RESUMEN
BACKGROUND: PCSK9 (proprotein convertase subtilisin-kexin type 9) chaperones the hepatic LDLR (low-density lipoprotein receptor) for lysosomal degradation, elevating serum LDL (low-density lipoprotein) cholesterol and promoting atherosclerotic heart disease. Though the major effect on the hepatic LDLR comes from secreted PCSK9, the details of PCSK9 reuptake into the hepatocyte remain unclear. In both tissue culture and animal models, HSPGs (heparan sulfate proteoglycans) on hepatocytes act as co-receptors to promote PCSK9 reuptake. We hypothesized that if this PCSK9:HSPG interaction is important in humans, disrupting it with unfractionated heparin (UFH) would acutely displace PCSK9 from the liver and increase plasma PCSK9. METHODS: We obtained remnant plasma samples from 160 subjects undergoing cardiac catheterization before and after administration of intravenous UFH. PCSK9 levels were determined using a commercial enzyme-linked immunosorbent assay. RESULTS: Median plasma PCSK9 was 113 ng/mL prior to UFH and 119 ng/mL afterward. This difference was not significant (P=0.83 [95% CI, -6.23 to 6.31 ng/mL]). Equivalence testing provided 95% confidence that UFH would not raise plasma PCSK9 by > 4.7%. Among all subgroups, only subjects with the lowest baseline PCSK9 concentrations exhibited a response to UFH (8.8% increase, adj. P=0.044). A modest correlation was observed between baseline plasma PCSK9 and the change in plasma PCSK9 due to UFH (RS=-0.3634; P<0.0001). CONCLUSIONS: Administration of UFH does not result in a clinically meaningful effect on circulating PCSK9 among an unselected population of humans. The results cast doubt on the clinical utility of disrupting the PCSK9:HSPG interaction as a general therapeutic strategy for PCSK9 inhibition. However, the observations suggest that in selected populations, disrupting the PCSK9:HSPG interaction could still affect PCSK9 reuptake and offer a therapeutic benefit.
Asunto(s)
Heparina , Proproteína Convertasa 9 , Animales , Humanos , Proproteína Convertasa 9/metabolismo , Serina Endopeptidasas , Proproteína Convertasas/metabolismo , Proteoglicanos de Heparán Sulfato , Receptores de LDL/metabolismo , LDL-Colesterol , SubtilisinasRESUMEN
BACKGROUND: Serum kappa, lambda, the K/λ light chain concentrations are used for screening, diagnosis, and monitoring of patients with multiple myeloma and other plasma cell disorders. Biological variation studies conducted on healthy subjects showed that free light chains have a low within and high between-individual variation. We determined if this variation were genetically linked. METHODS: We obtained a single serum sample from 16 pairs of identical twins, 8 neonate twins, and 19 presumed directly-related siblings children, measured Κ and λ light chains and computed the Κ/λ ratio. RESULTS: As expected, Κ/λ results from each twin neonate were near identical (reflecting maternal/placental transfer). For older children and adult twins, the Κ/λ ratio form a cluster of results that were a subset of the reference range. There was one outlier, a female with a high, different from her twin sister. She likely had a monoclonal gammopathy (no followup was possible). Excluding this pair, results from neonate twins (14.4% ±10.3%) and non-neonate twins (18.0 ± 15.3%) were not significantly different. Results between non-twin siblings were more scattered (53.2%±53.4%) and different from neonate and non-neonate twin adult and children. CONCLUSION: We suggest that the Κ/λ free light chains may be genetically linked.
Asunto(s)
Cadenas Ligeras de Inmunoglobulina , Hermanos , Gemelos , Adolescente , Adulto , Niño , Femenino , Humanos , Recién Nacido , Cadenas kappa de Inmunoglobulina , Cadenas lambda de Inmunoglobulina , Paraproteinemias/diagnóstico , PlacentaRESUMEN
OBJECTIVES: The destruction of red cells during blood collection or with the processing of the sample continues to occur at a high rate, especially among emergency department (ED) patients. This can produce pre-analytical laboratory errors, particularly for potassium. We determined the incidence of hemolyzed samples and discuss the potential medical impact for hypokalemic patients who potassium level is artificially normal (pseudoeukalemia). METHODS: Potassium results were obtained for a 6-month period. Using a measured hemolysis index (HI), hemolysis was present in 3.1â¯% for all potassium ordered (n=94,783) and 7.5â¯% for ED orders (n=22,770). Most of these samples were reported as having high normal result or were hyperkalemic. There were 22 hemolytic samples with a potassium of <3.5â¯mmol/L, and 57 hemolytic samples with a potassium in lower limit of normal (3.5-3.8â¯mmol/L). From this group, we examined the medical histories of 8 selected patients whose initially normal potassium levels were subsequently confirmed to have a potassium values that were below, at, or just above the lower limit of normal due to hemolysis. RESULTS: The primary complaint for these patients were: necrotizing soft tissue infection, pancreatitis, volume overload from heart failure with reduced ejection fraction, hypertension treated with hydrochlorothiazide, and presence of a short bowel syndrome. A subsequent non-hemolyzed sample was collected demonstrating hypokalemia in all of these patients. Within these cases, there was a potential for harm had hemolysis detection not been performed. CONCLUSIONS: We demonstrate the medical importance of detecting hemolysis for patients who have pseudoeukalemia. This is relevant because the HI cannot be obtained when electrolytes are tested using whole blood samples, and a normal potassium may lead to inappropriate patient management.
RESUMEN
BACKGROUND: While substance use is known to influence cardiovascular health, most prior studies only consider one substance at a time. We examined associations between the concurrent use of multiple substances and left ventricular mass index (LVMI) in unhoused and unstably housed women. METHODS: Between 2016 and 2019, we conducted a cohort study of unstably housed women in which measurements included an interview, serum/urine collection, vital sign assessment, and a single transthoracic echocardiogram at baseline. We evaluated independent associations between 39 separate substances confirmed through toxicology and echocardiography-confirmed LVMI. RESULTS: The study included 194 participants with a median age of 53.5 years and a high proportion of women of color (72.6%). Toxicology-confirmed substance use included: 69.1% nicotine, 56.2% cocaine, 28.9% methamphetamines, 28.9% alcohol, 23.2% opioid analgesics, and 9.8% opioids with catecholaminergic effects. In adjusted analysis, cocaine was independently associated with higher LVMI (Adjusted linear effect: 18%; 95% CI 9.9, 26.6). Associations with other substances did not reach levels of significance and did not significantly interact with cocaine. CONCLUSION: In a population of vulnerable women where the use of multiple substances is common, cocaine stands out as having particularly detrimental influences on cardiac structure. Blood pressure did not attenuate the association appreciably, suggesting direct effects of cocaine on LVMI. Routinely evaluating stimulant use as a chronic risk factor during risk assessment and preventive clinical care planning may reduce end organ damage, particularly in highly vulnerable women.
Asunto(s)
Trastornos Relacionados con Cocaína , Cocaína , Trastornos Relacionados con Sustancias , Humanos , Femenino , Persona de Mediana Edad , Estudios de Cohortes , Vivienda , Trastornos Relacionados con Cocaína/complicaciones , Trastornos Relacionados con Cocaína/epidemiología , Trastornos Relacionados con Sustancias/epidemiología , Analgésicos OpioidesRESUMEN
Loss-of-function CYP2C19 variants are associated with increased cumulative ischemic outcomes warranting CYP2C19 genotyping prior to clopidogrel administration. TAILOR-PCI was an international, multicenter (40 sites), prospective, randomized trial comparing rapid point of care (POC) genotype-guided vs. conventional anti-platelet therapy. The performance of buccal-based rapid CYP2C19 genotyping performed by non-laboratory-trained staff in TAILOR-PCI was assessed. Pre-trial training and evaluation involved rapid genotyping of 373 oral samples, with 99.5% (371/373) concordance with Sanger sequencing. During TAILOR-PCI, 5302 patients undergoing PCI were randomized to POC rapid CYP2C19 *2, *3, and *17 genotyping versus no genotyping. At 12 months post-PCI, TaqMan genotyping determined 99.1% (2,364/2,385) concordance with the POC results, with 90.7-98.8% sensitivity and 99.2-99.6% specificity. In conclusion, non-laboratory personnel can be successfully trained for on-site instrument operation and POC rapid genotyping with analytical accuracy and precision across multiple international centers, thereby supporting POC genotyping in patient-care settings, such as the cardiac catheterization laboratory.Clinical Trial Registration: https://www.clinicalTrials.gov (Identifier: NCT01742117).
Asunto(s)
Intervención Coronaria Percutánea , Humanos , Citocromo P-450 CYP2C19/genética , Inhibidores de Agregación Plaquetaria/uso terapéutico , Sistemas de Atención de Punto , Estudios Prospectivos , Genotipo , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Multicéntricos como AsuntoRESUMEN
BACKGROUND: The SARS-CoV-2 virus has mutated and evolved since the inception of the COVID-19 pandemic bringing into question the future effectiveness of current vaccines and antibody therapeutics. With evolution of the virus updated methods for the evaluation of the immune response in infected and vaccinated individuals are required to determine the durability of the immune response to SARS-CoV-2 variants. METHODS: We developed a multiplexed surrogate virus neutralization test (plex-sVNT) that simultaneously measures the ability of antibodies in serum to inhibit binding between angiotensin converting enzyme-2 (ACE2) and 7 SARS-CoV-2 trimeric spike protein variants, including wild type, B.1.1.7(α), B.1.351(ß), P.1(γ), B.1.617.2(δ), B.1.617.1(κ), and B.1.429(ε). The assay was validated against a plaque reduction neutralization test (PRNT).We evaluated 170 samples from 97 COVID-19 patients and 281 samples from 188 individuals that received the Pfizer-BioNTech or Moderna mRNA vaccines. RESULTS: The plex-sVNT demonstrated >96% concordance with PRNT. Antibody neutralization activity was significantly reduced for all SARS-CoV-2 variants compared to wild type in both the infected and vaccinated cohorts. There was a decline in overall antibody neutralization activity, within both cohorts, out to 5 months post infection or vaccination, with the rate of decline being more significant for the vaccinated. CONCLUSIONS: The plex-sVNT provides a correlative measure to PRNT and a convenient approach for evaluating antibody neutralization against SARS-CoV-2 variants. Neutralization of SARS-CoV-2 variants is reduced compared to wild type and declines over the ensuing months after exposure or vaccination within each cohort, however it is still unknown what degree of neutralizing capacity is protective.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Humanos , Pruebas de Neutralización , Pandemias , SARS-CoV-2/genética , VacunaciónRESUMEN
CONTEXT: Cardiovascular disease (CVD) and heart failure (HF) are major causes of mortality in low-income populations and differ by sex. Risk assessment that incorporates cardiac biomarkers is common. However, research evaluating the utility of biomarkers rarely includes controlled substances, which may influence biomarker levels and thus influence CVD risk assessment. MATERIALS AND METHODS: We identified the effects of multiple substances on soluble "suppression of tumorigenicity 2" (sST2), a biomarker of adverse cardiac remodelling, in 245 low-income women. Adjusting for CVD risk factors, we examined associations between substance use and sST2 over six monthly visits. RESULTS: Median age was 53 years and 74% of participants were ethnic minority women. An sST2 level > 35 ng/mL (suggesting cardiac remodelling) during ≥1 study visit was observed in 44% of participants. In adjusted analysis, higher sST2 levels were significantly and positively associated with the presence of cocaine (Adjusted Linear Effect [ALE]:1.10; 95% CI:1.03-1.19), alcohol (ALE:1.10; 95% CI:1.04-1.17), heroin (ALE:1.25; 95% CI:1.10-1.43), and the interaction between heroin and fentanyl use. CONCLUSION: Results suggest that the use of multiple substances influences the level of sST2, a biomarker often used to evaluate cardiovascular risk. Incorporating substance use alongside cardiac biomarkers may improve CVD risk assessment in vulnerable women.
Asunto(s)
Enfermedades Cardiovasculares , Insuficiencia Cardíaca , Trastornos Relacionados con Sustancias , Femenino , Humanos , Persona de Mediana Edad , Proteína 1 Similar al Receptor de Interleucina-1 , Remodelación Ventricular , Heroína , Etnicidad , Grupos Minoritarios , Biomarcadores , Insuficiencia Cardíaca/diagnóstico , PronósticoRESUMEN
BACKGROUND: The observed incidence of type 2 myocardial infarction (T2MI) is expected to increase with the implementation of increasingly sensitive cTn assays. However, it remains to be determined how to diagnose, risk-stratify, and treat patients with T2MI. We aimed to discriminate and risk-stratify T2MI using biomarkers. METHODS: Patients presenting to the emergency department with chest pain, enrolled in the CHOPIN study (Copeptin Helps in the early detection Of Patients with acute myocardial INfarction), were retrospectively analyzed. Two cardiologists adjudicated type 1 MI (T1MI) and T2MI. The prognostic ability of several biomarkers alone or in combination to discriminate T2MI from T1MI was investigated using receiver operating characteristic curve analysis. The biomarkers analyzed were cTnI, copeptin, MR-proANP (midregional proatrial natriuretic peptide), CT-proET1 (C-terminal proendothelin-1), MR-proADM (midregional proadrenomedullin), and procalcitonin. The prognostic utility of these biomarkers for all-cause mortality and major adverse cardiovascular event (a composite of acute myocardial infarction, unstable angina pectoris, reinfarction, heart failure, and stroke) at 180-day follow-up was also investigated. RESULTS: Among the 2071 patients, T1MI and T2MI were adjudicated in 94 and 176 patients, respectively. Patients with T1MI had higher levels of baseline cTnI, whereas those with T2MI had higher baseline levels of MR-proANP, CT-proET1, MR-proADM, and procalcitonin. The area under the receiver operating characteristic curve for the diagnosis of T2MI was higher for CT-proET1, MR-proADM, and MR-proANP (0.765, 0.750, and 0.733, respectively) than for cTnI (0.631). Combining all biomarkers resulted in a similar accuracy to a model using clinical variables and cTnI (0.854 versus 0.884, P=0.294). Addition of biomarkers to the clinical model yielded the highest area under the receiver operating characteristic curve (0.917). Other biomarkers, but not cTnI, were associated with mortality and major adverse cardiovascular event at 180 days among all patients, with no interaction between the diagnosis of T1MI or T2MI. CONCLUSIONS: Assessment of biomarkers reflecting pathophysiologic processes occurring with T2MI might help differentiate it from T1MI. All biomarkers measured, except cTnI, were significant predictors of prognosis, regardless of the type of myocardial infarction.
Asunto(s)
Biomarcadores/metabolismo , Infarto del Miocardio/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
The kinetics of IgG avidity maturation during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was studied. The IgG avidity assay, using a novel label-free immunoassay technology, revealed a strong correlation between IgG avidity and days since symptom onset. Peak readings were significantly higher in severe than mild disease cases.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Antivirales , Afinidad de Anticuerpos , Humanos , Inmunoglobulina G , Inmunoglobulina M , Cinética , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can be detected indirectly by measuring the host immune response. For some viruses, antibody concentrations correlate with host protection and viral neutralization, but in rare cases, antiviral antibodies can promote disease progression. Elucidation of the kinetics and magnitude of the SARS-CoV-2 antibody response is essential to understand the pathogenesis of coronavirus disease 2019 (COVID-19) and identify potential therapeutic targets. METHODS: Sera (nâ =â 533) from patients with real-time polymerase chain reaction-confirmed COVID-19 (nâ =â 94 with acute infections and nâ =â 59 convalescent patients) were tested using a high-throughput quantitative immunoglobulin M (IgM) and immunoglobulin G (IgG) assay that detects antibodies to the spike protein receptor binding domain and nucleocapsid protein. Individual and serial samples covered the time of initial diagnosis, during the disease course, and following recovery. We evaluated antibody kinetics and correlation between magnitude of the response and disease severity. RESULTS: Patterns of SARS-CoV-2 antibody production varied considerably. Among 52 patients with 3 or more serial specimens, 44 (84.6%) and 42 (80.8%) had observed IgM and IgG seroconversion at a median of 8 and 10 days, respectively. Compared to those with milder disease, peak measurements were significantly higher for patients admitted to the intensive care unit for all time intervals between 6 and 20 days for IgM, and all intervals after 5 days for IgG. CONCLUSIONS: High-sensitivity assays with a robust dynamic range provide a comprehensive picture of host antibody response to SARS-CoV-2. IgM and IgG responses were significantly higher in patients with severe than mild disease. These differences may affect strategies for seroprevalence studies, therapeutics, and vaccine development.
Asunto(s)
Formación de Anticuerpos , COVID-19 , Anticuerpos Antivirales , Humanos , Inmunoglobulina M , Cinética , SARS-CoV-2 , Estudios Seroepidemiológicos , Índice de Severidad de la EnfermedadRESUMEN
Methods designed to measure severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) humoral response include virus neutralization tests to determine antibody neutralization activity. For ease of use and universal applicability, surrogate virus neutralization tests (sVNTs) based on antibody-mediated blockage of molecular interactions have been proposed. A surrogate virus neutralization test was established on a label-free immunoassay platform (LF-sVNT). The LF-sVNT analyzes the binding ability of SARS-CoV-2 spike protein receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2) after neutralizing RBD with antibodies in serum. The LF-sVNT neutralizing antibody titers (50% inhibitory concentration [IC50]) were determined from serum samples (n = 246) from coronavirus disease 2019 (COVID-19) patients (n = 113), as well as the IgG concentrations and the IgG avidity indices. Although there was variability in the kinetics of the IgG concentrations and neutralizing antibody titers between individuals, there was an initial rise, plateau, and then in some cases a gradual decline at later time points after 40 days after symptom onset. The IgG avidity indices, in the same cases, plateaued after an initial rise and did not show a decline. The LF-sVNT can be a valuable tool in research and clinical laboratories for the assessment of the presence of neutralizing antibodies to COVID-19. This study is the first to provide longitudinal neutralizing antibody titers beyond 200 days post-symptom onset. Despite the decline of IgG concentration and neutralizing antibody titer, IgG avidity index increases, reaches a plateau, and then remains constant up to 8 months postinfection. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Humanos , Estudios Longitudinales , Pruebas de Neutralización , Glicoproteína de la Espiga del CoronavirusRESUMEN
BACKGROUND: As global confirmed cases and deaths from coronavirus disease 2019 (COVID-19) surpass 100 and 2.2 million, respectively, quantifying the effects of the widespread treatment of remdesivir (GS-5734, Veklury) and the steroid dexamethasone is becoming increasingly important. Limited pharmacokinetic studies indicate that remdesivir concentrations in serum decrease quickly after dosing, so its primary serum metabolite GS-441524 may have more analytical utility. OBJECTIVES: We developed and validated a method to quantify remdesivir, its metabolite GS-441524 and dexamethasone in human serum. METHODS: We used LC-MS/MS and applied the method to 23 serum samples from seven patients with severe COVID-19. RESULTS: The method has limits of detection of 0.0375 ng/mL for remdesivir, 0.375 ng/mL for GS-441524 and 3.75 ng/mL for dexamethasone. We found low intra-patient variability, but significant inter-patient variability, in remdesivir, GS-441524 and dexamethasone levels. CONCLUSIONS: The significant inter-patient variability highlights the importance of therapeutic drug monitoring of COVID-19 patients and possible dose adjustment to achieve efficacy.
Asunto(s)
Tratamiento Farmacológico de COVID-19 , Espectrometría de Masas en Tándem , Adenosina/análogos & derivados , Adenosina Monofosfato/análogos & derivados , Alanina/análogos & derivados , Antivirales/uso terapéutico , Cromatografía Liquida , Dexametasona , Furanos , Humanos , Pirroles , SARS-CoV-2 , TriazinasRESUMEN
BACKGROUND: Biomarkers have been widely explored for coronavirus disease 2019 diagnosis. Both viral RNA or antigens (Ag) in the respiratory system and antibodies (Ab) in blood are used to identify active infection, transmission risk, and immune response but have limitations. This study investigated the diagnostic utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N-Ag) in serum. METHODS: We retrospectively studied 208 randomly selected cases with SARS-CoV-2 infection confirmed by viral RNA test in swabs. N-Ag concentrations were measured in remnant serum samples, compared to viral RNA or Ab results, and correlated to electronic health records for clinical value evaluation. RESULTS: Serum N-Ag was detected during active infection as early as day 2 from symptom onset with a diagnostic sensitivity of 81.5%. Within 1 week of symptom onset, the diagnostic sensitivity and specificity reached 90.9% (95% CI, 85.1%-94.6%) and 98.3% (95% CI, 91.1%-99.9%), respectively. Moreover, serum N-Ag concentration closely correlated to disease severity, reflected by highest level of care, medical interventions, chest imaging, and the length of hospital stays. Longitudinal analysis revealed the simultaneous increase of Abs and decline of N-Ag. CONCLUSIONS: Serum N-Ag is a biomarker for SARS-CoV-2 acute infection with high diagnostic sensitivity and specificity compared to viral RNA in the respiratory system. There is a correlation between serum N-Ag concentrations and disease severity and an inverse relationship of N-Ag and Abs. The diagnostic value of serum N-Ag, as well as technical and practical advantages it could offer, may meet unsatisfied diagnostic and prognostic needs during the pandemic.
Asunto(s)
Prueba de COVID-19/métodos , COVID-19 , Proteínas de la Nucleocápside de Coronavirus/sangre , Anticuerpos Antivirales/sangre , COVID-19/diagnóstico , Humanos , Proteínas de la Nucleocápside , Fosfoproteínas/sangre , ARN Viral , Estudios Retrospectivos , SARS-CoV-2 , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: Troponin composition characterization has been implicated as a next step to differentiate among non-ST elevation myocardial infarction (NSTEMI) patients and improve distinction from other conditions with troponin release. We therefore studied coronary and peripheral troponin compositions in relation to clinical variables of NSTEMI patients. METHODS: Samples were obtained from the great cardiac vein (GCV), coronary sinus (CS), and peripheral circulation of 45 patients with NSTEMI. We measured total cTnI concentrations, and assessed both complex cTnI (binary cTnIC + all ternary cTnTIC forms), and large-size cTnTIC (full-size and partially truncated cTnTIC). Troponin compositions were studied in relation to culprit vessel localization (left anterior descending artery [LAD] or non-LAD), ischemic time window, and peak CK-MB value. RESULTS: Sampling occurred at a median of 25 hours after symptom onset. Of total peripheral cTnI, a median of 87[78-100]% consisted of complex cTnI; and 9[6-15]% was large-size cTnTIC. All concentrations (total, complex cTnI, and large-size cTnTIC) were significantly higher in the CS than in peripheral samples (P < 0.001). For LAD culprit patients, GCV concentrations were all significantly higher; in non-LAD culprit patients, CS concentrations were higher. Proportionally, more large-size cTnTIC was present in the earliest sampled patients and in those with the highest CK-MB peaks. CONCLUSIONS: In coronary veins draining the infarct area, concentrations of both full-size and degraded troponin were higher than in the peripheral circulation. This finding, and the observed associations of troponin composition with the ischemic time window and the extent of sustained injury may contribute to future characterization of different disease states among NSTEMI patients.
Asunto(s)
Infarto del Miocardio sin Elevación del ST/metabolismo , Troponina C/metabolismo , Troponina I/metabolismo , Troponina T/metabolismo , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Biomarcadores/metabolismo , Seno Coronario/irrigación sanguínea , Femenino , Humanos , Masculino , Infarto del Miocardio sin Elevación del ST/sangre , Flujo Sanguíneo Regional , Índice de Severidad de la Enfermedad , Factores de Tiempo , Troponina C/sangre , Troponina I/sangre , Troponina T/sangreRESUMEN
BACKGROUND: Heterogeneity of prostate cancer (PCa) contributes to inaccurate cancer screening and diagnosis, unnecessary biopsies, and overtreatment. We intended to develop non-invasive urine tests for accurate PCa diagnosis to avoid unnecessary biopsies. METHODS: Using a machine learning program, we identified a 25-Gene Panel classifier for distinguishing PCa and benign prostate. A non-invasive test using pre-biopsy urine samples collected without digital rectal examination (DRE) was used to measure gene expression of the panel using cDNA preamplification followed by real-time qRT-PCR. The 25-Gene Panel urine test was validated in independent multi-center retrospective and prospective studies. The diagnostic performance of the test was assessed against the pathological diagnosis from biopsy by discriminant analysis. Uni- and multivariate logistic regression analysis was performed to assess its diagnostic improvement over PSA and risk factors. In addition, the 25-Gene Panel urine test was used to identify clinically significant PCa. Furthermore, the 25-Gene Panel urine test was assessed in a subset of patients to examine if cancer was detected after prostatectomy. RESULTS: The 25-Gene Panel urine test accurately detected cancer and benign prostate with AUC of 0.946 (95% CI 0.963-0.929) in the retrospective cohort (n = 614), AUC of 0.901 (0.929-0.873) in the prospective cohort (n = 396), and AUC of 0.936 (0.956-0.916) in the large combination cohort (n = 1010). It greatly improved diagnostic accuracy over PSA and risk factors (p < 0.0001). When it was combined with PSA, the AUC increased to 0.961 (0.980-0.942). Importantly, the 25-Gene Panel urine test was able to accurately identify clinically significant and insignificant PCa with AUC of 0.928 (95% CI 0.947-0.909) in the combination cohort (n = 727). In addition, it was able to show the absence of cancer after prostatectomy with high accuracy. CONCLUSIONS: The 25-Gene Panel urine test is the first highly accurate and non-invasive liquid biopsy method without DRE for PCa diagnosis. In clinical practice, it may be used for identifying patients in need of biopsy for cancer diagnosis and patients with clinically significant cancer for immediate treatment, and potentially assisting cancer treatment follow-up.
Asunto(s)
Biomarcadores de Tumor/orina , Detección Precoz del Cáncer/métodos , Antígeno Prostático Específico/orina , Neoplasias de la Próstata/orina , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/terapia , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
BACKGROUND: Immunoassays based on label-free technologies (label-free immunoassay [LFIA]) offer an innovative approach to clinical diagnostics and demonstrate great promise for therapeutic drug monitoring (TDM) of monoclonal antibody (mAb) drugs. An LFIA measures immunocomplex formation in real time and allows for quantification on initial binding rate, which facilitates fast measurement within a few minutes. METHODS: Based on thin-film interferometry (TFI) technology, open-access LFIAs were developed for the quantification of the mAb drugs adalimumab (ADL) and infliximab (IFX) and for the detection of the antidrug antibodies (ADAs) to the mAb drugs (ADL-ADAs and IFX-ADAs). RESULTS: The LFIAs for active mAb drugs (ADL and IFX) and for ADAs (ADL-ADAs and IFX-ADAs) were validated. The analytical measurement range (AMR) for both ADL and IFX was from 2 to 100 µg/mL. The AMR for ADL-ADAs was from 5 to 100 µg/mL and for IFX-ADAs was 10 to 100 µg/mL. In the comparison of LFIAs and reporter gene assays, the correlation coefficient was 0.972 for the quantification of ADL and 0.940 for the quantification of IFX. The concordance rate was 90% for the detection of ADL-ADAs and 76% for the detection of IFX-ADAs. CONCLUSIONS: The LFIAs for active mAb drugs and ADAs were appropriate for the TDM of ADL and IFX. The TFI technology has unique advantages compared with other technologies used for the measurement of mAb drugs. Label-free technologies, especially those allowing for open-access LFIAs, have great potential for clinical diagnostics.
Asunto(s)
Adalimumab/sangre , Monitoreo de Drogas/métodos , Inmunoensayo/métodos , Infliximab/sangre , Adalimumab/inmunología , Biosimilares Farmacéuticos/sangre , Humanos , Infliximab/inmunología , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
BACKGROUND: Concerns exist regarding how the 99th percentile upper reference limit (URL) of cardiac troponin (cTn) is determined and whether it should be derived from normal healthy individuals. CONTENT: The 99th percentile URL of cTn is an important criterion to standardize the diagnosis of myocardial infarction (MI) for clinical, research, and regulatory purposes. Statistical heterogeneity in its calculation exists but recommendations have been proposed. Some negativity has resulted from the fact that with some high-sensitivity (hs) cTn assays, a greater number of increases above the 99th percentile are observed when transitioning from a contemporary assay. Increases reflect acute or chronic myocardial injury and provide valuable diagnostic and prognostic information. The etiology of increases can sometimes be difficult to determine, making a specific treatment approach challenging. For those reasons, some advocate higher cutoff concentrations. This approach can contribute to missed diagnoses. Contrary to claims, neither clinical or laboratory guidelines have shifted away from the 99th percentile. To support the diagnosis of acute MI, the 99th percentile URL remains the best-established approach given the absence of cTn assay standardization. Importantly, risk stratification algorithms using hs-cTn assays predict the possibility of MI diagnoses established using the 99th percentile. SUMMARY: The 99th percentile of cTn remains the best-established criterion for the diagnosis of acute MI. While not perfect, it is analytically and clinically evidence-based. Until there are robust data to suggest some other approach, staying with the 99th percentile, a threshold that has served the field well for the past 20 years, appears prudent.
Asunto(s)
Infarto del Miocardio/diagnóstico , Troponina I/sangre , Troponina T/sangre , Enfermedad Aguda , Biomarcadores/sangre , Humanos , Infarto del Miocardio/sangre , Valores de Referencia , Troponina I/normas , Troponina T/normasRESUMEN
BACKGROUND: How to select healthy reference subjects in deriving 99th percentiles for cardiac troponin assays still needs to be clarified. To assist with global implementation of high sensitivity (hs)-cardiac troponin (cTn) I and hs-cTnT assays in clinical practice, we determined overall and sex-specific 99th percentiles in 9 hs-cTnI and 3 hs-cTnT assays using a universal sample bank (USB). METHODS: The Universal Sample Bank (USB) comprised healthy subjects, 426 men and 417 women, screened using a health questionnaire. Hemoglobin A1c (>URL 6.5%), NT-proBNP (>URL 125 ng/L) and eGFR (<60 mL/min), were used as surrogate biomarker exclusion criteria along with statin use. 99th percentiles were determined by nonparametric, Harrell--Davis bootstrap, and robust methods. RESULTS: Subjects were ages 19 to 91 years, Caucasian 58%, African American 27%, Pacific Islander/Asian 11%, other 4%, Hispanic 8%, and non-Hispanic 92%. The overall and sex-specific 99th percentiles for all assays, before and after exclusions (n = 694), were influenced by the statistical method used, with substantial differences noted between and within both hs-cTnI and hs-cTnT assays. Men had higher 99th percentiles (ng/L) than women. The Roche cTnT and Beckman and Abbott cTnI assays (after exclusions) did not measure cTn values at ≥ the limit of detection in ≥50% women. CONCLUSIONS: Our findings have important clinical implications in that sex-specific 99th percentiles varied according to the statistical method and hs-cTn assay used, not all assays provided a high enough percentage of measurable concentrations in women to qualify as a hs-assay, and the surrogate exclusion criteria used to define normality tended to lower the 99th percentiles.
Asunto(s)
Bioensayo/métodos , Troponina I/sangre , Troponina T/sangre , Adulto , Anciano , Anciano de 80 o más Años , Bioensayo/normas , Bancos de Muestras Biológicas , Biomarcadores/sangre , Femenino , Humanos , Límite de Detección , Masculino , Persona de Mediana Edad , Infarto del Miocardio/diagnóstico , Juego de Reactivos para Diagnóstico , Valores de Referencia , Factores Sexuales , Troponina I/normas , Troponina T/normas , Adulto JovenAsunto(s)
Etnicidad/genética , Medicina , Grupos Raciales/genética , Racismo , Humanos , Estados UnidosRESUMEN
Laboratory tests for Clostridioides difficile infection (CDI) rely on the detection of free toxin or molecular detection of toxin genes. The Singulex Clarity C. diff toxins A/B assay is a rapid, automated, and ultrasensitive assay that detects C. difficile toxins A and B in stool. We compared CDI assays across two prospective multicenter studies to set a cutoff for the Clarity assay and to independently validate the performance compared with that of a cell culture cytotoxicity neutralization assay (CCCNA). The cutoff was set by two sites testing fresh samples from 897 subjects with suspected CDI and then validated at four sites testing fresh samples from 1,005 subjects with suspected CDI. CCCNA testing was performed at a centralized laboratory. Samples with discrepant results between the Clarity assay and CCCNA were retested with CCCNA when the Clarity result agreed with that of at least one comparator method; toxin enzyme immunoassays (EIA), glutamate dehydrogenase (GDH) detection, and PCR were performed on all samples. The cutoff for the Clarity assay was set at 12.0 pg/ml. Compared to results with CCCNA, the Clarity assay initially had 85.2% positive agreement and 92.4% negative agreement. However, when samples with discrepant results between the Clarity assay and CCCNA in the validation study were retested by CCCNA, 13/17 (76.5%) Clarity-negative but CCCNA-positive samples (Clarity+/CCCNA-) became CCCNA-, and 5/26 (19.2%) Clarity+/CCCNA- samples became CCCNA+, resulting in a 96.3% positive agreement and 93.0% negative agreement between Clarity and CCCNA results. The toxin EIA had 59.8% positive agreement with CCCNA. The Clarity assay was the most sensitive free-toxin immunoassay, capable of providing CDI diagnosis in a single-step solution. A different CCCNA result was reported for 42% of retested samples, increasing the positive agreement between Clarity and CCCNA from 85.2% to 96.3% and indicating the challenges of comparing free-toxin results to CCCNA results as a reference standard.