were calculated as percentage of labeled area with respect to the total area analyzed. Results from patient and control samples were expressed as fold increase (mean ± SEM) versus those obtained with the pool of a-plasma from healthy subjects. Plasma levels of tCP and aCP soluble factors, such as sC5b-9 and sFBb (respectively), were also measured (mean ± SEM). Circulating NETs were indirectly measured by quantifying circulant dsDNA plasmatic concentration (mean ± SEM) as a NET surrogate. RESULTS The present results were obtained with samples from 13 AAV-MPO patients who achieved complete remission (38% men, age 63 ± 14 years) and 10 controls (45% men, age 66 ± 6 years). At AAV-t1, there was a statistically significant increase (P &amp;lt; .05) of C5b-9 deposition on HMEC-1 in response to patients’ a-plasma (fold increase of 5.3 ± 1.3) compared with control samples (fold increase of 1.2 ± 0.2). Samples obtained at AAV-t2 induced less C5b-9 deposition than at AAV-t1 (fold increase of 0.9 ± 0.2; P &amp;lt; .05), with values similar to controls. Regarding soluble factors, levels of both sC5b-9 and sFBb were significantly increased in AAV-t1 (1882 ± 418 ng/mL and 3.2 ± 0.4 µg/mL, respectively; P &amp;lt; .05) versus AAV-t2 (852 ± 104 ng/mL and 1.9 ± 0.2 µg/mL, respectively; P &amp;lt; .05). At AAV-t2, levels were similar to controls (708 ± 42 ng/mL for sC5b-9 and 2.4 ± 0.2 µg/mL for sFBb). Circulating NETs were also increased in AAV-t1 (22.2 ± 3.5 µg/mL) compared with both AAV-t2 and controls (13.6 ± 1.1 µg/mL and 13.7 ± 0.3 µg/mL, respectively; P &amp;lt; .05). Moreover, NETs in AAV-t1 presented a significant correlation with sFBb levels, both in AAV-t1 (r = 0.709; P &amp;lt; .05) and in AAV-t2 (r = 0.585; P &amp;lt; .05). CONCLUSION There is a relationship between NETs, AAV activity and sFBb, which supports the role of NETs and cAP in AAV pathogenesis. Moreover, differences in C5b-9 deposition between the two stages of the disease suggest that tCP may be dysregulated in AAV. Further characterization of this dysregulation may lead to new diagnostic or disease activity biomarkers, as well as new therapeutic options for the management of patients with AAV.

SERA POOLED STABILITY AS A SGPT CONTROL MATERIAL WITH STORAGE TIME AND TEMPERATURE VARIATION

To improve the quality of laboratory examination results, it is absolutely necessary to carry out quality assurance and these activities usually require control materials. The price of expensive commercial control materials is an obstacle to carrying out laboratory quality control. Efforts to maintain quality control are using pooled sera as control material. One of the examinations that is often done is the examination of SGPT (Serum Glutamic Pyruvate Transaminase) blood. The choice of SGPT parameter is expected to represent the type of enzyme assay. The purpose of this study was to determine the stability of pooled sera used as control material for SGPT examination with time and temperature variations. Methods: This research is an experimental study, which was carried out using a collection of serum found in the TLM Clinical Chemistry Laboratory of the Health Ministry of Health, Jambi. By using 2 treatments, the samples were stored at a temperature of 20-25oC and -5oC. Data analysis using ANOVA and coefficient of variation value. Results: The results showed a significant value (p-value) of SGPT of p = 0.008. A significant value (p-value) which is greater than the value of = 0.05, indicates that there is an effect of storage time and temperature variations. Conclusion : There is a significant effect of storage time and temperature variation of pooled sera control material on the stability of SGPT examination.

Immune response of booster doses of BBIBP-CORV vaccines against the variants of concern of SARS-CoV-2.

BackgroundBooster doses for COVID-19 vaccinations are currently recommended and approved in many countries. However, we need more evidence on the immune response of individuals to booster doses of inactivated vaccines and the neutralizing effect against the variants of concerns of SARS-CoV-2.ObjectiveTo compare the fold reduction in antibody titers against the variants of concerns of SARS-CoV-2 between the primary doses and booster dose vaccine cohorts of inactivated BBIBP-CorV vaccine.Study designIn this observational study Plaque Reduction Neutralization Test (PRNT) assay was done on pooled serum samples of the recipients of primary two doses of inactivated BBIBP-CorV and on the pooled serum samples of recipients of a booster dose of inactive BBIBP-CorV. The neutralizing antibody titers against the wild (Wuhan) strain and the variants of concern (alpha, beta and delta) were compared.ResultsThe serum sample pool from the booster cohort had high neutralizing antibody titers against the SARS-CoV-2 variants compared to the pooled serum samples of the recipients of primary two doses of inactivated BBIBP-CorV and the difference was statistically significant. The observed fold reduction in antibody titers from the serum pool of recipients of two doses of BBIBP-CorV vaccine were 3.7-fold, 14.6-fold and 10.4-fold compared to 1.8 -fold, 6.5-fold and 3.8-fold reduction against the alpha, beta and delta lineages respectively in the serum pool of recipient of a booster dose (three doses of BBIBP-CorV).ConclusionBooster doses of inactive BBIBP-CORV offered better protection against the variants of concern of SARS-CoV-2.

Paraoxonase-1 Concentrations in Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis.

Obstructive sleep apnoea (OSA) is characterized by overproduction of reactive oxygen species and oxidative stress. The antioxidant enzyme paraoxonase-1 (PON-1) may be useful for monitoring the antioxidant defence systems and the effect of treatments in OSA patients. We investigated, by means of systematic review and meta-analysis, the serum concentrations of PON-1 in OSA patients and non-OSA controls. A literature search was conducted in PubMed, Web of Science, Scopus and Google Scholar databases, from the outset to November 2021, utilizing the terms: “paraoxonase” or “PON” or “paraoxonase-1” or “PON-1” and “obstructive sleep apnoea syndrome” or “OSAS” or “OSA”. Eleven studies in 429 OSA patients and 258 non-OSA controls were involved in the meta-analysis. The pooled serum PON-1 concentrations were significantly lower in OSA (standardized mean difference (SMD) = −0.70, 95% CI −1.13 to −0.28; p = 0.001). Despite the extreme between-study heterogeneity, the SMD values were not substantially affected by the sequential omission of individual studies. There was no publication bias. Our systematic review and meta-analysis supports the presence of an impaired antioxidant defence system in OSA, possibly the consequence of intermittent hypoxia. Further studies are required to determine the clinical use of PON-1 measurements for risk stratification and monitoring in OSA patients.

Synthesis of Deuterium-Labeled Vitamin D Metabolites as Internal Standards for LC-MS Analysis.

Blood levels of the vitamin D3 (D3) metabolites 25-hydroxyvitamin D3 (25(OH)D3), 24R,25-dihydroxyvitamin D3, and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) are recognized indicators for the diagnosis of bone metabolism-related diseases, D3 deficiency-related diseases, and hypercalcemia, and are generally measured by liquid-chromatography tandem mass spectrometry (LC-MS/MS) using an isotope dilution method. However, other D3 metabolites, such as 20-hydroxyvitamin D3 and lactone D3, also show interesting biological activities and stable isotope-labeled derivatives are required for LC-MS/MS analysis of their concentrations in serum. Here, we describe a versatile synthesis of deuterium-labeled D3 metabolites using A-ring synthons containing three deuterium atoms. Deuterium-labeled 25(OH)D3 (2), 25(OH)D3-23,26-lactone (6), and 1,25(OH)2D3-23,26-lactone (7) were synthesized, and successfully applied as internal standards for the measurement of these compounds in pooled human serum. This is the first quantification of 1,25(OH)2D3-23,26-lactone (7) in human serum.

The Allergen-Specific IgE Concentration Is Important for Optimal Histamine Release From Passively Sensitized Basophils.

BackgroundThe basophil histamine release (HR) assay can be used for allergy diagnosis in addition to the conventional measurement of allergen-specific IgE (sIgE). Passive sensitization of basophils increases the versatility and allows testing the biological relevance of allergen-induced IgE cross-linking in any serum unbiased by the cellular component. However, not all the patient sera perform equally well and we hypothesized that the absolute level and fraction of sIgE affect the performance. Choosing birch pollen allergy as a model, we investigated the concentration of sIgE needed for successful passive sensitization using soluble- or matrix-fixed Bet v 1.MethodsTwenty-eight sera with Bet v 1 sIgE [7 sera within each allergy class (1: 0.1–0.70 kUA/L, 2: 0.71–3.50 kUA/L, 3: 3.51–17.50 kUA/L, and 4+: >17.50 kUA/L)] and a negative control serum pool were used to passively sensitize donor basophils, obtained from buffy coat blood (n = 3). The cells were incubated (30 min) with a soluble allergen (rBet v 1 from 0.2 to 50 ng/ml), matrix-fixed allergen (ImmunoCAP™ containing recombinant Bet v 1), or phorbol 12-myristate 13-acetate (PMA)/ionomycin mixture (maximal HR) and released histamine was quantified fluorometrically.ResultsThe lowest level of Bet v 1 sIgE generating a detectable HR (HR > 10% of maximal release) in all the 3 runs was found to be 1.25 kUA/L (corresponding to allergy class 2, 0.71–3.50 kUA/L). Furthermore, sera from allergy classes 3 and 4+ ascertained a significant reproducible HR: 42/42 vs. 5/21 in allergy class 1 and 15/21 in allergy class 2. Using ImmunoCAP™s containing Bet v 1 as a matrix-fixed allergen system, similar results were obtained where the lowest sIgE concentration mediating an HR was 1.68 kUA/L and 7/7 for both allergy classes 3 and 4+.ConclusionThe results demonstrate that the IgE titer is strikingly robust in predicting the ability to sensitize basophils and produce a measurable HR.