Increased erythroferrone levels in malarial anaemia.

We assessed the diagnostic potential of erythroferrone as a biomarker for iron homeostasis comparing iron deficiency cases with anaemia of inflammation and controls. The dysregulation of the hepcidin axis was observed by Latour et al. in a mouse model of malarial anaemia induced by prolonged Plasmodium infection leading to increased erythroferrone concentrations. In line with that, we found significantly higher erythroferrone levels in cases with malaria and anaemia in an African population, compared to asymptomatic controls. Therefore, our findings extend the previous ones of the mouse model, suggesting also a dysregulation of the hepcidin axis in humans, which should be further corroborated in prospective studies and may lay the basis for the development of improved treatment strategies according to ERFE concentrations in such patients.

Exploring the host factors affecting asymptomatic Plasmodium falciparum infection: insights from a rural Burkina Faso study.

BACKGROUND: Asymptomatic Plasmodium falciparum parasitaemia forms a reservoir for the transmission of malaria disease in West Africa. Certain haemoglobin variants are known to protect against severe malaria infection. However, data on the potential roles of haemoglobin variants and nongenetic factors in asymptomatic malaria infection is scarce and controversial. Therefore, this study investigated the associations of iron homeostasis, inflammation, nutrition, and haemoglobin mutations with parasitaemia in an asymptomatic cohort from a P. falciparum-endemic region during the high transmission season. METHODS: A sub-study population of 688 asymptomatic individuals (predominantly children and adolescents under 15 years, n = 516) from rural Burkina Faso previously recruited by the NOVAC trial (NCT03176719) between June and October 2017 was analysed. Parasitaemia was quantified with conventional haemocytometry. The haemoglobin genotype was determined by reverse hybridization assays targeting a selection of 21 HBA and 22 HBB mutations. Demographics, inflammatory markers (interleukins 6 and 10, hepcidin), nutritional status (mid upper-arm circumference and body mass index), and anaemia (total haemoglobin, ferritin, soluble transferrin receptor) were assessed as potential predictors through logistic regression. RESULTS: Malaria parasites were detected in 56% of subjects. Parasitaemia was associated most strongly with malnutrition. The effect size increased with malnutrition severity (OR = 6.26, CI95: 2.45-19.4, p < 0.001). Furthermore, statistically significant associations (p < 0.05) with age, cytokines, hepcidin and heterozygous haemoglobin S were observed. CONCLUSIONS: According to these findings, asymptomatic parasitaemia is attenuated by haemoglobin S, but not by any of the other detected genotypes. Aside from evidence for slight iron imbalance, overall undernutrition was found to predict parasitaemia; thus, further investigations are required to elucidate causality and inform strategies for interventions.

Hb Bakersfield (HBA1: c.151_152insGGAGCC): The Insertion of Arg-His Between Codons 49 and 50 of the α1-Globin Chain Leads to Increased Oxygen Affinity.

We describe an insertion variant on the α1-globin gene (HBA1) identified in a 49-year-old woman of Jurassian ancestry presenting with macrocytosis and erythrocytosis. The variant resulted in a peak of 15.5% of the total hemoglobin (Hb) on high performance liquid chromatography (HPLC). Stability and oxygen affinity testing revealed that the variant was stable and had an increased oxygen affinity. Molecular genetic testing detected the heterozygous sequence variant Hb Bakersfield [α50(CE8)His→0; Arg-Ser-His- inserted between 49(CE7) and 51(CE9) of α1; HBA1: c.151_152insGGAGCC (p.Ser50_His51insArgSer)] in the index patient, one of her sons, as well as in two of her grandchildren, who showed a similar hematological pattern.

Retrospective validation of a ß-trace protein interpretation algorithm for the diagnosis of cerebrospinal fluid leakage.

BACKGROUND: Cerebrospinal fluid (CSF) leakage is a rare condition that can potentially lead to the development of serious complications. In the last decade, ß-trace protein (ß-TP) has been shown to be a valuable immunological biomarker that allows prompt and non-invasive identification of CSF leakage. At our institution, the measurement of ß-TP has been included in the diagnostic work-up of CSF leakage for more than 10 years. According to our diagnostic algorithm, the presence of CSF in secretion is excluded when ß-TP values are <0.7 mg/L, whereas ß-TP values ≥1.3 mg/L indicate the presence of CSF in secretion. ß-TP values between 0.7 and 1.29 mg/L indicate the presence of CSF if the ß-TP ratio (ß-TP secretion/ß-TP serum) is ≥2. This study aimed to validate this diagnostic algorithm using clinically defined nasal/ear secretions. METHODS: We performed a retrospective statistical analysis of three ß-TP interpretation strategies using data of 236 samples originating from 121 patients with suspect CSF leakage received at our laboratory between 2004 and 2012. RESULTS: The highest odds ratio was obtained when the proposed algorithm has been used for the interpretation of ß-TP results, showing a sensitivity of 98.3% and a specificity of 96%. Positive and negative predictive values were 89.2% and 99.4%, respectively. CONCLUSIONS: Our data suggest that the proposed ß-TP interpretation algorithm is a valuable tool for the diagnosis of CSF leakage in the clinical practice.

Where clinical chemistry meets medicinal chemistry. Systematic analysis of physico-chemical properties predicts stability of common used drugs in gel separator serum tubes.

BACKGROUND: As LC-MS/MS techniques are becoming more accessible even outside of highly specialized clinical laboratories, pre-analytical issues such as drug stability during specimen storage should be critically evaluated before implementing therapeutic drug monitoring. Our study investigated the influence of physico-chemical properties of different drugs in regard to their interaction with gel separators used in commercial available collection tubes. METHODS: Drug spiked blood samples were analyzed after storage in different commercial gel- and non-gel based serum tubes. LC-ESI-MS/MS based methods were used to determine drug concentration in serum samples. RESULTS: Lipophilic compounds, defined by logP>3 and a compatibility factor>20 are prone to be efficiently and rapidly absorbed by lipophilic gel barriers inducing a significant in-vitro decrease of drug concentration over a short storage time. Our data show a relevant drop of concentration of posaconazole, sertraline and citalopram when stored in gel based tubes. Molecular descriptors such as logP, polar surface area and protein binding seem to be good predictive markers to identify gel interacting drugs. CONCLUSION: For ease of handling and minimization of blood drawing times, we assume that tubes containing separator gel can be used for therapeutic drug monitoring of high hydrophilic drugs. In contrast lipophilic compounds showing logP higher than 3 and/or CF>20 should be critically considered and validated by extensive stability studies. ABBREVIATIONS: logP, partition coefficient; PSA, polar surface area; TDM, therapeutic drug monitoring; ACN, acetonitrile; MeOH, methanol; IVD, in-vitro diagnostic; CF, compatibility factor.

Performance of a Blood Glucose Monitoring System in a Point-of-Care Setting.

This study assesses and demonstrates that CONTOUR® XT-BGMS (CXT-BGMS) complies with the requirements of the German (RiliBÄK) and Swiss (QUALAB) quality control guidelines for point-of-care testing (POCT) and fulfills the ISO15197:2013 accuracy limits criteria under the routine conditions of a hospital point-of care setting. This single-center study was conducted in Switzerland using 105 venous blood samples from hospitalized patients. Each sample was tested in comparison to the hexokinase reference method. Compliance with POCT guidelines was assessed by daily BGMS measurements using control solutions. Accuracy of CXT-BGMS according to ISO limits was 98.41%. All control measurements were within the limits defined by RiliBÄK (within ± 11% of target values and root mean square error [RMSE] within RMSE limits), and QUALAB (within ± 10% of target values).

Increased endothelial microparticles and oxidative stress at extreme altitude.

PURPOSE: Hypoxia and oxidative stress affect endothelial function. Endothelial microparticles (MP) are established measures of endothelial dysfunction and influence vascular reactivity. To evaluate the effects of hypoxia and antioxidant supplementation on endothelial MP profiles, a double-blind, placebo-controlled trial, during a high altitude expedition was performed. METHODS: 29 participants were randomly assigned to a treatment group (n = 14), receiving vitamin E, C, A, and N-acetylcysteine daily, and a control group (n = 15), receiving placebo. Blood samples were obtained at 490 m (baseline), 3530, 4590, and 6210 m. A sensitive tandem mass spectrometry method was used to measure 8-iso-prostaglandin F2α and hydroxyoctadecadienoic acids as markers of oxidative stress. Assessment of MP profiles including endothelial activation markers (CD62+MP and CD144+MP) and cell apoptosis markers (phosphatidylserine+MP and CD31+MP) was performed using a standardized flow cytometry-based protocol. RESULTS: 15 subjects reached all altitudes and were included in the final analysis. Oxidative stress increased significantly at altitude. No statistically significant changes were observed comparing baseline to altitude measurements of phosphatidylserine expressing MP (p = 0.1718) and CD31+MP (p = 0.1305). Compared to baseline measurements, a significant increase in CD62+MP (p = 0.0079) and of CD144+MP was detected (p = 0.0315) at high altitudes. No significant difference in any MP level or oxidative stress markers were found between the treatment and the control group. CONCLUSION: Hypobaric hypoxia is associated with increased oxidative stress and induces a significant increase in CD62+ and CD144+MP, whereas phosphatidylserine+MP and CD31+MP remain unchanged. This indicates that endothelial activation rather than an apoptosis is the primary factor of hypoxia induced endothelial dysfunction.

Simultaneous determination of phosphatidylcholine-derived quaternary ammonium compounds by a LC-MS/MS method in human blood plasma, serum and urine samples.

The determination of circulating trimethylamine-N-oxide (TMAO), choline, betaine, l-carnitine and O-acetyl-l-carnitine concentration in different human matrices is of great clinical interest. Recent results highlighted the prognostic value of TMAO and quaternary ammonium containing metabolites in the field of cardiovascular and kidney diseases. Herein, we report a method for the rapid and simultaneous measurement of closely related phosphatidylcholine-derived metabolites in three different biological matrices by stable isotope dilution assay. Plasma, serum and urine samples were simply deproteinized and separated by HILIC-chromatography. Detection and quantification were performed using LC-MS/MS with electrospray ionization in positive mode. For accuracy and precision, full calibration was performed covering more than the full reference range. Assay performance metrics include intra- and interday imprecision were below 10% for all analytes. To exclude matrix effects standard addition methods were applied for all matrices. It was shown that calibration standards and quality control prepared in water can be used instead of matrix-matched calibration and controls. The LC/MS/MS-based assay described in this article may improve future clinical studies evaluating TMAO and related substances as prognostic markers for cardiovascular risk and all-cause mortality in different patient populations.

[Outcome studies with regard to medical laboratory testing]. / Outcome - Studien im Zusammenhang mit Laboranalysen.

Outcome studies and health technology assessment and appraisals have become more and more prominent in regard to the utility of laboratory testing in clinical medicine. In the past years many valuable and useful studies have been published that demonstrate an increasing value of laboratory testing in a variety of clinical situations or for a good number of disease diagnosis and monitoring. An excellent outcome using laboratory testing can only be achieved when the tests (methods) have an outstanding performance in terms of sensitivity, specificity, imprecision and robustness. Further, not only has the test per se to be outstanding, it is also of uttermost importance that the clinical setting, in which the test is performed, fits and that the preanalytic requirements are fulfilled as well as that the statistical rules are followed. The laboratory test has to be incorporated into an integrated approach respecting in a weighted attempt as many as possible aspects of health care.

Lipocalin-like prostaglandin D synthase (L-PGDS) concentration in aqueous humour in patients with open-angle glaucoma.

PURPOSE: To report on the concentration of lipocalin-like prostaglandin D synthase (L-PGDS) in the aqueous humour (AH) in patients with open-angle glaucoma (OAG). PATIENTS AND METHODS: Prospective assessment in 20 patients (13 female, 7 male, mean age 74±10.6 y) who underwent surgery for OAG. AH was sampled and analyzed for L-PGDS concentration. AH from 26 patients (11 female, 15 male, 72.4±14.4 y) without glaucoma who underwent cataract surgery, served as control subjects. RESULTS: The L-PGDS concentration in the AH sampled from the anterior chamber in the OAG group (5.9±2.4 mg/L) was significantly (P<0.001) higher than in the control group (3.3±1.3 mg/L). There were no significant differences between the concentrations of L-PGDS between the left and the right eye or between genders. CONCLUSIONS: L-PGDS concentration in the AH of patients with OAG was significantly elevated compared with its concentration in the AH of nonglaucomatous eyes. As L-PGDS is a biologically pluripotent protein, its possible role in glaucoma warrants further examination.

Oxidative stress in hypobaric hypoxia and influence on vessel-tone modifying mediators.

Increased pulmonary artery pressure is a well-known phenomenon of hypoxia and is seen in patients with chronic pulmonary diseases, and also in mountaineers on high altitude expedition. Different mediators are known to regulate pulmonary artery vessel tone. However, exact mechanisms are not fully understood and a multimodal process consisting of a whole panel of mediators is supposed to cause pulmonary artery vasoconstriction. We hypothesized that increased hypoxemia is associated with an increase in vasoconstrictive mediators and decrease of vasodilatators leading to a vasoconstrictive net effect. Furthermore, we suggested oxidative stress being partly involved in changement of these parameters. Oxygen saturation (Sao2) and clinical parameters were assessed in 34 volunteers before and during a Swiss research expedition to Mount Muztagh Ata (7549 m) in Western China. Blood samples were taken at four different sites up to an altitude of 6865 m. A mass spectrometry-based targeted metabolomic platform was used to detect multiple parameters, and revealed functional impairment of enzymes that require oxidation-sensitive cofactors. Specifically, the tetrahydrobiopterin (BH4)-dependent enzyme nitric oxide synthase (NOS) showed significantly lower activities (citrulline-to-arginine ratio decreased from baseline median 0.21 to 0.14 at 6265 m), indicating lower NO availability resulting in less vasodilatative activity. Correspondingly, an increase in systemic oxidative stress was found with a significant increase of the percentage of methionine sulfoxide from a median 6% under normoxic condition to a median level of 30% (p<0.001) in camp 1 at 5533 m. Furthermore, significant increase in vasoconstrictive mediators (e.g., tryptophan, serotonin, and peroxidation-sensitive lipids) were found. During ascent up to 6865 m, significant altitude-dependent changes in multiple vessel-tone modifying mediators with excess in vasoconstrictive metabolites could be demonstrated. These changes, as well as highly significant increase in systemic oxidative stress, may be predictive for increase in acute mountain sickness score and changes in Sao2.

Detection limit of architect hepatitis C core antigen assay in correlation with HCV RNA, and renewed confirmation algorithm for reactive anti-HCV samples.

BACKGROUND: hepatitis C infections are detected by anti-HCV screening tests. Reactive anti-HCV results give no information about the presence or absence of hepatitis C viruses, or of unspecific reactivity. To obtain information about the viral load, HCV RNA measurements, following a reactive anti-HCV result, are performed in well equipped and specialised laboratories. Anti-HCV immunoblots are the only means to exclude non specific reactivity. The measurement of HCV core antigen (HCV-Ag), as an alternative to HCV RNA, is discussed, as it can be analysed on the same instrument as anti-HCV. OBJECTIVES: The detection limit of HCV-Ag is crucial to use it in lieu of HCV RNA, in regard of the different genotypes. A renewed algorithm is proposed to exclude unspecific reactivity of anti-HCV. STUDY DESIGNS: Samples were tested on Architect i2000SR (Abbott) for anti-HCV and HCV-Ag. HCV RNA measurements were obtained by Cobas Ampliprep/Taqman (Roche) or m2000rt(®) (Abbott). RESULTS AND CONCLUSIONS: Comparison between HCV-Ag and HCV RNA from 126 samples of 101 patients with chronic hepatitis C gave linear regression R(2) 0.89, slope 0.885 and intercept -2.258, which were independent of the genotypes. The detection limit of HCV-Ag was between 2.4 and 4.5 Log(10)IU/mL. A renewed algorithm for confirmation of reactive anti-HCV results is proposed: active or resolved hepatitis C infections or false reactivity can be differentiated by sequenced reflex testing due to HCV-Ag, anti-HCV immunoblot and HCV RNA.

DNA methylation analysis.

DNA methylation, the addition of a methyl group to cytosines and adenosines, regulates gene expression on a level that is usually referred to as epigenetic, that is, stably maintained during cell divisions. In humans, aberrant DNA methylation is associated with several malignancies, including cancer and so-called imprinting disorders, making it an attractive target for diagnostic purposes. Here we give a brief introduction to the biology of DNA methylation and present the use of methylation biomarkers in laboratory medicine. DNA methylation assays have become the standard procedure in the diagnosis of imprinting disorders, and they are about to shift cancer diagnostics and prognostics to the next level of molecular medicine. However, there is evidence of problems associated with the introduction of such cancer assays in routine diagnostics. We review several assays that have been proposed for DNA methylation analysis. The assays presented analyse the methylation status of single loci and are based either on a bisulphite-treatment or on methylation-sensitive restriction of the DNA under investigation.

Detection of germline rearrangements in patients with α- and ß-thalassemia using high resolution array CGH.

Approximately 80% of α-thalassemia mutations are deletions in the α-globin cluster on chromosome 16 and about 10% of ß-thalassemia mutations are deletions in the ß-globin gene cluster on chromosome 11. Larger deletions involving the ß-globin gene cluster lead to (δß)-, (γδß)-, (εγδß)-thalassemia, or hereditary persistence of fetal hemoglobin (HPFH). Array comparative genomic hybridization (CGH) was applied to screen for deletions in the α- and ß-globin gene clusters not detected by routine gap-PCR. In total, in 13 patients with hypochromia and inclusion bodies (IBs) the α-globin gene cluster was analyzed and in 13 patients with increased fetal hemoglobin levels with or without hypochromia the ß-globin gene cluster was examined. All samples were subsequently investigated by multiplex ligation-dependent probe amplification (MLPA). In 9 out of 13 patients deletions of the α-globin gene cluster were identified; 5 of these deletions remove the entire α-globin cluster and extend to the telomere. Additional sequencing of the remaining 4 patients revealed polyadenylation mutation in 1 of them. 7 deletions were identified in the ß-globin gene cluster in 13 patients. Additional sequencing of the remaining 6 patients revealed mutations in one of the γ-globin gene promoters in 3 of them and a KLF1-mutation in 1 of them. Array CGH is a reliable method to screen for deletions in thalassemia and hemoglobinopathy. The method offers the advantage of a high resolution with the possibility to characterize breakpoints on sequence level.

Panhypopituitarism presenting as life-threatening heart failure caused by an inherited microdeletion in 1q25 including LHX4.

Clinical presentation of hypopituitarism in the neonate may be variable, ranging from absent to severe nonspecific symptoms and may be life-threatening in patients with adrenocorticotropic hormone deficiency. The LIM homeobox gene 4 (LHX4) transcription factor regulates early embryonic development of the anterior pituitary gland. Autosomal dominant mutations in LHX4 cause congenital hypopituitarism with variable combined pituitary hormone deficiency (CPHD). We report on a neonate with unexplained heart failure and minor physical anomalies, suggesting a midline defect. She was diagnosed with complete CPHD. Cardiac function was rescued by replacement with hydrocortisone and thyroxine; hypoglycaemia stopped under growth hormone therapy. Magnetic resonance imaging revealed a dysgenetic pituitary gland suggesting an early developmental defect. Array comparative genomic hybridization showed a maternally inherited 1.5-megabase microdeletion in 1q25.2q25.3, including the LHX4 gene. Haploinsufficiency of LHX4 likely explains the predominant pituitary phenotype in the proposita and we suggest variable intrafamilial penetrance of the inherited microdeletion. To the best of our knowledge, we are the first to report on heart failure as a rare nonspecific symptom of treatable CPHD in the newborn. Variably penetrant pituitary insufficiency, including this severe and atypical presentation, can be correlated with LHX4 insufficiency and highlights the role of LHX4 for pituitary development.

High resolution array in the clinical approach to chromosomal phenotypes.

Array genomic hybridization (AGH) has recently been implemented as a diagnostic tool for the detection of submicroscopic copy number variants (CNVs) in patients with developmental disorders. However, there is no consensus regarding the choice of the platform, the minimal resolution needed and systematic interpretation of CNVs. We report our experience in the clinical diagnostic use of high resolution AGH up to 100 kb on 131 patients with chromosomal phenotypes but previously normal karyotype. We evaluated the usefulness in our clinics and laboratories by the detection rate of causal CNVs and CNVs of unknown clinical significance and to what extent their interpretation would challenge the systematic use of high-resolution arrays in clinical application. Prioritizing phenotype-genotype correlation in our interpretation strategy to criteria previously described, we identified 33 (25.2%) potentially pathogenic aberrations. 16 aberrations were confirmed pathogenic (16.4% syndromic, 8.5% non-syndromic patients); 9 were new and individual aberrations, 3 of them were pathogenic although inherited and one is as small as approx 200 kb. 13 of 16 further CNVs of unknown significance were classified likely benign, for 3 the significance remained unclear. High resolution array allows the detection of up to 12.2% of pathogenic aberrations in a diagnostic clinical setting. Although the majority of aberrations are larger, the detection of small causal aberrations may be relevant for family counseling. The number of remaining unclear CNVs is limited. Careful phenotype-genotype correlations of the individual CNVs and clinical features are challenging but remain a hallmark for CNV interpretation.

Angioedema: patients experience and treatment relief.

Angioedema is defined as a swelling of the skin, mucosa and submucosa of the respiratory tract. It may also impair the intestinal epithelium and other mucous membranes. It can be potentially life-threatening if the upper respiratory tract is involved. In these cases emergency treatment is often required in particular if the pharynx and larynx are swollen. Beside the well-known etiologies of allergic angioedema, many forms of nonallergic angioedema are known and in the majority of these forms increased plasma and tissue concentrations of bradykinin play a critical role.

Cerebrospinal fluid dynamics between the basal cisterns and the subarachnoid space of the optic nerve in patients with papilloedema.

AIMS: To determine cerebrospinal fluid (CSF) dynamics between intracranial CSF spaces and CSF in the subarachnoid space (SAS) of optic nerves (ONs) in 10 patients with papilloedema. METHODS: Prospective assessment of 10 patients with papilloedema and two control subjects using CT cisternography and analysis of CSF for the presence of lipocalin-like prostaglandin D synthase (betatrace protein). RESULTS: CT cisternography showed a progressively reduced influx of contrast-loaded CSF from intracranial CSF spaces into the SAS. The lowest concentration of contrast-loaded CSF was found in the region of the ON immediately behind the globe, where the ON sheath was widened (possibly by unfolding) in all patients compared with normal subjects. The concentration of lipocalin-like prostaglandin D synthase differed between the spinal CSF and the CSF in the SAS, with a markedly higher concentration in the SAS. CONCLUSION: The results of this study suggest that CSF turnover in the SAS of the ON is reduced in patients with papilloedema from various causes and that the composition of CSF differs between spinal CSF and that surrounding the ON.