Potential preanalytical and analytical vulnerabilities in the laboratory diagnosis of coronavirus disease 2019 (COVID-19)

A novel zoonotic coronavirus outbreak is spreading all over the world. This pandemic disease has now been defined as novel coronavirus disease 2019 (COVID-19), and is sustained by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the current gold standard for the etiological diagnosis of SARS-CoV-2 infection is (real time) reverse transcription polymerase chain reaction (rRT-PCR) on respiratory tract specimens, the diagnostic accuracy of this technique shall be considered a foremost prerequisite. Overall, potential RT-PCR vulnerabilities include general preanalytical issues such as identification problems, inadequate procedures for collection, handling, transport and storage of the swabs, collection of inappropriate or inadequate material (for quality or volume), presence of interfering substances, manual errors, as well as specific aspects such as sample contamination and testing patients receiving antiretroviral therapy. Some analytical problems may also contribute to jeopardize the diagnostic accuracy, including testing outside the diagnostic window, active viral recombination, use of inadequately validated assays, insufficient harmonization, instrument malfunctioning, along with other specific technical issues. Some practical indications can hence be identified for minimizing the risk of diagnostic errors, encompassing the improvement of diagnostic accuracy by combining clinical evidence with results of chest computed tomography (CT) and RT-PCR, interpretation of RT-PCR results according to epidemiologic, clinical and radiological factors, recollection and testing of upper (or lower) respiratory specimens in patients with negative RT-PCR test results and high suspicion or probability of infection, dissemination of clear instructions for specimen (especially swab) collection, management and storage, together with refinement of molecular target(s) and thorough compliance with analytical procedures, including quality assurance

Thin Objects Are Not Transparent

In this short paper, we analyse whether assuming that mathematical objects are “thin” in Linnebo's sense simplifies the epistemology of mathematics. Towards this end, we introduce the notion of transparency and show that not all thin objects are transparent. We end by arguing that, far from being a weakness of thin objects, the lack of transparency of some thin objects is a fruitful characteristic mark of abstract mathematics

Current laboratory diagnostics of coronavirus disease 2019 (COVID-19)

Laboratory medicine provides an almost irreplaceable contribution to the diagnostic reasoning and managed care of most human pathologies. The novel coronavirus disease 2019 (COVID-19) is not an exception to this paradigm. Although the relatively recent emergence does not allow to draw definitive conclusions on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics, some standpoints can be conveyed. First and foremost, it seems now clear that we will be living together with this virus for quite a long time, so that our vigilance and responsiveness against the emergence of new local outbreaks shall be maintained at the highest possible levels. The etiological diagnosis of COVID-19 is, and will remain for the foreseeable future, deeply based on direct identification of viral RNA by means of molecular biology techniques in biological materials, especially upper and lower respiratory tract specimens. Whether other materials, such as blood, urine, stools, saliva and throat washing, will become valid alternatives has not been unequivocally defined so far. As concerns serological testing, promising information can be garnered from preliminary investigations, showing that the vast majority of COVID-19 patients seem to develop a sustained immune response against the virus, characterized especially by emergence of anti-SARS-CoV-2 IgG and IgA, 1 to 2 weeks after the onset of fever and/or respiratory symptoms. Whether these antibodies will have persistent neutralizing activity against the virus is still to be elucidated on individual and general basis. The availability of rapid tests for detecting either viral antigens or anti-SARS-CoV-2 antibodies are a potentially viable opportunity for purposes of epidemiologic surveillance, though more information is needed on accuracy and reliability of these portable immunoassays

Pancreatic cancer-derived S-100A8 N-terminal peptide: a diabetes cause?

BACKGROUND: Our aim was to identify the pancreatic cancer diabetogenic peptide. METHODS: Pancreatic tumor samples from patients with (n=15) or without (n=7) diabetes were compared with 6 non-neoplastic pancreas samples using SDS-PAGE. RESULTS: A band measuring approximately 1500 Da was detected in tumors from diabetics, but not in neoplastic samples from non-diabetics or samples from non-neoplastic subjects. Sequence analysis revealed a 14 amino acid peptide (1589.88 Da), corresponding to the N-terminal of the S100A8. At 50 nmol/L and 2 mmol/L, this peptide significantly reduced glucose consumption and lactate production by cultured C(2)C(12) myoblasts. The 14 amino acid peptide caused a lack of myotubular differentiation, the presence of polynucleated cells and caspase-3 activation. CONCLUSIONS: The 14 amino acid peptide from S100A8 impairs the catabolism of glucose by myoblasts in vitro and may cause hyperglycemia in vivo. Its identification in biological fluids might be helpful in diagnosing pancreatic cancer in patients with recent onset diabetes mellitus

Pancreatic cancer-associated diabetes mellitus: an open field for proteomic applications.

Background: Diabetes mellitus is associated with pancreatic cancer in more than 80% of the cases. Clinical, epidemiological, and experimental data indicate that pancreatic cancer causes diabetes mellitus by releasing soluble mediators which interfere with both beta-cell function and liver and muscle glucose metabolism. Methods: We analysed, by matrix-assisted laser desorption ionization time of flight (MALDI-TOF), a series of pancreatic cancer cell lines conditioned media, pancreatic cancer patients' peripheral and portal sera, comparing them with controls and chronic pancreatitis patients' sera. Results: MALDI-TOF analysis of pancreatic cancer cells conditioned media and patients' sera indicated a low molecular weight peptide to be the putative pancreatic cancer-associated diabetogenic factor. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of tumor samples from diabetic and non-diabetic patients revealed the presence of a 1500 Da peptide only in diabetic patients. The amino acid sequence of this peptide corresponded to the N-terminal of an S-100 calcium binding protein, which was therefore suggested to be the pancreatic cancer-associated diabetogenic factor. Conclusions: We identified a tumor-derived peptide of 14 amino acids sharing a 100% homology with an S-100 calcium binding protein, which is probably the pancreatic cancer-associated diabetogenic facto

Effects of Th2 cytokines on expression of collagen, MMP-1, and TIMP-1 in conjunctival fibroblasts.

PURPOSE. To determine whether cytokines involved in chronic allergic conjunctival disorders may affect formation of giant papillae and tissue remodeling. METHODS. Conjunctival fibroblast cultures were challenged with different concentrations of human recombinant interleukin (IL)-4, IL-13, interferon (IFN)- and tumor necrosis factor (TNF)-. Procollagens I (PIP) and III (PIIIP), matrix metalloproteinase (MMP)-1 and -9, and tissue inhibitor of metalloproteinase (TIMP)-1 were measured in supernatants, and their respective mRNAs were evaluated by RT-PCR. RESULTS. IL-4 and -13 (10 ng/mL) significantly increased production and expression of PIP compared with nonstimulated cells, whereas IFN- elicited the opposite effect, at both the protein and mRNA levels. Both IL-4 and -13 significantly decreased production of MMP-1 and increased that of TIMP-1, whereas TNF- increased production of MMP-1 and -9. Expression of MMP-1 was reduced by IL-4 and increased by the other tested cytokines, whereas expression of TIMP-1 was increased by all tested cytokines. CONCLUSIONS. IL-4 and -13 increased production of collagen and modified the equilibrium between MMP-1 and its inhibitor, TIMP-1. These effects were partially opposed by IFN- and TNF- .( Invest Ophthalmol Vis Sci. 2003;44:183‐189) DOI

Comparison of presepsin, procalcitonin, interleukin-8 and C-reactive protein in predicting bacteraemia in febrile neutropenic adult patients with haematological malignancies

Bacterial infections represent life-threatening complications in patients with febrile neutropenia (FN). Diagnostic biomarkers of infections may help to differentiate bacteraemia from non-bacteraemia FN. We aimed to evaluate the utility of procalcitonin (PCT), presepsin (PS), C-reactive protein (CRP) and interleukin-8 (IL-8) as biomarkers of bacteraemia in adult FN patients with haematological malignancies. Concentrations of PCT, PS, CRP and IL-8 were prospectively measured in 36 FN episodes experienced by 28 oncohaematological patients. 11 out of 36 episodes were classified as bacteraemia. PCT was the best biomarker to predict bacteraemia with the area under the curve (AUC) ROC of 0,9; specificity 100% and positive predictive value 100%, while the most sensitive was IL-8 (90,9%) with AUC ROC of 0,88 and negative predictive value 95,2%. All patients with PCT concentrations above 1,6 \u3bcg/l had bacteraemia. Patients with IL-8 concentrations superior to 170 pg/ml had a 40 times higher risk for bacteraemia than the ones with lower levels. Patients with PS concentrations superior to 410 pg/ml had 24 times higher risk for bacteraemia than the patients with lower levels. PCT has higher accuracy than CRP, IL-8 and PS in predicting bacteraemia in adult hematologic patients with FN

Polyclonal and monoclonal B lymphocytes response in HCV-infected patients treated with direct-acting antiviral agents

Hepatitis C virus (HCV) chronic infection can be associated with extrahepatic manifestations such as mixed cryoglobulinaemia and lymphoproliferative disorders that are endowed with increased rates of morbidity and all-cause mortality. In this study, we used flow cytometry to evaluate the effect of interferon-free antiviral treatment on peripheral blood lymphocytes in HCV-infected patients with or without associated lymphoproliferative disorders. Flow cytometry analysis of peripheral blood lymphocytes was performed at baseline and at the end of treatment. In HCV-infected patients with lymphoproliferative disorders, we evaluated immunoglobulin (Ig) light chain \u3ba/\u3bb ratio variations as a measure of monoclonal B-cell response to antiviral therapy. Healthy volunteers were enrolled as controls. A total of 29 patients were included, nine with and 20 without lymphoproliferative disorders. Sustained virological response was achieved in 29 of 29 patients. We observed a significant reduction in the B-cell compartment (39% global reduction) in eight of nine HCV-infected patients with lymphoproliferative disorders after viral clearance. We recognized the same trend, even if less pronounced, in HCV-infected patients without lymphoproliferative disorders (9% global reduction). Among HCV-infected patients with lymphoproliferative disorders, three showed an improvement/normalization of the immunoglobulin light chain ratio, whereas in the remaining six patients monoclonal B cells persisted to be clonally restricted even 1\ua0year after the end of treatment. Our data show that DAAs treatment can be effective in reducing the frequency of pathological B cells in the peripheral blood of HCV-infected patients affected by HCV-associated lymphoproliferative disorders; however, monoclonal populations can persist after viral eradication

POS1221 SARS-COV2 SEROLOGY SCREENING IN SPONDYLOARTHRITIS PATIENTS IN NORTH-EASTERN ITALY: A PILOT STUDY

Background:Serology could help defining the real extent of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV2) diffusion in the population, especially in individuals considered at higher risk of SARS-CoV2 infection (COVID-19), such as Spondiloarthritis (SpA) patients undergoing immunosuppressive therapy or health care workers (HCW). In fact, COVID-19 detection is complicated by the fact that many patients can be asymptomatic. In these cases, it has also been suggested that a weaker immune response might be elicited.In this context, the role of anti-cytokine targeted therapy –commonly used as treatment in SpA- is uncertain, as it is not clear whether it is detrimental or protective towards severe disease forms.Objectives:The aim of the study was to explore the potential role of serology in detecting previous contact with SARS-CoV2 in SpA patients and HCW, and compare the frequency of positive findings with a control population.Methods:Consecutive patients affected by axial or peripheral SpA, classified according to Assessment of SpondyloArthritis international Society (ASAS) criteria and undergoing cytokine-targeted therapy, as well as HCW and controls from the pre-COVID-19 era (control group, 2015) were recruited. In SpA patients, disease activity was assessed by Ankylosing Spondylitis Disease Activity Score (ASDAS) and Disease Activity Score on 28-joint-count (DAS28).Sera from all patients were analysed through chemiluminescent analytical system (CLIA) for the presence of IgG and IgM anti-SARS-CoV2. Patients with a positive serological test (either IgM or IgG) additionally underwent real time Polymerase Chain Reaction (RT-PCR) in nasopharyngeal swabs in order to test for active infection. In SpA patients, serology was repeated after 3 months. Data across the 3 groups were compared by ANOVA or Chi-square, while comparison between 2 groups were conducted by Wilcoxon signed rank test or Chi-Square, for continuous and categorical data respectively. P ≤ 0.05 were considered as significant.Results:A total of 396 patients were recruited: 200 SpA, 95 HCW and 101 healthy controls. SpA patients were mostly (54%) males, with mean age 49.6 ±14.7 years, and all were treated with anti-TNFα (78%), anti-IL-17 (9%) and anti-IL-23 drugs (7%), or small molecules (6%). Their disease activity level was moderate-low as assessed by ASDAS (1.95 ±0.98) and DAS28 (2.33 ±2.02). Among HCW and controls, 35% and 62% were male, with mean age 46.7 ±12.9 and 50.6±10.6 respectively.Positive serology (IgM or IgG, or both) was found in 12.5% SpA patients, 8.4% HCW, 0% controls (p=0.001). Among these, IgM titres were higher in the SpA group than in HCW (2.76±2.94 versus 0.80±0.67 KU/L, p= 0.016), while IgG mean titres were lower in the SpA group than in HCW (0.88±3.18 KU/L versus 1.05±0.88, p= 0.035). SpA patients with positive serology more frequently reported COVID-19 like symptoms than those with negative serology (20% vs 4%, p=0.009) and 2 had COVID-19 as confirmed by RT-PCR, none with a severe disease course. None of the HCW reported symptoms or tested positive by RT-PCR. In the SpA patients, at 3 months, the mean IgM titre decreased from 2.76±2.93 to 2.38±2.95 (p=0.001), while the IgG titres decreased from 0.89±3.25 to 0.31±0.87 (p=ns). Interestingly, the IgM or IgG titer at a single-patient level did not seem to change much in terms of absolute value (Figure 1), except in one patient, with documented COVID-19 (positive RT-PCR), in whom IgG level even decreased at 3 months.Conclusion:Serology revealed that exposure to COVID-19 in SpA patients, as well as HCW, was higher than expected based on reported symptoms. Targeted anti-cytokine therapy could act as a protective factor for a severe disease course in SpA patients. However, in this population, IgG and IgM titres did not change in a clinically significant manner at 3 months, and patient did not seem to develop an immune profile consistent with durable response. This result could be due to a weaker immune response in mild infections, but further studies are warranted to clarify the pathophysiology beyond these observations.Figure 1.Disclosure of Interests:Augusta Ortolan: None declared, Chiara Cosma: None declared, Mariagrazia Lorenzin: None declared, Giacomo Cozzi: None declared, Andrea Doria Speakers bureau: Novartis, Abbvie, Pfizer, MSD, Janssen, Glaxosmithkline, Mario Plebani: None declared, Roberta Ramonda Speakers bureau: Novartis, Abbvie, Pfizer, MSD, Jansse

State of the art of BNP and NT-proBNP immunoassays: The CardioOrmoCheck study

To evaluate differences in analytical performance and clinical results of BNP and NT-proBNP immunoassays, a proficiency testing program, called CardioOrmoCheck study, has been organized since 2005 under the patronage of the Study Group of the Cardiovascular Biomarkers of the Italian Society of Clinical Biochemistry (SIBIOC). On average more than 100 Italian laboratories were involved in the annual 2005–2011 cycles. In total, 72 study samples were distributed and measured by participant laboratories for a total of 6706 results. A great difference in between-method variability was found between BNP (43.0 CV%) and NT-proBNP (8.7 CV%) immunoassays. However, with the only exception of the POCT method for BNP assay, all immunoassay methods showed an imprecision≤10 CV% at the cut-off levels (i.e. 100 ng/L for BNP and 400 ng/L for NT-proBNP assay, respectively). Furthermore, CardioOrmoCheck study demonstrated that the most popular BNP immunoassays are affected by large systematic differences (on average more than 2 folds between TRIAGE Beckman-Coulter and ADVIA Centaur Siemens methods), while the agreement between NT-proBNP methods was better. CardioOrmoCheck study demonstrates that there are marked differences in analytical performance and measured values in particular among commercialmethods for BNP assay. These findings suggest that it may be not reasonable to recommend identical cut-off or decision values for all BNP immunoassays