Adult Serum Samples Research Articles

Lateral flow test versus enzyme-linked immunosorbent assay to measure infliximab trough concentrations: A head-to-head comparison.

Infliximab is an antitumour necrosis factor agent used to treat inflammatory bowel disease (IBD). Measurement of infliximab trough concentrations (C-troughs) are used to optimize drug exposure and improve outcomes. Currently, enzyme-linked immunosorbent assays (ELISAs) are used predominantly for this purpose. Novel lateral flow immunoassays provide a rapid result. We collected 100 paired serum samples of adolescents and young adults with IBD, who were treated with infliximab maintenance infusions. C-troughs were measured with the Quantum Blue® lateral flow test (QB) with ELISA. Results were categorized as low-range (mean C-trough ≤5 µg/mL) or high-range (>5 µg/mL). A Bland-Altman plot was created with limits of clinical acceptability set at ≤2 µg/mL for low-range and ≤40% for high-range C-troughs. A concordance matrix was created to evaluate the C-trough-based clinical scenario (whether or not to escalate infliximab) using a cutoff value of 5 µg/mL. Agreement between QB and ELISA was good (intraclass correlation coefficient: 0.85). In the low-range, 90% (95% confidence interval [CI]: 79-96) of measurements were within the limits of clinical acceptability. In the high-range this was 67% (95% CI: 53-79). QB provided higher results than ELISA. The concordance matrix showed 81% agreement (95% CI: 72-88, κ: 0.62). Lateral flow- and ELISA-based infliximab C-trough measurements were in agreement. The swift establishment of infliximab C-troughs matters for patients experiencing increased disease activity. In the event of a low C-trough, prompt dose escalation can be initiated.

A combined top-down and bottom-up LC-HRMS/MS method for the quantification of human growth hormone in plasma and serum

ObjectiveThe precise and accurate quantification of human growth hormone (GH) in plasma/ serum is crucial for the diagnosis and treatment of diseases like GH deficiency or acromegaly. However, the ligand-binding assays (LBAs) currently used for routine testing show considerable methodological variability. Here, we present a complementary, combined top-down and bottom-up LC-MS-based method to quantify (intact) GH in plasma and serum, which concurrently provides a basis for a MS-based analysis of GH in doping controls. DesignExtraction of GH from plasma/ serum was accomplished by protein precipitation, followed by an immunocapture step using protein A-coupled magnetic beads and a polyclonal anti-GH antibody. The intact protein was subsequently analyzed top-down on a 2D-LC-HRMS/MS system. In addition, sample extracts were digested with trypsin and analyzed for signal peptides corresponding to ‘total’, 22 kDa and 20 kDa GH (bottom-up). Both assays were validated according to current guidelines and compared to the GH isoform differential immunoassay used in routine doping control analysis. GH concentrations in serum samples of healthy adults, patients with acromegaly, and in samples obtained after administration of recombinant GH were analyzed as proof-of-principle. ResultsThe intact monomeric 22 kDa isoform of GH was selectively quantified in a representative working range of 0.5 to 10 ng/ml by top-down LC-HRMS/MS. Subsequent bottom-up analysis provided additional data on ‘total’ and 20 kDa GH. Top-down and bottom-up assay results for the 22 kDa isoform correlated well with the corresponding immunoassay results (R2 > 0.95). For a possible application of the method in an anti-doping context, the ratio between 22 kDa and ‘total’ GH was evaluated, indicating differences between the various donor groups, but only with limited significance. ConclusionThe top-down and bottom-up LC-HRMS/MS method developed here presents a valuable tool for the quantification of GH in plasma/ serum complementary to established LBAs used at present in clinical measurements. Albeit the examination of the GH isoform proportions by the LC-MS method does not yet allow for the assessment of GH abuse, the obtained findings provide an important basis to enable LC-MS-based GH analysis of doping control samples in the future.

Associations of circulating levels of phthalate metabolites with cytokines and acute phase reactants in a Spanish human cohort

The associations between human phthalate exposure and the onset of chronic diseases with an immunological component (e.g., metabolic syndrome, cancer) remain unclear, partly due to the uncertainties in the underlying mechanisms. This study investigates cross-sectional associations of the concentrations of 10 phthalate metabolites with 19 cytokines and acute phase proteins in 213 serum samples of Spanish adults. The associations were explored by Spearman's correlation, multivariable linear regression, and weighted quantile sum regression analyses. In the multivariable analyses, levels of plasminogen activator inhibitor (PAI)-1 were positively associated with mono-n-butyl phthalate (fold-change per one IQR increase in phthalate levels, 95% Confidence Interval: 1.65, 1.45–1.88) and mono-iso-butyl phthalate (3.07, 2.39–3.95), mono-ethyl phthalate (2.05, 1.62–2.61), as well as categorized mono-iso-decyl and mono-benzyl phthalates. The same phthalates also were significantly associated with leptin, interleukin (IL)-18 and monocyte chemoattractant protein-1. Moreover, the proinflammatory markers IL-1β, IL-17, IL-8, IL-6, IL-12, tumor necrosis factor, and lipopolysaccharide-binding protein showed positive and negative associations with, respectively, mono-(2-ethyl-hexyl) and mono-methyl phthalates. Finally, phthalate mixtures were positively associated with PAI-1, leptin, IL-18, IL-12, IL-8 and IL-1β. Despite the cross-sectional design limitation, these associations point to relevant subclinical immuno-inflammatory actions of these pollutants, warranting confirmation in future studies.

Identification of Immune Activation Markers in the Early Onset of COVID-19 Infection.

This study aimed to determine the specific cytokine profile in peripheral blood during the early onset of COVID-19 infection. This was a cross-sectional exploratory, single center study. A total of 55 plasma samples were studied. Serum samples of adults showing symptoms of COVID-19 infection who were tested positive for SARS-CoV-2 infection (CoV+, n=18) at the COVID-19 outpatient clinic of the Medical University of Vienna were screened for immune activation markers by Luminex technology. Additionally, age and gender-matched serum samples of patients displaying COVID-19 associated symptoms, but tested negative for SARS-CoV-2 (CoV-, n=16) as well as healthy controls (HC, n=21) were analyzed. COVID-19 positive (CoV+) patients showed a specific upregulation of BLC (141; 74-189 pg/mL), SCD30 (273; 207-576 pg/mL), MCP-2 (18; 12-30 pg/mL) and IP-10 (37; 23-96 pg/mL), compared to patients with COVID19-like symptoms but negative PCR test (CoV-), BLC (61; 22-100 pg/mL), sCD30L (161; 120-210 pg/mL), MCP-2 (8; 5-12 pg/mL) and IP-10 (9; 6-12 pg/mL) and healthy controls (HC) (BLC 22; 11-36 pg/mL, sCD30 74; 39-108 pg/mL, MCP-2 6; 3-9. pg/mL, IP-10 = 8; 5-13). The markers APRIL, sIL-2R, IL7, MIF, MIP-1b, SCF, SDF-1a, sTNF-RII were elevated in both CoV+ and CoV- patient groups compared to healthy controls. HGF, MDC and VEGF-A were elevated in CoV- but not CoV+ compared to healthy controls. BLC, sCD30, MCP-2 and IP-10 are specifically induced during early stages of COVID-19 infection and might constitute attractive targets for early diagnosis and treatment of this disease.

High Seropositivity Rate of Neutralizing Antibodies to Astrovirus VA1 in Human Populations.

ABSTRACTAstroviruses are common pathogens of the human gastrointestinal tract, but they have been recently identified from cases of fatal meningoencephalitis. Astrovirus VA1 is the most frequently detected astrovirus genotype from cases of human encephalitis, but the prevalence of neutralizing antibodies to VA1 in human sera is unknown. We developed a focus reduction neutralization assay (FRNT) for VA1 and measured the seroprevalence of neutralizing antibodies from two cohorts of adult and pediatric serum samples: (i) an age-stratified cohort from St. Louis, MO, collected from 2007 to 2008 and (ii) a cohort from the Peruvian Amazonian River Basin collected in the late 1990s. In the St. Louis cohort, the lowest seropositivity rate was in children 1 year of age (6.9%), rising to 63.3% by ages 9 to 12, and 76.3% of adults ≥20 years were positive. The Peruvian Amazon cohort showed similar seropositivity rates across all ages, with individuals under age 20 having a rate of 75%, while 78.2% of adults ≥20 years were seropositive. In addition, we also identified the presence neutralizing antibodies to VA1 from commercial lots of intravenous immunoglobulin (IVIG). Our results demonstrate that a majority of humans are exposed to VA1 by adulthood, with the majority of infections occurring between 2 and 9 years of age. In addition, our results indicate that VA1 has been circulating in two geographically and socioeconomically divergent study cohorts over the past 20 years. Nonetheless, a significant proportion of the human population lacks neutralizing immunity and remains at risk for acute infection.IMPORTANCE Astroviruses are human pathogens with emerging disease associations, including the recent recognition of their capacity to cause meningoencephalitis. Astrovirus VA1 is the most commonly identified astrovirus genotype from cases of human encephalitis, but it is unknown what percentage of the human population has neutralizing antibodies to VA1. We found that 76.3 to 78.2% of adult humans ≥20 years of age in two geographically and socioeconomically distinct cohorts are seropositive for VA1, with the majority of infections occurring between 2 and 9 years of age. These results demonstrate that VA1 has been circulating in human populations over the past 2 decades and that most humans develop neutralizing antibodies against this virus by adulthood. However, a subset of humans lack evidence of neutralizing antibodies and are at risk for diseases caused by VA1, including encephalitis.

Early Diagnosis of HIV-1 and HIV-2 Using Cobas HIV-1/HIV-2 Qualitative Test: A Novel Qualitative Nucleic Acid Amplification Test for Plasma, Serum, and Dried Blood Spot Specimens.

Background:Nucleic acid amplification tests (NATs) minimize the time from HIV infection to diagnosis, reducing transmission during acute HIV. NATs are especially useful for diagnosing HIV in children younger than 18 months and discriminating between HIV-1 and HIV-2.Methods:We evaluated the performance of the cobas HIV-1/HIV-2 qualitative (cobas HIV-1/2 Qual) test for use on cobas 6800/8800 Systems. The results of adult plasma and serum samples and pediatric dried blood spots were compared with those of the recomLine HIV-1 & HIV-2 Immunoglobulin G serological test and COBAS AmpliPrep/COBAS TaqMan HIV-1 qualitative test, v2.0. Genotype inclusivity and limits of detection were determined, and sensitivity on seroconversion panels was compared with that in the Bio-Rad Geenius HIV 1/2 Confirmatory Assay, Abbott ARCHITECT HIV Ag/Ab Combo serological test, and cobas TaqScreen MPX, v2.0.Results:Concordance of cobas HIV-1/2 Qual test with the comparator serological test and COBAS AmpliPrep/COBAS TaqMan test was ≥99.6% with all sample types. Reactivity with all HIV genotypes was 100%. LOD in plasma samples was 14.8, 12.6, and 27.9 copies/mL for HIV-1 group M, HIV-1 group O, and HIV-2, respectively, with similar results for serum samples. LOD in dried blood spots was 255 copies/mL for HIV-1 and 984 copies/mL for HIV-2. HIV infection was detected 18.9 days and 8.5 days earlier than the confirmatory and serological assays, respectively, and at a similar time to the NAT.Conclusions:The cobas HIV-1/2 Qual test enables early and accurate diagnoses of HIV-1 and HIV-2 in adults and children across sample types. The assay could help avert transmission during acute HIV, simplify HIV diagnostic algorithms, and promote the survival of HIV-infected children.

VA-MENGOC-BC Vaccination Induces Serum and Mucosal Anti Neisseria gonorrhoeae Immune Responses and Reduces the Incidence of Gonorrhea.

Overall, there are over 30 different sexually transmitted infections with Neisseria gonorrhoeae being the third most frequent with a reported 78 million cases per year. Gonococcal infection causes genital inflammation, which can be a risk factor for others sexually transmitted infections, particularly human immunodeficiency virus. Gonorrhea is a treatable disease, but recently an increase in antibiotic resistance has been of concern. There are currently no vaccines available. However, parenteral vaccination with anti N. meningitidis serogroup B vaccine has been reported to decrease the incidence of gonococcal burden in New Zealand and in Cuba despite the fact that parenteral vaccination is not deemed to induce mucosal IgA. Here we explore possible mechanisms of protection against gonococcal infection through parenteral meningococcal B vaccination. Ninety-two serum, saliva and oropharyngeal swabs samples of young adults (healthy and Neisseria carriers) of the internal higher school were obtained. They have been vaccinated with VA-MENGOC-BC (MBV) during their infancy and boosted with a third dose during this study. Serum and saliva samples were analyzed by ELISA and Western blot to measured IgG and IgA antibodies against N. meningitidis and N. gonorrhoeae antigens. N. meningitidis carriers were determined by standard microbiologic test. In addition, we reviewed epidemiologic data for N. meningitidis and N. gonorrhoeae infections in Cuba. Epidemiologic data show the influence of MBV over gonorrhea incidence suggesting to be dependent of sexual arrival age of vaccines but not over syphilis. Laboratorial data permit the detection of 70 and 22 noncarriers and carriers of N. meningitidis, respectively. Serum anti-MBV antigens (PL) responses were boosted by a third dose and were independent of carriage stages, but saliva anti-PL IgA responses were only present and were significant induced in carriers subjects. Carriers boosted with a third dose of MBV induced similar antigonococcal and -PL saliva IgA and serum IgG responses; meanwhile, serum antigonococcal IgG was significantly lower. In saliva, at least 2 gonococcal antigens were identified by Western blot. Finally, gonococcal-specific mucosal IgA antibody responses, in addition to the serum IgG antibodies, might contributed to the reduction of the incidence of N. gonorrhoeae. We hypothesize that this might have contributed to the observed reductions of the incidence of N. gonorrhoeae. These results suggest a mechanism for the influence of a Proteoliposome-based meningococcal BC vaccine on gonococcal incidence.

Selenium, Zinc, Chromium, and Vanadium Levels in Serum, Hair, and Urine Samples of Obese Adults Assessed by Inductively Coupled Plasma Mass Spectrometry.

The objective of this study was to investigate of selenium (Se), zinc (Zn), chromium (Cr), and vanadium (V) levels in blood serum, hair, and urine of adult obese patients. A total of 199 lean and 196 obese subjects were enrolled in the study. Serum, hair, and urinary metal and metalloid analysis were performed by inductively coupled plasma mass spectrometry at NexION 300D (PerkinElmer Inc., USA). The results established that obese subjects were characterized by 47% and 30% lower serum Cr and V levels compared with controls, respectively, whereas serum Se levels exceeded control values by 9%. In contrast, hair Cr, Se, and V content in obese subjects exceeded the control values by 51%, 21%, and 50%, respectively. In turn, hair Zn levels were found to be significantly lower by 11% compared with the lean control values. In urine, the levels of V and Zn were found to be 30% and 18% higher in obese patients. Prevalence of hypertension in obese subjects was associated with a trend for impaired Se and Zn levels. In a regression model adjusted for age, gender, hypertension, atherosclerosis, and glucose intolerance, serum Cr, V, and hair Zn were inversely associated with body mass index (BMI), whereas hair Se was considered as the positive predictor. Our data allow proposing that the observed alterations may at least partially contribute to metabolic disturbances in obesity. In turn, monitoring of Se exposure in a well-nourished adult population is required to reduce its potential contribution to obesity.

MON-386 Determining Vitamin D Status: Analytical Variability Between Available Assays

Clinical interest to evaluate serum 25-hydroxyvitamin D[25(OH)D] to assess Vitamin D status in health risks continue to increase exponentially over the last decade. Variability of 25(OH)D measurements remains controversial despite the international initiative Vitamin D Standardization Program (VDSP) to standardise the assays. The aim of the present study was to examine the correlation of 25(OH)D concentrations measured by different assays. We measured 25(OH)D using the new Abbott Alinity and DiaSorin LiaisonXL chemiluminescence immunoassays against the National Institute of Standards and Technology (NIST)-traceable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The immunoassay method were compared with the LC-MS/MS using Passing-Bablok regression and Bland-Altman analysis. Common 25(OH)D cut-point for classification of vitamin D deficiency was used to compare the different assays.125 adult serum samples were randomly selected and measured 25(OH)D levels ranged between <10 nmol/L to 290 nmol/L as determined by LC-MS/MS. Compared to the LC-MS/MS, both immunoassays demonstrated strong positive relationship based on Passing-Bablok regression analysis. The results were as follows: Abbott Alinity = 0.85x + 1.29nmol/L, 95% CI: -2.39 to 5.03 (r=0.94); DiaSorin LiaisonXL= 0.74x + 2.54nmol/L, 95% CI: -2.53 to 6.18 (r=0.91).Despite apparent good correlation, the overall mean bias was -12.6% for Abbott Alinity and -24.4% for DiaSorin LiaisonXL assays. A higher percentage of patients were classified as vitamin D deficient (25(OH)D <50 nmol/L) using DiaSorin LiaisonXL (53%) followed by Abbott Alinity (49%), when compared with LC-MS/MS (34%). Using 25(OH)D ≥ 50nmol/L as “adequate” determined by LC-MS/MS method, 22% (18/82) and 28% (23/82) of patients were classified as “deficient” when analysed on Abbott Alinity and DiaSorin LiaisonXL respectively.Clinician should be aware of the inter-method variability among different Vitamin D assays despite standardization efforts. These differences could be due to cross‐reactivity with 25(OH)D2 and vitamin D metabolites, such as 24,25(OH)2D and epimeric forms. 3‐epi‐25(OH)D is not separated chromatographically by the LC-MS/MS method used in this study. Therefore, the negative bias observed might be due to interference from the 3‐epi‐25(OH)D, whereby clinical significance is uncertain. It is present in low concentrations in adult human serum, 1 but seen in significant amounts in neonatal serum.2 It is advisable to monitor serum 25(OH)D level following treatment in the same laboratory.1. Lensmeyer G, et al. The C-3 epimer of 25-hydroxyvitamin D3 is present in adult serum. JCEM 2012; 97: 163–8.2. Singh RJ, et al. C-3 epimers can account for a significant portion of total circulating 25-hydroxyvitamin D in infants, complicating accurate measurement and interpretation of vitamin D status. JCEM 2006; 91: 3055-61.

Prokaryotic expression, purification and identification of the N protein of middle east respiratory syndrome coronavirus

Objective To express the N protein of middle east respiratory syndrome coronavirus （ MERS-CoV） in prokaryotic expression system and evaluate the immunogenicity of the purified recombinant N protein.Methods The gene encoding N protein of MERS-CoV was synthesized and cloned into the vector pET30a to construct the recombinant expression plasmid pET30a-MERS-CoV-N.The transformed E.coli BL21 （ DE3） strains carrying expression plasmid were induced by IPTG to express N protein.The expressed protein was purified by using affinity chromatography.SDS-PAGE and Western blot assays were used to iden-tify the expressed N protein and evaluate its immunogenicity.Results The recombinant N protein was suc-cessfully expressed in soluble form with the size of 46×103 .The results of Western blot assay showed that the recombinant N protein could specifically react with rabbit serum samples positive for antibodies against N protein B-cell epitope peptide and mouse anti-His tag antibodies.No positive band against N protein was found when primary antibody was used with thirty adult serum samples from Beijing in 2008.Conclusion N protein of MERS-CoV was successfully expressed in prokaryotic expression system.The successful expres-sion of N protein laid the foundation for immunological diagnosis of N protein of MERS-CoV and researches on its immunogenicity. Key words: Middle east respiratory syndrome coronavirus; N protein; Prokaryotic expression; Purification ; Identification

High serum concentration of selenium, but not calcium, cobalt, copper, iron, and magnesium, increased the risk of both hyperglycemia and dyslipidemia in adults: A health examination center based cross-sectional study

BackgroundMetabolic disorders of glucose and lipid were associated with some mineral elements, and data were warranted from various contexts to make the association more explicit. ObjectiveTo investigate the relationships between the serum concentrations of six mineral elements (calcium, cobalt, copper, iron, magnesium, and selenium) and the risk of hyperglycemia and dyslipidemia in adults. MethodsThe basic information and the over-night fasting serum samples of adults were randomly collected at a health examination center. The serum concentrations of glucose and lipids were measured with an automatic biochemical analyzer, and the mineral elements were measured with an inductively coupled plasma mass spectrometer. Data were analyzed between the hyperglycemia group (HGg) and the normal glucose group (NGg) as well as between the dyslipidemia group (DLg) and the normal lipid group (NLg). ResultsA total of 1466 adults aged 22–81 years (male/female = 1.8) were included, 110 in the HGg and 1356 in the NGg, or 873 in the DLg and 593 in the NLg. The serum element concentration medians [P50 (P25–P75)] significantly different between the HGg and the NGg were 0.83 (0.75–0.94) vs. 0.76 (0.68–0.87) mg/L for copper and 100 (90–110) vs. 94 (87–103) μg/L for selenium (P < 0.001), while those between the DLg and the NLg were 99 (92–110) vs. 97 (90–106) mg/L for calcium, 0.78 (0.69–0.88) vs. 0.75 (0.66–0.85) mg/L for copper, 1.7 (1.4–2.0) vs. 1.6 (1.3–2.0) mg/L for iron, 24 (22–28) vs. 23 (22–27) mg/L for magnesium, and 97 (89–106) vs. 92 (84–100) μg/L for selenium (P < 0.05). When the copper and selenium between the HGg and the NGg were analyzed by logistic regression with age, gender, body mass index, and mineral elements adjusted, only the highest quartile of selenium concentration had association with the increased risk of hyperglycemia [quartile (Q) 4 against Q1: OR = 2.9, 95 % CI = 1.5–5.5, P < 0.001). When the five differed mineral elements between the DLg and the NLg were similarly analyzed, only iron and selenium had associations with the increased risk of dyslipidemia (e.g., Q4 against Q1: OR = 1.4, 95 % CI = 1.1–2.0 for iron and OR = 2.9, 95 % CI = 2.1–4.0 for selenium, P < 0.05). ConclusionIn contrast to those of calcium, cobalt, copper, iron, and magnesium, the higher serum concentration of selenium increased the risk of both hyperglycemia and dyslipidemia in the study population of adult Chinese.

Exploration of the serum differential biomarkers for osteoarticular tuberculosis based on matrix-assisted laser desorption/ionization time of flight mass spectrometry

Objective Toinvestigatestatistically significant peptide peaks as biomarkersto diagnose osteoarticular tuberculosis, matrix-assisted laser desorption/ ionization time of flight mass spectrometry (MALDI-TOF MS) was applied to identify the characteristic fingerprint among the serum of patients with osteoarticular tuberculosis, rheumatoid arthritis and healthy adults. Methods Clinical Study. Serum samples of untreatedpatients with osteoarticular tuberculosis and rheumatoid arthritis were collected from August 2018 to December 2018, and serum samples of healthy adults from physical examination were collected as control. After analysis with MALDI-TOF MS, the serum peptide fingerprint datawas imported into software, and protein polypeptide peaks with obvious differences were screened to establish diagnostic models. Results Established the diagnostic model of osteoarticular tuberculosis and healthy adults with m/z 2 943.9, 5 929.6, 7 615.4 and 9 033.8 as differential protein polypeptides, the diagnostic model of osteoarticular tuberculosis and rheumatoid arthritis with m/z 4 195.6, 5 847.6, 5 929.6 and 7 748.6 as differential protein polypeptides. To these two models, the sensitivity were 95.00% and 97.50%, respectively. The specificity were 85.71% and 88.46%, respectively. The accuracy rates were 89.58% and 92.39%, respectively. The AUC value of ROC curves were 0.885 9 and 0.870 9, respectively. Conclusions By mass spectrometry and software analysis, the serum protein polypeptides with statistical difference were found successfully. The related diagnostic modelsarealso established, which has certain reference value for auxiliary diagnosis of osteoarticular tuberculosis. Key words: Tuberculosis, osteoarticular; Arthritis, rheumatoid; Spectrometry, mass, matrix-assisted laser desorption-ionization; Peptide mapping; Biomarkers

Development of a CDC-certified total testosterone assay for adult and pediatric samples using LC–MS/MS

BackgroundHighly accurate and sensitive method to measure testosterone in hypogonadal male, female and children is vital for proper diagnosis of hormone-related conditions and their treatment. ObjectiveTo develop an accurate and robust total testosterone ESI-LC-MS/MS quantification method with a simple sample preparation workflow and sufficient sensitivity for serum or plasma samples of all gender and age groups, via ketone functional group derivatization (using Amplifex™ Keto Reagent). MethodA simple sample preparation method to accommodate both low and high numbers of samples was developed using simultaneous protein precipitation and derivatization with Amplifex™ Keto reagent, followed by centrifugation and direct injection of supernatant into an LC-MS/MS system (SCIEX Topaz™ IVD LC-MS/MS, in which MS is equivalent to a SCIEX 4500MD Mass Spectrometer). Total testosterone in human serum or plasma samples was quantified using an external calibration curve generated by calibrators spanning a broad concentration range of ∼1–2000 ng/dL (10–20,000 pg/mL), traceable to NIST 971 SRM. 13C3-enriched testosterone was used as an internal standard to correct for both analyte loss during sample preparation and matrix effect during analysis (Supplementary Information: SI Fig. 4C). Two methods, one using a 96-well filter plate and another using Eppendorf tubes, were developed. Both methods were certified by the Centers for Disease Control (CDC) hormone standardization (HoSt) program for total serum testosterone. The feasibility of implementing the method for plasma and serum samples was tested via a small-scale method comparison study between matched pediatric serum and plasma samples derived from the same donor. In addition, plasma samples originating from the same donor collected in two different anticoagulant tube types (Li-heparin and K2EDTA) were compared. ResultsUsing in-house formulated NIST 971-traceable calibrators, the method was linear (r2 > 0.999) between 1 and 2000 ng/dL (10 and 20,000 pg/mL) with a limit of detection of approximately 1 ng/dL (10 pg/mL). The testosterone concentration bias against 40 reference samples from the HoSt certification program was absolute <3% with an average %CV of ∼3–4%. More than 78% of samples passed the CDC bias criterion of ±6.4%. Comparison between pediatric matched serum and plasma samples resulted in high correlation (r2 = 0.997) and bias of <5%. The calculated % difference between matched adult serum and plasma samples was ∼1%. ConclusionsFeasibility for an accurate and streamlined method suitable for measuring total testosterone in all human samples was demonstrated with a choice of sample preparation workflow to suit low or high number of samples. The method can potentially be used for plasma matrix from different blood collection tubes (Li-Heparin and K2EDTA).

Identification of preexisting adaptive immunity to Cas9 proteins in humans.

The CRISPR-Cas9 system is a powerful tool for genome editing, which allows the precise modification of specific DNA sequences. Many efforts are underway to use the CRISPR-Cas9 system to therapeutically correct human genetic diseases1-6. The most widely used orthologs of Cas9 are derived from Staphylococcus aureus and Streptococcus pyogenes5,7. Given that these two bacterial species infect the human population at high frequencies8,9, we hypothesized that humans may harbor preexisting adaptive immune responses to the Cas9 orthologs derived from these bacterial species, SaCas9 (S. aureus) and SpCas9 (S. pyogenes). By probing human serum for the presence of anti-Cas9 antibodies using an enzyme-linked immunosorbent assay, we detected antibodies against both SaCas9 and SpCas9 in 78% and 58% of donors, respectively. We also found anti-SaCas9 T cells in 78% and anti-SpCas9 T cells in 67% of donors, which demonstrates a high prevalence of antigen-specific T cells against both orthologs. We confirmed that these T cells were Cas9-specific by demonstrating a Cas9-specific cytokine response following isolation, expansion, and antigen restimulation. Together, these data demonstrate that there are preexisting humoral and cell-mediated adaptive immune responses to Cas9 in humans, a finding that should be taken into account as the CRISPR-Cas9 system moves toward clinical trials.

Effect and elimination methods of neonatal hyperbilirubinemia on the chemiluminescent detection of HBsAg

Objective Investigate the effect of neonatal hyperbilirubinemia on the detection of HBsAg by chemiluminescence and its elimination methods. Methods Case control study. The HBsAg in human serum was detected in 200 cases of hyperbilirubinemia neonates who were hospitalized in Beijing Children′s Hospital, Capital Medical University from July 2015 to May 2016 and whose serum total bilirubin level exceeded 200 μmol/L. The positive serum was further detected by 16 200×g high-speed centrifugation or blue light irradiation for 8 hours, and the results of re-assay of HBsAg were recorded. The retest positive serum was tested for HBV DNA load and checked the results of their mother′s examination in HBV. 136 adult serum samples with total bilirubin levels exceeding 200 μmol/L in the Peking University First Hospital, were taken as reference to compare the influence of hyperbilirubinemia between adults and newborns on the determination of HBsAg. Results The median level of serum total bilirubin in neonates was 259.0 μmol/L (226.5, 312.5); median level of indirect bilirubin 244.1 μmol/L(212.5, 295.8).Median level of serum total bilirubin in adults 356.4 μmol/L(295.9,435.1); median level of indirect bilirubin 137.1 μmol/L (107.8,172.7).The HBsAg test was negative in adults, 11 cases (5.5%) were positive in newborns, their HBV DNA load was less than<100 IU/ml. Among them, 9 have inoculated hepatitis B vaccine and 2 were unknown. 10 of 11 mothers of infants were healthy and 1 was positive for HBsAg, HBeAb, HBcAb. 2 of the 11 positive specimens turned negative of HBsAg after high-speed centrifugation. In addition to high speed centrifugation, 4 cases turned negative after blue light irradiation.5 cases remained positive after high speed centrifugation and blue light irradiation. Conclusions Neonatal hyperbilirubinemia, which is different from that of adults, is mainly caused by indirectly bilirubin increased,which is one of the main reasons for false positive detection of HBsAg by chemiluminescence in neonates. High-speed centrifugation and blue light irradiation can eliminate the influence of serum indirect bilirubin on the detection of HBsAg to the greatest extent. Key words: Hyperbilirubinemia; Neonatal; Hepatitis B surface antigens; Luminescent measurements

Seroepidemiological investigation of HAdV-4 infection among healthy adults in China and in Sierra Leone, West Africa

An apparent increase in the frequency of human adenovirus type 4 (HAdV-4) infections among general populations has been observed over the past 10 years. However, available epidemiological data that may reflect previous viral circulation and assist in predicting potential outbreaks are sparse, particularly in mainland China and Africa. In this study, a convenient neutralization assay for use in the surveillance of historical HAdV-4 infections was established based on a recombinant luciferase-expressing virus. Subsequently, the neutralizing antibodies (nAbs) of 1013 healthy adult serum samples from China and Sierra Leone were evaluated. Our results showed that over 50% of the participants from China and nearly 70% of donors from Sierra Leone had detectable nAbs against HAdV-4 despite the few infection cases officially reported in these regions. Furthermore, the prevalence of nAbs to HAdV-4 is lower than that to HAdV-5, and both varied by geographic location. In addition, the seropositive rates of both HAdV-4 and HAdV-5 nAbs increased with age. However, the nAbs stimulated by HAdV-4 remained stable at low (≤200) levels among the different age groups, whereas moderate (201–1000) or high (>1000) nAb levels were produced by HAdV-5 and tended to decrease with age. These results elucidate the human humoral immune response against HAdV-4 and revealed that this virus may be an underestimated causative agent of respiratory disease among adults in China and West Africa, demonstrating the importance of HAdV-4 surveillance and providing useful insights for the future development of HAdV-4-based vaccines.

Serum titers of autoantibodies against α-synuclein and tau in child- and adulthood

Autoreactive antibodies against the proteins alpha-synuclein (α-syn) and tau are detectable in body fluids of both healthy and diseased elderly people. However, nothing is known about their presence or titers in children. To close this gap and to characterize their temporary expression levels, we used ELISA techniques to investigate the serum titers of α-syn and tau reactive autoantibodies in 37 and 32 adults and 37 and 31 children, respectively. Most serum samples from the children exhibited both antibody types and interestingly, the levels were similar to those observed in the adult serum samples. Furthermore, sex-specific analysis revealed significantly increased α-syn reactive autoantibody titers in female children. The presence of α-syn and tau reactive autoantibodies in early childhood indicates that both immunoglobulins belong to the pool of naturally occurring autoantibodies (nAbs), as their antigen-independent synthesis from birth is a crucial characteristic. Due to their general participation in the maintenance of the physiological homeostasis, we hypothesize that both investigated nAbs are involved in the metabolic regulation of their specific antigen. Therefore, they may be a part of a mechanism that already exists in the innate immunological repertoire to provide protection from pathologies caused by dysregulated α-syn and tau metabolisms.

Antibiotics in a general population: Relations with gender, body mass index (BMI) and age and their human health risks

Recently, increasing regulatory and public attention has been paid to the exposure risks of antibiotics due to their occurrence and antibiotic resistance worldwide. However, limited information on antibiotic levels in general populations is available. Forty antibiotics, including 9 sulfonamides, 5 fluoroquinolones, 4 macrolides, 4 tetracyclines, 3 chloramphenicols, 12 β-lactams and 3 others, were analyzed in 107 serum samples of normal adults collected from a hospital in Dalian, North China, between 2015 and 2016 using solid-phase extraction (SPE) coupled with HPLC-MS/MS. The results clearly showed that antibiotics were present in the serum of these adults. Specifically, 28 antibiotics were detected in the samples, with detection frequencies ranging from 0.9% to 17.8%. The total antibiotic concentrations in 26.2% of the serum samples were between the LOD and 20.0ng/mL. Importantly, the maximum concentrations of 5 antibiotics (trimethoprim, ciprofloxacin, cefaclor, lincomycin and erythromycin) were above 1000ng/mL in 3.7% of the samples. Furthermore, the detection frequencies of 5 veterinary antibiotics, 7 human antibiotics and 16 human/veterinary antibiotics in the serum samples were 23.4%, 17.8% and 29.0%, respectively. Significant differences of the veterinary antibiotics between female and male adults and of the sulfonamides between different BMI (body mass index) groups were observed (p<0.05). The concentrations of sulfonamides in elderly individuals were significantly higher (p<0.05) than those in young people. Finally, our results showed that almost all of the adults had no health risks related to exposure to antibiotics at such levels despite the high effect ratio (ER=1.74) for azithromycin in one sample. This study is the first to report the current status of antibiotics in human blood, which can help in better understanding the long-term effects of antibiotics on general populations and in identifying susceptible populations that are at high risk to antibiotic exposure.

MEASLES VIRUS IMMUNITY LEVEL STUDY IN PARTICULAR POPULATION GROUPS OF THE REPUBLIC OF GUINEA WITHIN THE FRAMEWORK OF GLOBAL MEASLES ELIMINATION PROGRAM. REPORT 2

A goal for measles elimination globally by 2010–2020 was recognized as one of the priorities in the WHO program “Health for All in the 21st Century” (1998). However measles outbreaks occurred in 2010–2016 in countries with high level of measles vaccine coverage including USA and some European countries.Large measles outbreaks were also registered on the African continent and particular in the Republic of Guinea as a result of the decline of measles vaccine coverage due to the Ebola virus epidemic in the Republic of Guinea in 2014–2015. WHO recommends carrying out the routine measles vaccination as well as the supplemental immunization activities after the stop of the Ebola virus transmission. Effectiveness of the activities is definitely connected with the detection of the epidemically significant for the supplemental immunization age groups. The aim of the study was to evaluate the measles immunity level in different age groups of population in the Republic of Guinea. Materials and methods. Twenty five blood serum samples of healthy adult Guineans aged 28–66 and 121 blood serum samples of adolescences and adults admitted to hospital in the town of Kindia (Republic of Guinea) for indoor treatment were tested by ELISA. The specific measles virus antibodies were detected using the following commercial ELISA test-systems produced by Euroimmun Medizinische Labordiagnostika AG Company (Germany): IgM-antibodies — by “Anti-Measles Virus ELISA (IgM)”, IgG-antibodi es — by “Anti-Measles Virus ELISA (IgG)”, IgG-avidity measles virus antibodies — by “Avidity: Anti-Measles Virus ELISA (IgG)”. A part of sera was studied by “Vector-Best IgM-measles” and “Vector-Best IgG-measles” ELISA test-systems (Russia). Results and discussion. The comparative quantitative study of the measles immunity level (i.e. IgG-antibodies titers) of the healthy adult Guineans in 2015 and 2016 revealed the lack of IgGantibodies in serum of only one person aged 30. In 68.7% of cases studied the IgG-antibodies titers didn’t change significantly during the year. In the most part (68.0%) of the 25 tested sera the high levels of the IgG-antibodies titers were detected (≥ 1000 IU/L). In addition the IgG-antibodies of high avidity were revealed in the most part (87.5%) of blood serum samples thus evidencing the history of measles virus infection in the past among the examined adults aged 28+. The ELISA studies of 121 blood serum samples from patients with different clinical diagnosis being on indoor treatment in the hospital of the town of Kindia (Republic of Guinea) revealed 21 anti-measles IgG negative patients. Among patients with the known age (n = 113) IgG-antibodies to measles virus were determined in 78.8% of the samples tested. At the same time in each age group the seronegative patients as well as the patients with low titers of the specific IgG-antibodies to measles virus were revealed. Among patients of 18–40 years of age the part of seronegative patients was equal to 28.5±5.1%. This cohort may be susceptible to measles virus infection and facilitate the support as well as the development of active epidemic process in case of measles outbreaks in the Republic of Guinea.

Untargeted metabolomic analysis of human serum samples associated with exposure levels of Persistent organic pollutants indicate important perturbations in Sphingolipids and Glycerophospholipids levels

Persistent organic pollutants (POPs) are distributed globally and are associated with adverse health effects in humans. A study combining gas chromatography-mass spectrometry (GC-MS), high resolution mass spectrometry (UPLC-QTof-MS) and chemometrics for the analysis of adult human serum samples was undertaken. Levels of serum POPs found were in the low range of what has been reported in similar populations across Europe (median 33.84 p, p′-DDE, 3.02 HCB, 83.55 β-HCH, 246.62 PCBs ng/g lipids). Results indicated that compounds concentrations were significantly different between the two groups of POPs exposure (high vs low) and classes (DDE, β-HCH, HCB, PCBs). Using orthogonal partial last-squares discriminant analysis (OPLS-DA), multivariate models were created for both modes of acquisition and POPs classes, explaining the maximum amount of variation between sample groups (positive mode R2 = 98–90%; Q2 = 94–75%; root mean squared error of validation (RMSEV) = 12–20%: negative mode R2 = 98–91%; Q2 = 94–81%; root mean squared error of validation (RMSEV) = 10−19%. In the serum samples analyzed, a total 3076 and 3121 ions of interest were detected in positive and negative mode respectively. Of these, 40 were found to be significantly different (p < 0.05) between exposure levels. Sphingolipids and Glycerophospholipids lipids families were identified and found significantly (p < 0.05) different between high and low POPs exposure levels. This study has shown that the elucidation of metabolomic fingerprints may have the potential to be classified as biomarkers of POPs exposure.