Dynamic establishment of recipient resident memory T cell repertoire after human intestinal transplantation

BACKGROUND

Understanding formation of the human tissue resident memory T cell (TRM) repertoire requires longitudinal access to human non-lymphoid tissues.

METHODS

By applying flow cytometry and next generation sequencing to serial blood, lymphoid tissue, and gut samples from 16 intestinal transplantation (ITx) patients, we assessed the origin, distribution, and specificity of human TRMs at phenotypic and clonal levels.

FINDINGS

Donor age ≥1 year and blood T cell macrochimerism (peak level ≥4%) were associated with delayed establishment of stable recipient TRM repertoires in the transplanted ileum. T cell receptor (TCR) overlap between paired gut and blood repertoires from ITx patients was significantly greater than that in healthy controls, demonstrating increased gut-blood crosstalk after ITx. Crosstalk with the circulating pool remained high for years of follow-up. TCR sequences identifiable in pre-Tx recipient gut but not those in lymphoid tissues alone were more likely to populate post-Tx ileal allografts. Clones detected in both pre-Tx gut and lymphoid tissue had distinct transcriptional profiles from those identifiable in only one tissue. Recipient T cells were distributed widely throughout the gut, including allograft and native colon, which had substantial repertoire overlap. Both alloreactive and microbe-reactive recipient T cells persisted in transplanted ileum, contributing to the TRM repertoire.

INTERPRETATION

Our studies reveal human intestinal TRM repertoire establishment from the circulation, preferentially involving lymphoid tissue counterparts of recipient intestinal T cell clones, including TRMs. We have described the temporal and spatial dynamics of this active crosstalk between the circulating pool and the intestinal TRM pool.

FUNDING

This study was funded by the National Institute of Allergy and Infectious Diseases (NIAID) P01 grant AI106697.

Raine's syndrome: rare disease from neurosurgical perspective

Raine's syndrome (RS) is a rare genetic disorder. Only 25 cases are in literature. Occurs due to genetic mutation resulting in deranged bone metabolism. Few cases are reported discussing the neurosurgical ramifications of the disease. We report a child diagnosed with RS. He was presented with multisutural synostosis requiring craniofacial intervention with two vault expansions. Additionally, required VP shunt due to hydrocephalus. We consider our case unique among reports of RS, as our patient has survived for 10. He died due to valve obstruction of the VP shunt. We also present a review of relevant medical literature.

The Craniofacial Collaboration UK: Developmental Outcomes in 7- and 10-Year-Old Children With Metopic Synostosis

The Craniofacial Collaboration (CC-UK) is a shared initiative across the Psychology teams attached to 4 highly specialized craniofacial centers in the United Kingdom. The CC-UK aims to address key limitations in the existing craniofacial literature by analyzing data for homogenous samples of children with craniosynostosis. This article presents the fifth wave of CC-UK data collection, focused on 7- and 10-year olds who have undergone primary corrective surgery for metopic synostosis (MS). Data for children with sagittal synostosis and MS have previously been presented at 3 and 5 years. This paper continues to build on this with consideration to older age groups, presenting the first CC-UK analysis of cognitive assessment data using the Wechsler Abbreviated Scale of Intelligence-Second Edition. Results show that the majority of children with MS fall within the average ranges across behavioral and neurodevelopmental domains. However, several domains indicated a trend of heightened concern when compared with normative data, particularly for parent-reported outcomes, suggesting that there may be some subtle difficulties for children with MS. Consideration of how these findings compare with that of previous CC-UK analyses is explored. Further, implications for clinical practice and future research are considered, with the need for longitudinal analyses, as well as data from multiple perspectives (eg, school, parents, and self) at older age points to establish patterns over time. Through collaboration across the highly specialized craniofacial centers, the CC-UK hopes to work toward this goal moving forward.

Intracranial Empyemas in the COVID-19 Era: A New Phenomenon? A Paediatric Case Series and Review of the Literature

INTRODUCTION

We present the largest series of paediatric intracranial empyemas occurring after COVID-19 infection to date, and discuss the potential implications of the pandemic on this neurosurgical pathology.

METHODS

Patients admitted to our centre between January 2016 and December 2021 with a confirmed radiological diagnosis of intracranial empyema were retrospectively reviewed, excluding non-otorhinological source cases. Patients were grouped according to onset before or after onset of the COVID-19 pandemic and COVID-19 status. A literature review of all post-COVID-19 intracranial empyemas was performed. SPSS v27 was used for statistical analysis.

RESULTS

Sixteen patients were diagnosed with intracranial empyema: n = 5 prior to 2020 and n = 11 after, resulting in an average annual incidence of 0.3% prior to onset of the pandemic and 1.2% thereafter. Of those diagnosed since the pandemic, 4 (25%) were confirmed to have COVID-19 on recent PCR test. Time from COVID-19 infection until empyema diagnosis ranged from 15 days to 8 weeks. Mean age for post-COVID-19 cases was 8.5 years (range: 7-10 years) compared to 11 years in non-COVID cases (range: 3-14 years). Streptococcus intermedius was grown in all cases of post-COVID-19 empyema, and 3 of 4 (75%) post-COVID-19 cases developed cerebral sinus thromboses, compared to 3 of 12 (25%) non-COVID-19 cases. All cases were discharged home with no residual deficit.

CONCLUSION

Our post-COVID-19 intracranial empyema series demonstrates a greater proportion of cerebral sinus thromboses than non-COVID-19 cases, potentially reflecting the thrombogenic effects of COVID-19. Incidence of intracranial empyema at our centre has increased since the start of the pandemic, causes of which require further investigation and multicentre collaboration.

Anti-CD3 Mono-Fab co-potentiates TCR antigen recognition in human T cells

TCR mediated antigen recognition results in a signaling cascade leading to T cell activation. Antigen binding to its cognate TCR drives receptor aggregation and conformational changes that trigger signaling from the receptor. Conformational change in the CD3 complex (CD3Δc) is required for robust signaling and productive T cell responses. In contrast, weakly recognized antigens do not induce CD3Δc and the resulting T cell response is poor. Thus, T cell responses to weak antigens may be improved by induction of CD3Δc. We previously described an anti-mouse CD3ɛ monovalent Fab (Mono-7D6-Fab) that induced CD3Δc and synergized with weak antigens to enhance the T cell response, a process we termed co-potentiation. However, Mono-7D6-Fab did not induce classical T cell signaling in the absence of antigenic ligation. Mono-7D6-Fab effectively co-potentiated T cells against murine B16-F10 melanoma cells and reduced tumor burden in vivo in a T cell dependent manner. We exploited a model of human cytomegalovirus (CMV) to generate proof of concept that co-potentiation may enhance T cell antigen recognition in humans. Anti-human CD3ɛ monovalent Fab (Mono-OKT3-Fab) improved the CD8 T cell response to the CMV pp65495–503 peptide as measured by increased T cell proliferation, cytokine production, and the ability to kill target cells. Co-potentiation was dependent on antigen specificity, as 1) the effects were dampened when antigen recognition was impaired and 2) sequencing of the TCRs revealed a restricted number of expanded TCR clones. Our results suggest that Mono-OKT3-Fab may have therapeutic clinical applications to achieve a more robust antigen-specific T cell response in the context of diverse human disease, from cancer to chronic infection.

Anesthetic Considerations for Automated High-Frequency Jet Ventilation During Electromagnetic Navigation Bronchoscopy

Newly advanced diagnostic bronchoscopic procedures, such as electromagnetic navigation bronchoscopy using navigation system technology (superDimension, Medtronic), provides computed tomography referenced and computerized 3-dimensional imaging. To increase accuracy and higher diagnostic biopsy yield, electromagnetic navigation bronchoscopy necessitates special anesthetic and ventilation techniques providing the interventional pulmonologist minimal respiratory lung motion. This anesthetic meets 2 important goals by limiting almost all interference from diaphragmatic and lung movement while allowing the anesthesia provider to achieve hands-free management. Proposed here is an anesthetic ventilation technique by automated high-frequency jet ventilation (HFJV) via double-lumen micro jet endotracheal tubes. This ventilation technique delivers consistent very low tidal volumes. Automated HFJV provides the pulmonologist the advantage of more accurate navigation and target alignment in this Global Positioning System-guided biopsy procedure. The technique offers essentially no chest motion, without interrupting ventilation. Additionally, HFJV allows the anesthetist better availability to attend to total intravenous anesthesia, adjustments, and interventions. The intention of this article is to detail an anesthetic method that provides a hands-free technique that requires only one anesthesia provider.

Abstract B78: Co-potentiation of human T cells to identify subdominant tumor neoantigens from melanoma patients responding to immune checkpoint blockade

Malignant melanoma is the most aggressive form of skin cancer, accounting for 10,000 deaths annually. Largely resistant to conventional cytotoxic chemotherapy and radiation, immune checkpoint blockade (ICB) therapies have revolutionized patient care, accounting for partial or complete responses in up to 70% of patients. An important aspect of cancer elimination is activation of the cytotoxic T lymphocyte (CTL) response. Recent data suggest that ICB mediated broadening of the peripheral blood CTL repertoire correlates with good clinical outcomes. Thus, recent studies in cancer immunotherapy have focused on targeting tumor neoantigens (tNeoAg) with cancer vaccines for use in combination with ICB. Computational algorithm-driven predictions of immunogenic tNeoAgs yield vast numbers of potential peptide targets, only a fraction of which may be immunogenic in patients. This likely contributed to the modest success of cancer vaccines targeting predicted, high-avidity tNeoAgs, emphasizing the importance of identifying true tumor rejection antigens, including sub-dominant antigens, outside the scope of predictive models. In addition to promoting T cell-mediated tumor rejection, ICB often comes at the expense of treatment-induced immune-related adverse effects (irAE) that frequently require discontinuation of treatment. Modulation of ICB towards antitumor immunity and away from autoimmunity may dramatically improve the therapeutic index of modern cancer therapy. This appears feasible considering the clinical observation that antitumor efficacy does not correlate with type/severity of irAE, suggesting that the mechanisms of both processes, though likely related (CTL mediated), may not be identical. We aim to identify and separate non-cross-reacting antigenic targets mediating tumor rejection from those mediating irAEs to enable therapeutic interventions that maximize the efficacy of ICB, expanding tumor-specific CTLs with vaccines while minimizing irAEs through desensitization. We have access to samples from responding/nonresponding melanoma patients subjected to ICB with varying degrees of irAEs. We have designed an experimental approach that combines established mass spectrometry and sequencing techniques to identify peptides and matching TCR clones with a novel strategy that targets the TCR-associated CD3 complex to allow inclusion of subdominant antigens in our studies. T-cell “co-potentiation” is achieved when anti-CD3 monovalent Fabs induce a conformational change in the CD3 complex that sustains the T-cell response to weak antigenic stimulation. We have successfully used anti-human CD3 Fabs to co-potentiate in vitro the activation and subsequent response to weak peptide-HLA/TCR interactions of human T cells found in PBMCs isolated from healthy donors. Our preliminary data suggest T-cell co-potentiation may allow identification of ICB-induced CTL clones specific for subdominant tNeoAgs and irAE targets in patients with melanoma undergoing active immunotherapy.

Citation Format: Laura Elsbernd, Alfreda Nelson, Hien Huynh, Michele Hoffmann, Christopher Parks, Wendy Nevala, Shari Sutor, Larry Pease, Adam Schrum, Diana Gil, Svetomir N. Markovic. Co-potentiation of human T cells to identify subdominant tumor neoantigens from melanoma patients responding to immune checkpoint blockade [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B78.

Standardized Definitions of Bleeding After Transbronchial Lung Biopsy: A Delphi Consensus Statement From the Nashville Working Group

BACKGROUND

Transbronchial lung biopsies are commonly performed for a variety of indications. Although generally well tolerated, complications such as bleeding do occur. Description of bleeding severity is crucial both clinically and in research trials; to date, there is no validated scale that is widely accepted for this purpose. Can a simple, reproducible tool for categorizing the severity of bleeding after transbronchial biopsy be created?

METHODS

Using the modified Delphi method, an international group of bronchoscopists sought to create a new scale tailored to assess bleeding severity among patients undergoing flexible bronchoscopy with transbronchial lung biopsies. Cessation criteria were specified a priori and included reaching > 80% consensus among the experts or three rounds, whichever occurred first.

RESULTS

Thirty-six expert bronchoscopists from eight countries, both in academic and community practice settings, participated in the creation of the scale. After the live meeting, two iterations were made. The second and final scale was vetted by all 36 participants, with a weighted average of 4.47/5; 53% were satisfied, and 47% were very satisfied. The panel reached a consensus and proposes the Nashville Bleeding Scale.

CONCLUSIONS

The use of a simplified airway bleeding scale that can be applied at bedside is an important, necessary tool for categorizing the severity of bleeding. Uniformity in reporting clinically significant airway bleeding during bronchoscopic procedures will improve the quality of the information derived and could lead to standardization of management. In addition to transbronchial biopsies, this scale could also be applied to other bronchoscopic procedures, such as endobronchial biopsy or endobronchial ultrasound-guided needle aspiration.

FP2-3 Ten years of paediatric neuro-oncology surgery: quantifying and predicting complications after surgery for intracranial tumour excision

Objectives

To measure complications of paediatric neurooncology surgery using the Clavien Dindo grading scale, and identify predictors of surgical morbidity.

Design

Retrospective review of prospectively collected data.

Subjects

All paediatric patients treated with craniotomy for excision of intracranial tumour between 2008 and 2017 in a single tertiary paediatric neurosurgery centre.

Methods

Demographics, surgical details and perioperative complications were prospectively recorded between 0 and 30 days post operatively. These were retrospectively graded using the CD scale. Data analysis was done in R using logistic regression. Significance was defined as p<0.05

Results

Between 3/1/2008 and 21/12/2017 there were 322 operations, on 254 patients (142 Male). Median age at surgery was 9 years (IQR 4–13 years). 48% were without complication on the CD scale. Maximum CD grade complication for each procedure was 1 in 11%, 2 in 19%, 3A in 2%, 3B in 14%, and 4 in 0.6% of operations. 30 day mortality was 0.9%. CD grade of 3B or over was associated with infratentorial tumours (OR 2.24; CI 1.10–4.68; p=0.004) and WHO grade III tumours (OR 4.12; CI 1.56–10.86; p=0.028).

Conclusions

Complications in paediatric neurooncology surgery are common overall, but our results are favourable in comparison to the literature. The CD scale has limitations in neurosurgery but gives insight into the health economic impact of complications. Infratentorial tumours, and WHO grade III tumours were associated with increased morbidity.

TP1-10 Non tumour brain biopsies in alder hey paediatric neurosurgery

Objectives

To review the utility of non-tumour brain biopsies in Alder Hey Children’s NHS Foundation Trust Paediatric Neurosurgery Department.

Methods

Operative records were searched for ‘biopsy’. Case notes were reviewed for referral source, histology, surgical complication and outcome. Tumour, epilepsy and non-brain biopsy cases were excluded.

Results

83 ‘biopsy’ cases were identified between 2008 and 2017. 31 tumour, 5 epilepsy, 2 infections and 28 non brain/other biopsies were excluded. 17 brain biopsies for non-tumour causes were seen. 15 patients were referred by neurology, 2 by rheumatology. 14 underwent a craniotomy/mini-craniotomy, 3 had burrholes.4 biopsies were non diagnostic, 2 were abnormal but inconclusive for diagnosis. Diagnoses included: 3 demyelinating lesions, 2 normal brain tissue, 1 neurosarcoidosis, 1 autoimmune encephalitis, 1 definite Rasmussen’s Encephalitis, 1 possible Rasmussen’s Encephalitis, 1 systemic lupus erythematosus associated CNS vasculitis, 1 inflammatory infiltrate (secondary to hydrocephalus/ventriculitis), 1 patient developed a late wound infection. No other surgical morbidities/mortalities were recorded. 11 of these cases had a change in management or the treating team were reassured due to the result of the biopsy (i.e. were able to start immunomodulatory drugs in the absence of infection).

Conclusions

65% of brain biopsies were diagnostic. 71% of biopsies either changed management or reassured the treating team about a line of management. The procedure is low risk with 0.06% morbidity and 0% mortality.

P98 A decade of primary tumours of the spine in the paediatric population

Objectives

Primary spinal tumours in children are rare and poorly understood; we review 10 years of surgical experience.

Design

Retrospective review of prospectively maintained database.

Subjects

Children receiving surgical management of primary spinal tumours in a single, tertiary paediatric neurosurgery centre.

Methods

Operations for primary spinal tumours were abstracted from our prospectively maintained surgical database and supplemented with data from case notes, operative records, and imaging studies.

Results

Between 2008 and 2017, 37 procedures were performed on 29 patients (19 male; Median age 7.5 years, IQR 2–11.25). 28 had their primary procedure in our unit: 21 excisions, and 7 biopsies (of which 5 proceeded to further surgery). Tumours were classified as extradural (10), intradural extramedullary (3), intradural intramedullary (11) or bony (4). Tumours were found at the following levels: Cervical (8; 29%), Cervicothoracic (2; 7.1%), Thoracic (10; 36%), Thoracolumbar (3; 11%), Lumbar (2; 7.1%), Lumbosacral (2; 7.1%) and Sacral (1; 3.6%). Histology comprised: Pilocytic Astrocytoma (6), Other Astrocytoma (4), Schwannoma (3), Ewing Sarcoma (2), Langerhans cell histiocytosis (2), Lymphoma (2), Neurofibroma (2), and others (7) including one Myxopapillary Ependymoma.

Conclusions

The rarity and heterogeneity of paediatric spinal tumours makes treatment challenging. We propose a national online registry including a tissue bank, and invite collaboration with other units.

Investigation of age-adjusted D-dimer using an uncommon assay

BACKGROUND

Use of an age-adjusted D-dimer for the evaluation of acute pulmonary embolus (PE) has been prospectively validated in the literature and has become a practice recommendation from major medical societies. Most research on this subject involves the most common D-dimer assays reporting in Fibrinogen Equivalent Units (FEU) with a non-age-adjusted manufacturer-recommended cutoff of 500 ng/ml FEU. Limited research to date has evaluated age-adjustment in assays that report in D-Dimer Units (D-DU), which use a manufacturer-recommended cutoff of 230 ng/ml D-DU. Despite scant evidence, an age-adjusted formula using D-DU has been recently endorsed by the American College of Emergency Physicians (ACEP). This formula seems arbitrary in its derivation and unnecessarily deviates from existing thresholds, thus prompting the creation of our novel-age adjustment formula. The goal of this study was to retrospectively evaluate the test characteristics of our novel age-adjusted D-dimer formula using the D-DU assay in comparison to existing traditional and age-adjusted D-dimer thresholds for the evaluation of acute PE in the ED.

METHODS

This was a retrospective chart review at an academic quaternary health system with three EDs and 195,000 combined annual ED visits. Only patients with D-dimer testing and CT PE protocol (CTPE) imaging were included. Admission and discharge diagnosis codes were used to identify acute PE. Outcome measures were sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of an unadjusted traditional threshold (230) compared with both novel and ACEP-endorsed age adjusted thresholds, (Age × 5) - 20 and Age × 5 if >50, respectively. Estimates with their exact 95% threshold were performed.

RESULTS

4846 adult patients were evaluated from January 2012 to July 2017. Group characteristics include a mean age of 52 and a frequency of acute PE diagnosis by CTPE of 8.25%. Traditional D-dimer cutoff demonstrated a sensitivity of 99.8% (95% CI 98.6-100), specificity of 16.7% (95% CI 15.6-17.8) and NPV of 99.9% (95% CI 99.3-100). Our novel age-adjusted D-dimer thresholds had a sensitivity of 97.0% (95% CI 94.8-98.4), specificity of 27.9% (95% CI 26.6-29.2) and NPV of 99.0% (95% CI 98.3-99.5) with the ACEP-endorsed formula demonstrating similar test characteristics.

CONCLUSION

Use of an age-adjusted D-dimer on appropriately selected patients being evaluated for acute PE in the ED with a D-DU assay increases specificity while maintaining a high sensitivity and NPV. Both our novel formula and the ACEP-endorsed age-adjusted formula performed well, with our novel formula showing a trend towards improved testing characteristics.

Bacterially expressed HIV-1 gp120 outer-domain fragment immunogens with improved stability and affinity for CD4-binding site neutralizing antibodies

Protein minimization is an attractive approach for designing vaccines against rapidly evolving pathogens such as human immunodeficiency virus, type 1 (HIV-1), because it can help in focusing the immune response toward conserved conformational epitopes present on complex targets. The outer domain (OD) of HIV-1 gp120 contains epitopes for a large number of neutralizing antibodies and therefore is a primary target for structure-based vaccine design. We have previously designed a bacterially expressed outer-domain immunogen (OD_EC) that bound CD4-binding site (CD4bs) ligands with 3-12 μm affinity and elicited a modest neutralizing antibody response in rabbits. In this study, we have optimized OD_EC using consensus sequence design, cyclic permutation, and structure-guided mutations to generate a number of variants with improved yields, biophysical properties, stabilities, and affinities (K_D of 10-50 nm) for various CD4bs targeting broadly neutralizing antibodies, including the germline-reverted version of the broadly neutralizing antibody VRC01. In contrast to OD_EC, the optimized immunogens elicited high anti-gp120 titers in rabbits as early as 6 weeks post-immunization, before any gp120 boost was given. Following two gp120 boosts, sera collected at week 22 showed cross-clade neutralization of tier 1 HIV-1 viruses. Using a number of different prime/boost combinations, we have identified a cyclically permuted OD fragment as the best priming immunogen, and a trimeric, cyclically permuted gp120 as the most suitable boosting molecule among the tested immunogens. This study also provides insights into some of the biophysical correlates of improved immunogenicity.

In-vivo stiffness assessment of distal femur fracture locked plating constructs

BACKGROUND

The purpose of this study was to design and validate a novel stiffness-measuring device using locked plating of distal femur fractures as a model.

METHODS

All patients underwent a laterally-based approach, with a bridging locked construct after indirect reduction. A custom and calibrated intraoperative stiffness device was applied and the stiffness of the construct was blindly recorded. Fourteen of twenty-seven patients enrolled with distal femur fractures (AO/OTA 33A and 33C) completed the study. Correlations between stiffness and callus formation, working length, working length/plate length ratio, number of distal locking screws, and fracture pattern were explored.

FINDINGS

Callus and modified radiographic union scale in tibias scores as a linear function of stiffness did not correlate (R2 = 0.06 and 0.07, respectively). Construct working length and working length to plate length ratio did not correlate to stiffness (R2 = 0.18 and 0.16 respectively). A combined delayed and nonunion rate was 14%. Lower extremity measure scores were not statistically different when comparing delayed and nonunion with healed fractures.

INTERPRETATION

The lack of correlation may have been due to the mechanical properties of the plate itself and its large contribution to the overall stiffness of the construct. To our knowledge, clinically relevant stiffness has not been described and this study may provide some estimates. This methodology and these preliminary findings may lay the groundwork for further investigations into this prevalent clinical problem. Other parameters not investigated may play a key role such as body mass index and bone mineral density.

LEVEL OF EVIDENCE

Diagnostic/Prognostic Level II.

Football-Related Pediatric Extremity Fractures and Dislocations: Size Matters

Football remains a popular sport in the United States despite sometimes significant injuries, such as fractures and dislocations, occurring. The objective of this study was to evaluate pediatric extremity fractures and dislocations related to football. A retrospective review was conducted at a level 1 pediatric trauma center to identify patients who were treated specifically for American football-related injuries (International Classification of Diseases, Ninth Revision, code E007.0). All patients with football-related injuries presenting to the emergency department during a 6-year period (2007-2012) were reviewed for inclusion in the study. Patients with only fractures or dislocations involving the extremities were analyzed. Exclusion criteria included patients older than 18 years, non-football-related sports-related injuries, and patients presenting to non-emergency department health care facilities. Demographic information was collected in addition to type of injury, body mass index, and type of treatment. A total of 193 patients with 96 fractures and 7 dislocations were included. More than two-thirds of all fractures occurred in the lower extremities, with tibia (17.0%) and femoral shaft (14.2%) fractures being the most common. Thirty-five percent of the fractures and dislocations required operative treatment. No statistically significant correlations were identified pertaining to age, race, and timing of the injuries in the season. Regarding body mass index, underweight patients were associated with 3.6 times greater odds of sustaining a fracture when compared with patients who were not underweight (P=.006). Underweight patients may be at a higher risk for fractures or dislocations. Identifying at-risk children may result in improved patient and coach education, potentially leading to better preventive measures and fewer injuries. [Orthopedics. 2018; 41(4):216-221.].

Recent Enhancements to Interline and Electron Multiplying CCD Image Sensors

This paper describes recent process modifications made to enhance the performance of interline and electron-multiplying charge-coupled-device (EMCCD) image sensors. By use of MeV ion implantation, quantum efficiency in the NIR region of the spectrum was increased by 2×, and image smear was reduced by 6 dB. By reducing the depth of the shallow photodiode (PD) implants, the photodiode-to-vertical-charge-coupled-device (VCCD) transfer gate voltage required for no-lag operation was reduced by 3 V, and the electronic shutter voltage was reduced by 9 V. The thinner, surface pinning layer also resulted in a reduction of smear by 4 dB in the blue portion of the visible spectrum. For EMCCDs, gain aging was eliminated by providing an oxide-only dielectric under its multiplication phase, while retaining the oxide-nitride-oxide (ONO) gate dielectrics elsewhere in the device.

Breast cancer and incidence of non-caseating granulomas diagnosed in PET avid chest lymphadenopahy

e12549

Background: Breast cancer is known to metastasize to the lung parenchyma and lymph nodes. Most breast malignancies are clinically staged using radiographic modalities (e.g. PET scans). Importantly, several inflammatory disorders will present lymph node FDG-uptake on PET, which can be mistaken for breast cancer metastasis. This may alter staging and implicitly treatment for individuals within whom both undiagnosed autoimmune disorders and breast cancer co-occur. We aim to examine the frequency of non-caseating granulomas diagnosed in PET avid mediastinal/hilar nodes in patients with known breast cancer. Methods: Between March 2013 and December 2015, 46 women diagnosed with breast cancer were staged by PET-CT. Those with positive result in the mediastinum/hilum underwent linear endobronchial ultrasound (EBUS) for pathologic diagnosis and ensuing treatment Results: Of the 46 patients with avid mediastinal/hilar adenopathy, 31 (67%) had malignant cytology on EBUS; the remaining 15 had positive PET but negative cytology for malignancy. Twelve of the 15 patients with false positive PET had reactive lymph nodes, and 3 had non-caseating granulomas on cytology (see table). Twenty percent of the patients with negative cytology and positive PET had non-caseating granuloma, and 6.5 % of all patients with positive PET had non-caseating granulomas. Conclusions: To our knowledge, this study represents the largest cohort of breast cancer patients, where the incidence of non-caseating granulomas is investigated in PET-positive mediastinal/hilar nodes. We conclude that in selected patients, in addition to imaging, pathologic staging should be done. Also, the finding of non-caseating granulomas in these patients may either indicate an incidental diagnosis of early stage sarcoidosis, or an inflammatory reaction to the current treatment (sarcomatoid reaction). We also suggest that these patients should be followed for any manifestations of sarcoidosis. [Table: see text]

Management of Chiari I malformation in children: effectiveness of intra-operative ultrasound for tailoring foramen magnum decompression

PURPOSE

Patients with Chiari I malformation (CM-1) commonly undergo foramen magnum decompression (FMD). However, there is no consensus on how this should be achieved. An approach would be to rationalize surgical steps based on pre-operative imaging and intra-operative findings. The aim of this study is to assess the usefulness of intra-operative ultrasound scanning (IOUS) in tailoring foramen magnum decompression in children with CM-1 and whether the use of IOUS is effective in reducing the risk of complications without increasing the need for re-operation.

METHOD

We performed a retrospective study. IOUS was utilized during FMD: a subjective assessment was made on whether there was adequate cerebellar tonsillar and/or CSF pulsation following suboccipital craniectomy. If there was adequate pulsation, the dura was not opened. Additional data were collected including age and gender of patients, presence of pre-operative syringomyelia, intra-operative ultrasound findings, length of follow-up, complications and radiological and clinical outcome. The statistical analysis was performed with XLStat®(Addinsoft SARL™, France).

RESULTS

Nineteen patients underwent FMD from June 2011 to December 2012. The mean age was 10.5 years; there were nine females and ten males. Eleven patients had syringomyelia at diagnosis. Based on IOUS, eight patients underwent dural decompression and 11 patients bony decompression only. One patient had a post-operative pseudomeningocoele and two patients required re-operation. There was no significant statistical difference between the two groups regarding post-operative improvement in the syrinx.

CONCLUSION

We found that tailoring FMD for patients with CM-1 using intra-operative findings using ultrasound scan was useful in avoiding unnecessary manoeuvres, while not compromising on the outcome.

Activating self-tolerant T cells with altered structure of MHC class I (TUM2P.1024)

Self-tolerant T cells can cross-react weakly on self, but are usually incapable of activation. However, when activated these T cells can cross-react effectively on cells expressing self antigens. We have observed that mutants of the MHC class I molecule H2-Kb have structural differences resulting in altered antigen presentation. We hypothesize that structural manipulation of MHC class I can increase stabile amino acid contacts with the TCR. Increasing stabile contacts may decrease the energy barrier required to overcome the threshold for activation, breaking tolerance for self antigens. Using computer modeling techniques, amino acid substitutions at specific sites of MHC class I were predicted to result in stabilization of the TCR:pMHC complex. These altered MHC molecules were made and expressed in cell lines. We have shown that altered MHC enhanced TCR binding. Altered MHC enhanced activation and proliferation of naïve T cells in response to a non-stimulatory, weak antigen. Altered MHC also induced CTL killing against self-antigens. In an in vivo transplant model, protective immunity was induced against a native tumor after an altered MHC expressing tumor challenge. By altering the structure of MHC class I we have activated normally tolerant T cells that are capable of cross-reacting on self.

A monomeric fab fragment capable of inducing CD3 conformational change increases T cell receptor reactivity to poorly immunogenic antigens (TUM2P.1020)

TCR interactions with agonist pMHCs induce a conformational change in the tails of the associated CD3 complex (CD3Δc) that contributes to efficient TCR/CD3 triggering and productive T cell responses. In contrast, TCR engagement by antagonistic pMHCs does not induce either CD3Δc or full TCR/CD3 signaling in mature T cells. Here, we have used a monovalent Fab fragment (Mono-Fab) specific for the murine CD3 complex to provide induction of CD3Δc to mature T cells engaging pMHC ligands. This Mono-Fab does not interfere with TCR capacity to bind pMHC and fails to elicit signaling in the absence of TCR/MHC interactions. Using OT-I Tg T cells and a collection of altered peptide ligands derived of the agonist peptide OVA, we show that addition of CD3Δc to OT-I T cells using Mono-Fab enables T cell responses to antagonist ligands that fail to induce CD3Δc on their own. Moreover, using a mouse model of metastatic melanoma, we show that Mono-Fab promotes in vivo T cell dependent anti-melanoma responses that are antigen-specific. This Mono-Fab can also be combined with established therapies targeting signals 2 and 3 involved in T cell activation for a synergistic effect. Our data suggests that in-trans CD3Δc provision decreases the activation threshold of T cells. We propose that targeting the CD3 complex for the induction of CD3Δc could be exploited to achieve efficient TCR/CD3 triggering by poorly immunogenic antigens in the context of vaccination against cancer and infectious diseases.

Accessory limb with myelomeningocele: a rare case challenging previously held beliefs

INTRODUCTION

There have been previous reports of intra-scapular limbs associated with a closed spina bifida and this has led to a causative theory. It is thought that these dysraphic appendages could not occur with defects of primary neurulation.

CASE

The authors present a rare case of this abnormality associated with a large open myelomeningocele in a 6-day-old infant presenting to a paediatric neurosurgical hospital in Uganda. The appendage was removed and the spina bifida closed. There was significant stigma associated with such abnormality in this region.

DISCUSSION

The first reported co-existence of these two lesions challenges previously held beliefs regarding the embryological origin of intra-scapular dysraphic appendage.

Cerebellopontine angle oligodendroglioma in a child: first case report

The reported incidence of oligodendrogliomas in the paediatric population is less than 1 %. The posterior fossa is a rare location, with the vast majority arising in the cerebral hemispheres. We report the first paediatric case of a WHO grade II oligodendroglioma arising in the cerebellopontine angle (CPA). CPA oligodendrogliomas in children appear to behave aggressively and adjuvant therapy must be considered early; especially when complete resection cannot be achieved.

A role for CD3 conformation in the preTCR/CD3 complex (P4428)

Mature T cells recognize and respond to antigens through the T cell antigen receptor (TCR). We have established that upon TCR antigenic engagement, the TCR/CD3 complex undergoes a conformational change (CD3dc) of its CD3 epsilon tails to expose a proline-rich sequence and allow downstream signaling to occur. CD3dc has been shown to be required for full TCR/CD3 signaling and function of mature T cells. Pre-TCR assembly with the CD3 complex serves as a developmental checkpoint that ensures the expression of a function variant TCRβ chain in thymocytes. Interestingly, stimulation of the preTCR complex has been found to be ligand-independent; assembly is sufficient. Knowing this, we first determined the stoichiometry of the preTCR/CD3 complex and asked the question, how does assembly impact its ability to undergo conformational change? To answer this question, we employed various novel biochemical methods developed in our laboratory including a flow-cytommetry based immunoprecipitation (IP-FCM) as well as a CD3-pull down assay (CD3-PD). We aim to study the conformation of CD3 in the preTCR/CD3 complex and establish whether or not the assembly of this receptor is enough to induce the active CD3 conformation that supports functional CD3 signaling in mature cells. With our data, we are further able to characterize previously unstudied requirements for CD3 conformational change in the preTCR/CD3 complex with the potential of using this knowledge to manipulate CD3dc in the future.

A case for research consortia to accelerate vaccine candidate discovery: identification of a stable antigenic HIV-1 Clade A Env candidate (P6370)

IAVI’s NAC provides a multi-disciplinary platform to decipher the interaction of bNAbs with HIV Env and accelerate translation to development of vaccines capable of eliciting potent neutralizing abs. Recent successes highlight the value of a consortium to expedite progress. IAVI initiated Protocol G to identify neutralizing sera from HIV-1 infected patients. Using these samples, a cross-disciplinary team discovered abs with unprecedented potency against HIV. PG9 was isolated from a subject infected with HIV-1 clade A. Consortium members reasoned that Env sequences from the clade A infected donor could lead to immunogen discovery. Using bioinformatics, MRCA sequence was aligned with 99 subtype A gp160 sequences from the Los Alamos HIV database and BG505 was identified with the highest homology. Soluble BG505 retains features of native trimer. While native Env trimer is the target for bnAbs, its instability impedes efforts to develop recombinant Env. Because BG505 retains features of native trimer, it might be optimal for immunogen design. NAC partners report construction of a soluble trimer from BG505 that binds PG9 with high affinity and show it is uniquely stable. Formulations of gp120 and trimers are under analysis for immunogenicity. Challenges remain in development including analysis of structure, immunogenicity, ab responses elicited; and production for human testing. A consortium approach of multidisciplinary experience will be required to expedite advancement of vaccine concepts.

Safety of pacemakers and defibrillators in electromagnetic navigation bronchoscopy

BACKGROUND

Electromagnetic Navigation Bronchoscopy (ENB) (InReach iLogic system; superDimension Inc) is a relatively new discipline, with promising diagnostic and therapeutic applications in patients with lung lesions. Navigation is performed in a magnetic field and, therefore, has been considered relatively contraindicated in patients with pacemakers and automated implantable cardioverter-defibrillators (AICDs). Potential risks include altering the function and shutting off the device, device damage, lead displacement, and potential overheating. Over the past decade, there has been extensive literature about the safety of pacemakers in either the 1.5-T or 3-T magnetic fields used in current MRI scanners. Although the magnetic field used in ENB is significantly weaker, 0.0001 T or approximately equal to the earth's gravity, its safety in patients with pacemakers is yet to be elucidated. We present our initial experience with ENB in patients with cardiac implanted electrical devices.

METHODS

Twenty-four procedures in 24 patients with lung lesions and permanent pacemakers were performed. A cardiac electrophysiologist and programmer were present during the procedure. At baseline, the pacers were interrogated, and ECG was recorded. Continuous cardiac monitoring was performed during the procedure, and at the end, the pacer settings and function were reinterrogated to check for any changes.

RESULTS

The procedures were all successfully concluded. None of the patients suffered any arrhythmias or disruption to their pacemakers' function.

CONCLUSION

ENB appears to be safe when performed in patients with pacemakers and AICDs. Larger multicenter studies are needed to prove the final safety in this patient population.

Can the prognosis of individual patients with glioblastoma be predicted using an online calculator?

BACKGROUND

In an exploratory subanalysis of the European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada (EORTC/NCIC) trial data, Gorlia et al. identified a variety of factors that were predictive of overall survival, including therapy administered, age, extent of surgery, mini-mental score, administration of corticosteroids, World Health Organization (WHO) performance status, and O-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. Gorlia et al. developed 3 nomograms, each intended to predict the survival times of patients with newly diagnosed glioblastoma on the basis of individual-specific combinations of prognostic factors. These are available online as a "GBM Calculator" and are intended for use in patient counseling. This study is an external validation of this calculator.

METHOD

One hundred eighty-seven patients from 2 UK neurosurgical units who had histologically confirmed glioblastoma (WHO grade IV) had their information at diagnosis entered into the GBM calculator. A record was made of the actual and predicted median survival time for each patient. Statistical analysis was performed to assess the accuracy, precision, correlation, and discrimination of the calculator.

RESULTS

The calculator gives both inaccurate and imprecise predictions. Only 23% of predictions were within 25% of the actual survival, and the percentage bias is 140% in our series. The coefficient of variance is 76%, where a smaller percentage would indicate greater precision. There is only a weak positive correlation between the predicted and actual survival among patients (R(2) of 0.07). Discrimination is inadequate as measured by a C-index of 0.62.

CONCLUSIONS

The authors would not recommend the use of this tool in patient counseling. If departments were considering its use, we would advise that a similar validating exercise be undertaken.

Electromagnetic navigation bronchoscopy

In 2009, lung cancer was estimated to be the second most common form of cancer diagnosed in men, after prostate, and the second, after breast cancer, in women. It is estimated that it caused 159,390 deaths more than breast, colon and prostate cancers combined. While age-adjusted death rates for this cancer have been declining since 2000, they remain high.