Distinct Hodgkin lymphoma subtypes defined by noninvasive genomic profiling

The scarcity of malignant Hodgkin and Reed-Sternberg cells hampers tissue-based comprehensive genomic profiling of classic Hodgkin lymphoma (cHL). By contrast, liquid biopsies show promise for molecular profiling of cHL due to relatively high circulating tumour DNA (ctDNA) levels1-4. Here we show that the plasma representation of mutations exceeds the bulk tumour representation in most cases, making cHL particularly amenable to noninvasive profiling. Leveraging single-cell transcriptional profiles of cHL tumours, we demonstrate Hodgkin and Reed-Sternberg ctDNA shedding to be shaped by DNASE1L3, whose increased tumour microenvironment-derived expression drives high ctDNA concentrations. Using this insight, we comprehensively profile 366 patients, revealing two distinct cHL genomic subtypes with characteristic clinical and prognostic correlates, as well as distinct transcriptional and immunological profiles. Furthermore, we identify a novel class of truncating IL4R mutations that are dependent on IL-13 signalling and therapeutically targetable with IL-4Rα-blocking antibodies. Finally, using PhasED-seq5, we demonstrate the clinical value of pretreatment and on-treatment ctDNA levels for longitudinally refining cHL risk prediction and for detection of radiographically occult minimal residual disease. Collectively, these results support the utility of noninvasive strategies for genotyping and dynamic monitoring of cHL, as well as capturing molecularly distinct subtypes with diagnostic, prognostic and therapeutic potential.

Biallelic mutations in the CFHR genes underlying atypical hemolytic uremic syndrome in a patient with catastrophic adult-onset Still's disease and recurrent macrophage activation syndrome: A case report

We report the fatal case of a 20-year-old woman with refractory adult-onset Still's disease (AOSD) accompanied by fulminant macrophage activation syndrome (MAS) and atypical hemolytic uremic syndrome (aHUS). Anakinra and tocilizumab temporarily controlled AOSD. In 2021, she presented to ICU with generalized tonic-clonic seizure, lymphocytic aseptic meningitis, and acute kidney injury. Despite hemodialysis and methylprednisolone, she developed another seizure, MAS, and disseminated intravascular coagulation (DIC). Following brief control, MAS flares -reflected by increased plasma CXCL9 and CXCL10- re-emerged and were controlled through dexamethasone, etoposide, cyclosporin and tofacitinib. No mutations were detected in haemophagocytic lymphohistiocytosis (HLH)-associated genes, nor in genes associated with periodic fever syndromes. Post-mortem genetic testing revealed loss-of-function biallelic deletions in complement factor H-related proteins (CFHR) genes, predisposing aHUS. This case underscores the importance of prompt genetic assessment of complement-encoding alleles, in addition to HLH-related genes, in patients with severe AOSD with recurrent MAS and features of thrombotic microangiopathy (TMA).

A Rare Case of Subcutaneous Amyloidoma Associated with Localized Lymphoplasmacytic Lymphoma: Diagnostic Challenges and Treatment Considerations

BACKGROUND AL amyloidomas are solitary, localized, tumor-like deposits of immunoglobulin light-chain-derived amyloid fibrils in the absence of systemic amyloidosis. A rare entity, they have been described in various anatomical sites, typically in spatial association with a sparse lymphoplasmacytic infiltrate, ultimately corresponding to a clonal, malignant, lymphomatous disorder accounting for the amyloidogenic activity. Most frequently, the amyloidoma-associated hematological disorder corresponds to either a solitary plasmacytoma or an extranodal marginal zone lymphoma of MALT. Much rarer is the association with lymphoplasmacytic lymphoma, which by itself is usually a bone marrow-bound disorder with systemic burden. The almost anecdotic combination of an amyloidoma and a localized lymphoplasmacytic lymphoma deserves attention, as it entails a thorough diagnostic workup to exclude systemic involvement and a proportionate therapeutic approach to avoid overtreatment. A review of the literature provides an insight on pathogenesis and prognosis, and can assist both pathologists and clinicians in establishing optimal patient management strategies. CASE REPORT We herein report the incidental finding of a subcutaneous amyloidoma caused by a spatially related, similarly localized lymphoplasmacytic lymphoma diagnosed in a 54-year-old female patient with no other disease localizations and a complete remission following 2 subsequent surgical excisions. CONCLUSIONS Whatever the specific combination of an amyloidoma and the related hematological neoplasm, a multidisciplinary collaboration and a comprehensive clinical-pathological staging are warranted to exclude systemic involvement and identify patients with localized diseases who would benefit from local active treatment and close follow-up.

The spectrum of nodular lymphocyte predominant Hodgkin lymphoma: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology

Session 4 of the 2021 European Association of Haematopathology/Society for Hematopathology Workshop focused on nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). First, the spectrum of immunophenotypic variations in NLPHL and the defining criteria for classic Hodgkin Lymphoma (CHL) were discussed. The added value of further immunophenotypic characterization of both tumor cells and microenvironment to support the differential diagnosis was presented. Next, unusual cases with combined growth patterns and evolution of morphological features over time were presented to explore the clinicopathological impact of presumed high-risk patterns. Based on a large collection of cases, the defining morphological, immunophenotypical, and gene expression features of T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) and THRLBCL-like NLPHL (pattern E) were reviewed to explore this challenging differential diagnosis and critically evaluate whether aggressive behavior and transformation of NLPHL can be predicted in practice.

Homozygous DBF4 mutation as a cause of severe congenital neutropenia

BACKGROUND

Severe congenital neutropenia presents with recurrent infections early in life as a result of arrested granulopoiesis. Multiple genetic defects are known to block granulocyte differentiation; however, a genetic cause remains unknown in approximately 40% of cases.

OBJECTIVE

We aimed to characterize a patient with severe congenital neutropenia and syndromic features without a genetic diagnosis.

METHODS

Whole exome sequencing results were validated using flow cytometry, Western blotting, coimmunoprecipitation, quantitative PCR, cell cycle and proliferation analysis of lymphocytes and fibroblasts and granulocytic differentiation of primary CD34+ and HL-60 cells.

RESULTS

We identified a homozygous missense mutation in DBF4 in a patient with mild extra-uterine growth retardation, facial dysmorphism and severe congenital neutropenia. DBF4 is the regulatory subunit of the CDC7 kinase, together known as DBF4-dependent kinase (DDK), the complex essential for DNA replication initiation. The DBF4 variant demonstrated impaired ability to bind CDC7, resulting in decreased DDK-mediated phosphorylation, defective S-phase entry and progression and impaired differentiation of granulocytes associated with activation of the p53-p21 pathway. The introduction of wild-type DBF4 into patient CD34+ cells rescued the promyelocyte differentiation arrest.

CONCLUSION

Hypomorphic DBF4 mutation causes autosomal-recessive severe congenital neutropenia with syndromic features.

Breast implant associated EBV-positive Diffuse Large B-cell lymphoma: an underrecognized entity?

Breast-implant associated (BIA) lymphoma is an infrequent type of cancer occurring in the fluid and fibrous capsule around a textured breast implant. Recently, both the 2022 WHO 5th edition classification of Haematological tumours (WHO HAEM5) and 2022 International Consensus Classification of Mature Lymphoid Neoplasms (22ICC), recognized breast implant-associated Anaplastic Large Cell Lymphoma (BIA-ALCL) as a definitive entity, defined as a mature CD30-positive T-cell lymphoma, confined by a fibrous capsule, in a breast implant setting. Only few B-cell lymphomas have been reported in the literature to be associated with breast implants. Here we report two EBV-positive Diffuse Large B-cell lymphomas (EBV + DLBCL) in relation to a breast implant, both expressing CD30 as well as EBV latency type 3. Both lesions were considered as DLBCL associated with chronic inflammation (CI-DLBCL), but one presented as a 7 cm solid mass, while the other presented as a fibrin-associated DLBCL (FA-DLBCL) in an HIV patient. Clinically, both are in complete remission 6 months or longer after capsulectomy and graft removal, without additional chemotherapy.Such cases, characterized by large CD30-positive cells, can easily be misdiagnosed as BIA-ALCL if the cell of origin is not further established. Therefore, a diagnostic panel including lineage-specific B-and T-cell markers and EBER in situ hybridization is essential to recognize this rare entity, to understand lymphomagenesis, to predict outcome and to define clinical approach.

Pyroptosis in Alzheimer's disease: cell type-specific activation in microglia, astrocytes and neurons

The major neuropathological hallmarks of Alzheimer's disease (AD) are amyloid β (Aβ) plaques and neurofibrillary tangles (NFT), accompanied by neuroinflammation and neuronal loss. Increasing evidence is emerging for the activation of the canonical NOD-, LRR- and pyrin domain-containing 3 (NLRP3) inflammasome in AD. However, the mechanisms leading to neuronal loss in AD and the involvement of glial cells in these processes are still not clear. The aim of this study was to investigate the contribution of pyroptosis, a pro-inflammatory mechanism of cell death downstream of the inflammasome, to neurodegeneration in AD. Immunohistochemistry and biochemical analysis of protein levels were performed on human post-mortem brain tissue. We investigated the presence of cleaved gasdermin D (GSDMD), the pyroptosis effector protein, as well as the NLRP3 inflammasome-forming proteins, in the medial temporal lobe of 23 symptomatic AD, 25 pathologically defined preclinical AD (p-preAD) and 21 non-demented control cases. Cleaved GSDMD was detected in microglia, but also in astrocytes and in few pyramidal neurons in the first sector of the cornu ammonis (CA1) of the hippocampus and the temporal cortex of Brodmann area 36. Only microglia expressed all NLRP3 inflammasome-forming proteins (i.e., ASC, NLRP3, caspase-1). Cleaved GSDMD-positive astrocytes and neurons exhibited caspase-8 and non-canonical inflammasome protein caspase-4, respectively, potentially indicating alternative pathways for GSDMD cleavage. Brains of AD patients exhibited increased numbers of cleaved GSDMD-positive cells. Cleaved GSDMD-positive microglia and astrocytes were found in close proximity to Aβ plaques, while cleaved GSDMD-positive neurons were devoid of NFTs. In CA1, NLRP3-positive microglia and cleaved GSDMD-positive neurons were associated with local neuronal loss, indicating a possible contribution of NLRP3 inflammasome and pyroptosis activation to AD-related neurodegeneration. Taken together, our results suggest cell type-specific activation of pyroptosis in AD and extend the current knowledge about the contribution of neuroinflammation to the neurodegenerative process in AD via a direct link to neuron death by pyroptosis.

[18F]FDG-PET/CT volumetric parameters can predict outcome in untreated mantle cell lymphoma

Several studies have shown a strong predictive value for pretreatment [¹⁸F]FDG-PET/CT metabolic parameters in different lymphoma subtypes. However, few publications exist concerning the role of metabolic parameters in mantle cell lymphoma (MCL). We retrospectively investigated the prognostic value of baseline metabolic tumor volume (MTV) and lesion dissemination in untreated MCL. We compared it to currently used prognostic factors such as stage, mantle cell lymphoma international prognostic index (MIPI) and KI-67. We report that a higher baseline MTV is a risk factor for worse overall survival (OS), progression-free survival (PFS), and disease-specific survival (DSS) in univariate analysis. In multivariate analysis, MTV was significantly associated with DSS, but not with OS and PFS. We found no correlation between lesion dissemination and outcome. The MIPI score remains the strongest predictor of outcome. These results show that MTV is an important prognostic tool and can improve patient risk stratification at staging of untreated MCL.

B-cell lymphoblastic lymphoma following intravenous BNT162b2 mRNA booster in a BALB/c mouse: A case report

Unprecedented immunization campaigns have been rolled out worldwide in an attempt to contain the ongoing COVID-19 pandemic. Multiple vaccines were brought to the market, among two utilizing novel messenger ribonucleic acid technology. Despite their undisputed success in decreasing COVID-19-associated hospitalizations and mortality, various adverse events have been reported. The emergence of malignant lymphoma is one of such rare adverse events that has raised concern, although an understanding of the mechanisms potentially involved remains lacking. Herein, we present the first case of B-cell lymphoblastic lymphoma following intravenous high-dose mRNA COVID-19 vaccination (BNT162b2) in a BALB/c mouse. Two days following booster vaccination (i.e., 16 days after prime), at only 14 weeks of age, our animal suffered spontaneous death with marked organomegaly and diffuse malignant infiltration of multiple extranodal organs (heart, lung, liver, kidney, spleen) by lymphoid neoplasm. Immunohistochemical examination revealed organ sections positive for CD19, terminal deoxynucleotidyl transferase, and c-MYC, compatible with a B-cell lymphoblastic lymphoma immunophenotype. Our murine case adds to previous clinical reports on malignant lymphoma development following novel mRNA COVID-19 vaccination, although a demonstration of direct causality remains difficult. Extra vigilance is required, with conscientious reporting of similar cases and a further investigation of the mechanisms of action explaining the aforementioned association.

Characteristics and Outcome of Post-Transplant Lymphoproliferative Disorders After Solid Organ Transplantation: A Single Center Experience of 196 Patients Over 30 Years

Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication after transplantation. In this retrospective, monocentric study we aimed to collect real life data regarding PTLD and determine the role of Epstein Barr Virus (EBV) status and year of diagnosis on prognosis. We identified 196 biopsy-proven PTLD after solid organ transplantation (SOT) diagnosed at the University Hospitals Leuven (Belgium) from 1989 to 2019. EBV status was positive in 61% of PTLD. The median overall survival (OS) was 5.7 years (95% CI: 2.99-11.1). Although EBV positivity was not significantly correlated with OS in multivariate analyses (HR: 1.44 (95% CI: 0.93-2.24); p = 0.10), subgroup analysis showed a significantly better median OS for EBV negative post-transplant diffuse large B-cell lymphoma (DLBCL) compared to EBV positive post-transplant DLBCL (8.8 versus 2.5 years respectively; p = 0.0365). There was a significant relation between year of PTLD diagnosis and OS: the more recent the PTLD diagnosis, the lower the risk for death (adjusted HR: 0.962 (95% CI: 0.931-0.933); p = 0.017). In conclusion, the prognosis of PTLD after SOT has improved in the past decades. Our analysis shows a significant relation between EBV status and OS in post-transplant DLBCL.

Aberrant MYCN expression drives oncogenic hijacking of EZH2 as a transcriptional activator in peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of hematological cancers arising from the malignant transformation of mature T cells. In a cohort of 28 PTCL cases, we identified recurrent overexpression of MYCN, a member of the MYC family of oncogenic transcription factors. Approximately half of all PTCL cases was characterized by a MYC expression signature. Inducible expression of MYCN in lymphoid cells in a mouse model caused T-cell lymphoma that recapitulated human PTCL with an MYC expression signature. Integration of mouse and human expression data identified EZH2 as a key downstream target of MYCN. Remarkably, EZH2 was found to be an essential cofactor for the transcriptional activation of the MYCN-driven gene expression program, which was independent of methyltransferase activity but dependent on phosphorylation by CDK1. MYCN-driven T-cell lymphoma was sensitive to EZH2 degradation or CDK1 inhibition, which displayed synergy with US Food and Drug Administration-approved histone deacetylase (HDAC) inhibitors.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

A Novel Homozygous Stop Mutation in IL23R Causes Mendelian Susceptibility to Mycobacterial Disease

PURPOSE

Mendelian susceptibility to mycobacterial disease (MSMD) is caused by inborn errors of IFN-γ immunity. The most frequent genetic defects are found in IL12 or a subunit of its receptor. IL23R deficiency in MSMD has only been reported once, in two pediatric patients from the same kindred with isolated disseminated Bacille Calmette-Guérin disease. We evaluated the impact of a homozygous stop mutation in IL23R (R381X), identified by whole exome sequencing, in an adult patient with disseminated non-tuberculous mycobacterial disease.

METHODS

We performed functional validation of the R381X mutation by evaluating IL23R expression and IL-23 signaling (STAT3 phosphorylation, IFN-γ production) in primary cells (PBMCs, EBV-B cells) and cell lines (HeLa) with or without back-complementation of wild-type IL23R.

RESULTS

We report on a 48-year-old male with disseminated non-tuberculous mycobacterial disease. We identified and characterized a homozygous loss-of-function stop mutation underlying IL23R deficiency, resulting in near absent expression of membrane bound IL23R. IL23R deficiency was characterized by impaired IL-23-mediated IFN-γ secretion in CD4⁺, CD8⁺ T, and mucosal-associated invariant T (MAIT) cells, and low frequencies of circulating Th17 (CD3⁺CD45RA^-CCR4⁺CXCR3^-RORγT⁺), Th1* (CD45RA^-CCR4^-CXCR3⁺RORγT⁺), and MAIT (CD3⁺CD8⁺Vα7.2⁺CD161⁺) cells. Although the patient did not have a history of recurrent fungal infections, impaired Th17 differentiation and blunted IL-23-mediated IL-17 secretion in PBMCs were observed.

CONCLUSION

We demonstrate that impaired IL-23 immunity caused by a homozygous R381X mutation in IL23R underlies MSMD, corroborating earlier findings with a homozygous p.C115Y IL23R mutation. Our report further supports a model of redundant contribution of IL-23- to IL-17-mediated anti-fungal immunity.1.

A genomic-augmented multivariate prognostic model for the survival of Natural-killer/T-cell lymphoma patients from an international cohort

With lowering costs of sequencing and genetic profiling techniques, genetic drivers can now be detected readily in tumors but current prognostic models for Natural-killer/T cell lymphoma (NKTCL) have yet to fully leverage on them for prognosticating patients. Here, we used next-generation sequencing to sequence 260 NKTCL tumors, and trained a genomic prognostic model (GPM) with the genomic mutations and survival data from this retrospective cohort of patients using LASSO Cox regression. The GPM is defined by the mutational status of 13 prognostic genes and is weakly correlated with the risk-features in International Prognostic Index (IPI), Prognostic Index for Natural-Killer cell lymphoma (PINK) and PINK-Epstein-Barr virus (PINK-E). Cox-proportional hazard multivariate regression also showed that the new GPM is independent and significant for both progression-free survival (PFS, HR: 3.73, 95% CI 2.07-6.73; P<0.001) and overall survival (OS, HR: 5.23, 95% CI 2.57-10.65; P=0.001) with known risk-features of these indices. When we assign an additional risk-score to samples, which are mutant for the GPM, the Harrell's C-indices of GPM-augmented IPI, PINK and PINK-E improved significantly (P<0.001, χ² test) for both PFS and OS. Thus, we report on how genomic mutational information could steer towards better prognostication of NKTCL patients. This article is protected by copyright. All rights reserved.

Primary mediastinal large B-cell lymphoma is characterized by large-scale copy-neutral loss of heterozygosity

Development of primary mediastinal B-cell lymphoma (PMBL) is driven by cumulative genomic aberrations. We discovered a unique copy-neutral loss of heterozygosity (CN-LOH) landscape of PMBL which distinguishes this tumour from other B-cell malignancies, including the biologically related diffuse large B-cell lymphoma. Using single nucleotide polymorphism array analysis we identified large-scale CN-LOH lesions in 91% (30/33) of diagnostic PMBLs and both investigated PMBL-derived cell lines. Altogether, the cohort showed 157 extra-large (25.3-248.4 Mb) CN-LOH lesions affecting up to 14 chromosomes per case (mean of 4.4) and resulting in a reduction of heterozygosity an average of 9.9% (range 1.3-51%) of the genome. Predominant involvement of terminal chromosomal segments suggests the implication of B-cell specific crossover events in the pathogenesis of PMBL. Notably, CN-LOH stretches non-randomly clustered on 6p (60%), 15 (37.2%) and 17q (40%), and frequently co-occurred with homozygous mutations in the MHC I (6p21), B2M (15q15) and GNA13 (17q23) genes, respectively, as shown by preliminary whole-exome/genome sequencing data. Altogether, our findings implicate CN-LOH as a novel and distinct mutational process contributing to the molecular pathogenesis of PMBL. The aberration acting as 'second hit' in the Knudson hypothesis, ranks as the major mechanism converting to homozygosity the PMBL-related driver genes. Screening of the cohort of 199 B cell leukamia/lymphoma whole-genomes revealed significant differences in the CN-LOH landscape of PMBL and other B-cell malignancies, including the biologically related diffuse large B-cell lymphoma.

Biological and Clinical Implications of Gene-Expression Profiling in Diffuse Large B-Cell Lymphoma: A Proposal for a Targeted BLYM-777 Consortium Panel as Part of a Multilayered Analytical Approach

Gene-expression profiling (GEP) is used to study the molecular biology of lymphomas. Here, advancing insights from GEP studies in diffuse large B-cell lymphoma (DLBCL) lymphomagenesis are discussed. GEP studies elucidated subtypes based on cell-of-origin principles and profoundly changed the biological understanding of DLBCL with clinical relevance. Studies integrating GEP and next-generation DNA sequencing defined different molecular subtypes of DLBCL entities originating at specific anatomical localizations. With the emergence of high-throughput technologies, the tumor microenvironment (TME) has been recognized as a critical component in DLBCL pathogenesis. TME studies have characterized so-called "lymphoma microenvironments" and "ecotypes". Despite gained insights, unexplained chemo-refractoriness in DLBCL remains. To further elucidate the complex biology of DLBCL, we propose a novel targeted GEP consortium panel, called BLYM-777. This knowledge-based biology-driven panel includes probes for 777 genes, covering many aspects regarding B-cell lymphomagenesis (f.e., MYC signature, TME, immune surveillance and resistance to CAR T-cell therapy). Regarding lymphomagenesis, upcoming DLBCL studies need to incorporate genomic and transcriptomic approaches with proteomic methods and correlate these multi-omics data with patient characteristics of well-defined and homogeneous cohorts. This multilayered methodology potentially enhances diagnostic classification of DLBCL subtypes, prognostication, and the development of novel targeted therapeutic strategies.

Genetic and phenotypic attributes of splenic marginal zone lymphoma

Splenic marginal zone B-cell lymphoma (SMZL) is a heterogeneous clinico-biological entity. The clinical course is variable, multiple genes are mutated with no unifying mechanism, and essential regulatory pathways and surrounding microenvironments are diverse. We sought to clarify the heterogeneity of SMZL by resolving different subgroups and their underlying genomic abnormalities, pathway signatures, and microenvironment compositions to uncover biomarkers and therapeutic vulnerabilities. We studied 303 SMZL spleen samples collected through the IELSG46 multicenter international study (NCT02945319) by using a multiplatform approach. We carried out genetic and phenotypic analyses, defined self-organized signatures, validated the findings in independent primary tumor metadata and in genetically modified mouse models, and determined correlations with outcome data. We identified 2 prominent genetic clusters in SMZL, termed NNK (58% of cases, harboring NF-κB, NOTCH, and KLF2 modules) and DMT (32% of cases, with DNA-damage response, MAPK, and TLR modules). Genetic aberrations in multiple genes as well as cytogenetic and immunogenetic features distinguished NNK- from DMT-SMZLs. These genetic clusters not only have distinct underpinning biology, as judged by differences in gene-expression signatures, but also different outcomes, with inferior survival in NNK-SMZLs. Digital cytometry and in situ profiling segregated 2 basic types of SMZL immune microenvironments termed immune-suppressive SMZL (50% of cases, associated with inflammatory cells and immune checkpoint activation) and immune-silent SMZL (50% of cases, associated with an immune-excluded phenotype) with distinct mutational and clinical connotations. In summary, we propose a nosology of SMZL that can implement its classification and also aid in the development of rationally targeted treatments.

Rapid Progression of Angioimmunoblastic T Cell Lymphoma Following BNT162b2 mRNA Vaccine Booster Shot: A Case Report

Since nucleoside-modified mRNA vaccines strongly activate T follicular helper cells, it is important to explore the possible impact of approved SARS-CoV-2 mRNA vaccines on neoplasms affecting this cell type. Herein, we report and discuss unexpected rapid progression of lymphomatous lesions after administration of a BNT162b2 mRNA vaccine booster in a man recently diagnosed with AITL.

The role of microscopic bone marrow examination and [123I]MIBG scintigraphy in detection of bone marrow involvement in patients with neuroblastoma

OBJECTIVES

For the detection of bone marrow (BM) metastases in patients with neuroblastoma, microscopic BM examination and [¹²³I]MIBG scintigraphy are advised. The aims of this study were to assess the concordance of [¹²³I]MIBG and microscopic BM examination (aspirate and biopsy) in detecting BM involvement and to compare invasive disease in BM biopsies and aspirates, both at diagnosis and before autologous stem cell collection (ASCC).

METHODS

Fifty-five patients with stage 4 or stage 4S disease were included, and 37 of them received an autologous hematopoietic stem cell transplantation (AHSCT). The concordance rate was measured and paired binary data were analysed by the McNemar test to look for a systematic difference between diagnostic tests.

RESULTS

At diagnosis and before ASCC, we found acceptable concordance rates for [¹²³I]MIBG versus microscopic BM examination (77.1% and 85.3% respectively). Discordant results were found in both directions and at both time points. The concordance rate for biopsy versus aspirate at diagnosis was 80.6%, however, before ASCC a much higher concordance rate between both microscopic examinations was found (94.1%). While none of the aspirates showed neuroblastoma cells before ASCC, two biopsies still showed tumor invasion.

CONCLUSION

For patients with neuroblastoma, a [¹²³I]MIBG scintigraphy and a microscopic examination of BM aspirate and its biopsy should be used as complementary tools in the evaluation of BM involvement, and this both at diagnosis and during treatment (before ASCC).

Acquired C1-inhibitor deficiency due to splenic marginal zone lymhoma: Case Report

We present the case of a 67-year-old woman who suffered recurrent episodes of angioedema of the face and larynx. After thorough biochemical investigations, an acquired deficiency of C1-INH was suspected. To evaluate a potential underlying malignancy, a whole-body FDG-PET/CT was performed and showed solely a marked splenomegaly pointing towards a splenic marginal zone lymphoma, which was confirmed by pathological examination.With this case, we discuss the pathophysiology, diagnosis and management of recurrent acquired angioedema attacks as the first presentation of an underlying lymphoproliferative disease.

Fusion transcripts FYN-TRAF3IP2 and KHDRBS1-LCK hijack T cell receptor signaling in peripheral T-cell lymphoma, not otherwise specified

Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of non-Hodgkin lymphomas with poor prognosis. Up to 30% of PTCL lack distinctive features and are classified as PTCL, not otherwise specified (PTCL-NOS). To further improve our understanding of the genetic landscape and biology of PTCL-NOS, we perform RNA-sequencing of 18 cases and validate results in an independent cohort of 37 PTCL cases. We identify FYN-TRAF3IP2, KHDRBS1-LCK and SIN3A-FOXO1 as new in-frame fusion transcripts, with FYN-TRAF3IP2 as a recurrent fusion detected in 8 of 55 cases. Using ex vivo and in vivo experiments, we demonstrate that FYN-TRAF3IP2 and KHDRBS1-LCK activate signaling pathways downstream of the T cell receptor (TCR) complex and confer therapeutic vulnerability to clinically available drugs.

Comprehensive genome-wide analysis of routine non-invasive test data allows cancer prediction: A single-center retrospective analysis of over 85,000 pregnancies

BACKGROUND

Implausible false positive results in non-invasive prenatal testing (NIPT) have been occasionally associated with the detection of occult maternal malignancies. Hence, there is a need for approaches allowing accurate prediction of whether the NIPT result is pointing to an underlying malignancy, as well as for organized programs ensuring efficient downstream clinical management of these cases.

METHODS

Using a data set of 88,294 NIPT performed at University Hospital Leuven (Belgium) between November 2013 and March 2020, we retrospectively evaluated the positive predictive value (PPV) of our NIPT approach for cancer detection. In this approach, whole-genome cell-free DNA (cfDNA) data from NIPT were scrutinized for the presence of (sub)chromosomal copy number alterations (CNAs) predictive for a malignancy, using an unbiased NIPT analysis pipeline coined GIPSeq. For suspected cases, the presence of a maternal cancer was evaluated via subsequent multidisciplinary clinical follow-up examinations. The cancer-specificity of the identified CNAs in cfDNA was assessed through genetic analyses of a tumor biopsy.

FINDINGS

Fifteen women without a cancer history were identified with a GIPSeq result suggestive of a malignant process. Their cfDNA profiles showed either genome-wide aberrations or a single trisomy 8. Upon clinical examinations, a solid or hematological cancer was identified in 4 and 7 cases, respectively. Three women were identified as having a clonal mosaicism. For one case no underlying condition was found. These numbers add to a PPV of 73%. Based on this experience, we presented a multidisciplinary care path for efficient clinical management of these cases.

INTERPRETATION

The presented approach for analysing NIPT results has a high PPV, yet unknown sensitivity, for detecting asymptomatic malignancies upon routine NIPT. Given the complexity of diagnosing a pregnant woman with cancer, clinical follow-up should occur in a well-designed multidisciplinary setting, such as via the care model that we presented here.

FUNDING

This work was supported by Research Foundation Flanders and KU Leuven funding.

Ultra-low coverage whole genome sequencing of ccfDNA in multiple myeloma: A tool for laboratory routine?

Multiple myeloma (MM), is a heterogeneous disease in which chromosomal abnormalities are important for prognostic risk stratification. Cytogenetic profiling with FISH on plasma cells from bone marrow samples (BM-PCs) is the current gold standard, but variable infiltration of plasma cells or failed aspiration can hamper this process. Ultra-low coverage sequencing (ULCS) of circulating cell-free DNA (ccfDNA) may offer a minimally invasive alternative for the work-up of these cases. We compared ULCS, aCGH and FISH on selected BM-PCs in a routine setting with ULCS of ccfDNA for the detection of somatic copy number aberrations (CNAs) in MM.

METHODS

Purified CD138+ BM-PCs of 23 MM patients at initiation of their treatment were subjected to aCGH, FISH and ULCS. Paired samples of peripheral blood-ccfDNA obtained at diagnosis were analyzed by ULCS and compared to the results found in BM-PCs.

RESULTS

Using ULCS of ccfDNA, cytogenetic markers were identified in 18 out of 23 patients; five cases could not be analyzed due to low (≤3%) tumor fraction (TF). High similarity between CNA profiles of BM-PCs and ccfDNA was found. Moreover, 78% of the ccfDNA profiles resulted in the same risk classification as the routine FISH and/or BM-PCs ULCS and aCGH. Chromothripsis was detected in five patients; these had the highest TF values (range 7.1% to 42%) in our series and their profiles showed other high-risk anomalies.

CONCLUSION

This proof-of-principle study indicates that ULCS of ccfDNA can reveal CNAs in MM and should be explored further as a cost-efficient alternative, especially in cases where BM-PC purification fails.

Sequence of proteome profiles in preclinical and symptomatic Alzheimer's disease

Proteome profile changes in Alzheimer's disease (AD) brains have been reported. However, it is unclear whether they represent a continuous process, or whether there is a sequential involvement of distinct proteins. To address this question, we used mass spectrometry. We analyzed soluble, dispersible, sodium dodecyl sulfate, and formic acid fractions of neocortex homogenates (mainly Brodmann area 17-19) from 18 pathologically diagnosed preclinical AD, 17 symptomatic AD, and 18 cases without signs of neurodegeneration. By doing so, we identified four groups of AD-related proteins being changed in levels in preclinical and symptomatic AD cases: early-responding, late-responding, gradually-changing, and fraction-shifting proteins. Gene ontology analysis of these proteins and all known AD-risk/causative genes identified vesicle endocytosis and the secretory pathway-related processes as an early-involved AD component. In conclusion, our findings suggest that subtle changes involving the secretory pathway and endocytosis precede severe proteome changes in symptomatic AD as part of the preclinical phase of AD. The respective early-responding proteins may also contribute to synaptic vesicle cycle alterations in symptomatic AD.

Case Report: Spontaneous Remission of an Infraorbital Follicular B-Cell Lymphoma: Case Report and Review of the Literature

Non-Hodgkin lymphomas comprise a heterogeneous group of malignancies, with a wide scope of clinical, radiological and histological presentations. In this paper, a case is presented of a 59-year-old white male with an infraorbital follicular B-cell lymphoma, which appeared as a painless mass in the left cheek. The lymphoma achieved spontaneous remission five and a half months after his diagnostic incision biopsy. The literature is reviewed, focusing on this rare site of presentation and spontaneous remission. In literature, only four cases have been reported with a follicular B-cell lymphoma of the cheek or infraorbital region, and only 26 cases of spontaneous remission of an extracranial non-Hodgkin lymphoma in the head and neck region have been described. To the authors’ best knowledge, this is the first time spontaneous remission of an infraorbital follicular lymphoma could be observed. The nature of the processes inducing spontaneous remission remains obscure. It is important to recognize this phenomenon as this might prevent unnecessary treatment.

Correspondence-Aware Manifold Learning for Microscopic and Spatial Omics Imaging: A Novel Data Fusion Method Bringing Mass Spectrometry Imaging to a Cellular Resolution

High-dimensional molecular measurements are transforming the field of pathology into a data-driven discipline. While hematoxylin and eosin (H&E) stainings are still the gold standard to diagnose diseases, the integration of microscopic and molecular information is becoming crucial to advance our understanding of tissue heterogeneity. To this end, we propose a data fusion method that integrates spatial omics and microscopic data obtained from the same tissue slide. Through correspondence-aware manifold learning, we can visualize the biological trends observed in the high-dimensional omics data at microscopic resolution. While data fusion enables the detection of elements that would not be detected taking into account the separate data modalities individually, out-of-sample prediction makes it possible to predict molecular trends outside of the measured tissue area. The proposed dimensionality reduction-based data fusion paradigm will therefore be helpful in deciphering molecular heterogeneity by bringing molecular measurements such as mass spectrometry imaging (MSI) to the cellular resolution.

Burkitt lymphoma in children causing an osteolytic lesion in the mandible: A case report

Imaging is the first step in diagnosing a persistent swelling of the jaw. A lymphoma in the jaw typically manifests as a poorly defined osteolytic lesion. A biopsy is mandatory and will result in definite diagnosis.

Semi-Quantitative Characterization of Post-Transplant Lymphoproliferative Disorder Morphological Subtypes with [18F]FDG PET/CT

Background: Post-transplant lymphoproliferative disorder (PTLD) is a complication of organ transplantation classified according to the WHO as nondestructive, polymorphic, monomorphic, and classic Hodgkin Lymphoma subtypes. In this retrospective study, we investigated the potential of semi-quantitative 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) PET/computed tomography (CT)-based parameters to differentiate between the PTLD morphological subtypes. Methods: 96 patients with histopathologically confirmed PTLD and baseline [¹⁸F]FDG PET/CT between 2009 and 2019 were included. Extracted semi-quantitative measurements included: Maximum, peak, and mean standardized uptake value (SUV_max, SUV_peak, and SUV_mean). Results: Median SUVs were highest for monomorphic PTLD followed by polymorphic and nondestructive subtypes. The median SUV_peak at the biopsy site was significantly higher in monomorphic PTLD (17.8, interquartile range (IQR):16) than in polymorphic subtypes (9.8, IQR:13.4) and nondestructive (4.1, IQR:6.1) (p = 0.04 and p ≤ 0.01, respectively). An SUV_peak ≥ 24.8 was always indicative of a monomorphic PTLD in our dataset. Nevertheless, there was a considerable overlap in SUV across the different morphologies. Conclusion: The median SUV_peak at the biopsy site was significantly higher in monomorphic PTLD than polymorphic and nondestructive subtypes. However, due to significant SUV overlap across the different subtypes, these values may only serve as an indication of PTLD morphology, and SUV-based parameters cannot replace histopathological classification.

A double-edged sword

A 33-year old man presented because of progressive fatigue, loss of appetite and malaise for 2 months. While carrying out his job as a baggage handler at the airport, he noticed exertional dyspnoea (New York Heart Association class II) with a slight nonproductive cough. There was no weight loss or fever, although he mentioned paroxysmal hot flushes. There were no recent infections and his past medical and familial history were negative. The patient denied the use of drugs, nicotine or alcohol, reported no recent travel and had a stable relationship.

In medicine, not everything is what it seems and sometimes you need all the pieces of the puzzle in order to complete the diagnosis. This is a case of a disease with two different faces and a review of its respiratory impact.https://bit.ly/2SDKwE5

An atypical case of a pulmonary mass in an immunocompromised patient

OBJECTIVES

Pulmonary lymphomatoid granulomatosis (PLG) is a rare angiocentric and angiodestructive EBV-associated lymphoproliferative disorder which almost always affects the lungs. PLG is more commonly diagnosed in patients with immunodeficiency and is associated with Epstein-Barr virus (EBV). 'Drug induced PLG' or 'iatrogenic immunodeficiency-associated lymphoproliferative disorder' is a special form of PLG described in patient with inflammatory bowel diseases treated with Azathioprine.

METHODS

We report a case of drug-induced PLG in a 68-year-old patient with Crohn's disease presenting with pain at the right hemithorax, fatigue and shortness of breath with a pulmonary mass.

RESULTS

Although initial diagnostic findings were misleading, an open lung biopsy eventually led to the diagnosis of drug-induced PLG.

CONCLUSION

The diagnosis of PLG is challenging because the disease is rare and the histological features can be very subtle. Correct diagnosis relies on histopathology and immunohistochemical staining and EBV RNA in situ hybridization with sampling of large and different amounts of pathologic tissue in the hands of expert pathologists. In drug-induced PLG specifically, withdrawal of the immunosuppressive agent can lead to disease regression.

Intracerebroventricular delivery of vascular endothelial growth factor in patients with amyotrophic lateral sclerosis, a phase I study

We studied the feasibility, safety, tolerability and pharmacokinetics of intracerebroventricular delivery of recombinant human vascular endothelial growth factor in patients with amyotrophic lateral sclerosis. In this phase I study in patients with amyotrophic lateral sclerosis, the study drug was delivered using an implantable programmable pump connected to a catheter inserted in the frontal horn of the lateral cerebral ventricle. A first cohort received open label vascular endothelial growth factor (0.2, 0.8 and 2 µg/day), a second cohort received placebo, 0.8 or 2 µg/day of study dug. After the 3-month study period, all patients could participate in an open label extension study. In total, 18 patients with amyotrophic lateral sclerosis, seen at the University Hospitals in Leuven were included. The surgical procedure was well tolerated in most patients. One patient had transient postoperative seizures, due to an ischemic lesion along the catheter tract. The first 3-month study period was completed by 15/18 patients. Administration of 2 µg/day vascular endothelial growth factor resulted in sustained detectable levels in cerebrospinal fluid. A pulmonary embolus occurred in 3 patients, in 1 patient in the first 3-month study, and in 2 patients during the open label extension study. The study drug was well tolerated in the other patients, for up to 6 years in the open label extension study. Our study shows that intracerebroventricular administration of 2 µg/day of vascular endothelial growth factor to patients with amyotrophic lateral sclerosis is feasible, results in detectable cerebrospinal fluid levels and is well tolerated in most patients. The most common serious adverse event was a pulmonary embolus.

Correction to: Different aspects of Alzheimer's disease-related amyloid β-peptide pathology and their relationship to amyloid positron emission tomography imaging and dementia

An amendment to this paper has been published and can be accessed via the original article.

Noninvasive prenatal testing detected acute myeloid leukemia in paucisymptomatic pregnant patient

To the authors' best knowledge, this is the first report of acute myeloid leukemia (AML) detected by noninvasive prenatal testing. This was an aggressive case that otherwise would have been difficult to characterize due to disadvantages of "gold‐standard" techniques.

Ultra-low depth sequencing of plasma cell DNA for the detection of copy number aberrations in multiple myeloma

Cytogenetic abnormalities are powerful prognostic factors in multiple myeloma (MM) and are routinely analyzed by FISH on bone marrow (BM) plasma cells (PC). Although considered the gold standard, FISH experiments can be laborious and expensive. Therefore, array-CGH (aCGH) has been introduced as an alternative approach for detecting copy number aberrations (CNA), reducing the number of FISH experiments per case and yielding genome-wide information. Currently, next generation sequencing (NGS) technologies offer new perspectives for the diagnostic workup of malignant disorders. In this study, we examined ultra-low depth whole genome sequencing (LDS) as a valid alternative for aCGH for the detection of CNA in BM PC in MM. To this end, BM aspirates obtained in a diagnostic setting from 20 MM cases were analyzed. CD138+ cell-sorted samples were subjected to FISH analysis. DNA was extracted for subsequent aCGH and LDS analysis. CNA were detected by aCGH and LDS in all but one case. Importantly, all CNA identified by parallel first generation aCGH analysis were also detected by LDS, along with six additional CNA in five cases. One of these additional aberrations was in a region of prognostic importance in MM and was confirmed using FISH. However, risk stratification in these particular cases was unaffected. Thus, a perfectly concordant prognostication between array-CGH and LDS was observed. This validates LDS as a novel and cost-efficient tool for the detection of CNA in MM.

Distinct molecular patterns of TDP-43 pathology in Alzheimer's disease: relationship with clinical phenotypes

The co-existence of multiple pathologies and proteins is a common feature in the brains of cognitively impaired elderly individuals. Transactive response DNA-binding protein (TDP-43) has been discovered to accumulate in limbic brain regions of a portion of late-onset Alzheimer's disease (AD) patients, in addition to amyloid-β and τ protein. However, it is not yet known whether the TDP-43 species in the AD brain differ in their composition, when compared among different AD cases and to frontotemporal lobar degeneration cases with TDP-43 inclusions (FTLD-TDP). Furthermore, it is not known whether TDP-43 pathology in AD is related to symptoms of the frontotemporal dementia (FTD) spectrum. In this study, we investigated the molecular pattern of TDP-43 lesions with five different antibodies against different phosphorylated (pTDP-43) and non-phosphorylated TDP-43 epitopes. We analyzed a cohort of 97 autopsy cases, including brains from 20 non-demented individuals, 16 cognitively normal pathologically-defined preclinical AD (p-preAD), 51 neuropathologically-confirmed AD cases and 10 FTLD-TDP cases as positive controls. We observed distinct neuropathological patterns of TDP-43 among AD cases. In 11 neuropathologically-confirmed AD cases we found dystrophic neurites (DNs), neuronal cytoplasmic inclusions (NCIs) and/or neurofibrillary tangle (NFT)-like lesions not only positive for pTDP-43409/410, but also for pTDP-43 phosphorylated at serines 403/404 (pTDP-43403/404) and non-phosphorylated, full-length TDP-43, as seen with antibodies against C-terminal TDP-43 and N-terminal TDP-43. These cases were referred to as ADTDP + FL because full-length TDP-43 was presumably present in the aggregates. FTLD-TDP cases showed a similar molecular TDP-43 pattern. A second pattern, which was not seen in FTLD-TDP, was observed in most of p-preAD, as well as 30 neuropathologically-confirmed AD cases, which mainly exhibited NFTs and NCIs stained with antibodies against TDP-43 phosphorylated at serines 409/410 (pTDP-43409, pTDP-43409/410). Because only phosphorylated C-terminal species of TDP-43 could be detected in the lesions we designated these AD cases as ADTDP + CTF. Ten AD cases did not contain any TDP-43 pathology and were referred to as ADTDP-. The different TDP-43 patterns were associated with clinically typical AD symptoms in 80% of ADTDP + CTF cases, 63,6% of ADTDP + FL and 100% of the ADTDP- cases. On the other hand, clinical symptoms characteristic for FTD were observed in 36,4% of ADTDP + FL, in 16,6% of the ADTDP + CTF, and in none of the ADTDP- cases. Our findings provide evidence that TDP-43 aggregates occurring in AD cases vary in their composition, suggesting the distinction of different molecular patterns of TDP-43 pathology ranging from ADTDP- to ADTDP + CTF and ADTDP + FL with possible impact on their clinical picture, i.e. a higher chance for FTD-like symptoms in ADTDP + FL cases.

Cutaneous barrier leakage and gut inflammation drive skin disease in Omenn syndrome

Background

Severe early-onset erythroderma and gut inflammation, with massive tissue infiltration of oligoclonal activated T cells are the hallmark of Omenn syndrome (OS).

Objective

The impact of altered gut homeostasis in the cutaneous manifestations of OS remains to be clarified.

Methods

We analyzed a cohort of 15 patients with OS and the 129Sv/C57BL/6 knock-in Rag2^R229Q/R229Q (Rag2^R229Q) mouse model. Homing phenotypes of circulating lymphocytes were analyzed by flow cytometry. Inflammatory cytokines and chemokines were examined in the sera by ELISA and in skin biopsies by immunohistochemistry and in situ RNA hybridization. Experimental colitis was induced in mice by dextran sulfate sodium salt.

Results

We show that memory/activated T cells from patients with OS and from the Rag2^R229Q mouse model of OS abundantly express the skin homing receptors cutaneous lymphocyte associated antigen and CCR4 (Ccr4), associated with high levels of chemokine C-C motif ligands 17 and 22. Serum levels of LPS are also elevated. A broad T_h1/T_h2/T_h17 inflammatory signature is detected in the periphery and in the skin. Increased Tlr4 expression in the skin of Rag2^R229Q mice is associated with enhanced cutaneous inflammation on local and systemic administration of LPS. Likewise, boosting colitis in Rag2^R229Q mice results in increased frequency of Ccr4⁺ splenic T cells and worsening of skin inflammation, as indicated by epidermal thickening, enhanced epithelial cell activation, and dermal infiltration by T_h1 effector T cells.

Conclusions

These results support the existence of an interplay between gut and skin that can sustain skin inflammation in OS.

Binding of [18F]AV1451 in post mortem brain slices of semantic variant primary progressive aphasia patients

Purpose

In vivo tau-PET tracer retention in the anterior temporal lobe of patients with semantic variant primary progressive aphasia (SV PPA) has consistently been reported. This is unexpected as the majority of these patients have frontotemporal lobar degeneration TDP (FTLD-TDP).

Methods

We conducted an in vitro [¹⁸F]AV1451 autoradiography binding study in five cases with a clinical diagnosis of SV PPA constituting the range of pathologies (i.e., three FTLD-TDP, one Alzheimer’s disease (AD), and one Pick’s disease (PiD)). Binding was compared with two controls without neurodegeneration, two typical AD, one corticobasal syndrome with underlying AD, and one frontotemporal dementia behavioral variant with FTLD-TDP. The effect of blocking with the authentic reference material and with the MAO-B inhibitor deprenyl was assessed. Immunohistochemistry was performed on adjacent cryosections.

Results

Absence of specific [¹⁸F]AV1451 binding was observed for all three SV PPA FTLD-TDP cases. The absence of binding in controls as well as the successful blocking with authentic AV1451 in cases with tauopathy demonstrated specificity of the [¹⁸F]AV1451 signal for tau. The specific [¹⁸F]AV1451 binding was highest in AD, followed by PiD. This binding colocalized with the respective tau lesions and could not be blocked by deprenyl. Similar pilot findings were obtained with [¹⁸F]THK5351.

Conclusion

In vitro autoradiography showed no [¹⁸F]AV1451 binding in SV PPA due to FTLD-TDP, while specific binding was present in SV PPA due to AD and PiD. The discrepancy between in vitro and in vivo findings remains to be explained. The discordance is not related to [¹⁸F]AV1451 idiosyncrasies as [¹⁸F]THK5351 findings were similar.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04631-x) contains supplementary material, which is available to authorized users.

Aβ-induced acceleration of Alzheimer-related τ-pathology spreading and its association with prion protein

Extracellular deposition of amyloid β-protein (Aβ) in amyloid plaques and intracellular accumulation of abnormally phosphorylated τ-protein (p-τ) in neurofibrillary tangles (NFTs) represent pathological hallmark lesions of Alzheimer's disease (AD). Both lesions develop in parallel in the human brain throughout the preclinical and clinical course of AD. Nevertheless, it is not yet clear whether there is a direct link between Aβ and τ pathology or whether other proteins are involved in this process. To address this question, we crossed amyloid precursor protein (APP) transgenic mice overexpressing human APP with the Swedish mutation (670/671 KM → NL) (APP23), human wild-type APP (APP51/16), or a proenkephalin signal peptide linked to human Aβ₄₂ (APP48) with τ-transgenic mice overexpressing human mutant 4-repeat τ-protein with the P301S mutation (TAU58). In 6-month-old APP23xTAU58 and APP51/16xTAU58 mice, soluble Aβ was associated with the aggravation of p-τ pathology propagation into the CA1/subiculum region, whereas 6-month-old TAU58 and APP48xTAU58 mice neither exhibited significant amounts of p-τ pathology in the CA1/subiculum region nor displayed significant levels of soluble Aβ in the forebrain. In APP23xTAU58 and APP51/16xTAU58 mice showing an acceleration of p-τ propagation, Aβ and p-τ were co-immunoprecipitated with cellular prion protein (PrP^C). A similar interaction between PrP^C, p-τ and Aβ was observed in human AD brains. This association was particularly noticed in 60% of the symptomatic AD cases in our sample, suggesting that PrP^C may play a role in the progression of AD pathology. An in vitro pull-down assay confirmed that PrP^C is capable of interacting with Aβ and p-τ. Using a proximity ligation assay, we could demonstrate proximity (less than ~ 30-40 nm distance) between PrP^C and Aβ and between PrP^C and p-τ in APP23xTAU58 mouse brain as well as in human AD brain. Proximity between PrP^C and p-τ was also seen in APP51/16xTAU58, APP48xTAU58, and TAU58 mice. Based on these findings, it is tempting to speculate that PrP^C is a critical player in the interplay between Aβ and p-τ propagation at least in a large group of AD cases. Preexisting p-τ pathology interacting with PrP^C, thereby, appears to be a prerequisite for Aβ to function as a p-τ pathology accelerator via PrP^C.

Different aspects of Alzheimer's disease-related amyloid β-peptide pathology and their relationship to amyloid positron emission tomography imaging and dementia

Alzheimer’s disease (AD)-related amyloid β-peptide (Aβ) pathology in the form of amyloid plaques and cerebral amyloid angiopathy (CAA) spreads in its topographical distribution, increases in quantity, and undergoes qualitative changes in its composition of modified Aβ species throughout the pathogenesis of AD. It is not clear which of these aspects of Aβ pathology contribute to AD progression and to what extent amyloid positron emission tomography (PET) reflects each of these aspects. To address these questions three cohorts of human autopsy cases (in total n = 271) were neuropathologically and biochemically examined for the topographical distribution of Aβ pathology (plaques and CAA), its quantity and its composition. These parameters were compared with neurofibrillary tangle (NFT) and neuritic plaque pathology, the degree of dementia and the results from [¹⁸F]flutemetamol amyloid PET imaging in cohort 3. All three aspects of Aβ pathology correlated with one another, the estimation of Aβ pathology by [¹⁸F]flutemetamol PET, AD-related NFT pathology, neuritic plaques, and with the degree of dementia. These results show that one aspect of Aβ pathology can be used to predict the other two, and correlates well with the development of dementia, advancing NFT and neuritic plaque pathology. Moreover, amyloid PET estimates all three aspects of Aβ pathology in-vivo. Accordingly, amyloid PET-based estimates for staging of amyloid pathology indicate the progression status of amyloid pathology in general and, in doing so, also of AD pathology. Only 7.75% of our cases deviated from this general association.

Advanced Doppler imaging and trucut biopsy of a late-stage cervical lymphoma

Extranodal lymphomas of the cervix are rare entities that are often misdiagnosed. Imaging and tissue diagnosis are a key to early identification and differentiation from other types of cervical lesions. We report on a case of cervical lymphoma, assessed with three-dimensional Doppler-augmented Radiantflow^™ technology and subjected to deep cervical sampling through trucut core needle biopsy.