HemoCue Hb-801 Provides More Accurate Hemoglobin Assessment in Blood Donors Than OrSense NBM-200

Hemoglobin levels are commonly assessed to prevent causing or worsening of anemia in prospective blood donors. We compared head-to-head the accuracy of different technologies for measuring hemoglobin suitable for use in mobile donation units. We included 144 persons donating platelets at the Central Institute for Blood Transfusion and Immunology in Innsbruck, Austria. Hemoglobin levels were measured in venous blood using the portable hemoglobinometer HemoCue Hb-801 and noninvasively using OrSense NBM-200, and compared to values obtained with the Sysmex XN-430, an automated hematology analyzer employing the sodium lauryl sulphate method, which is broadly used as reference method in everyday clinical practice. Mean age of participants was 34.2 years (SD 13.0); 34.0% were female. Hemoglobin values measured with HemoCue were more strongly correlated with the Sysmex XN-430 (r = 0.90 [95% CI: 0.87-0.93]) than measured with OrSense (r = 0.49 [0.35-0.60]). On average, HemoCue overestimated hemoglobin by 0.40 g/dL (0.31-0.48) and OrSense by 0.75 g/dL (95% CI: 0.54-0.96). When using OrSense, we found evidence for higher overestimation at higher hemoglobin levels (proportional bias) specifically in females but not in males (Pdifference = .003). Sensitivity and specificity for classifying donors according to the hemoglobin donation thresholds were 99.2% (95% CI: 95.3%-100.0%) and 43.8% (23.1%-66.8%) for HemoCue vs 95.3% (89.9%-98.0%) and 12.5% (2.2%-37.3%) for OrSense. Areas under the receiver operating characteristic curves were higher using HemoCue vs OrSense both in females (0.933 vs 0.547; P = .044) and males (0.948 vs 0.628; P < .001). HemoCue Hb-801 measures hemoglobin more accurately than OrSense NBM-200 in the setting of mobile blood donation units. Our findings are particularly relevant for females, having in mind that anemia is more prevalent in females than in males.

Aspergillus terreus Antibody Serosurveillance in Tyrol: A Population-Based, Cross-Sectional Study of a Healthy Population

The rare, but emerging mold Aspergillus terreus is an important pathogen in some geographical areas, like Tyrol (Austria) and Houston (Texas). The reason for this high prevalence is unknown. The present serosurveillance study aimed to evaluate the trends in levels of A. terreus-specific IgG antibodies in various regions of Tyrol and to compare the results to the environmental spread of A. terreus in Tyrol. Therefore, 1058 serum samples from healthy blood donors were evaluated. Data revealed a significant difference between the Tyrolean Upland and Lowland. Moreover, female participants had higher A. terreus IgG antibody levels than male participants. The differences found in our study are consistent with the distributional differences in environmental and clinical samples described in previous studies, supporting that A. terreus IgG antibody levels reflect the environmental epidemiology of A. terreus in Tyrol.

Novel thiazolopyridine derivatives of diflapolin as dual sEH/FLAP inhibitors with improved solubility

Inflammatory responses are orchestrated by a plethora of lipid mediators, and perturbations of their biosynthesis or degradation hinder resolution and lead to uncontrolled inflammation, which contributes to diverse pathologies. Small molecules that induce a switch from pro-inflammatory to anti-inflammatory lipid mediators are considered valuable for the treatment of chronic inflammatory diseases. Commonly used non-steroidal anti-inflammatory drugs (NSAIDs) are afflicted with side effects caused by the inhibition of beneficial prostanoid formation and redirection of arachidonic acid (AA) into alternative pathways. Multi-target inhibitors like diflapolin, the first dual inhibitor of soluble epoxide hydrolase (sEH) and 5-lipoxygenase-activating protein (FLAP), promise improved efficacy and safety but are confronted by poor solubility and bioavailability. Four series of derivatives bearing isomeric thiazolopyridines as bioisosteric replacement of the benzothiazole core and two series additionally containing mono- or diaza-isosteres of the phenylene spacer were designed and synthesized to improve solubility. The combination of thiazolo[5,4-b]pyridine, a pyridinylen spacer and a 3,5-Cl2-substituted terminal phenyl ring (46a) enhances solubility and FLAP antagonism, while preserving sEH inhibition. Moreover, the thiazolo[4,5-c]pyridine derivative 41b, although being a less potent sEH/FLAP inhibitor, additionally decreases thromboxane production in activated human peripheral blood mononuclear cells. We conclude that the introduction of nitrogen, depending on the position, not only enhances solubility and FLAP antagonism (46a), but also represents a valid strategy to expand the scope of application towards inhibition of thromboxane biosynthesis.

Molecular Screening of Blood Donors for Babesia in Tyrol, Austria

Introduction

Babesia is a tick-borne intraerythrocytic parasite that is globally ubiquitous, yet understudied. Several species of Babesia have been shown to be transfusion-transmissible. Babesia has been reported in blood donors, animals, and ticks in the Tyrol (Western Austria), and regional cases of human babesiosis have been described. We sought to characterize the risk of Babesia to the local blood supply.

Methods

Prospective molecular testing was performed on blood donors who presented to regional, mobile blood collection drives in the Tyrol, Austria (27 May to October 4, 2021). Testing was conducted using the cobas® Babesia assay (Roche Molecular Systems, Inc.), a commercial PCR assay approved for blood donor screening that is capable of detecting the 4 primary species causing human babesiosis (i.e., B. microti, B. divergens, B. duncani, and B. venatorum). A confirmatory algorithm to manage initial PCR-reactive samples was developed, as were procedures for donor and product management.

Results

A total of 7,972 donors were enrolled and screened; 4,311 (54.1%) were male, with a median age of 47 years (IQR = 34-55). No positive cases of Babesia were detected, corresponding with an overall prevalence of 0.00% (95% CI: 0.00%, 0.05%).

Discussion

The findings suggest that the prevalence of Babesia is low in Austrian blood donors residing in the Tyrol, even during months of peak tick exposure. Although one cannot conclude the absence of Babesia in this population given the limited sample size, the findings suggest that the regional risk of transfusion-transmitted babesiosis is low.

Increasing the collection flow rate to 2 mL/min is effective and reduces the procedure time in off-line photopheresis

BACKGROUND

Extracorporeal photopheresis (ECP) treatment, mostly based on apheresis technology, is used for immunomodulation in various diseases such as cutaneous T-cell lymphoma, graft versus host disease and other (auto)immune disorders. The aim of this study was to collect high cell counts and purity in shorter procedure times using an ECP off-line system with an increased collection flow rate of 2 mL/min to a target volume of 200 mL buffy coat.

STUDY DESIGN AND METHODS

In this prospective study, data of routinely performed off-line photopheresis treatments were collected and analyzed at the Central Institute for Blood Transfusion & Department of Immunology (ZIB) of the Tirol Kliniken, to assess absolute cell counts and procedure times and to calculate collection efficiencies (CE2).

RESULTS

A total of 22 patients participated in this study. The processed blood volume was 4312 mL, the collection time 120 min, overall procedure time 157 min and the absolute cell counts of treated white blood cells (WBC) and mononuclear cells (MNC) were 5.0 and 4.3 × 109 respectively (median values). The calculated CE2 for WBC and MNC was 21.1% and 58.5%, the proportion of treated MNCs of the total number of MNCs present was 55.0%.

CONCLUSION

The data presented in this study show high therapeutically effective cell counts collected with a high MNC purity within a shorter overall collection/procedure time due to an increased collection flow rate.

Persistent Symptoms and IFN-γ-Mediated Pathways after COVID-19

After COVID-19, patients have reported various complaints such as fatigue, neurological symptoms, and insomnia. Immune-mediated changes in amino acid metabolism might contribute to the development of these symptoms. Patients who had had acute, PCR-confirmed COVID-19 infection about 60 days earlier were recruited within the scope of the prospective CovILD study. We determined the inflammatory parameters and alterations in tryptophan and phenylalanine metabolism in 142 patients cross-sectionally. Symptom persistence (pain, gastrointestinal symptoms, anosmia, sleep disturbance, and neurological symptoms) and patients' physical levels of functioning were recorded. Symptoms improved in many patients after acute COVID-19 (n = 73, 51.4%). Still, a high percentage of patients had complaints, and women were affected more often. In many patients, ongoing immune activation (as indicated by high neopterin and CRP concentrations) and enhanced tryptophan catabolism were found. A higher phenylalanine to tyrosine ratio (Phe/Tyr) was found in women with a lower level of functioning. Patients who reported improvements in pain had lower Phe/Tyr ratios, while patients with improved gastrointestinal symptoms presented with higher tryptophan and kynurenine values. Our results suggest that women have persistent symptoms after COVID-19 more often than men. In addition, the physical level of functioning and the improvements in certain symptoms appear to be associated with immune-mediated changes in amino acid metabolism.

Positive Effects of Probiotic Therapy in Patients with Post-Infectious Fatigue

Post-infectious fatigue is a common complication that can lead to decreased physical efficiency, depression, and impaired quality of life. Dysbiosis of the gut microbiota has been proposed as a contributing factor, as the gut-brain axis plays an important role in regulating physical and mental health. This pilot study aimed to investigate the severity of fatigue and depression, as well as the quality of life of 70 patients with post-infectious fatigue who received a multi-strain probiotic preparation or placebo in a double-blind, placebo-controlled trial. Patients completed questionnaires to assess their fatigue (fatigue severity scale (FSS)), mood (Beck Depression Inventory II (BDI-II)), and quality of life (short form-36 (SF-36)) at baseline and after 3 and 6 months of treatment. Routine laboratory parameters were also assessed, including immune-mediated changes in tryptophan and phenylalanine metabolism. The intervention was effective in improving fatigue, mood, and quality of life in both the probiotic and placebo groups, with greater improvements seen in the probiotic group. FSS and BDI-II scores declined significantly under treatment with both probiotics and placebo, but patients who received probiotics had significantly lower FSS (p < 0.001) and BDI-II (p < 0.001) scores after 6 months. Quality of life scores improved significantly in patients who received probiotics (p < 0.001), while patients taking a placebo only saw improvements in the "Physical limitation" and "Energy/Fatigue" subcategories. After 6 months neopterin was higher in patients receiving placebo, while no longitudinal changes in interferon-gamma mediated biochemical pathways were observed. These findings suggest that probiotics may be a promising intervention for improving the health of patients with post-infectious fatigue, potentially through modulating the gut-brain axis.

A Chlorophyll-Derived Phylloxanthobilin Is a Potent Antioxidant That Modulates Immunometabolism in Human PBMC

Phyllobilins are natural products derived from the degradation of chlorophyll, which proceeds via a common and strictly controlled pathway in higher plants. The resulting tetrapyrrolic catabolites—the phyllobilins—are ubiquitous in nature; despite their high abundance, there is still a lack of knowledge about their physiological properties. Phyllobilins are part of human nutrition and were shown to be potent antioxidants accounting with interesting physiological properties. Three different naturally occurring types of phyllobilins—a phylloleucobilin, a dioxobilin-type phylloleucobilin and a phylloxanthobilin (PxB)—were compared regarding potential antioxidative properties in a cell-free and in a cell-based antioxidant activity test system, demonstrating the strongest effect for the PxB. Moreover, the PxB was investigated for its capacity to interfere with immunoregulatory metabolic pathways of tryptophan breakdown in human blood peripheral mononuclear cells. A dose-dependent inhibition of tryptophan catabolism to kynurenine was observed, suggesting a suppressive effect on pathways of cellular immune activation. Although the exact mechanisms of immunomodulatory effects are yet unknown, these prominent bioactivities point towards health-relevant effects, which warrant further mechanistic investigations and the assessment of the in vivo extrapolatability of results. Thus, phyllobilins are a still surprisingly unexplored family of natural products that merit further investigation.

Perioperative Blood Transfusion in Head and Neck Cancer Revisited

OBJECTIVE

To reevaluate the frequency of perioperative blood transfusion, transfusion triggers, and survival impact in patients with incident, surgically treated head and neck cancer (HNC) in restrictive transfusion regimens.

METHODS

Retrospective analysis of surgically treated patients with incident HNC with and without perioperative blood transfusion between 2008 and 2019 at the Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Innsbruck, according to the department's clinical Head and Neck Tumor Registry.

RESULTS

Of the 590 patients included, perioperative transfusions were administered in 6.3% (n = 37, transfusion group). Following multivariable logistic regression, likelihood of blood transfusions was increased in patients with poorer general health conditions (ASA score III/IV; OR 3.7; 95% CI 1.9-8.6; p = 0.002), hemoglobin <12.5 g/dL (OR 2.7; 95% CI 1.1-6.4; p = 0.03), longer duration of surgery (OR 1.006 per minute of surgery time; 95% CI 1.003-1.008; p < 0.001), and negative p16 status (OR 5.3; 95% CI = 1.1-25; p = 0.03). Based on 14 matching variables related to survival and perioperative blood transfusion, a control group of 37 matching patients without perioperative transfusion was identified. Using univariate analysis, overall survival in transfusion and control groups did not differ significantly (p = 0.25). After adjusting for four parameters with limited matching accuracy (Chi square p < 0.2) in Cox regression analysis, a transfusion related hazard ratio close to 1 (HR 0.92; 95% CI 0.34-2.51; p = 0.87) was observed.

CONCLUSION

Considering current restrictive transfusion regimens and general transfusion risks, the administration of blood products in HNC patients during the perioperative period is not associated with additional oncologic hazard.

LEVEL OF EVIDENCE

III Laryngoscope, 2022.

Upregulation of Checkpoint Ligand Programmed Death-Ligand 1 in Patients with Paroxysmal Nocturnal Hemoglobinuria Explained by Proximal Complement Activation

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hemolytic disease driven by impaired complement regulation. Mutations in genes encoding the enzymes that build the GPI anchors are causative, with somatic mutations in the PIG-A gene occurring most frequently. As a result, the important membrane-bound complement regulators CD55 and CD59 are missing on the affected hematopoietic stem cells and their progeny, rendering those cells vulnerable to complement attack. Immune escape mechanisms sparing affected PNH stem cells from removal are suspected in the PNH pathogenesis, but molecular mechanisms have not been elucidated. We hypothesized that exuberant complement activity in PNH results in enhanced immune checkpoint interactions, providing a molecular basis for the potential immune escape in PNH. In a series of PNH patients, we found increased expression levels of the checkpoint ligand programmed death-ligand 1 (PD-L1) on granulocytes and monocytes, as well as in the plasma of PNH patients. Mechanistically, we demonstrate that complement activation leading to the decoration of particles/cells with C3- and/or C4-opsonins increased PD-L1 expression on neutrophils and monocytes as shown for different in vitro models of classical or alternative pathway activation. We further establish in vitro that complement inhibition at the level of C3, but not C5, inhibits the alternative pathway-mediated upregulation of PD-L1 and show by means of soluble PD-L1 that this observation translates into the clinical situation when PNH patients are treated with either C3 or C5 inhibitors. Together, the presented data show that the checkpoint ligand PD-L1 is increased in PNH patients, which correlates with proximal complement activation.

Comparison of procedure times and collection efficiencies using integrated and multistep nonintegrated procedures for extracorporeal photopheresis

Background

Extracorporeal photopheresis (ECP) is a blood‐based therapeutic procedure increasingly used for modulation of immune dysregulation in various underlying disease settings. The aim of this study was to compare the procedure times and blood collection efficiencies between the two approaches currently utilized in European centers: the integrated versus the multistep nonintegrated procedures.

Methods

A retrospective data analysis was conducted, comparing treatment data from patients who received ECP therapy at the Central Institute for Blood Transfusion & Department of Immunology (ZIB) of the Tirol Kliniken GmbH, where the integrated and multistep nonintegrated procedures are routinely used in an approximated setup.

Results

During the observation period, a total of 15 patients who were treated with alternating systems on 2 consecutive days were identified. This allowed treatment pair comparisons with minimal interpatient variabilities, similar to a cross‐over design even though analyzed retrospectively. Total average procedure times with the integrated system were 99.3 vs 122.0 minutes with the multistep nonintegrated procedures, respectively. Significant differences were observed for all steps of the ECP procedure: (a) time for buffy coat collection, 66.5 vs 74.7; (b) handling/transfer, 2.8 vs 18.7; (c) irradiation, 20.3 vs 11.7; and (d) reinfusion/handling time, 9.6 vs 16.3 minutes. The calculated collection throughput was 7.79 mL/min for the integrated and 7.84 mL/min for the multistep nonintegrated procedures, and with a white blood cell (WBC) collection efficiency of 34.2% and 21.0%, respectively.

Conclusion

The data presented in this study show a significant shorter overall procedure time and higher WBC collection efficiency for the integrated ECP system.

Prevalence of SARS-CoV-2 antibodies in healthy blood donors from the state of Tyrol, Austria, in summer 2020

Background

Seroepidemiological studies provide important insight into the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV‑2) in our society. We aimed to determine seropositivity of SARS-CoV‑2 antibodies and its cross-sectional correlates in a large cohort of blood donors.

Methods

In this observational cohort study, we tested healthy blood donors residing in Tyrol, Austria, for SARS-CoV‑2 antibodies using the Abbott SARS-CoV‑2 IgG chemiluminescent microparticle immunoassay. We estimated 95% confidence intervals (95% CI) of seroprevalences using bootstrapping and tested for differences by participant characteristics using logistic regression.

Findings

Between 8 June and 4 September 2020, we screened 5345 healthy individuals at local blood donor sessions (mean age 42.7 years, SD 13.5 years, 46.7% female). Overall seroprevalence was 3.1% (95% CI 2.7–3.6%, 165 cases), which is 5.1-fold higher (95% CI 4.5–6.0%) than the case number identified by the health authorities in the state-wide testing program (0.6%; 4536 out of 757,634). Seroprevalence was higher in the district Landeck (16.6%, P < 0.001) and in individuals aged < 25 years (4.7%, P = 0.043), but did not differ by gender, blood types, or medication intake. The odds ratio for seropositivity was 2.51 for participants who had travelled to Ischgl (1.49–4.21, P = 0.001), 1.39 who had travelled to other federal states (1.00–1.93, P = 0.052), and 2.41 who had travelled abroad (1.61–3.63, P < 0.001). Compared to participants who had a suspected/confirmed SARS-CoV‑2 infection but were seronegative, seropositive participants more frequently reported loss of smell (odds ratio = 2.49, 1.32–4.68, P = 0.005) and taste (odds ratio = 2.76, 1.54–4.92, P = 0.001).

Conclusion

In summer 2020, SARS-CoV‑2 seroprevalence in Tyrolean blood donors was 3.1%. Our study revealed regional variation and associations with young age, travel history and specific symptoms.

Oxyresveratrol modulates the immune response in vitro

The naturally occurring stilbenoid oxyresveratrol was shown to influence inflammatory and metabolic processes. During cellular immune activation, tryptophan breakdown and neopterin formation via the enzymes indoleamine 2,3-dioxygenase-1 (IDO-1) and GTP-cyclohydrolase, respectively, are induced. Neopterin and the kynurenine to tryptophan ratio are reliable and pertinent biomarkers of Th1-type immune response and are also used in vitro to monitor effects of active plant ingredients on peripheral blood mononuclear cells (PBMCs). We investigated the effects of oxyresveratrol on the activity of the above-mentioned pathways in mitogen-stimulated human PBMC and in the myelomonocytic cell line THP-1. Oxyresveratrol exerted suppressive effects on tryptophan breakdown in both stimulated cell models. Of note, in PBMC, tryptophan breakdown was induced at lower concentrations (5–20 µM) and suppressed at higher treatment concentrations only. Neopterin formation was decreased dose-dependently in stimulated PBMC. In unstimulated PBMC similar, albeit lesser effects were observed. Data indicate that oxyresveratrol exerts distinct and concentration-dependent effects on different immune cell types. IDO-1 is targeted by oxyresveratrol and its activity can be modulated in both directions. Detailed investigations of the interactions would be interesting to fully explore the activity of this phytocompound.

Clinical validation of the Siemens quantitative SARS-CoV-2 spike IgG assay (sCOVG) reveals improved sensitivity and a good correlation with virus neutralization titers

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections cause coronavirus disease 2019 (COVID-19) and induce a specific antibody response. Serological assays detecting IgG against the receptor binding domain (RBD) of the spike (S) protein are useful to monitor the immune response after infection or vaccination. The objective of our study was to evaluate the clinical performance of the Siemens SARS-CoV-2 IgG (sCOVG) assay.

METHODS

Sensitivity and specificity of the Siemens sCOVG test were evaluated on 178 patients with SARS-CoV-2-infection and 160 pre-pandemic samples in comparison with its predecessor test COV2G. Furthermore, correlation with virus neutralization titers was investigated on 134 samples of convalescent COVID-19 patients.

RESULTS

Specificity of the sCOVG test was 99.4% and sensitivity was 90.5% (COV2G assay 78.7%; p<0.0001). S1-RBD antibody levels showed a good correlation with virus neutralization titers (r=0.843; p<0.0001) and an overall qualitative agreement of 98.5%. Finally, median S1-RBD IgG levels increase with age and were significantly higher in hospitalized COVID-19 patients (median levels general ward: 25.7 U/mL; intensive care: 59.5 U/mL) than in outpatients (3.8 U/mL; p<0.0001).

CONCLUSIONS

Performance characteristics of the sCOVG assay have been improved compared to the predecessor test COV2G. Quantitative SARS-CoV-2 S1-RBD IgG levels could be used as a surrogate for virus neutralization capacity. Further harmonization of antibody quantification might assist to monitor the humoral immune response after COVID-19 disease or vaccination.

Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay

OBJECTIVES

Serological tests detect antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the ongoing coronavirus disease-19 (COVID-19) pandemic. Independent external clinical validation of performance characteristics is of paramount importance.

METHODS

Four fully automated assays, Roche Elecsys Anti-SARS-CoV-2, Abbott SARS-CoV-2 IgG, Siemens SARS-CoV-2 total (COV2T) and SARS-CoV-2 IgG (COV2G) were evaluated using 350 pre-pandemic samples and 700 samples from 245 COVID-19 patients (158 hospitalized, 87 outpatients).

RESULTS

All tests showed very high diagnostic specificity. Sensitivities in samples collected at least 14 days after disease onset were slightly lower than manufacturers' claims for Roche (93.0%), Abbott (90.8%), and Siemens COV2T (90.3%), and distinctly lower for Siemens COV2G (78.8%). Concordantly negative results were enriched for immunocompromised patients. ROC curve analyses suggest a lowering of the cut-off index for the Siemens COV2G assay. Finally, the combination of two anti-SARS-CoV-2 antibody assays is feasible when considering borderline reactive results.

CONCLUSIONS

Thorough on-site evaluation of commercially available serologic tests for detection of antibodies against SARS-CoV-2 remains imperative for laboratories. The potentially impaired sensitivity of the Siemens COV2G necessitates a switch to the company's newly filed SARS-CoV-2 IgG assay for follow-up studies. A combination of tests could be considered in clinical practice.

The 'rejuvenating factor' TIMP-2 is detectable in human blood components for transfusion

Background and Objectives

Tissue inhibitor of metalloproteinases 2 (TIMP‐2) is a protein suspected to be crucial in numerous physiological and pathological processes such as morphogenesis, tissue remodelling and metastasis suppression. In animal models, the administration of TIMP‐2 to aged mice improved their cognitive functions. Therefore, one can hypothesize that differences in TIMP‐2 levels between blood donors and recipients might influence cognitive functions also in humans. However, the stability of TIMP‐2 during processing and storage of blood components for transfusion has not been intensively investigated so far. This study determined TIMP‐2 concentrations in fresh‐frozen plasma (FFP), erythrocyte concentrate (EC) and pathogen‐inactivated platelet concentrate (PI‐PC) depending on the donor's demographic factors age and gender.

Materials and Methods

Tissue inhibitor of metalloproteinases 2 was measured in FFP (n = 30), EC (n = 12) and PI‐PC (n = 12) using a Q‐Plex single‐plex immunoassay for chemiluminescence‐based detection. Absolute quantification of TIMP‐2 was performed with Q‐view software. Fresh umbilical cord plasma was used as a positive control.

Results

Tissue inhibitor of metalloproteinases 2 was detected in FFP (30/30 samples), EC (11/12 samples) and PI‐PC (12/12 samples). The median TIMP‐2 concentration in EC (17·2 ng/ml; range: 0–26·5 ng/ml) was significantly lower compared with FFP (63·4 ng/ml; range: 44·4–87·3 ng/ml) or PI‐PC (69·9 ng/ml; range: 39·9–83·6 ng/ml). Across all blood components, TIMP‐2 levels are comparable in male and female donors and independent of age.

Conclusion

Tissue inhibitor of metalloproteinases 2 is detectable and stable in FFP, PI‐PC and, in low concentration, EC. It can be hypothesized that TIMP‐2 will be transmitted to recipients during transfusion.

Linkage of alterations in systemic iron homeostasis to patients' outcome in sepsis: a prospective study

Background

Sepsis, a dysregulated host response following infection, is associated with massive immune activation and high mortality rates. There is still a need to define further risk factors and laboratory parameters predicting the clinical course. Iron metabolism is regulated by both, the body’s iron status and the immune response. Iron itself is required for erythropoiesis but also for many cellular and metabolic functions. Moreover, iron availability is a critical determinant in infections because it is an essential nutrient for most microbes but also impacts on immune function and intravascular oxidative stress. Herein, we used a prospective study design to investigate the putative impact of serum iron parameters on the outcome of sepsis.

Methods

Serum markers of iron metabolism were measured in a prospective cohort of 61 patients (37 males, 24 females) with sepsis defined by Sepsis-3 criteria in a medical intensive care unit (ICU) and compared between survivors and non-survivors. Regulation of iron parameters in patients stratified by focus of infection and co-medication as well as association of the markers with sepsis severity scores and survival were investigated with linear and logistic regression corrected for sex and age effects.

Results

Positive correlations of increased serum iron and ferritin concentrations upon ICU admission with the severity of organ failure (SOFA score) and with mortality were observed. Moreover, high TF-Sat, elevated ferritin and serum iron levels and low transferrin concentrations were associated with reduced survival. A logistic regression model consisting of SOFA and transferrin saturation (SOFA–TF-Sat) had the best predictive power for survival in septic ICU patients. Of note, administration of blood transfusions prior to ICU admission resulted in increased TF-Sat and reduced survival of septic patients.

Conclusions

Our study could show an important impact of serum iron parameters on the outcome of sepsis. Furthermore, we identified transferrin saturation as a stand-alone predictor of sepsis survival and as a parameter of iron metabolism which may in a combined model improve the prediction power of the SOFA score.

Trial registration

The study was carried out in accordance with the recommendations of the Declaration of Helsinki on biomedical research. The study was approved by the institutional ethics review board of the Medical University Innsbruck (study AN2013-0006).

Pharmacological Targets of Kaempferol Within Inflammatory Pathways-A Hint Towards the Central Role of Tryptophan Metabolism

The flavonoid kaempferol is almost ubiquitously contained in edible and medicinal plants and exerts a broad range of interesting pharmacological activities. Interactions with central inflammatory processes can be exploited to treat or attenuate symptoms of disorders associated with chronic immune activation during infections, malignancies, and neurodegenerative or cardiovascular disorders. Many drugs, phytochemicals, and nutritional components target the catabolism of the essential amino acid tryptophan by indoleamine 2,3-dioxygenase 1 (IDO-1) for immunomodulation. We studied the effects of kaempferol by in vitro models with human peripheral blood mononuclear cells (PBMC) and THP-1 derived human myelomonocytic cell lines. Kaempferol suppressed interferon-γ dependent immunometabolic pathways: Formation of the oxidative stress biomarker neopterin and catabolism of tryptophan were inhibited dose-dependently in stimulated cells. In-silico docking studies revealed a potential interaction of kaempferol with the catalytic domain of IDO-1. Kaempferol stimulated nuclear factor kappa B (NF-κB) signaling in lipopolysaccharide (LPS)-treated THP-1 cells, thereby increasing the mRNA expression of interleukin (IL) 1 beta, tumor necrosis factor, and nuclear factor kappa B subunit 1, while IL6 was downregulated. Data suggest that concerted effects of kaempferol on multiple immunologically relevant targets are responsible for its immunomodulatory activity. However, the immunosuppressive effects may be more relevant in a T-cell dominated context.

The "Aging Factor" Eotaxin-1 (CCL11) Is Detectable in Transfusion Blood Products and Increases with the Donor's Age

Background: High blood levels of the chemokine eotaxin-1 (CCL11) have recently been associated with aging and dementia, as well as impaired memory and learning in humans. Importantly, eotaxin-1 was shown to pass the blood-brain-barrier (BBB) and has been identified as crucial mediator of decreased neurogenesis and cognitive impairment in young mice after being surgically connected to the vessel system of old animals in a parabiosis model. It thus has to be assumed that differences in eotaxin-1 levels between blood donors and recipients might influence cognitive functions also in humans. However, it is unknown if eotaxin-1 is stable during processing and storage of transfusion blood components. This study assesses eotaxin-1 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC), and platelet concentrate (PC) in dependence of storage time as well as the donor’s age and gender.

Methods: Eotaxin-1 was measured in FFP (n = 168), EC (n = 160) and PC (n = 8) ready-to-use for transfusion employing a Q-Plex immunoassay for eotaxin-1. Absolute quantification of eotaxin-1 was performed with Q-view software.

Results: Eotaxin-1 was consistently detected at a physiological level in FFP and EC but not PC. Eotaxin-1 levels were comparable in male and female donors but increased significantly with rising age of donors in both, FFP and EC. Furthermore, eotaxin-1 was not influenced by storage time of either blood component. Finally, eotaxin-1 is subject to only minor fluctuations within one donor over a longer period of time.

Conclusion: Eotaxin-1 is detectable and stable in FFP and EC and increases with donor’s age. Considering the presumed involvement in aging and cognitive malfunction, differences in donor- and recipient eotaxin-1 levels might affect mental factors after blood transfusion.

No molecular or serological evidence of Zikavirus infection among healthy blood donors living in or travelling to regions where Aedes albopictus circulates

BACKGROUND

Previous studies have shown that Zika virus can infect and be transmitted by A. albopictus. The World Health organization (WHO) has raised concerns of autochthonous transmission of the virus in regions where the vector is endemic. The aim of this pilot study was to assess the occurrence of Zika virus (ZIKV) in western Austria (Tyrol) especially after a history of travel to A. albopictus endemic regions.

METHODS

The study participants were healthy blood donors at randomly selected donation sites in the west Austrian region Tyrol. Rest blood (plasma) samples were tested for the presence of ZIKV nucleic acid and antibodies against the virus.

RESULTS

Mean age of the study participants was 44.6 (SD = 12.9) and 58.8% were men. Eighty percent reported to have received vaccine against TBEV, whereas only 4.9 and 0.9% had received YFV and JEV vaccines. Three out of 1001 (0.03%) participants tested positive solely for ZIKV IgM antibody but not for other flaviviruses. Only one individual had ZIKV IgG antibody. All four donors were negative in the neutralization (confirmation) assay. No viral RNA was detected in any of the samples.

CONCLUSION

The null finding of our study refutes WHO's initial fear of global expansion of ZIKV infection including its occurrence in Europe. There appears to be no urgent need to introduce universal screening of donated blood for ZIKV in central Europe at least until the next warm season. Further, Euroimmun anti-Zika ELISA proved to be a highly suitable and reliable test system in populations with high prevalence of TBEV infection and/or immunization.

Impact of platelet pathogen inactivation on blood component utilization and patient safety in a large Austrian Regional Medical Centre

BACKGROUND

In clinical studies, pathogen inactivation (PI) of platelet concentrates (PC) with amotosalen and UVA light did not impact patient risk for haemorrhage but may affect transfusion frequency and component utilization. We evaluated the influence of platelet PI on PC, red cell concentrate (RCC) and plasma use and safety in routine practice in a large regional hospital.

STUDY DESIGN AND METHODS

Comparative effectiveness of conventional vs. PI-treated PC was analysed during two 21-month periods, before and after PI implementation.

RESULTS

Similar numbers of patients were transfused in the pre-PI (control, 1797) and post-PI (test, 1694) periods with comparable numbers of PC (8611 and 7705, respectively). The mean numbers of PC per patient transfused (4·8 vs. 4·5, P = 0·43) were not different but days of PC support (5·9 vs. 5·0, P < 0·01) decreased. Most patients received RCC (86·8% control vs. 84·8% test, P = 0·90) with similar mean numbers transfused (10·8 vs. 10·2 RCC, P = 0·22), and fewer patients (55·4% control vs. 44·7% test, P < 0·01) received less plasma units (mean 9·9 vs. 7·8, respectively, P < 0·01) in the test period. The frequencies of transfusion-related adverse events (AE) were comparable (1·3% vs. 1·4%, P = 0·95). Analysis of haematology-oncology (522 control, 452 test), cardiac surgery (739 control, 711 test), paediatric (157 control, 130 test) and neonate (23 control, 20 test) patients revealed no increase in PC, plasma and RCC utilization, or AE.

CONCLUSION

Component utilization and patient safety were not impacted by adoption of PI for PC. RCC use per patient was comparable, suggestive of no increase in significant bleeding.

Not Only Sleepwalking But NREM Parasomnia Irrespective of the Type Is Associated with HLA DQB1*05:01

STUDY OBJECTIVES

Despite the high prevalence and clinical relevance of NREM parasomnias, data on supportive genetic markers are scarce, and mainly refer to sleepwalking only.

METHODS

We retrospectively analyzed clinical, polysomnographic, and HLA findings of 74 adults (37 men) with NREM parasomnia gathered from four neurological sleep centers. Parasomniac events were classified according to ICSD-2 criteria. HLA DQB1 genotyping was compared to regional-matched reference allele-frequencies.

RESULTS

Fifty-six patients had more than 2 different parasomnia type: 11 sleepwalking, 4 sleep terrors, 3 confusional arousals only. Parasomniac events were documented during video-polysomnography (V-PSG) in 70% (49/70) of subjects (71.4% confusional arousals, 8.2% sleep terrors, 4.1% sleepwalking, 16.3% ≥ 2 NREM parasomnia types). Violent behavior during V-PSG occurred in 8.5% (6/71). NREM parasomnia onset was reported after the age of 30 years in 6.8% (5/74). The HLA DQB1*05:01 allele was present in 41% (29/71) compared to 24.2% in the regional-matched reference allele group (p < 0.05). This haplotype prevalence did not differ within the NREM parasomnia type. Epworth Sleepiness Score was 10 or higher in 28.6%.

CONCLUSIONS

This is a large polysomnography-based case series of patients with NREM parasomnia. In patients with suspected sleepwalking or sleep terrors, polysomnography is highly useful in detecting arousals from NREM sleep as a marker of NREM parasomnia. We confirmed previous findings by demonstrating a high prevalence of the HLA DQB1*05:01 genotype for different types of NREM parasomnias. Our findings therefore support a common genetic background, and corroborate the importance of video-polysomnography in the work-up of parasomnia.

Bisphenol A suppresses Th1-type immune response in human peripheral blood mononuclear cells in vitro

Bisphenol A (BPA) is a widely used plasticizer, which came into focus because of its genotoxic and sensitizing potential. Besides its toxic properties, BPA is also well-known for its antioxidant chemical properties. This in vitro study investigated the interference of BPA with interferon-γ (IFN-γ)-induced tryptophan breakdown and neopterin production in human peripheral blood mononuclear cells (PBMC). The pro-inflammatory cytokine IFN-γ induces the conversion of the essential amino acid tryptophan into kynurenine via the enzyme indoleamine-2,3-dioxygenase (IDO-1). In parallel, GTP-cyclohydrolase produces neopterin, a marker of immune activation. A model system of phytohaemagglutinin (PHA)-stimulated PBMC was used to assess potential immunomodulatory properties of BPA. Treatment of cells with BPA [12.5-200μM] resulted in a significant and dose-dependent suppression of mitogen-induced tryptophan breakdown and neopterin formation along with a decrease of IFN-γ levels. Similar but less pronounced effects were observed in unstimulated cells. We postulate that the inhibitory effects of BPA on both T-cell activation and IDO-1 activity that we describe here may be critical for immune surveillance and is likely to influence T helper (Th) type 1/Th2 balance. Such immunosuppressive effects likely contribute to counteract inflammation. Further studies are required to address the in vivo relevance our in vitro findings.

Bioactivites of two common polyphenolic compounds: Verbascoside and catechin

CONTEXT

Natural products can present remarkable biological and pharmacological activities. In traditional medicine, plants have been used historically in treating cancer, infections, and other inflammatory conditions.

OBJECTIVE

Verbascoside and catechin are widespread polyphenolic plant compounds that could play a role in the anti-inflammatory and health-promoting effects of plants and plant extracts.

MATERIALS AND METHODS

This study compares the potential cytotoxic effects of polyphenols verbascoside and catechin (6.25-200 µM) on human peripheral blood mononuclear cells (PBMC) for 48 h and myelomonocytic THP-1 and THP-1 Blue cells for 24 h. The effects of the compounds on immune activation markers such as indoleamine 2,3-dioxygenase (IDO) activity as well as on neopterin formation and nuclear factor-κB (NF-κB) activation were investigated. Cytotoxicity of the compounds was tested using Cell-Titer Blue assay.

RESULTS

Verbascoside exhibited significant suppressive effects in mitogen-stimulated PBMC on tryptophan breakdown (>50 µM; IC50 value: 58.6 µM) and the production of neopterin (>6.25 µM; IC50 value: 217 µM). These effects correlated with a decline in cell viability, while THP-1 Blue cells were less sensitive. NF-κB activity was slightly enhanced at lower concentrations (<50 µM verbascoside) in stimulated cells and at the highest concentration used in unstimulated cells. Catechin had no relevant effects on cell viability and on the tested inflammation markers, except NF-κB activation in THP-1 Blue cells.

DISCUSSION AND CONCLUSION

The results obtained show that verbascoside and catechin represent effective compounds which interfere with immunobiochemical pathways that are highly relevant for immunosurveillance and competing virus infections.

Head-to-head comparison between two screening systems for HBsAG, anti-HBc, anti-HCV and HIV combination immunoassays in an international, multicentre evaluation study

BACKGROUND

Mandatory screening of blood donations for hepatitis B and hepatitis C viruses and human immunodeficiency viruses 1 and 2 requires assays with exceptional sensitivity and specificity. This study reports the results from a direct head-to-head comparison of the Elecsys HBsAG II, Elecsys Anti-HBc, Elecsys Anti-HCV II and Elecsys HIV combi PT immunoassays with the respective ABBOTT PRISM/Architect instrument immunoassays in a multicentre blood bank evaluation study.

STUDY DESIGN AND METHODS

Assay validation was performed in the blood screening laboratories of four blood bank centres in Austria, Germany, Spain and Thailand, where both first-time donor samples (approximately 6000 donors) and repeat donor samples (approximately 14,000 donors) were screened.

RESULTS

Of all screened donor samples, 93 (0.46%) were confirmed to be positive using assays from both manufacturers. The specificity of all immunoassays was >99.5% and was comparable between first-time and multiple-time donors. A direct comparison between the assays from Roche and ABBOTT according to Bland and Altman analysis demonstrated equivalent quality.

CONCLUSIONS

These results suggest that the Elecsys immunoassays for HBV, HCV and HIV infection, with a comparative sensitivity of 100% and a specificity exceeding the common technical specification threshold of >99.5%, meet the stringent performance criteria stipulated for blood donor screening for these infectious agents. Significant differences in the specificity between first-time and repeat donors were not detectable.

Serum tryptophan, kynurenine, phenylalanine, tyrosine and neopterin concentrations in 100 healthy blood donors

Formation of neopterin, a biomarker of the activated human immune system, is linked with tryptophan (TRP) and phenylalanine (PHE) metabolism. To obtain normal values, in this study, serum concentrations of neopterin as well as of TRP, PHE and their respective metabolites kynurenine (KYN) and tyrosine (TYR) were investigated in 100 successive blood donor serum specimens from the University Clinics of Innsbruck, Austria. In addition, nitrite concentrations were determined. Donors had passed anamnestic examination at entry and were therefore considered as healthy. The mean age of participants was 49±11.4 (mean±SD) years; 18% were older than 60 years. Both genders were included in the analysis. Neopterin concentrations measured by enzyme-linked immunosorbent assay were 5.9±1.6 nmol/L (mean±SD). Levels of amino acids and metabolites were determined by HPLC. Mean KYN and TRP concentrations were 1.78±0.42 μmol/L and 67.4±10.2 μmol/L, respectively. KYN to TRP ratio (KYN/TRP), an estimate for the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase, was 26.7±6.2 μmol/mmol. Mean PHE and TYR concentrations were 65.2±11.1 μmol/L and 90.6±22.9 μmol/L. PHE to TYR ratio (PHE/TYR), an estimate for the activity of PHE-converting enzyme phenylalanine hydroxylase, was 0.75±0.14 μmol/μmol. Nitrite concentrations, estimated by Griess-Ilosvay reagent, were 44.9±32.0 μmol/L. Males were taller and heavier than females (both p<0.01), but body mass index did not differ. Males presented with significantly higher TRP and TYR concentrations than females (both p<0.05). There existed significant correlations between neopterin and KYN (rs=0.368), KYN/TRP (rs=0.453), TYR (rs=–0.267; all p<0.01) and PHE/TYR (rs=0.236; p<0.05) concentrations. Data indicate that also in a population of healthy individuals an association exists between “low-grade” immune activation as is indicated by slightly higher neopterin concentrations and biochemical alterations in the amino acid metabolism. Although minor, such changes may interfere with psychoneuroimmunological regulatory networks and thus be of clinical relevance.

Lavender oil suppresses indoleamine 2,3-dioxygenase activity in human PBMC

BACKGROUND

Lavender remedies have been used in traditional medicine because of antimicrobial, anti-inflammatory and mood alleviating effects, but underlying molecular mechanisms are not yet fully elucidated. Recently, studies investigating the effects of lavender oil in the context of psychiatric disorders have indicated potent pharmacological properties. Metabolism of tryptophan by indoleamine 2,3-dioxygenase (IDO) was found to provide a biochemical link between immunology and neuroendocrinology and to be a frequent target of natural products.

METHODS

In this in vitro study, interferences of lavender oil and constituents (-)-linalool, (+)-α-pinene and (+)-limonene with tryptophan catabolism by IDO and formation of neopterin via guanosine triphosphate (GTP)-cyclohydrolase-I and of interferon-γ have been investigated using unstimulated and phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PBMC).

RESULTS

Treatment with lavender oil dose-dependently suppressed PHA-induced tryptophan breakdown and kynurenine formation. Similar effects were observed for the three constituents. In parallel, formation of neopterin and interferon-γ was diminished upon lavender oil treatment. In unstimulated PBMC, effect of lavender oil treatment was similar, but less pronounced.

CONCLUSION

Data from this in vitro study suggest that lavender oil treatment might contribute to the modulation of the immune and neuroendocrine system by interfering with activation-induced tryptophan breakdown and IDO activity.

Antiphospholipid antibodies predict progression of abdominal aortic aneurysms

Antiphospholipid antibodies (aPLs) frequently occur in autoimmune and cardiovascular diseases and correlate with a worse clinical outcome. In the present study, we evaluated the association between antiphospholipid antibodies (aPLs), markers of inflammation, disease progression and the presence of an intra-aneurysmal thrombus in abdominal aortic aneurysm (AAA) patients.

APLs ELISAs were performed in frozen serum samples of 96 consecutive AAA patients and 48 healthy controls yielding positive test results in 13 patients (13.5%) and 3 controls (6.3%; n.s.). Nine of the 13 aPL-positive AAA patients underwent a second antibody testing >12 weeks apart revealing a positive result in 6 cases. APL-positive patients had increased levels of inflammatory markers compared to aPL-negative patients. Disease progression was defined as an increase of the AAA diameter >0.5 cm/year measured by sonography. Follow-up was performed in 69 patients identifying 41 (59.4%) patients with progressive disease. Performing multipredictor logistic regression analysis adjusting for classical AAA risk factors as confounders, the presence of aPLs at baseline revealed an odds ratio of 9.4 (95% CI 1.0–86.8, p = 0.049) to predict AAA progression. Fifty-five patients underwent a computed tomography in addition to ultrasound assessment indicating intra-aneurysmal thrombus formation in 82.3%. Median thrombus volume was 46.7 cm³ (1.9–377.5). AAA diameter correlated with the size of the intra-aneurysmal thrombus (corr_coeff = 0.721, p<0.001), however neither the presence nor the size of the intra-aneurysmal thrombus were related to the presence of aPLs.

In conclusion, the presence of aPLs is associated with elevated levels of inflammatory markers and is an independent predictor of progressive disease in AAA patients.

Investigations on California serogroup orthobunyaviruses in the Tyrols: first description of Tahyna virus in the Alps

Seroprevalence rates for immunoglobulin G (IgG) antibodies to Tahyna virus (TAHV) and Inkoo virus (INKV) were determined in sera of 1630 blood donors from North, East, and South Tyrol by immunofluorescence assays (IFAs) and confirmatory serum neutralization tests (SNTs). Ten sera (0.6%) reacted positive by TAHV IFA, five of which (0.3%) were confirmed by SNT. Eleven sera (0.7%) reacted positive in the INKV IFA; only one thereof (0.06%) was verified by subsequent SNT. To identify the source of infections, mosquitoes were trapped at 18 sampling sites in the study area, resulting in the collection of 2571 adult mosquitoes: 1254 individuals of the genus Aedes (48.8% of total) including A. albopictus, 640 Culex (24.9%), 303 Coquillettidia (11.8%), 252 Ochlerotatus (9.8%), 49 Anopheles (1.9%), and 73 mosquitoes of the genus Culiseta (2.8%). The mosquitoes were pooled according to species, trapping site, and time, and were tested by RT-PCR for the presence of California serogroup orthobunyavirus nucleic acids. PCR amplification products were obtained in five of 195 pools (2.6%), and all were identified as TAHVs by subsequent sequencing. This represents the first evidence of TAHV circulation and human exposure in the Tyrols and in the alpine region in general. Interestingly, all TAHV sequences were identified in Culex pipiens/torrentium mosquitoes. Whether other California serogroup orthobunyaviruses such as INKV are also circulating in this area is subject of further investigations on larger numbers of mosquitoes.

Risk assessment of transfusion-associated babesiosis in Tyrol: appraisal by seroepidemiology and polymerase chain reaction

BACKGROUND

After malaria, babesiosis is the second most common transfusion-transmitted parasitic disease in the United States. In Europe, one reported transfusion case, concerning Babesia microti, occurred in Germany.

STUDY DESIGN AND METHODS

Due to the fact that Babesia spp. are present in Tyrolean ticks, the aim of this study is to assess the occurrence of immunoglobulin (Ig)G antibodies against the Babesia divergens complex, including B. divergens and Babesia venatorum (EU1), as well as B. microti by screening a representative collective of 988 blood donors from North and East Tyrol (Austria) with indirect immunofluorescence antibody test. Additionally, we investigated 206 local ixodid ticks for the presence of babesial DNA by polymerase chain reaction.

RESULTS

Seroprevalence data resulted in rates of 2.1% for IgG antibodies against the B. divergens complex and 0.6% against B. microti in Tyrolean blood donors. All sera could be confirmed by independent retesting. Our data indicate that cross-reactivity is high between B. divergens and B. venatorum and lower than 19.8% between B. divergens and B. microti.

CONCLUSIONS

This study shows that Babesia spp. are present in the Tyrols, which blood donors come into serologic contact with, and that we have to consider how to sustain blood product safety concerning this new challenge. Additionally, it is the first description of B. venatorum in the Tyrols, found in one Ixodes ricinus at the Italian border.

Comparison of in vitro tests for antioxidant and immunomodulatory capacities of compounds

Oxidative stress is considered to be critically involved in the normal aging process but also in the development and progression of various human pathologies like cardiovascular and neurodegenerative diseases, as well as of infections and malignant tumors. These pathological conditions involve an overwhelming production of reactive oxygen species (ROS), which are released as part of an anti-proliferative strategy during pro-inflammatory immune responses. Moreover, ROS themselves are autocrine forward regulators of the immune response. Most of the beneficial effects of antioxidants are considered to derive from their influence on the immune system. Due to their antioxidant and/or radical scavenging nature, phytochemicals, botanicals and herbal preparations can be of great importance to prevent oxidation processes and to counteract the activation of redox-regulated signaling pathways. Antioxidants can antagonize the activation of T-cells and macrophages during the immune response and this anti-inflammatory activity could be of utmost importance for the treatment of above-mentioned disorders and for the development of immunotolerance. Herein, we provide an overview of in vitro assays for the measurement of antioxidant and anti-inflammatory activities of plant-derived substances and extracts, by discussing possibilities and limitations of these methods. To determine the capacity of antioxidants, the oxygen radical absorbance capacity (ORAC) assay and the cell-based antioxidant activity (CAA) assay are widely applied. To examine the influence of compounds on the human immune response more closely, the model of mitogen stimulated human peripheral blood mononuclear (PBMC) cells can be applied, and the production of the inflammatory marker neopterin as well as the breakdown of the amino acid tryptophan in culture supernatants can be used as readout to indicate an immunomodulatory potential of the tested compound. These two biomarkers of immune system activation are robust and correlate with the course of cardiovascular, neurodegenerative and malignant tumor diseases, but also with the normal aging process, and they are strongly predictive. Thus, while the simpler ORAC and CAA assays provide insight into one peculiar chemical aspect, namely the neutralization of peroxyl radicals, the more complex PBMC assay is closer to the in vivo conditions as the assay comprehensively enlights several properties of immunomodulatory test compounds.

TiO(2) nanoparticles and bulk material stimulate human peripheral blood mononuclear cells

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Effects on immunobiochemical pathways of TiO₂ materials were investigated in vitro.

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TiO₂ bulk and nanomaterial stimulated neopterin production in human PBMC.

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There was no stimulatory influence of particles on tryptophan breakdown.

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At high particles concentrations, tryptophan breakdown was suppressed.

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Results suggest that the total effect of particles is even stronger pro-inflammatory.

Nanomaterials are increasingly produced and used throughout recent years. Consequently the probability of exposure to nanoparticles has risen. Because of their small 1–100 nm size, the physicochemical properties of nanomaterials may differ from standard bulk materials and may pose a threat to human health. Only little is known about the effects of nanoparticles on the human immune system. In this study, we investigated the effects of TiO₂ nanoparticles and bulk material in the in vitro model of human peripheral blood mononuclear cells (PBMC) and cytokine-induced neopterin formation and tryptophan breakdown was monitored. Both biochemical processes are closely related to the course of diseases like infections, atherogenesis and neurodegeneration. OCTi60 (25 nm diameter) TiO₂ nanoparticles and bulk material increased neopterin production in unstimulated PBMC and stimulated cells significantly, the effects were stronger for OCTi60 compared to bulk material, while P25 TiO₂ (25 nm diameter) nanoparticles had only little influence. No effect of TiO₂ nanoparticles on tryptophan breakdown was detected in unstimulated cells, whereas in stimulated cells, IDO activity and IFN-γ production were suppressed but only at the highest concentrations tested. Because neopterin was stimulated and tryptophan breakdown was suppressed in parallel, data suggests that the total effect of particles would be strongly pro-inflammatory.

Neopterin suppresses the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase in human peripheral blood mononuclear cells

In vitro, large amounts of neopterin are released from human monocyte-derived macrophages and dendritic cells primarily upon stimulation with Th1-type cytokine interferon-γ (IFN-γ). IFN-γ also induces the enzyme indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan (TRP) to form kynurenine (KYN). IDO-mediated TRP catabolism is very effective in suppressing the proliferation of T lymphocytes as well as of pathogens in vitro and in vivo. In this study, we investigated whether exogenously added neopterin may influence IDO activity in resting and in stimulated peripheral blood mononuclear cells (PBMC). PBMC were isolated from healthy donors, and neopterin was added in a concentration range from 0.01 to 50 μmol/L. After 30 min, PBMC were stimulated or not with 10 μg/mL of mitogen phytohemagglutinin (PHA). After 48 h, culture supernatants were collected, KYN and TRP concentrations were measured by high-performance liquid chromatography, and the ratio of KYN vs. TRP was calculated as an estimate of IDO activity. Spontaneous as well as PHA-induced TRP breakdown was suppressed by exogenously added neopterin in a dose-dependent way; the lowest active concentration of neopterin was <100 nmol/L. As neopterin concentrations in the nanomolar range are commonly observed in patients suffering from infections, sepsis, or uremia, our results suggest that neopterin formation might also serve as a feedback mechanism to slow down TRP degradation in vivo.

The liver graft as Trojan horse-multilineage donor-derived hematopoiesis after liver transplantation: case report

Hematopoietic macrochimerism, which is rarely seen after orthotopic liver transplantation (OLT), has been linked to the development of graft versus host disease (GvHD). We report on a patient with GvHD after OLT in whom full engraftment of donor-derived, multilineage hematopoiesis occurred, indicating that the liver contains pluripotent hematopoietic progenitor cells (HPC) capable to restore hematopoiesis in recipients. Although preventing graft rejection, standard immunosuppressive therapy may be under certain immunological conditions not sufficient to prevent GvHD. Age-, disease-, and treatment-related variables might be critical determinants for the development of an effective alloreactive T-cell response leading to the establishment of full hematopoietic chimerism.

Simultaneous measurement of phenylalanine and tyrosine by high performance liquid chromatography (HPLC) with fluorescence detection

OBJECTIVES

An HPLC method was developed to quantify serum concentrations of phenylalanine and tyrosine simultaneously using fluorescence detection without derivatization.

METHODS

Serum protein is precipitated with trichloroacetic acid, 0.015mM dihydrogen-phosphate solution is used for separation on reversed-phase C18 material, and acetonitrile is avoided. Both amino acids are monitored utilizing their natural fluorescence at 210nm excitation and 302nm emission wavelengths.

RESULTS

One analytical run is completed within 7min. Lower detection limit for Phe and Tyr is 0.3μM. Comparison of the new method with a classical HPLC method for total amino acids and using UV-absorption detection reveals a highly significant relationship for Phe and Tyr.

CONCLUSION

The new HPLC method allows rapid and very sensitive measurement of phenylalanine and tyrosine concentrations.

Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase

Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells in vitro methanol and ethylacetate seed extracts were prepared from cold pressed seed cakes of C. tinctorius and three lignan derivatives, trachelogenin, arctigenin and matairesinol were isolated. The influence on tryptophan breakdown was investigated in peripheral blood mononuclear cells (PBMCs). Effects were compared to neopterin production in the same cellular assay. Both seed extracts suppressed tryptophan breakdown in stimulated PBMC. The three structurally closely related isolates exerted differing suppressive activity on PBMC: arctigenin (IC50 26.5μM) and trachelogenin (IC50 of 57.4μM) showed higher activity than matairesinol (IC50 >200μM) to inhibit tryptophan breakdown. Effects on neopterin production were similar albeit generally less strong. Data show an immunosuppressive property of compounds which slows down IDO activity. The in vitro results support the view that some of the anti-inflammatory, anticancer and antidepressant properties of C. tinctorius lignans might relate to their suppressive influence on tryptophan breakdown.