Multiparametric MRI-based 5-year Risk Prediction Model for Biochemical Recurrence of Prostate Cancer after Radical Prostatectomy

Background Current predictive tools to estimate the risk of biochemical recurrence (BCR) after treatment of prostate cancer do not consider multiparametric MRI (mpMRI) information. Purpose To develop a risk prediction tool that considers mpMRI findings to assess the risk of 5-year BCR after radical prostatectomy. Materials and Methods In this retrospective single-center analysis in 1459 patients with prostate cancer who underwent mpMRI before radical prostatectomy (in 2012-2015), the outcome of interest was 5-year BCR (two consecutive prostate-specific antigen [PSA] levels > 0.2 ng/mL [0.2 µg/L]). Patients were randomly divided into training (70%) and test (30%) sets. Kaplan-Meier plots were applied to the training set to estimate survival probabilities. Multivariable Cox regression models were used to test the relationship between BCR and different sets of exploratory variables. The C-index of the final model was calculated for the training and test sets and was compared with European Association of Urology, University of California San Francisco Cancer of the Prostate Risk Assessment, Memorial Sloan-Kettering Cancer Center, and Partin risk tools using the partial likelihood ratio test. Five risk categories were created. Results The median duration of follow-up in the whole cohort was 59 months (IQR, 32-81 months); 376 of 1459 (25.8%) patients had BCR. A multivariable Cox regression model (referred to as PIPEN, and composed of PSA density, International Society of Urological Pathology grade group, Prostate Imaging Reporting and Data System category, European Society of Urogenital Radiology extraprostatic extension score, nodes) fitted to the training data yielded a C-index of 0.74, superior to that of other predictive tools (C-index 0.70 for all models; P ≤ .01) and a median higher C-index on 500 test set replications (C-index, 0.73). Five PIPEN risk categories were identified with 5-year BCR-free survival rates of 92%, 84%, 71%, 56%, and 26% in very low-, low-, intermediate-, high-, and very high-risk patients, respectively (all P < .001). Conclusion A five-item model for predicting the risk of 5-year BCR after radical prostatectomy for prostate cancer was developed and internally verified, and five risk categories were identified. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Aguirre and Ortegón in this issue.

Alice in wonderland syndrome "through the looking-glass" in a rare presentation of non-convulsive status epilepticus in cerebral venous sinus thrombosis and COVID-19

Alice in Wonderland Syndrome (AIWS) is a rare perceptual disorder, rarely associated with epileptic etiology. We report the case of a 23-year-old man with subacute onset of right peri-orbital headache and visual misperceptions consistent with AIWS Type B, who underwent laboratory tests, brain CT with venography, ophthalmic examination, and neurological assessment that turned out to be normal except for visuospatial difficulties and constructional apraxia. A nasopharyngeal SARS-CoV2 swab taken as screening protocol was positive. The EEG performed because of the persistence of AIWS showed a focal right temporo-occipital non-convulsive status epilepticus; a slow resolution of clinical and EEG alterations was achieved with anti-seizure medications. Brain MRI showed right cortical temporo-occipital signal abnormalities consistent with peri-ictal changes and post-contrast T1 revealed a superior sagittal sinus thrombosis, thus anticoagulant therapy was initiated. AIWS is associated with temporo-parieto-occipital carrefour abnormalities, where visual and somatosensory inputs are integrated to generate the representation of body schema. In this patient, AIWS is caused by temporo-occipital status epilepticus without anatomical and electroencephalographic involvement of the parietal region, consistent with the absence of somatosensory symptoms of the syndrome. Status epilepticus can be the presenting symptom of cerebral venous sinus thrombosis (CVST) which, in this case, is possibly due to the hypercoagulable state associated with COVID-19.

Selection of cross-reactive T cells by commensal and food-derived yeasts drives cytotoxic TH1 cell responses in Crohn's disease

Aberrant CD4+ T cell reactivity against intestinal microorganisms is considered to drive mucosal inflammation in inflammatory bowel diseases. The disease-relevant microbial species and the corresponding microorganism-specific, pathogenic T cell phenotypes remain largely unknown. In the present study, we identified common gut commensal and food-derived yeasts, as direct activators of altered CD4+ T cell reactions in patients with Crohn's disease (CD). Yeast-responsive CD4+ T cells in CD display a cytotoxic T helper cell (TH1 cell) phenotype and show selective expansion of T cell clones that are highly cross-reactive to several commensal, as well as food-derived, fungal species. This indicates cross-reactive T cell selection by repeated encounter with conserved fungal antigens in the context of chronic intestinal disease. Our results highlighted a role of yeasts as drivers of aberrant CD4+ T cell reactivity in patients with CD and suggest that both gut-resident fungal commensals and daily dietary intake of yeasts might contribute to chronic activation of inflammatory CD4+ T cell responses in patients with CD.

Candida albicans-specific Th17 cell-mediated response contributes to alcohol-associated liver disease

Alcohol-associated liver disease is accompanied by intestinal mycobiome dysbiosis, yet the impacts on liver disease are unclear. We demonstrate that Candida albicans-specific T helper 17 (Th17) cells are increased in circulation and present in the liver of patients with alcohol-associated liver disease. Chronic ethanol administration in mice causes migration of Candida albicans (C. albicans)-reactive Th17 cells from the intestine to the liver. The antifungal agent nystatin decreased C. albicans-specific Th17 cells in the liver and reduced ethanol-induced liver disease in mice. Transgenic mice expressing T cell receptors (TCRs) reactive to Candida antigens developed more severe ethanol-induced liver disease than transgene-negative littermates. Adoptively transferring Candida-specific TCR transgenic T cells or polyclonal C. albicans-primed T cells exacerbated ethanol-induced liver disease in wild-type mice. Interleukin-17 (IL-17) receptor A signaling in Kupffer cells was required for the effects of polyclonal C. albicans-primed T cells. Our findings indicate that ethanol increases C. albicans-specific Th17 cells, which contribute to alcohol-associated liver disease.

Antigen specificity and cross-reactivity drive functionally diverse anti-Aspergillus fumigatus T cell responses in cystic fibrosis

BACKGROUNDThe fungus Aspergillus fumigatus causes a variety of clinical phenotypes in patients with cystic fibrosis (pwCF). Th cells orchestrate immune responses against fungi, but the types of A. fumigatus-specific Th cells in pwCF and their contribution to protective immunity or inflammation remain poorly characterized.METHODSWe used antigen-reactive T cell enrichment (ARTE) to investigate fungus-reactive Th cells in peripheral blood of pwCF and healthy controls.RESULTSWe show that clonally expanded, high-avidity A. fumigatus-specific effector Th cells, which were absent in healthy donors, developed in pwCF. Individual patients were characterized by distinct Th1-, Th2-, or Th17-dominated responses that remained stable over several years. These different Th subsets target different A. fumigatus proteins, indicating that differential antigen uptake and presentation directs Th cell subset development. Patients with allergic bronchopulmonary aspergillosis (ABPA) are characterized by high frequencies of Th2 cells that cross-recognize various filamentous fungi.CONCLUSIONOur data highlight the development of heterogenous Th responses targeting different protein fractions of a single fungal pathogen and identify the development of multispecies cross-reactive Th2 cells as a potential risk factor for ABPA.FUNDINGGerman Research Foundation (DFG), under Germany's Excellence Strategy (EXC 2167-390884018 "Precision Medicine in Chronic Inflammation" and EXC 2051-390713860 "Balance of the Microverse"); Oskar Helene Heim Stiftung; Christiane Herzog Stiftung; Mukoviszidose Institut gGmb; German Cystic Fibrosis Association Mukoviszidose e.V; German Federal Ministry of Education and Science (BMBF) InfectControl 2020 Projects AnDiPath (BMBF 03ZZ0838A+B).

Determining Breast Implant Prevalence: A Population Study of Italian Chest Radiographs

BACKGROUND

Current breast implant prevalence within the general population remains elusive. An accurate prevalence is critical to serve as the denominator for any assessment of breast implant-related complication. The purpose of this manuscript is to assess this prevalence in women aged 20-70 years in Italy.

MATERIALS AND METHODS

Eight reviewers, demonstrating a mean sensitivity of 87.0% and specificity of 97.0%, were recruited for retrospective identification of implants on chest radiographs from a tertiary academic hospital in a major urban setting. Three final reviewers were selected, and they assessed all eligible chest radiographs collected between January and December 2019. The hospital-based population was compared to epidemiological data at a local, regional and national level to demonstrate homogeneity of age structures using the phi correlation coefficient.

RESULTS

We identified 3,448 chest X-rays which yielded 140 implants, with an overall prevalence of 4.1% for women aged 20-70. Implants were bilateral in 76% of cases and unilateral in 24%. They were placed cosmetically in 47.1% cases and used for reconstruction in 52.9% cases. Phi correlation coefficient found no differences across hospital-based, local, regional and national populations.

CONCLUSION

A validated method was performed to estimate implant prevalence from an academic hospital in a major urban setting at 4.1% and was used to estimate national prevalence in Italy. The implications of this epidemiologic study may reach across national borders for improved understanding of breast implant epidemiology and in predicting the total number of patients within a given population that may be affected by device complications.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A novel unconventional T cell population enriched in Crohn's disease

OBJECTIVE

One of the current hypotheses to explain the proinflammatory immune response in IBD is a dysregulated T cell reaction to yet unknown intestinal antigens. As such, it may be possible to identify disease-associated T cell clonotypes by analysing the peripheral and intestinal T-cell receptor (TCR) repertoire of patients with IBD and controls.

DESIGN

We performed bulk TCR repertoire profiling of both the TCR alpha and beta chains using high-throughput sequencing in peripheral blood samples of a total of 244 patients with IBD and healthy controls as well as from matched blood and intestinal tissue of 59 patients with IBD and disease controls. We further characterised specific T cell clonotypes via single-cell RNAseq.

RESULTS

We identified a group of clonotypes, characterised by semi-invariant TCR alpha chains, to be significantly enriched in the blood of patients with Crohn's disease (CD) and particularly expanded in the CD8⁺ T cell population. Single-cell RNAseq data showed an innate-like phenotype of these cells, with a comparable gene expression to unconventional T cells such as mucosal associated invariant T and natural killer T (NKT) cells, but with distinct TCRs.

CONCLUSIONS

We identified and characterised a subpopulation of unconventional Crohn-associated invariant T (CAIT) cells. Multiple evidence suggests these cells to be part of the NKT type II population. The potential implications of this population for CD or a subset thereof remain to be elucidated, and the immunophenotype and antigen reactivity of CAIT cells need further investigations in future studies.

Resolving SARS-CoV-2 CD4+ T cell specificity via reverse epitope discovery

The current strategy to detect immunodominant T cell responses focuses on the antigen, employing large peptide pools to screen for functional cell activation. However, these approaches are labor and sample intensive and scale poorly with increasing size of the pathogen peptidome. T cell receptors (TCRs) recognizing the same epitope frequently have highly similar sequences, and thus, the presence of large sequence similarity clusters in the TCR repertoire likely identify the most public and immunodominant responses. Here, we perform a meta-analysis of large, publicly available single-cell and bulk TCR datasets from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals to identify public CD4+ responses. We report more than 1,200 αβTCRs forming six prominent similarity clusters and validate histocompatibility leukocyte antigen (HLA) restriction and epitope specificity predictions for five clusters using transgenic T cell lines. Collectively, these data provide information on immunodominant CD4+ T cell responses to SARS-CoV-2 and demonstrate the utility of the reverse epitope discovery approach.

The pre-exposure SARS-CoV-2-specific T cell repertoire determines the quality of the immune response to vaccination

SARS-CoV-2 infection and vaccination generates enormous host-response heterogeneity and an age-dependent loss of immune-response quality. How the pre-exposure T cell repertoire contributes to this heterogeneity is poorly understood. We combined analysis of SARS-CoV-2-specific CD4⁺ T cells pre- and post-vaccination with longitudinal T cell receptor tracking. We identified strong pre-exposure T cell variability that correlated with subsequent immune-response quality and age. High-quality responses, defined by strong expansion of high-avidity spike-specific T cells, high interleukin-21 production, and specific immunoglobulin G, depended on an intact naive repertoire and exclusion of pre-existing memory T cells. In the elderly, T cell expansion from both compartments was severely compromised. Our results reveal that an intrinsic defect of the CD4⁺ T cell repertoire causes the age-dependent decline of immune-response quality against SARS-CoV-2 and highlight the need for alternative strategies to induce high-quality T cell responses against newly arising pathogens in the elderly.

Prediction of immunodominant CD4+ SARS-CoV-2 epitopes with TCR repertoire sequencing data

The T cell receptor (TCR) is a hypervariable molecule defining the specificity of T cells for peptide-MHC complex. Defining exact epitopes is crucial to profile T cell responses in COVID-19 and yet very few MHC-II restricted SARS-CoV-2 epitopes are currently known. Here, we propose a reverse epitope discovery technique, which, instead of using large pools of peptides to identify reactive T cells, utilizes TCR repertoire sequencing data as the means to predict immunodominant epitopes. The core idea of the approach is to combine information from large, publicly available TCR repertoire datasets: TCRbeta repertoires from cohorts of COVID-19 patients and controls, and paired TCR repertoires of single T cells activated by SARS-CoV-2 peptides. Our pipeline allows us to predict the HLA-restriction of public SARS-CoV-2 specific TCR clonotypes, which in turn allows us to predict binding to a specific peptide. We applied this approach to single cell TCR repertoires of CD4+ T cells from COVID-19 patients, and predicted six MHC-II restricted immunodominant epitopes and alpha-beta TCR motifs recognising them and tested our predictions experimentally. We further applied this technique to bulk TCRalpha repertoires from T follicular helper cells from draining lymph nodes of healthy donors after BNT162b2 mRNA vaccination. We found that the DPB1*04 restricted S167–180 epitope is responsible for the largest public CD4+ response, and recognition of this epitope is driven by a semi-invariant TCR alpha chain. This finding led to generation of the DPB1*04 S167–180 tetramer, allowing to track SARS-CoV-2 specific CD4 cells in peripheral blood and lymph node samples with flow cytometry.

This work was partially supported by R01AI136514 grant.

This work was partially supported by R01AI136514 grant. 

SARS-CoV-2 mRNA vaccination elicits a robust and persistent T follicular helper cell response in humans

SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine-needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we evaluated the T cell receptor sequences and phenotype of lymph node TFH. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLA-DPB1∗04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.

Characterization of SARS-CoV-2 public CD4+ αβ T cell clonotypes through reverse epitope discovery

The amount of scientific data and level of public sharing produced as a consequence of the COVID-19 pandemic, as well as the speed at which these data were produced, far exceeds any previous effort against a specific disease condition. This unprecedented situation allows for development and application of new research approaches. One of the major technical hurdles in immunology is the characterization of HLA-antigen-T cell receptor (TCR) specificities. Most approaches aim to identify reactive T cells starting from known antigens using functional assays. However, the need for a reverse approach identifying the antigen specificity of orphan TCRs is increasing. Utilizing large public single-cell gene expression and TCR datasets, we identified highly public CD4 ⁺ T cell responses to SARS-CoV-2, covering >75% of the analysed population. We performed an integrative meta-analysis to deeply characterize these clonotypes by TCR sequence, gene expression, HLA-restriction, and antigen-specificity, identifying strong and public CD4 ⁺ immunodominant responses with confirmed specificity. CD4 ⁺ COVID-enriched clonotypes show T follicular helper functional features, while clonotypes depleted in SARS-CoV-2 individuals preferentially had a central memory phenotype. In total we identify more than 1200 highly public CD4+ T cell clonotypes reactive to SARS-CoV-2. TCR similarity analysis showed six prominent TCR clusters, for which we predicted both HLA-restriction and cognate SARS-CoV-2 immunodominant epitopes. To validate our predictions we used an independent cohort of TCR repertoires before and after vaccination with ChAdOx1 , a replication-deficient simian adenovirus-vectored vaccine, encoding the SARS-CoV-2 spike protein. We find statistically significant enrichment of the predicted spike-reactive TCRs after vaccination with ChAdOx1 , while the frequency of TCRs specific to other SARS-CoV-2 proteins remains stable. Thus, the CD4-associated TCR repertoire differentiates vaccination from natural infection. In conclusion, our study presents a novel reverse epitope discovery approach that can be used to infer HLA- and antigen-specificity of orphan TCRs in any context, such as viral infections, antitumor immune responses, or autoimmune disease.

HIGHLIGHTS

Identification of highly public CD4+ T cell responses to SARS-CoV-2Systematic prediction of exact immunogenic HLA class II epitopes for CD4+ T cell responseMethodological framework for reverse epitope discovery, which can be applied to other disease contexts and may provide essential insights for future studies and clinical applications.

A Multi-Factorial Observational Study on Sequential Fecal Microbiota Transplant in Patients with Medically Refractory Clostridioides difficile Infection

Fecal microbiota transplantation (FMT) is highly effective in recurrent Clostridioides difficile infection (CDI); increasing evidence supports FMT in severe or fulminant Clostridioides difficile infection (SFCDI). However, the multifactorial mechanisms that underpin the efficacy of FMT are not fully understood. Systems biology approaches using high-throughput technologies may help with mechanistic dissection of host-microbial interactions. Here, we have undertaken a deep phenomics study on four adults receiving sequential FMT for SFCDI, in which we performed a longitudinal, integrative analysis of multiple host factors and intestinal microbiome changes. Stool samples were profiled for changes in gut microbiota and metabolites and blood samples for alterations in targeted epigenomic, metabonomic, glycomic, immune proteomic, immunophenotyping, immune functional assays, and T-cell receptor (TCR) repertoires, respectively. We characterised temporal trajectories in gut microbial and host immunometabolic data sets in three responders and one non-responder to sequential FMT. A total of 562 features were used for analysis, of which 78 features were identified, which differed between the responders and the non-responder. The observed dynamic phenotypic changes may potentially suggest immunosenescent signals in the non-responder and may help to underpin the mechanisms accompanying successful FMT, although our study is limited by a small sample size and significant heterogeneity in patient baseline characteristics. Our multi-omics integrative longitudinal analytical approach extends the knowledge regarding mechanisms of efficacy of FMT and highlights preliminary novel signatures, which should be validated in larger studies.

Optimization of contrast medium volume for abdominal CT in oncologic patients: prospective comparison between fixed and lean body weight-adapted dosing protocols

Background

Patient body size represents the main determinant of parenchymal enhancement and by adjusting the contrast media (CM) dose to patient weight may be a more appropriate approach to avoid a patient over dosage of CM. To compare the performance of fixed-dose and lean body weight (LBW)-adapted contrast media dosing protocols, in terms of image quality and parenchymal enhancement.

Results

One-hundred cancer patients undergoing multiphasic abdominal CT were prospectively enrolled in this multicentric study and randomly divided in two groups: patients in fixed-dose group (n = 50) received 120 mL of CM while in LBW group (n = 50) the amount of CM was computed according to the patient’s LBW. LBW protocol group received a significantly lower amount of CM (103.47 ± 17.65 mL vs. 120.00 ± 0.00 mL, p < 0.001). Arterial kidney signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) and pancreatic CNR were significantly higher in LBW group (all p ≤ 0.004). LBW group provided significantly higher arterial liver, kidney, and pancreatic contrast enhancement index (CEI) and portal venous phase kidney CEI (all p ≤ 0.002). Significantly lower portal vein SNR and CNR were observed in LBW-Group (all p ≤ 0.020).

Conclusions

LBW-adapted CM administration for abdominal CT reduces the volume of injected CM and improves both image quality and parenchymal enhancement.

Clonal expansion and activation of tissue-resident memory-like Th17 cells expressing GM-CSF in the lungs of severe COVID-19 patients

Hyperinflammation contributes to lung injury and subsequent acute respiratory distress syndrome (ARDS) with high mortality in patients with severe coronavirus disease 2019 (COVID-19). To understand the underlying mechanisms involved in lung pathology, we investigated the role of the lung-specific immune response. We profiled immune cells in bronchoalveolar lavage fluid and blood collected from COVID-19 patients with severe disease and bacterial pneumonia patients not associated with viral infection. By tracking T cell clones across tissues, we identified clonally expanded tissue-resident memory-like Th17 cells (Trm17 cells) in the lungs even after viral clearance. These Trm17 cells were characterized by a a potentially pathogenic cytokine expression profile of IL17A and CSF2 (GM-CSF). Interactome analysis suggests that Trm17 cells can interact with lung macrophages and cytotoxic CD8+ T cells, which have been associated with disease severity and lung damage. High IL-17A and GM-CSF protein levels in the serum of COVID-19 patients were associated with a more severe clinical course. Collectively, our study suggests that pulmonary Trm17 cells are one potential orchestrator of the hyperinflammation in severe COVID-19.

Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such as delineation could not be made because of tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a transethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40 691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analyzed the physicochemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we not only identified consistent associations (regarding effects directions/magnitudes) across different ethnicities but also identified population-specific signals (regarding differences in allele frequencies). We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins.

Percutaneous endoscopic gastrojejunostomy in pediatric intestinal pseudo-obstruction

Pediatric intestinal pseudoobstruction (PIPO) is the "tip of the iceberg" of the most severe gut motility disorders. In patients with PIPO, the impairment of gastrointestinal propulsive patterns is such as to result in progressive obstructive symptoms without evidence of mechanical causes. PIPO is an important cause of intestinal failure and affects growth and pubertal development. Bowel loop and abdominal distension represent one of the main features of intestinal pseudo-obstruction syndromes, hence intestinal decompression is a mainstay in the management of PIPO. So far, pharmacologic, endoscopic, and surgical treatments failed to achieve long-term relief of bowel distension and related symptoms, including pain. Recent data, however, indicated that percutaneous endoscopic gastrojejunostomy (PEG-J) might be a minimally invasive approach for intestinal decompression, thereby improving abdominal symptoms and nutritional status in adult patients with chronic intestinal pseudo-obstruction. Based on these promising results, we treated for the first time a 12-y-old patient affected by PIPO refractory to any therapeutic options to obtain intestinal decompression by PEG-J. We showed that PEG-J yielded sustained small bowel decompression in the reported PIPO patient with considerable improvement of both abdominal symptoms and nutritional status. The positive outcome of the present case provides a basis to test the actual efficacy PEG-J versus other therapeutic approaches to intestinal decompression in patients with PIPO.

Longitudinal high-throughput TCR repertoire profiling reveals the dynamics of T-cell memory formation after mild COVID-19 infection

COVID-19 is a global pandemic caused by the SARS-CoV-2 coronavirus. T cells play a key role in the adaptive antiviral immune response by killing infected cells and facilitating the selection of virus-specific antibodies. However, neither the dynamics and cross-reactivity of the SARS-CoV-2-specific T-cell response nor the diversity of resulting immune memory is well understood. In this study, we use longitudinal high-throughput T-cell receptor (TCR) sequencing to track changes in the T-cell repertoire following two mild cases of COVID-19. In both donors, we identified CD4+ and CD8+ T-cell clones with transient clonal expansion after infection. We describe characteristic motifs in TCR sequences of COVID-19-reactive clones and show preferential occurrence of these motifs in publicly available large dataset of repertoires from COVID-19 patients. We show that in both donors, the majority of infection-reactive clonotypes acquire memory phenotypes. Certain T-cell clones were detected in the memory fraction at the pre-infection time point, suggesting participation of pre-existing cross-reactive memory T cells in the immune response to SARS-CoV-2.

Low-Avidity CD4+ T Cell Responses to SARS-CoV-2 in Unexposed Individuals and Humans with Severe COVID-19

CD4⁺ T cells reactive against SARS-CoV-2 can be found in unexposed individuals, and these are suggested to arise in response to common cold coronavirus (CCCoV) infection. Here, we utilized SARS-CoV-2-reactive CD4⁺ T cell enrichment to examine the antigen avidity and clonality of these cells, as well as the relative contribution of CCCoV cross-reactivity. SARS-CoV-2-reactive CD4⁺ memory T cells were present in virtually all unexposed individuals examined, displaying low functional avidity and multiple, highly variable cross-reactivities that were not restricted to CCCoVs. SARS-CoV-2-reactive CD4⁺ T cells from COVID-19 patients lacked cross-reactivity to CCCoVs, irrespective of strong memory T cell responses against CCCoV in all donors analyzed. In severe but not mild COVID-19, SARS-CoV-2-specific T cells displayed low functional avidity and clonality, despite increased frequencies. Our findings identify low-avidity CD4⁺ T cell responses as a hallmark of severe COVID-19 and argue against a protective role for CCCoV-reactive T cells in SARS-CoV-2 infection.

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Low avidity and broad cross-reactivities of pre-existing SARS-CoV-2 memory T cells

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Strong CCCoV-specific memory CD4⁺ T cell responses in all analyzed individuals

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SARS-CoV-2-specific CD4⁺ T cells in COVID-19 patients lack cross-reactivity to CCCoVs

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Low avidity and clonality of SARS-CoV-2-specific T cell responses in severe COVID-19

Longitudinal Multi-omics Analyses Identify Responses of Megakaryocytes, Erythroid Cells, and Plasmablasts as Hallmarks of Severe COVID-19

Temporal resolution of cellular features associated with a severe COVID-19 disease trajectory is needed for understanding skewed immune responses and defining predictors of outcome. Here, we performed a longitudinal multi-omics study using a two-center cohort of 14 patients. We analyzed the bulk transcriptome, bulk DNA methylome, and single-cell transcriptome (>358,000 cells, including BCR profiles) of peripheral blood samples harvested from up to 5 time points. Validation was performed in two independent cohorts of COVID-19 patients. Severe COVID-19 was characterized by an increase of proliferating, metabolically hyperactive plasmablasts. Coinciding with critical illness, we also identified an expansion of interferon-activated circulating megakaryocytes and increased erythropoiesis with features of hypoxic signaling. Megakaryocyte- and erythroid-cell-derived co-expression modules were predictive of fatal disease outcome. The study demonstrates broad cellular effects of SARS-CoV-2 infection beyond adaptive immune cells and provides an entry point toward developing biomarkers and targeted treatments of patients with COVID-19.

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SARS-CoV2 infection elicits dynamic changes of circulating cells in the blood

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Severe COVID-19 is characterized by increased metabolically active plasmablasts

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Elevation of IFN-activated megakaryocytes and erythroid cells in severe COVID-19

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Cell-type-specific expression signatures are associated with a fatal COVID-19 outcome

Unbiased Characterization of Peptide-HLA Class II Interactions Based on Large-Scale Peptide Microarrays; Assessment of the Impact on HLA Class II Ligand and Epitope Prediction

Human Leukocyte Antigen class II (HLA-II) molecules present peptides to T lymphocytes and play an important role in adaptive immune responses. Characterizing the binding specificity of single HLA-II molecules has profound impacts for understanding cellular immunity, identifying the cause of autoimmune diseases, for immunotherapeutics, and vaccine development. Here, novel high-density peptide microarray technology combined with machine learning techniques were used to address this task at an unprecedented level of high-throughput. Microarrays with over 200,000 defined peptides were assayed with four exemplary HLA-II molecules. Machine learning was applied to mine the signals. The comparison of identified binding motifs, and power for predicting eluted ligands and CD4+ epitope datasets to that obtained using NetMHCIIpan-3.2, confirmed a high quality of the chip readout. These results suggest that the proposed microarray technology offers a novel and unique platform for large-scale unbiased interrogation of peptide binding preferences of HLA-II molecules.

Identification of Disease-associated Traits and Clonotypes in the T Cell Receptor Repertoire of Monozygotic Twins Affected by Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Intestinal inflammation in inflammatory bowel diseases [IBD] is thought to be T cell mediated and therefore dependent on the interaction between the T cell receptor [TCR] and human leukocyte antigen [HLA] proteins expressed on antigen presenting cells. The collection of all TCRs in one individual, known as the TCR repertoire, is characterised by enormous diversity and inter-individual variability. It was shown that healthy monozygotic [MZ] twins are more similar in their TCR repertoire than unrelated individuals. Therefore MZ twins, concordant or discordant for IBD, may be useful to identify disease-related and non-genetic factors in the TCR repertoire which could potentially be used as disease biomarkers.

METHODS

Employing unique molecular barcoding that can distinguish between polymerase chain reaction [PCR] artefacts and true sequence variation, we performed deep TCRα and TCRβ repertoire profiling of the peripheral blood of 28 MZ twin pairs from Denmark and Germany, 24 of whom were discordant and four concordant for IBD.

RESULTS

We observed disease- and smoking-associated traits such as sharing, diversity and abundance of specific clonotypes in the TCR repertoire of IBD patients, and particularly in patients with active disease, compared with their healthy twins.

CONCLUSIONS

Our findings identified TCR repertoire features specific for smokers and IBD patients, particularly when signs of disease activity were present. These findings are a first step towards the application of TCR repertoire analyses as a valuable tool to characterise inflammatory bowel diseases and to identify potential biomarkers and true disease causes.

Primary and secondary anti-viral response captured by the dynamics and phenotype of individual T cell clones

The diverse repertoire of T-cell receptors (TCR) plays a key role in the adaptive immune response to infections. Using TCR alpha and beta repertoire sequencing for T-cell subsets, as well as single-cell RNAseq and TCRseq, we track the concentrations and phenotypes of individual T-cell clones in response to primary and secondary yellow fever immunization — the model for acute infection in humans — showing their large diversity. We confirm the secondary response is an order of magnitude weaker, albeit ∼10 days faster than the primary one. Estimating the fraction of the T-cell response directed against the single immunodominant epitope, we identify the sequence features of TCRs that define the high precursor frequency of the two major TCR motifs specific for this particular epitope. We also show the consistency of clonal expansion dynamics between bulk alpha and beta repertoires, using a new methodology to reconstruct alpha-beta pairings from clonal trajectories.

Construction and benchmarking of a multi-ethnic reference panel for the imputation of HLA class I and II alleles

Genotype imputation of the human leukocyte antigen (HLA) region is a cost-effective means to infer classical HLA alleles from inexpensive and dense SNP array data. In the research setting, imputation helps avoid costs for wet lab-based HLA typing and thus renders association analyses of the HLA in large cohorts feasible. Yet, most HLA imputation reference panels target Caucasian ethnicities and multi-ethnic panels are scarce. We compiled a high-quality multi-ethnic reference panel based on genotypes measured with Illumina’s Immunochip genotyping array and HLA types established using a high-resolution next generation sequencing approach. Our reference panel includes more than 1,300 samples from Germany, Malta, China, India, Iran, Japan and Korea and samples of African American ancestry for all classical HLA class I and II alleles including HLA-DRB3/4/5. Applying extensive cross-validation, we benchmarked the imputation using the HLA imputation tool HIBAG, our multi-ethnic reference and an independent, previously published data set compiled of subpopulations of the 1000 Genomes project. We achieved average imputation accuracies higher than 0.924 for the commonly studied HLA-A, -B, -C, -DQB1 and -DRB1 genes across all ethnicities. We investigated allele-specific imputation challenges in regard to geographic origin of the samples using sensitivity and specificity measurements as well as allele frequencies and identified HLA alleles that are challenging to impute for each of the populations separately. In conclusion, our new multi-ethnic reference data set allows for high resolution HLA imputation of genotypes at all classical HLA class I and II genes including the HLA-DRB3/4/5 loci based on diverse ancestry populations.

Vedolizumab is associated with changes in innate rather than adaptive immunity in patients with inflammatory bowel disease

OBJECTIVE

Vedolizumab, a monoclonal antibody directed against the integrin heterodimer α4β7, is approved for the treatment of Crohn's disease and ulcerative colitis. The efficacy of vedolizumab has been suggested to result from inhibition of intestinal T cell trafficking although human data to support this conclusion are scarce. We therefore performed a comprehensive analysis of vedolizumab-induced alterations in mucosal and systemic immunity in patients with inflammatory bowel disease (IBD), using anti-inflammatory therapy with the TNFα antibody infliximab as control.

DESIGN

Immunophenotyping, immunohistochemistry, T cell receptor profiling and RNA sequencing were performed using blood and colonic biopsies from patients with IBD before and during treatment with vedolizumab (n=18) or, as control, the anti-TNFα antibody infliximab (n=20). Leucocyte trafficking in vivo was assessed using single photon emission computed tomography and endomicroscopy.

RESULTS

Vedolizumab was not associated with alterations in the abundance or phenotype of lamina propria T cells and did not affect the mucosal T cell repertoire or leucocyte trafficking in vivo. Surprisingly, however, α4β7 antibody treatment was associated with substantial effects on innate immunity including changes in macrophage populations and pronounced alterations in the expression of molecules involved in microbial sensing, chemoattraction and regulation of the innate effector response. These effects were specific to vedolizumab, not observed in response to the TNFα antibody infliximab, and associated with inhibition of intestinal inflammation.

CONCLUSION

Our findings suggest that modulation of innate immunity contributes to the therapeutic efficacy of vedolizumab in IBD.

TRIAL REGISTRATION NUMBER

NCT02694588.

RNA based individualized drug selection in breast cancer patients without patient-matched normal tissue

Background

While standard RNA expression tests stratify patients into risk groups, RNA-Seq can guide personalized drug selection based on expressed mutations, fusion genes, and differential expression (DE) between tumor and normal tissue. However, patient-matched normal tissue may be unavailable. Additionally, biological variability in normal tissue and technological biases may confound results. Therefore, we present normal expression reference data for two sequencing methods that are suitable for breast biopsies.

Results

We identified breast cancer related and drug related genes that are expressed uniformly across our normal samples. Large subsets of these genes are identical for formalin fixed paraffin embedded samples and fresh frozen samples. Adipocyte signatures were detected in frozen compared to formalin samples, prepared by surgeons and pathologists, respectively. Gene expression confounded by adipocytes was identified using fat tissue samples. Finally, immune repertoire statistics were obtained for healthy breast, tumor and fat tissues.

Conclusions

Our reference data can be used with patient tumor samples that are asservated and sequenced with a matching aforementioned method. Coefficients of variation are given for normal gene expression. Thus, potential drug selection can be based on confidently overexpressed genes and immune repertoire statistics.

Materials and Methods

Normal expression from formalin and frozen healthy breast tissue samples using Roche Kapa RiboErase (total RNA) (19 formalin, 9 frozen) and Illumina TruSeq RNA Access (targeted RNA-Seq, aka TruSeq RNA Exome) (11 formalin, 1 frozen), and fat tissue (6 frozen Access). Tumor DE using 10 formalin total RNA tumor samples and 1 frozen targeted RNA tumor sample.

The Changing Landscape of Naive T Cell Receptor Repertoire With Human Aging

Human aging is associated with a profound loss of thymus productivity, yet naïve T lymphocytes still maintain their numbers by division in the periphery for many years. The extent of such proliferation may depend on the cytokine environment, including IL-7 and T-cell receptor (TCR) “tonic” signaling mediated by self pMHCs recognition. Additionally, intrinsic properties of distinct subpopulations of naïve T cells could influence the overall dynamics of aging-related changes within the naïve T cell compartment. Here, we investigated the differences in the architecture of TCR beta repertoires for naïve CD4, naïve CD8, naïve CD4⁺CD25⁻CD31⁺ (enriched with recent thymic emigrants, RTE), and mature naïve CD4⁺CD25⁻CD31⁻ peripheral blood subsets between young and middle-age/old healthy individuals. In addition to observing the accumulation of clonal expansions (as was shown previously), we reveal several notable changes in the characteristics of T cell repertoire. We observed significant decrease of CDR3 length, NDN insert, and number of non-template added N nucleotides within TCR beta CDR3 with aging, together with a prominent change of physicochemical properties of the central part of CDR3 loop. These changes were similar across CD4, CD8, RTE-enriched, and mature CD4 subsets of naïve T cells, with minimal or no difference observed between the latter two subsets for individuals of the same age group. We also observed an increase in “publicity” (fraction of shared clonotypes) of CD4, but not CD8 naïve T cell repertoires. We propose several explanations for these phenomena built upon previous studies of naïve T-cell homeostasis, and call for further studies of the mechanisms causing the observed changes and of consequences of these changes in respect of the possible holes formed in the landscape of naïve T cell TCR repertoire.

Overview of methodologies for T-cell receptor repertoire analysis

Background

The T-cell receptor (TCR), located on the surface of T cells, is responsible for the recognition of the antigen-major histocompatibility complex, leading to the initiation of an inflammatory response. Analysing the TCR repertoire may help to gain a better understanding of the immune system features and of the aetiology and progression of diseases, in particular those with unknown antigenic triggers. The extreme diversity of the TCR repertoire represents a major analytical challenge; this has led to the development of specialized methods which aim to characterize the TCR repertoire in-depth. Currently, next generation sequencing based technologies are most widely employed for the high-throughput analysis of the immune cell repertoire.

Results

Here, we report on the latest methodological advancements in the field by describing and comparing the available tools; from the choice of the starting material and library preparation method, to the sequencing technologies and data analysis.

Finally, we provide a practical example and our own experience by reporting some exemplary results from a small internal benchmark study, where current approaches from the literature and the market are employed and compared.

Conclusions

Several valid methods for clonotype identification and TCR repertoire analysis exist, however, a gold standard method for the field has not yet been identified. Depending on the purpose of the scientific study, some approaches may be more suitable than others. Finally, due to possible method specific biases, scientists must be careful when comparing results obtained using different methods.

Electronic supplementary material

The online version of this article (doi:10.1186/s12896-017-0379-9) contains supplementary material, which is available to authorized users.

Enhancement of Lysosomal Glycohydrolase Activity in Human Primary B Lymphocytes during Spontaneous Apoptosis

It has been shown that lysosomes are involved in B cell apoptosis but lysosomal glycohydrolases have never been investigated during this event. In this study we determined the enzymatic activities of some lysosomal glycohydrolases in human tonsil B lymphocytes (TBL) undergoing in vitro spontaneous apoptosis. Fluorimetric methods were used to evaluate the activities of β-hexosaminidases, α-mannosidase, β-mannosidase, β-galactosidase, β-glucuronidase and α-fucosidase. Results show that in TBL during spontaneous apoptosis, there is a significant increase in the activity of β-hexosaminidases, α-mannosidase, β-mannosidase and β-galactosidase. Also β-glucuronidase and α-fucosidase activities increase but not in a significant manner. Further studies on β-hexosaminidases revealed that also mRNA expression of the α- and β-subunits, which constitute these enzymes, increases during spontaneous TBL apoptosis. When TBL are protected from apoptosis by the thiol molecule N-acetyl-L-cysteine (NAC), there is no longer any increase in glycohydrolase activities and mRNA expression of β-hexosaminidase α- and β-subunits. This study demonstrates for the first time that the activities and expression of some lysosomal glycohydrolases are enhanced in TBL during spontaneous apoptosis and that these increases are prevented when TBL apoptosis is inhibited.

Effects of perceptive rehabilitation on balance control in patients with Parkinson's disease

BACKGROUND

Subjects affected by Parkinson's disease have substantially impaired static and dynamic balance, leading to diminished functional ability. Conventional and innovative exercises have been suggested, but most of them were focused on motor features of posture and gait, deserving poor attention to perceptive aspects of balance.

OBJECTIVE

To evaluate the efficacy of the perceptive rehabilitation, based on perceptual surfaces, for postural balance (primary aim) and pain, depression and activity daily living.

METHODS

In this pilot study, we have treated 9 patients with Parkinson's disease undergone rehabilitation aiming to restoring their correct body midline perception, according a schema treatment - no treatment - treatment.

RESULTS

During the rehabilitative intervention, both Tinetti balance score (p = 0.007 in both phases) and Tinetti gait score (p = 0.011 and p = 0.016, respectively), such as pain relief assessed by Visual Analogue Scale (p = 0.011, p = 0.010) were improved. Conversely in the phase of no-intervention, lasting the same amount of time, it was showed a significant reduction of Tinetti Balance score (p = 0.010) and no significant changes in terms of Tinetti Gait score and Visual Analogue Scale.

CONCLUSIONS

These preliminary results highlighted the importance of introducing perceptive training into the exercises proposed to patients with Parkinson's disease for reducing both their static and dynamic balance impairments.

Emergency transanal haemorrhoidal Doppler guided dearterialization for acute and persistent haemorrhoidal bleeding

AIM

The effectiveness of Doppler guided transanal haemorrhoidal dearterialization (THD) for arresting persistent haemorrhoidal bleeding in patients admitted as an emergency was studied.

METHOD

Eleven patients with severe anal bleeding underwent emergency THD as definitive treatment for haemorrhoids. In the majority of patients antiplatelet or anticoagulant therapy was ongoing and severe anaemia was present in six patients.

RESULTS

The mean operative time was 39.7 min. Six to nine feeding arteries were ligated. Intra-operative blood loss was nil. Bleeding was well controlled in all patients. No blood transfusion was required. Mean pain score per verbal numeric scale was 3.6 and 1.4 on day 1 and day 3 respectively. The mean time to resumption of normal activities was 8 days. No major complications were experienced. Six months follow-up demonstrated good control of haemorrhoidal disease.

CONCLUSION

THD is effective in controlling acute haemorrhoidal bleeding with a low incidence of postoperative complications.

Silica particle size and shape: in vitro effects on extracellular matrix metabolism and viability of human bronchial epithelial cells

Crystal micro-morphology and dimension of silica particles could be responsible for the high prevalence of silicosis as recently found among goldsmiths. In the present study we investigated two samples of silica particles with different surface sizes and shapes for their capacity to induce changes in ECM component production. In addition we investigated if their different effects could be related to cytotoxicity and apoptotic effects. Human bronchial epithelial cells were cultured with or without a sample of Silica used for casting gold jewellery, named in our experiments Silica P or a commercial sample of Silica with different physical and chemical properties, named in our experiments Silica F. After 48 h of exposure PCR analysis determined levels of several matrix components. As induction of the apoptosis cascade, annexin assay, caspase 3 activity and cellular cytoxicity by MTT assay were assayed. Silica F promoted fibronectin, MMP12, tenascin C and Integrins b5 gene expressions more than Silica P. Silica P stimulated more TGF&#223;1 and its TGF&#223;R1 receptor than Silica F. Cytotoxic effects were induced by the two samples of Silica. On the contrary, no alteration in classic apoptotic marker protein expression was observed in presence of either Silica F or Silica P, suggesting silica particles affect ECM production and metalloproteases through a mechanism that does not involve apoptotic activation. Different Silica micromorphology and TGF&#223; signal pathway are linked to lung fibrotic effects but the potential role Silica in apoptotic and toxic reaction remains to be ascertained.

[Assessment and monitoring of organizational appropriateness of inpatient rehabilitation facilities in Lazio region: tools and working methods, results and comparison with other regional experiences]

Aim of this paper is to analyze the tools and working methods, used in the Lazio Region, to assess organizational appropriateness in the context of Inpatient Rehabilitation Facilities, and the results obtained. It illustrates also the regional experiences of Veneto and Lombardia, which characterized by dynamism and originality in an attempt to overcome the obvious place for the critical assessment of this area of care.

[Multicentric study to evaluate the quality of discharge abstract coding of admissions in which the treatment was not performed and to identify a possible appropriateness indicator]

The aim of this study was to assess the quality of discharge abstract data regarding admissions in which the planned treatment was not performed, in 4 hospitals in the Rome metropolitan area. The main objective was to evaluate the appropriateness of admissions through use of the Italian version of the Appropriateness Evaluation Protocol (AEP/PRUO). Inconsistencies between discharge abstract forms and hospital records were found in 95/142 (66,9%) of examined records. These were subsequently evaluated through the Appropriateness Evaluation Protocol and overall , 95,6% of inconsistent records were found to be inappropriate admissions. Monitoring V64 codes may represent an indirect indicator of appropriateness.

Minimal handling and bronchopulmonary dysplasia in extremely low-birth-weight infants

Over the last 16 years a minitouch regime, i.e., nasal continuous positive airway pressure (n-CPAP) and/or nasal intermittent positive pressure ventilation (n-IPPV), together with a minimal intubation policy has been routinely used for the treatment of respiratory distress syndrome (RDS) in preterm infants. Only 1.39 (1 out of 72) of the extremely low-birth-weight babies admitted to our Neonatal Intensive Care Unit (NICU) and surviving for at least 36 weeks' postconceptional age developed bronchopulmonary dysplasia at 36 weeks (BPD 36-wk). The BPD-36 wk incidence observed in our population is significantly lower than expected (30%) from the literature (p=0.000002).

CONCLUSION

Our experience supports the effectiveness of the minitouch regime as a way to ventilate premature babies, reducing BPD risk.

[Statine and endothelium dysfunction in diabetes]

Diabetes is associated with significant morbidity and mortality in the setting of acute coronary syndromes. Exists a progressive relationship between glucose levels and cardiovascular risk. Hyperglycemy in fact produces endothelial dysfunction recognised to be a key accessory to diabetic microangiopathy and macroangiopathy. Furthermore diabetics present high levels of cholesterol which elevate the risk of CHD. The statins, for their effects, may represent the fit therapy. The beneficial effects of statins may extend beyond improving the lipid profile. There are several proposed mechanisms for event reduction by lipid-lowering therapy, which include improved endothelium-dependent vasodilation, stabilization of atherosclerotic lesions, reduction in inflammatory stimuli, and prevention, slowed progression, or regression of atherosclerotic lesions (pleiotropic effects). Cellular experiments suggest that statins have an impact on endothelial function by preventing oxidized LDL-induced reduction of nitric oxide production and increased nitric oxide synthesis. Statins also impact chronic inflammation by reducing mitogen (PDGF) responsiveness, inhibiting smooth muscle cell proliferation, inhibiting monocyte chemotaxis and migration, and by reducing macrophage protease production. The absolute clinical benefit achieved may be greater in diabetic than in nondiabetic patients with CHD because diabetic patients have a higher absolute risk of recurrent CHD events and other atherosclerotic events.

IL-7-enhanced T-cell response to myelin proteins in multiple sclerosis

In this study, we investigated the in vitro proliferative response of peripheral blood T lymphocytes from MS patients and controls to MBP and MOG either in the absence or in the presence of the conditioning factor IL-7. In the absence of IL-7, T-cell reactivity to MOG and MBP was similar in MS patients and controls even if an increased MBP response was found in a subgroup of patients with active disease. In the presence of IL-7, increased T-cell reactivity to MBP was observed in MS patients suggesting that their MBP-specific T cells are in a different functional state.

[Sweet syndrome in a female patient with intestinal multiple lipomas and diverticular disease of the colon]

Sweet's syndrome (SS), or acute febrile neutrophilic dermatosis, is a condition characterized by the sudden onset of fever, leukocytosis, and painful, erythematous, well-demarcated papules and plaques which show dense, neutrophilic infiltrates on histologic examination. Myalgias and arthralgias are common. Although it may occur in the absence of other known disease, SS is often associated with hematologic disease (including leukemia), and immunologic disease (rheumatoid arthritis, inflammatory bowel disease). A case of SS is reported. Furthermore the patient presented multiple intestinal lipomas and diverticular colon disease. The authors, on the ground of recent studies which correlate SS with several digestive system disorders, hypothesize an association between acute febrile neutrophilic dermatosis and patient's intestinal diseases. Treatment with systemic corticosteroids is usually successful.

Group B Streptococcus induces apoptosis in macrophages

Group B Streptococcus (GBS) is a pathogen that has developed some strategies to resist host immune defenses. Because phagocytic killing is an important pathogenetic mechanism for bacteria, we investigated whether GBS induces apoptosis in murine macrophages. GBS type III strain COH31 r/s (GBS-III) first causes a defect in cell membrane permeability, then at 24 h, apoptosis. Apoptosis was confirmed by several techniques based on morphological changes and DNA fragmentation. Cytochalasin D does not affect apoptosis, suggesting that GBS-III needs not be within the macrophage cytoplasm to promote apoptosis. Inhibition of host protein synthesis prevents apoptosis, whereas inhibition of caspase-1 or -3, does not. Therefore, GBS can trigger an apoptotic pathway independent of caspase-1 and -3, but dependent on protein synthesis. Inhibition of apoptosis by EGTA and PMA, and enhancement of apoptosis by calphostin C and GF109203X suggests that an increase in the cytosolic calcium level and protein kinase C activity status are important in GBS-induced apoptosis. Neither alteration of plasma membrane permeability nor apoptosis were induced by GBS grown in conditions impeding hemolysin expression or when we used dipalmitoylphosphatidylcholine, which inhibited GBS beta-hemolytic activity, suggesting that GBS beta-hemolysin could be involved in apoptosis. beta-Hemolysin, by causing membrane permeability defects, could allow calcium influx, which initiates macrophage apoptosis. GBS also induces apoptosis in human monocytes but not in tumor lines demonstrating the specificity of its activity. This study suggests that induction of macrophage apoptosis by GBS is a novel strategy to overcome host immune defenses.

In vitro effects of meropenem and imipenem/cilastatin on some functions of human natural effector cells

Meropenem, a new carbapenem antibiotic, was assessed to evaluate its effects on some functional parameters of human polymorphonuclear (PMN) and natural killer (NK) cells in comparison with imipenem/cilastatin. Both drugs significantly inhibited PMN phagocytosis and chemotaxis at concentrations of 2,000 and 4,000 microg/ml. They affected PMN microbicidal activity, evaluated against Candida albicans, only at 4,000 microg/ml. A study of the effects of both drugs on peripheral NK populations and the human NK line (NK-92) showed that even at 4,000 microg/ml there was no effect on antitumor activity. These data indicate that meropenem can reduce some PMN antimicrobial functions only at very high concentrations like imipenem/cilastatin, whereas no concentration influenced NK activity.

Scintigraphic evaluation of gastroesophageal reflux in newborns

OBJECTIVES

This study was carried out to verify whether during neonatal stage gastroesophageal scintigraphy, may be useful not only to diagnose gastroesophageal reflux (GER), but also to detect pulmonary aspiration, at times responsible for respiratory symptoms frequently associated with GER.

PATIENTS AND METHODS

Gastroesophageal scintigraphy was performed on 50 newborns admitted to NICU of Brindisi in the last two years who presented symptoms as cyanosis, apnoea, bradycardia, laringeal stridor, wheezing, not related to respiratory or cardiac problems, but suspected to be clinical suggestive symptoms of "pathological" GER. After administration of 99mTC mixed with the usual meal formula, we obtained a recording period of 60-90 minutes and a later recording at 4 and 24 hours to document radioactive material in lungs.

RESULTS

Scintigraphy showed GER in 40/50 cases and despite frequent observation of respiratory symptoms (39/40 cases) in these newborns never radiation in pulmonary fields.

CONCLUSIONS

Our results could indicate that scintigraphy, noninvasive and low in radiation, may be considered effective and reliable to diagnose GER in newborns. The absence of radiation in pulmonary fields could indicate that respiratory symptoms frequently associated with GER could depend on involuntary mechanism of vagal type and not on pulmonary aspiration.