Assessing the Performance of a Novel Point-of-Care Qualitative Assay for Early Diagnosis of Acute Coronary Syndrome

BACKGROUND

Early and accurate diagnosis of acute coronary syndrome (ACS) is essential for initiating lifesaving interventions. In this article, the diagnostic performance of a novel point-of-care rapid assay (SensAheart©) is analyzed. This assay qualitatively determines the presence of 2 cardiac biomarkers troponin I and heart-type fatty acid-binding protein that are present soon after onset of myocardial injury.

METHODS

We conducted a prospective observational study of consecutive patients who presented to the emergency department with typical chest pain. Simultaneous high-sensitive cardiac troponin T (hs-cTnT) and SensAheart testing was performed upon hospital admission. Diagnostic accuracy was computed using SensAheart or hs-cTnT levels versus the final diagnosis defined as positive/negative.

RESULTS

Of 225 patients analyzed, a final diagnosis of ACS was established in 138 patients, 87 individuals diagnosed with nonischemic chest pain. In the overall population, as compared to hs-cTnT, the sensitivity of the initial SensAheart assay was significantly higher (80.4 vs. 63.8%, p = 0.002) whereas specificity was lower (78.6 vs. 95.4%, p = 0.036). The overall diagnostic accuracy of SensAheart assay was similar to the hs-cTnT (82.7% compared to 76.0%, p = 0.08).

CONCLUSIONS

Upon first medical contact, the novel point-of-care rapid SensAheart assay shows a diagnostic performance similar to hs-cTnT. The combination of 2 cardiac biomarkers in the same kit allows for very early detection of myocardial damage. The SensAheart assay is a reliable and practical tool for ruling-in the diagnosis of ACS.

Realizing the simultaneous liquid chromatography-tandem mass spectrometry based quantification of >1200 biotoxins, pesticides and veterinary drugs in complex feed

The first quantitative multiclass approach enabling the accurate quantification of >1200 biotoxins, pesticides and veterinary drugs in complex feed using liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed. Optimization of HPLC/UHPLC (chromatographic column, flow rate and injection volume) and MS/MS conditions (dwell time and cycle time) were carried out in order to allow the combination of five major substance classes and the high number of target analytes with different physico-chemical properties. Cycle times and retention windows were carefully optimized and ensured appropriate dwell times reducing the overall measurement error. Validation was carried out in two compound feed matrices according to the EU SANTE validation guideline. Apparent recoveries matching the acceptable range of 60-140% accounted 60% and 79% for all analytes in cattle and chicken feed, respectively. High extraction efficiencies were obtained for all analyte/matrix combinations and revealed matrix effects as the main source for deviation of the targeted performance criteria. Concerning the methods repeatability 99% of all analytes in chicken and 96% in cattle feed complied with the acceptable RSD ≤ 20% criterion. Limits of quantification were between 1-10 µg/kg for the vast majority of compounds. Finally, the methods applicability was tested in >130 real compound feed samples and provides first insights into co-exposure of agro-contaminants in animal feed.

Validation of an LC-MS/MS-based dilute-and-shoot approach for the quantification of > 500 mycotoxins and other secondary metabolites in food crops: challenges and solutions

This paper describes the validation of an LC-MS/MS-based method for the quantification of > 500 secondary microbial metabolites. Analytical performance parameters have been determined for seven food matrices using seven individual samples per matrix for spiking. Apparent recoveries ranged from 70 to 120% for 53-83% of all investigated analytes (depending on the matrix). This number increased to 84-94% if the recovery of extraction was considered. The comparison of the fraction of analytes for which the precision criterion of RSD ≤ 20% under repeatability conditions (for 7 replicates derived from different individual samples) and intermediate precision conditions (for 7 technical replicates from one sample), respectively, was met (85-97% vs. 93-94%) highlights the contribution of relative matrix effects to the method uncertainty. Statistical testing of apparent recoveries between pairs of matrices exhibited a significant difference for more than half of the analytes, while recoveries of the extraction showed a much better agreement. Apparent recoveries and matrix effects were found to be constant over 2-3 orders of magnitude of analyte concentrations in figs and maize, whereas the LOQs differed less than by a factor of 2 for 90% of the investigated compounds. Based on these findings, this paper discusses the applicability and practicability of current guidelines for multi-analyte method validation. Investigation of (apparent) recoveries near the LOQ seems to be insufficiently relevant to justify the enormous time-effort for manual inspection of the peaks of hundreds of analytes. Instead, more emphasis should be put on the investigation of relative matrix effects in the validation procedure. Graphical abstract.

Evaluation of Matrix Effects and Extraction Efficiencies of LC-MS/MS Methods as the Essential Part for Proper Validation of Multiclass Contaminants in Complex Feed

This work provides a proposal for proper determination of matrix effects and extraction efficiencies as an integral part of full validation of liquid chromatography coupled to tandem mass spectrometry-based multiclass methods for complex feedstuff. Analytical performance data have been determined for 100 selected analytes in three compound feed matrices and twelve single feed ingredients using seven individual samples per matrix type. Apparent recoveries ranged from 60-140% for 52-89% of all compounds in single feed materials and 51-72% in complex compound feed. Regarding extraction efficiencies, 84-97% of all analytes ranged within 70-120% in all tested feed materials, implying that signal suppression due to matrix effects is the main source for the deviation from 100% of the expected target deriving from external calibration. However, the comparison between compound feed and single feed materials shows great variances regarding the apparent recoveries and matrix effects. Therefore, model compound feed formulas for cattle, pig, and chicken were prepared in-house in order to circumvent the issue of the lack of a true blank sample material and to simulate compositional uncertainties. The results of this work highlight that compound feed modeling enables a more realistic estimation of the method performance and therefore should be implemented in future validation guidelines.

Mycotoxins in maize harvested in Serbia in the period 2012-2015. Part 2: Non-regulated mycotoxins and other fungal metabolites

The main objective of this study was to screen, for the first time, the natural occurrence of non-regulated fungal metabolites in 204 maize samples harvested in Serbia in maize growing seasons with extreme drought (2012), extreme precipitation and flood (2014) and moderate drought conditions (2013 and 2015). In total, 109 non-regulated fungal metabolites were detected in examined samples, whereby each sample was contaminated between 13 and 55 non-regulated fungal metabolites. Moniliformin and beauvericin occurred in all samples collected from each year. In samples from year 2012, oxaline, questiomycin A, cyclo (l-Pro-l-Val), cyclo (l-Pro-l-Tyr), bikaverin, kojic acid and 3-nitropropionic acid were the most predominant (98.0-100%). All samples from 2014 were contaminated with 7-hydroxypestalotin, 15-hydroxyculmorin, culmorin, butenolid and aurofusarin. Bikaverin and oxaline were quantified in 100% samples from 2013 and 2015, while 3-nitropropionic acid additionally occurred in 100% samples from 2015.

Equalizer 2.0-Convergence of a Parallel Rendering Framework

Developing complex, real world graphics applications which leverage multiple GPUs and computers for interactive 3D rendering tasks is a complex task. It requires expertise in distributed systems and parallel rendering in addition to the application domain itself. We present a mature parallel rendering framework which provides a large set of features, algorithms and system integration for a wide range of real-world research and industry applications. Using the Equalizer parallel rendering framework, we show how a wide set of generic algorithms can be integrated in the framework to help application scalability and development in many different domains, highlighting how concrete applications benefit from the diverse aspects and use cases of Equalizer. We present novel parallel rendering algorithms, powerful abstractions for large visualization setups and virtual reality, as well as new experimental results for parallel rendering and data distribution.

Mycotoxins in maize harvested in Republic of Serbia in the period 2012-2015. Part 1: Regulated mycotoxins and its derivatives

The main objective of this study was to apply a liquid chromatography-tandem mass spectrometric method to investigate the presence of 20 mycotoxins in 204 maize samples harvested in Northern Serbia in the period 2012-2015, including seasons with extreme drought (2012), hot and dry conditions (2013 and 2015) and extreme precipitation (2014). Between 2 and 20 mycotoxins contaminated examined samples. In samples collected from each year, all of six examined fumonisins were detected with very high prevalence (from 76% to 100%). Aflatoxin B₁ was detected in 94% and 90% maize samples from 2012 and 2015, respectively. In samples from year 2014, deoxynivalenol, zearalenone and its derivatives were detected in 100% of samples. Furthermore, ochratoxin A (25%) was the most predominant in samples from 2012. The obtained results indicate that changes in weather conditions, recorded in the period of four years, had significant influence on the occurrence of examined mycotoxins in maize.

Morphological, immunophenotypical and molecular features of hypermutation in colorectal carcinomas with mutations in DNA polymerase ε (POLE)

AIMS

Colorectal carcinomas (CRC) with mismatch repair (MMR) deficiency have increased tumour mutation burden and respond to immune check-point inhibitor therapy. The Cancer Genome Atlas identified hypermutated CRCs with somatic mutations in DNA polymerase ε (POLE) with mutation burdens exceeding that of MMR-deficient CRCs.

METHODS AND RESULTS

To identify the morphological, immunophenotypical and molecular features of POLE-mutated CRCs, 63 consecutive MMR-intact CRCs were evaluated by Sanger sequencing for POLE exonuclease domain mutations in exons 9, 11, 13 and 14 and confirmed by next-generation sequencing. Tumour immune microenvironment and IMMUNOSCORE®¹ were assessed in POLE-mutated CRCs using immunohistochemistry to detect CD3⁺ /CD8⁺ tumour-infiltrating lymphocytes and compared to 59 non-POLE mutated MMR-intact CRC, 10 non-POLE mutated MMR-deficient CRCs and 223 normal colonic mucosa.

CONCLUSIONS

A total of 4.8% CRC (four MMR-intact primary and one MMR-intact metastasis) harboured POLE mutations in amino acid 286 in exon 9 (p.P286R) or exon 13 (p.V411L). POLE-mutated CRCs arose in the transverse colon and rectum, were male-predominant, younger and showed increased tumour-infiltrating lymphocytes and immune cells at the tumour-stromal interface. The patient with metastatic POLE-mutated CRC was placed on PD-1 inhibitor treatment with marked and sustained response. These data indicate that POLE-mutated CRCs have hypermutated phenotypes despite MMR-intact status, with mutation burdens higher than that in microsatellite-unstable CRCs. Given the recent approval for treatment of microsatellite-unstable cancer with immune check-point inhibitors, assessment of POLE status may help to guide therapeutic decisions for hypermutated tumours with intact MMR that would otherwise be missed by routine testing.

Towards a dietary-exposome assessment of chemicals in food: An update on the chronic health risks for the European consumer

An informed opinion to a hugely important question, whether the food on the Europeans' plate is safe to eat, is provided. Today, the Europeans face food-borne health risks from non-communicable diseases induced by excess body weight, outbreaks caused by pathogens, antimicrobial resistance and exposures to chemical contaminants. In this review, these risks are first put in an order of importance. Then, not only potentially injurious dietary chemicals are discussed but also beneficial factors of the food. This review can be regarded as an attempt towards a dietary-exposome evaluation of the chemicals, the average European adult consumers could chronically expose to during their life-times. Risk ranking reveals that currently the European adults are chronically exposed to a mixture of potentially genotoxic-carcinogenic contaminants, particularly food process contaminants, at the potential risk levels. Furthermore, several of the contaminants whose dietary exposures pose risks appear to be carcinogens operating with a genotoxic mode of action targeting the liver. This suggests that combined health risks from the exposure to a mixture of the chemical contaminants poses a greater potential risk than the risks assessed for single compounds. Over 100 European-level risk assessments are examined. Finally, the importance of a diversified and balanced diet is emphasized.

Determining cell type abundance and expression from bulk tissues with digital cytometry

Single-cell RNA-sequencing has emerged as a powerful technique for characterizing cellular heterogeneity, but it is currently impractical on large sample cohorts and cannot be applied to fixed specimens collected as part of routine clinical care. We previously developed an approach for digital cytometry, called CIBERSORT, that enables estimation of cell type abundances from bulk tissue transcriptomes. We now introduce CIBERSORTx, a machine learning method that extends this framework to infer cell-type-specific gene expression profiles without physical cell isolation. By minimizing platform-specific variation, CIBERSORTx also allows the use of single-cell RNA-sequencing data for large-scale tissue dissection. We evaluated the utility of CIBERSORTx in multiple tumor types, including melanoma, where single-cell reference profiles were used to dissect bulk clinical specimens, revealing cell-type-specific phenotypic states linked to distinct driver mutations and response to immune checkpoint blockade. We anticipate that digital cytometry will augment single-cell profiling efforts, enabling cost-effective, high-throughput tissue characterization without the need for antibodies, disaggregation or viable cells.

Multiresolution Volume Filtering in the Tensor Compressed Domain

Signal processing and filter operations are important tools for visual data processing and analysis. Due to GPU memory and bandwidth limitations, it is challenging to apply complex filter operators to large-scale volume data interactively. We propose a novel and fast multiscale compression-domain volume filtering approach integrated into an interactive multiresolution volume visualization framework. In our approach, the raw volume data is decomposed offline into a compact hierarchical multiresolution tensor approximation model. We then demonstrate how convolution filter operators can effectively be applied in the compressed tensor approximation domain. To prevent aliasing due to multiresolution filtering, our solution (a) filters accurately at the full spatial volume resolution at a very low cost in the compressed domain, and (b) reconstructs and displays the filtered result at variable level-of-detail. The proposed system is scalable, allowing interactive display and filtering of large volume datasets that may exceed the available GPU memory. The desired filter kernel mask and size can be modified online, producing immediate visual results.

Antigranulocyte scintigraphy of septic loosening of hip prosthesis: influence of different analyzing methods

Aim: Diagnosis of infection with help of antigranulocyte scintigraphy near body stem is difficult because of contemporary visualisation of bone marrow. Therefore, we investigated, whether it is possible to improve the accuracy in diagnosing septic loosening of hip endoprosthesis by changing the analyzing methods. Methods: In 28 patients, the results of a visual interpretation of late scan, a visual interpretation and a quantitative interpretation of time-activity-course were compared. These results were verified by histology respectively microbiology. Results: Histological and microbiological verification found 14 septic loosening and 14 aseptic loosening of the hip protheses. Therefore, sensitivity, specifity, negative and positive predictive value for the visual interpretation of late scan were 0.86,0.57,0.80 and 0.67. For visual and quantitative interpretation of time-activity-course we found 0.86,0.79,0.85 and 0.80 respectively 1,0.93, 1,0.93. For interobserver agreement we found kappa coefficients of 0.28 ± 0.2 for visual interpretation of late scan, 0.48 ±0.17 for visual interpretation and 1.0 ± 0 for quantitative interpretation of time-activity-course. Conclusion: In all investigated values quantitative interpretation of time-activity-course was superior to the other analyzing methods. Therefore, antigranulocyte scintigraphy for septic loosening of hip endoprosthesis should be interpreted quantitativly.

[Disseminated osteolytic lesions in a 28-year-old refugee]

A 28-year-old Syrian refugee presented with right-sided knee pain and progressive deterioration of the general condition over the past months. Laboratory diagnostics revealed severe hypercalcemia due to primary hyperparathyroidism, and computed tomography (CT) scanning demonstrated disseminated osteolytic lesions throughout the skeleton. Histologically, these lesions were characterized by multinuclear giant cells (defining these lesions as so-called brown tumors). Finally, surgical removal of a jugular mass allowed the histopathologic diagnosis of a sporadic parathyroid carcinoma. In the patient, this condition was associated with a mutation in the HPRT2 gene locus.

Antigen presentation profiling reveals T-cell recognition of lymphoma immunoglobulin neoantigens

Presentation of novel antigenic peptides (neoantigens) that distinguish malignant from normal cells by major histocompatibility complexes (MHC) can serve as potent substrates for specific anti-tumor immune responses. We sought to identify mantle cell lymphoma (MCL) neoantigens by taking an integrated genomic and proteomic strategy that interrogates antigen peptides presented by MHC-class I and class II. Peptides bound to MHC were purified via immunoprecipitation followed by identification using mass spectrometry. Mass spectra were searched against patient-specific proteome databases generated by whole exome sequencing and targeted immunoglobulin gene sequencing. This approach was applied to systematically characterize over 36,000 immunopeptides from 17 patients’ tumor specimens. Interestingly, 52 neoantigenic peptides were derived from the lymphoma immunoglobulin (Ig) heavy or light chain variable regions. Although we identified MHC presentation of private germline polymorphic alleles, no mutated peptides were recovered from non-Ig somatically mutated genes. Furthermore, somatic mutations within the immunoglobulin variable region were almost exclusively presented by MHC-II. T-cells specific for Ig-derived neoantigens were found in two patients. Following ex vivo activation and expansion, the T-cells were remarkably able to mediate killing of autologous lymphoma cells. These results demonstrate that combining MHC isolation, peptide identification and exome sequencing is an effective platform to uncover tumor neoantigens. Application of this strategy to MCL implicates immunoglobulin neoantigens as targets for lymphoma immunotherapy.

Scalp reconstruction: A 10-year retrospective study

Scalp reconstruction is a challenging task for the reconstructive surgeon. In consideration of the anatomical and cosmetic characteristics, the defect depth and size, an armamentarium of reconstructive procedures ranging from skin grafts over local flaps to free tissue transfer has been described. In this 10-year retrospective study, 85 operative procedures for scalp reconstruction were performed at our department. The underlying entity, defect size/depth, reconstructive procedure, complications, and mean hospital stay were analyzed. In most cases, scalp reconstruction was necessary after oncologic resection (67%) or radiation therapy (16%). A total of 85 operative procedures were performed for scalp reconstruction including local flaps (n = 50), free tissue transfer (n = 18), and skin grafts (n = 17). Regarding the complication rate, we could detect an overall major complication rate of 16.5% with one free flap loss. Briefly, local flaps are an adequate and safe procedure for limited scalp defects. In the case of extensive scalp defects affecting the calvarium, prior multiple surgical interventions and/or radiation, we prefer free tissue transfer.

A comparative reference study for the validation of HLA-matching algorithms in the search for allogeneic hematopoietic stem cell donors and cord blood units

The accuracy of human leukocyte antigen (HLA)‐matching algorithms is a prerequisite for the correct and efficient identification of optimal unrelated donors for patients requiring hematopoietic stem cell transplantation. The goal of this World Marrow Donor Association study was to validate established matching algorithms from different international donor registries by challenging them with simulated input data and subsequently comparing the output. This experiment addressed three specific aspects of HLA matching using different data sets for tasks of increasing complexity. The first two tasks targeted the traditional matching approach identifying discrepancies between patient and donor HLA genotypes by counting antigen and allele differences. Contemporary matching procedures predicting the probability for HLA identity using haplotype frequencies were addressed by the third task. In each task, the identified disparities between the results of the participating computer programs were analyzed, classified and quantified. This study led to a deep understanding of the algorithms participating and finally produced virtually identical results. The unresolved discrepancies total to less than 1%, 4% and 2% for the three tasks and are mostly because of individual decisions in the design of the programs. Based on these findings, reference results for the three input data sets were compiled that can be used to validate future matching algorithms and thus improve the quality of the global donor search process.

Comparative validation of computer programs for haplotype frequency estimation from donor registry data

Estimation of human leukocyte antigen (HLA) haplotype frequencies from unrelated stem cell donor registries presents a challenge because of large sample sizes and heterogeneity of HLA typing data. For the 14th International HLA and Immunogenetics Workshop, five bioinformatics groups initiated the 'Registry Diversity Component' aiming to cross-validate and improve current haplotype estimation tools. Five datasets were derived from different donor registries and then used as input for five different computer programs for haplotype frequency estimation. Because of issues related to heterogeneity and complexity of HLA typing data identified in the initial phase, the same five implementations, and two new ones, were used on simulated datasets in a controlled experiment where the correct results were known a priori. These datasets contained various fractions of missing HLA-DR modeled after European haplotype frequencies. We measured the contribution of sampling fluctuation and estimation error to the deviation of the frequencies from their true values, finding equivalent contributions of each for the chosen samples. Because of patient-directed activities, selective prospective typing strategies and the variety and evolution of typing technology, some donors have more complete and better HLA data. In this setting, we show that restricting estimation to fully typed individuals introduces biases that could be overcome by including all donors in frequency estimation. Our study underlines the importance of critical review and validation of tools in registry-related activity and provides a sustainable framework for validating the computational tools used. Accurate frequencies are essential for match prediction to improve registry operations and to help more patients identify suitably matched donors.

Increased extracellular matrix and proangiogenic factor transcription in endothelial cells after cocultivation with primary human osteoblasts

The most promising strategies in bone engineering have concentrated on providing sufficient vascularization to support the newly forming tissue. In this context, recent research in the field has focused on studying the complex interactions between bone forming and endothelial cells. Our previous work has demonstrated that direct contact cocultivation of human umbilical vein endothelial cells (HUVECs) with primary human osteoblasts (hOBs) induces the osteogenic phenotype and survival of hOBs. In order to investigate the mechanisms that lead to this effect, we performed microarray gene expression profiling on HUVECs following cocultivation with hOBs. Our data reveal profound transcriptomic changes that are dependent on direct cell contact between these cell populations. Pathway analysis using the MetaCore™ platform and literature research suggested a striking upregulation of transcripts related to extracellular matrix and cell-matrix interactions. Upregulation of a number of major angiogenetic factors confirms previous observations that HUVECs enter a proangiogenic state upon cocultivation with osteoblasts. Interestingly, the downregulated transcripts clustered predominantly around cell cycle-related processes. The microarray data were confirmed by quantitative real-time RT-PCR on selected genes. Taken together, this study provides a platform for further inquiries in complex interactions between endothelial cells and osteoblasts.

[A 75-year-old female patient with pleural effusion and gastric metastases of a poorly differentiated carcinoma]

A 75-year-old woman was found to have left-sided pleural effusion and endoscopy revealed the rare entity of adenoid cystic carcinoma metastases in the gastric mucosa. Approximately 20% of patients with this carcinoma suffer from distant metastases. For the initial staging detection of adenoid cystic carcinoma metastasis with positron emission tomography (PET) or PET computed tomography (CT) is recommended. The recurrent t(6;9)(q22-23;p23-24) translocation that results in a fusion of the two transcription factor genes MYB and NFIB is detectable in half of the cases. As in our case molecular pathology can confirm the correct diagnosis and identification of the localization of the primary tumor.

Imaging of chronic inflammatory bowel disease with 18F-FDG PET in children and adolescents

Standard for diagnosis of inflammatory bowel disease (IBD) is the endoscopy of the stomach and the intestine. Aim of this study was to determine the value of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in pediatric patients with mild to moderate IBD.We included 23 children and adolescents between 8 and 17 years (median 15 years, 13 boys, 10 girls) in this retrospective study in a routine clinical setting. Diagnoses were Crohn's disease in 19 and ulcerative colitis in 4 cases.3 children had a conventional FDG-PET, 20 patients a combined FDG-PET-computed tomography exam. All children had upper and lower intestinal endoscopy with biopsy and a Hydro-MRI exam to assess the jejunum and proximal ileum. The gastrointestinal tract was divided in 7 segments: Stomach plus duodenum, jejunum and proximal ileum, terminal ileum, cecum plus ascending colon, transverse colon, descending colon, and rectosigmoid.Superficial gastric lesions were missed, gastric ulcerations were detected. For the stomach, the sensitivity was 0.25, the specificity was 1.00, the positive predictive value was 1.00, for the lower intestine (terminal ileum and colon) the values were 0.74, 0.88, and 0.96; for the terminal ileum 0.89, 0.75 and 0.94, respectively.The sensitivity and specificity for of ileal and colonic lesions is high. FDG-PET has to be discussed as a tool for the determination of extent and degree of inflammation, especially in those parts of the small bowel that are not accessible to endoscopy. This has to be weighed against the additional radiation exposure administrated.

16(th) IHIW: global analysis of registry HLA haplotypes from 20 million individuals: report from the IHIW Registry Diversity Group

This project has the goal to validate bioinformatics methods and tools for HLA haplotype frequency analysis specifically addressing unique issues of haematopoietic stem cell registry data sets. In addition to generating new methods and tools for the analysis of registry data sets, the intent is to produce a comprehensive analysis of HLA data from 20 million donors from the Bone Marrow Donors Worldwide (BMDW) database. This report summarizes the activity on this project as of the 16IHIW meeting in Liverpool.

Ex vivo fucosylation improves human cord blood engraftment in NOD-SCID IL-2Rγ(null) mice

Delayed engraftment remains a major hurdle after cord blood (CB) transplantation. It may be due, at least in part, to low fucosylation of cell surface molecules important for homing to the bone marrow microenvironment. Because fucosylation of specific cell surface ligands is required before effective interaction with selectins expressed by the bone marrow microvasculature can occur, a simple 30-minute ex vivo incubation of CB hematopoietic progenitor cells with fucosyltransferase-VI and its substrate (GDP-fucose) was performed to increase levels of fucosylation. The physiologic impact of CB hematopoietic progenitor cell hypofucosylation was investigated in vivo in NOD-SCID interleukin (IL)-2Rγ(null) (NSG) mice. By isolating fucosylated and nonfucosylated CD34(+) cells from CB, we showed that only fucosylated CD34(+) cells are responsible for engraftment in NSG mice. In addition, because the proportion of CD34(+) cells that are fucosylated in CB is significantly less than in bone marrow and peripheral blood, we hypothesize that these combined observations might explain, at least in part, the delayed engraftment observed after CB transplantation. Because engraftment appears to be correlated with the fucosylation of CD34(+) cells, we hypothesized that increasing the proportion of CD34(+) cells that are fucosylated would improve CB engraftment. Ex vivo treatment with fucosyltransferase-VI significantly increases the levels of CD34(+) fucosylation and, as hypothesized, this was associated with improved engraftment. Ex vivo fucosylation did not alter the biodistribution of engrafting cells or pattern of long-term, multilineage, multi-tissue engraftment. We propose that ex vivo fucosylation will similarly improve the rate and magnitude of engraftment for CB transplant recipients in a clinical setting.

Imaging long-term fate of intramyocardially implanted mesenchymal stem cells in a porcine myocardial infarction model

The long-term fate of stem cells after intramyocardial delivery is unknown. We used noninvasive, repetitive PET/CT imaging with [(18)F]FEAU to monitor the long-term (up to 5 months) spatial-temporal dynamics of MSCs retrovirally transduced with the sr39HSV1-tk gene (sr39HSV1-tk-MSC) and implanted intramyocardially in pigs with induced acute myocardial infarction. Repetitive [(18)F]FEAU PET/CT revealed a biphasic pattern of sr39HSV1-tk-MSC dynamics; cell proliferation peaked at 33-35 days after injection, in periinfarct regions and the major cardiac lymphatic vessels and lymph nodes. The sr39HSV1-tk-MSC-associated [(18)F]FEAU signals gradually decreased thereafter. Cardiac lymphography studies using PG-Gd-NIRF813 contrast for MRI and near-infrared fluorescence imaging showed rapid clearance of the contrast from the site of intramyocardial injection through the subepicardial lymphatic network into the lymphatic vessels and periaortic lymph nodes. Immunohistochemical analysis of cardiac tissue obtained at 35 and 150 days demonstrated several types of sr39HSV1-tk expressing cells, including fibro-myoblasts, lymphovascular cells, and microvascular and arterial endothelium. In summary, this study demonstrated the feasibility and sensitivity of [(18)F]FEAU PET/CT imaging for long-term, in-vivo monitoring (up to 5 months) of the fate of intramyocardially injected sr39HSV1-tk-MSC cells. Intramyocardially transplanted MSCs appear to integrate into the lymphatic endothelium and may help improve myocardial lymphatic system function after MI.

Ex vivo graft purging and expansion of autologous blood progenitor cell products from patients with multiple myeloma

Autologous peripheral blood progenitor cell (PBPC) transplantation is the treatment of choice for selected myeloma patients. However, tumor cells contaminating the apheresis product are a potential source of relapse. Here we report a sequential purging strategy targeting mature and immature clonogenic myeloma cell populations in the autograft. Thawed PBPC products of myeloma patients were treated with rituximab to kill CD138(-)20(+) B cells (highly clonogenic immature cells), and bortezomib to target CD138(+) cells (normal and differentiated myeloma plasma cells), followed by coculture with allogeneic mesenchymal stem cells (MSC) from normal donors. After 7 days of coculture, nonadherent cells were removed and cultured in the absence of MSC for an additional 7 days. Then, efficacy of purging (removal of CD138(-)20(+) and CD138(+) cells) was assessed by flow cytometry and PCR. We used our ex vivo purging strategy to treat frozen aphereses from 16 patients. CD138(+) and CD138(-)20(+)(19(+)) cells present in the initial products were depleted more than 3 and 4 logs, respectively based on 10(6) flow-acquisition events, and to levels below the limit of detection by PCR. In contrast, total nucleated cell (TNC), CD34(+) cell, and colony-forming cell numbers were increased by approximately 12 to 20, 8-, and 23-fold, respectively. Overall, ex vivo treatment of apheresis products with rituximab, bortezomib, and coculture with normal donor MSC depleted mature and immature myeloma cells from clinical aphereses while expanding the normal hematopoietic progenitor cell compartment.

MicroRNA regulation of helper T cell cytokine production and proliferation (109.29)

MicroRNAs have been implicated as important regulators of many aspects of immune cell function. We and others have previously shown that deletion of the microRNA biogenesis enzymes Dicer and Drosha from T cells results in abnormal cytokine production and decreased proliferation of CD4+ T cells ex vivo. However, the role of individual miRNAs in this phenotype remains poorly understood. We conducted a screen for miRNA function in primary T cells and report the identification of individual miRNAs that can independently rescue the defects of miRNA-deficient helper T cells. Multiple members of the miR-17 and miR-92 families rescued proliferation while miR-29 rescued the aberrant IFN-γ expression by these cells. Repression of IFN-γ by miR-29 involved the regulation of both T-bet and Eomes, two transcription factors known to induce IFN-γ production. These results represent a novel screening strategy for miRNA function in primary T cells and further demonstrate the impressive regulatory capability of individual miRNAs in the immune system.

Noninvasive bioluminescent imaging demonstrates long-term multilineage engraftment of ex vivo-expanded CD34-selected umbilical cord blood cells

The use of umbilical cord blood (UCB) grafts for hematopoietic stem cell transplantation (HSCT) is a promising technique that permits a degree of human leukocyte antigen mismatch between the graft and the host without the concomitant higher rate of graft-versus-host disease that would be observed between an adult marrow graft and a mismatched host. A disadvantage to the use of UCB for HSCT is that immune reconstitution may be significantly delayed because of the low stem cell dose available in the graft. Ex vivo expansion of UCB CD34 cells would provide a greater number of stem cells; however, there are persistent concerns that ex vivo-expanded CD34 cells may lose pluripotency and the ability to contribute meaningfully to long-term engraftment. To address this issue, we transduced CD34-selected UCB cells with a lentiviral construct expressing luciferase, and determined homing and engraftment patterns in vivo by noninvasive bioluminescent imaging in sublethally irradiated NOD/SCID/IL-2Rgamma(-/-) (NSG) mice. Graft contribution to multilineage commitment was also confirmed by analysis of primary and secondary transplants by flow cytometry and immunohistochemistry. Our results demonstrate that, other than a mild delay at the onset of engraftment, there were no significant differences in lineage repopulation or in long-term or secondary engraftment between culture-expanded and unexpanded UCB CD34-selected cells. The results suggest that multipotent stem cells can be expanded ex vivo and can contribute meaningfully to long-term hematopoietic engraftment.

CD3(+) and/or CD14(+) depletion from cord blood mononuclear cells before ex vivo expansion culture improves total nucleated cell and CD34(+) cell yields

Cord blood (CB) is used increasingly in transplant patients lacking sibling or unrelated donors. A major hurdle in the use of CB is its low cell dose, which is largely responsible for an elevated risk of graft failure and a significantly delayed neutrophil and platelet engraftment. As a positive correlation has been shown between the total nucleated cell (TNC) and CD34(+) cell dose transplanted and time to neutrophil and platelet engraftment, strategies to increase these measures are under development. One strategy includes the ex vivo expansion of CB mononuclear cells (MNC) with MSC in a cytokine cocktail. We show that this strategy can be further improved if CD3(+) and/or CD14(+) cells are first depleted from the CB MNC before ex vivo expansion. Ready translation of this depletion strategy to improve ex vivo CB expansion in the clinic is feasible as clinical-grade devices and reagents are available. Ultimately, the aim of improving TNC and CD34(+) transplant doses is to further improve the rate of neutrophil and platelet engraftment in CB recipients.

Repetitive noninvasive monitoring of HSV1-tk-expressing T cells intravenously infused into nonhuman primates using positron emission tomography and computed tomography with 18F-FEAU

Adoptive transfer of antigen-specific cytotoxic T lymphocytes (CTLs) has been successfully used to treat patients with different types of cancer. However, the long-term spatial-temporal dynamics of the distribution of systemically infused CTLs remains largely unknown. Noninvasive imaging of adoptively transferred CTLs using molecular-genetic reporter imaging with positron emission tomography and computed tomography (PET-CT) represents an innovative approach to understanding the long-term migratory patterns and therapeutic potential of adoptively transferred T cells. Here we report the application of repetitive PET-CT imaging with [18F]fluoro-5-ethyl-1-beta-D-arabinofuranosyluracil (18F-FEAU) in two nonhuman primates demonstrating that autologous polyclonal macaque T lymphocytes activated and transduced with a retroviral vector encoding for the sr39 mutant herpes simplex virus 1 thymidine kinase (sr39HSV1-tk) reporter gene can be detected after intravenous infusion in discrete lymphoid organs and in sites of inflammation. This study represents a proof of principle and supports the application of 18F-FEAU PET-CT imaging for monitoring the distribution of intravenously administered sr39HSV1-tk gene-transduced CTLs in humans.

Th-1 polarization is regulated by dendritic-cell comparison of MHC class I and class II antigens

In the control of T-helper type I (Th-1) polarization, dendritic cells (DCs) must interpret a complex array of stimuli, many of which are poorly understood. Here we demonstrate that Th-1 polarization is heavily influenced by DC-autonomous phenomena triggered by the loading of DCs with antigenically matched major histocompatibility complex (MHC) class I and class II determinants, that is, class I and II peptide epitopes exhibiting significant amino acid sequence overlap (such as would be physiologically present during infectious processes requiring Th-1 immunity for clearance). Data were derived from 13 independent antigenic models including whole-cell systems, single-protein systems, and 3 different pairs of overlapping class I and II binding epitopes. Once loaded with matched class I and II antigens, these "Th-1 DCs" exhibited differential cytokine secretion and surface marker expression, a distinct transcriptional signature, and acquired the ability to enhance generation of CD8(+) T lymphocytes. Mechanistically, tRNA-synthetases were implicated as components of a putative sensor complex involved in the comparison of class I and II epitopes. These data provide rigorous conceptual explanations for the process of Th-1 polarization and the antigenic specificity of cognate T-cell help, enhance the understanding of Th-1 responses, and should contribute to the formulation of more effective vaccination strategies.

PTPN22 deficiency cooperates with the CD45 E613R allele to break tolerance on a non-autoimmune background

Pep and CD45 are tyrosine phosphatases whose targets include the Src-family kinases, critical mediators of Ag receptor signaling. A polymorphism in PTPN22, the gene that encodes the human Pep orthologue Lyp, confers susceptibility to multiple human autoimmune diseases in the context of complex genetic backgrounds. However, the functional significance of the R620W risk allele is not clear. We report that misexpression of wild-type or R620W Pep/Lyp in Jurkat cells, in the context of its binding partner Csk, unmasks the risk allele as a hypomorph. It has been shown previously that although Pep-deficient mice on the B6 background have hyperresponsive memory T cells, autoimmunity does not develop. Mice containing a point mutation in the CD45 juxtamembrane wedge domain (E613R) develop a B cell-driven, lupus-like disease on the mixed 129/B6 background, but not on the B6 background. We studied the ability of Pep deficiency to act as a genetic modifier of the CD45 E613R mutation on the nonautoimmune B6 background to understand how complex susceptibility loci might interact in autoimmunity. In this study we report that double mutant mice develop a lupus-like disease as well as lymphadenopathy, polyclonal lymphocyte activation, and accelerated memory T cell formation. Following Ag receptor stimulation, peripheral B cells in the double mutant mice phenocopy hyperresponsive CD45 E613R B cells, whereas peripheral T cells respond like Pep(-/-) T cells. These studies suggest that Pep(-/-) T cells in the context of a susceptible microenvironment can drive hyperresponsive CD45 E613R B cells to break tolerance.