The Genetic Landscape of Primary Breast Marginal Zone Lymphoma Identifies a Mutational-driven Disease With Similarities to Ocular Adnexal Lymphoma.

Extranodal marginal zone lymphomas (eMZL) can occur in any organ and site of the body. Recent research has shown that they differ from organ to organ in terms of their mutational profile. In this study, we investigated a cohort of primary breast marginal zone lymphomas (PBMZL) to get a better insight into their morphologic and molecular profile. A cohort of 15 cases (14 female and 1 male) was characterized by immunohistochemistry (IHC) for 19 markers, fluorescence in situ hybridization (FISH), and high throughput sequencing (HTS) using a lymphoma panel comprising 172 genes. In addition, PCR for the specific detection of Borrelia spp. and metagenomics whole genome sequencing were performed for infectious agent profiling. Follicular colonization was observed in most cases, while lymphoepithelial lesions, though seen in many cases, were not striking. All 15 cases were negative for CD5, CD11c, and CD21 and positive for BCL2 and pan B-cell markers. There were no cases with BCL2, BCL10, IRF4, MALT1, or MYC translocation; only 1 had a BCL6 rearrangement. HTS highlighted TNFAIP3 (n=4), KMT2D (n=2), and SPEN (n=2) as the most frequently mutated genes. There were no Borrelia spp., and no other pathogens detected in our cohort. One patient had a clinical history of erythema chronicum migrans affecting the same breast. PBMZL is a mutation-driven disease rather than fusion-driven. It exhibits mutations in genes encoding components affecting the NF-κB pathway, chromatin modifier-encoding genes, and NOTCH pathway-related genes. Its mutational profile shares similarities with ocular adnexal and nodal MZL.

Post-transplant Inflammatory Bowel Disease Associated with Donor-Derived TIM-3 Deficiency.

Inflammatory bowel disease (IBD) occurring following allogeneic stem cell transplantation (aSCT) is a very rare condition. The underlying pathogenesis needs to be better defined. There is currently no systematic effort to exclude loss- or gain-of-function mutations in immune-related genes in stem cell donors. This is despite the fact that more than 100 inborn errors of immunity may cause or contribute to IBD. We have molecularly characterized a patient who developed fulminant inflammatory bowel disease following aSCT with stable 100% donor-derived hematopoiesis. A pathogenic c.A291G; p.I97M HAVCR2 mutation encoding the immune checkpoint protein TIM-3 was identified in the patient's blood-derived DNA, while being absent in DNA derived from the skin. TIM-3 expression was much decreased in the patient's serum, and in vitro-activated patient-derived T cells expressed reduced TIM-3 levels. In contrast, T cell-intrinsic CD25 expression and production of inflammatory cytokines were preserved. TIM-3 expression was barely detectable in the immune cells of the patient's intestinal mucosa, while being detected unambiguously in the inflamed and non-inflamed colon from unrelated individuals. In conclusion, we report the first case of acquired, "transplanted" insufficiency of the regulatory TIM-3 checkpoint linked to post-aSCT IBD.

Primary bone diffuse large B-cell lymphoma (PB-DLBCL): a distinct extranodal lymphoma of germinal centre origin, with a common EZB-like mutational profile and good prognosis.

AIMS: Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is not recognized as a separate entity by the current classification systems. Here we define and highlight its distinctive clinical presentation, morphology, phenotype, gene expression profile (GEP), and molecular genetics. METHODS: We collected 27 respective cases and investigated their phenotype, performed gDNA panel sequencing covering 172 genes, and carried out fluorescence in situ hybridization to evaluate MYC, BCL2, and BCL6 translocations. We attempted to genetically subclassify cases using the Two-step classifier and performed GEP for cell-of-origin subtyping and in silico comparison to uncover up- and downregulated genes as opposed to other DLBCL. RESULTS: Most cases (n = 22) were germinal centre B-cell-like (GCB) by immunohistochemistry and all by GEP. Additionally, PB-DLBCL had a mutational profile similar to follicular lymphoma and nodal GCB-DLBCL, with the exception of more frequent TP53 and B2M mutations. The GEP of PB-DLBCL was unique, and the frequency of BCL2 rearrangements was lower compared to nodal GCB-DLBCL. The Two-step classifier categorized eight of the cases as EZB, three as ST2, and one as MCD. CONCLUSION: This study comprehensively characterizes PB-DLBCL as a separate entity with distinct clinical and morpho-molecular features. These insights may aid in developing tailored therapeutic strategies and shed light on its pathogenesis.

Ectopic Salivary Glands - a Differential Diagnosis to a Thyroglossal Duct Cyst.

Background: Midline developmental neck lesions primarily consist of thyroglossal duct remnants. Their recurrence is uncommon following thorough resection, which includes hyoid removal (the Sistrunk procedure). Case report: A 3-year-old girl presented with mucoid secretion drainage and swelling in the anterior mid-neck region, clinically resembling a thyroglossal duct remnant. Following an initial Sistrunk procedure, the lesion recurred, prompting a subsequent resection. Histological analysis revealed a mucocele alongside acinar and mucous ectopic salivary glands. Conclusions: The ectopic salivary gland can manifest along the midline of the neck and may clinically resemble the signs and symptoms of a thyroglossal duct cyst. Importantly, it can exhibit recurrence post-surgery, even following hyoid resection.

Molecular characterization and genetic subclassification comparison of diffuse large B-cell lymphoma (DLBCL) - real-life experience with 74 cases.

INTRODUCTION: Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous entity. Lately, several algorithms achieving therapeutically and prognostically relevant DLBCL subclassification have been published. METHODS: A cohort of 74 routine DLBCL cases was broadly characterized by immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) of the BCL2, BCL6 and MYC loci, and comprehensive high throughput sequencing (HTS). Based on the genetic alterations found, cases were reclassified using two probabilistic tools - LymphGen and Two-step classifier, allowing for comparison of the two models. RESULTS: Hans and Tally's overall IHC-based subclassification success rate was 96% and 82%, respectively. HTS and FISH data allowed the LymphGen algorithm to successfully classify 11/55 cases, (1 - BN2, 7 - EZB, 1 - MCD, and 2 - genetically composite EZB/N1). The total subclassification rate was 20%. On the other hand, the Two-step classifier categorized 36/55 cases, with 65.5% success (9 - BN2, 12 - EZB, 9 - MCD, 2 - N1, and 4 - ST2). Clinical correlations highlighted MCD as an aggressive subtype associated with higher relapse and mortality. CONCLUSIONS: The Two-step algorithm has a better success rate at subclassifying DLBCL cases based on genetic differences. Further improvement of the classifiers is required to increase the number of classifiable cases and thus prove their applicability in routine diagnostics.

[CD23 positive, BCL2 rearrangement-negative germinal centre lymphomas]. / CD23-positive, BCL2-Rearrangement-negative Keimzentrumslymphome.

Acknowledgeing that the group of follicular lymphomas is to be regarded as very heterogeneous, a group of follicular lymphomas has been delineated in recent years that was characterised by an often diffuse growth (without formation of evident follicular structures) as well as expression of CD23 in the lymphoma cells and the absence of the classic BCL2 translocation. Further characteristics are a preferred inguinal localisation of the lymphomas and a localised stage with a good prognosis. Genetically, this lymphoma group is characterised by a high rate of either STAT6 or SOCS1 mutations.The ICC classification took this development into account by introducing the provisional entity CD23 positive, BCL2 rearrangement-negative germinal centre lymphoma. Further studies must now show how exactly this entity can be defined (combination of morphology, immunohistochemical phenotype, focus on genetic alterations) in order to pave the way towards a uniform classification and a better clinical characterisation of these cases - especially with regard to possible new therapeutic treatment options.

Case Report: Gene expression profiling of COVID-19 vaccination-related lymphadenopathies reveals evidence of a dominantly extrafollicular immune response.

mRNA-based vaccines against SARS-CoV-2 have been proven to be very efficient in preventing severe COVID-19. Temporary lymphadenopathy (LA) has been observed as a common adverse event following immunization. Here we describe a case series of three female patients with prominent local to generalized LA after SARS-CoV-2 mRNA-1273 vaccination, which led to lymph node biopsy due to the suspicion of lymphoma or metastasis. All three patients morphologically showed similar patterns of follicular hyperplasia and especially extrafollicular blast activation. Two of the three patients only had short-lasting humoral immune responses to the vaccination. Gene expression profiling (GEP) using the HTG Immune response panel revealed that all three patients clustered together and clearly differed from the GEP-patterns of COVID-19, infectious mononucleosis and non-specific follicular hyperplasia. The closest similarities were seen with lymph nodes showing extrafollicular activation of B-blasts as well as hemophagocytosis. The GEP of the vaccination-induced LA was reminiscent of an immune response with little potential of immunologic memory. mRNA-1273 vaccination-induced LA may to a certain extend reflect disordered immune response with potentially poor immunologic memory in affected individuals.

Combined therapy with ibrutinib and bortezomib followed by ibrutinib maintenance in relapsed or refractory mantle cell lymphoma and high-risk features: a phase 1/2 trial of the European MCL network (SAKK 36/13).

Background: The Bruton's tyrosine kinase inhibitor ibrutinib and the proteasome inhibitor bortezomib have single-agent activity, non-overlapping toxicities, and regulatory approval in mantle cell lymphoma (MCL). In vitro, their combination provides synergistic cytotoxicity. In this investigator-initiated phase 1/2 trial, we established the recommended phase 2 dose of ibrutinib in combination with bortezomib, and assessed its efficacy in patients with relapsed or refractory MCL. Methods: In this phase 1/2 study open in 15 sites in Switzerland, Germany and Italy, patients with relapsed or refractory MCL after ≤2 lines of chemotherapy and both ibrutinib-naïve and bortezomib-naïve received six cycles of ibrutinibb and bortezomib, followed by ibrutinib maintenance. For the phase 1 study, a standard 3 + 3 dose escalation design was used to determine the recommended phase 2 dose of ibrutinib in combination with bortezomib. The primary endpoint in phase 1 was the dose limiting toxicities in cycle 1. The phase 2 study was an open-label, single-arm trial with a Simon's two-stage min-max design, with a primary endpoint of overall response rate (ORR) assessed by CT/MRI. This study was registered with ClinicalTrials.gov, NCT02356458. Findings: Between August 2015 and September 2016, nine patients were treated in the phase 1 study, and 49 patients were treated between November 2016 and March 2020 in the phase 2 of the trial. The ORR was 81.8% (90% CI 71.1, 89.8%, CR(u) 21.8%) which increased with continued ibrutinib (median 10.6 months) to 87.3%, (CR(u) 41.8%). 75.6% of patients had at least one high-risk feature (Ki-67 > 30%, blastoid or pleomorphic variant, p53 overexpression, TP53 mutations and/or deletions). In these patients, ibrutinib and bortezomib were also effective with an ORR of 74%, increasing to 82% during maintenance. With a median follow-up of 25.4 months, the median duration of response was 22.7, and the median PFS was 18.6 months. PFS reached 30.8 and 32.9 months for patients with a CR or Cru, respectively. Interpretation: The combination of ibrutinib and bortezomib shows durable efficacy in patients with relapsed or refractory MCL, also in the presence of high-risk features. Funding: SAKK (Hubacher Fund), Swiss State Secretariat for Education, Research and Innovation, Swiss Cancer Research Foundation, and Janssen.

Randomized Trial to Assess the Clinical Utility of Renal Allograft Monitoring by Urine CXCL10 Chemokine.

SIGNIFICANCE STATEMENT: This study is the first randomized controlled trial to investigate the clinical utility of a noninvasive monitoring biomarker in renal transplantation. Although urine CXCL10 monitoring could not demonstrate a beneficial effect on 1-year outcomes, the study is a rich source for future design of trials aiming to explore the clinical utility of noninvasive biomarkers. In addition, the study supports the use of urine CXCL10 to assess the inflammatory status of the renal allograft. BACKGROUND: Urine CXCL10 is a promising noninvasive biomarker for detection of renal allograft rejection. The aim of this study was to investigate the clinical utility of renal allograft monitoring by urine CXCL10 in a randomized trial. METHODS: We stratified 241 patients, 120 into an intervention and 121 into a control arm. In both arms, urine CXCL10 levels were monitored at three specific time points (1, 3, and 6 months post-transplant). In the intervention arm, elevated values triggered performance of an allograft biopsy with therapeutic adaptations according to the result. In the control arm, urine CXCL10 was measured, but the results concealed. The primary outcome was a combined end point at 1-year post-transplant (death-censored graft loss, clinical rejection between month 1 and 1-year, acute rejection in 1-year surveillance biopsy, chronic active T-cell-mediated rejection in 1-year surveillance biopsy, development of de novo donor-specific HLA antibodies, or eGFR <25 ml/min). RESULTS: The incidence of the primary outcome was not different between the intervention and the control arm (51% versus 49%; relative risk (RR), 1.04 [95% confidence interval, 0.81 to 1.34]; P = 0.80). When including 175 of 241 (73%) patients in a per-protocol analysis, the incidence of the primary outcome was also not different (55% versus 49%; RR, 1.11 [95% confidence interval, 0.84 to 1.47]; P = 0.54). The incidence of the individual end points was not different as well. CONCLUSIONS: This study could not demonstrate a beneficial effect of urine CXCL10 monitoring on 1-year outcomes (ClinicalTrials.gov_ NCT03140514 ).

[Classification of aggressive B-cell lymphomas : News and open questions]. / Klassifikation aggressiver B-Zell-Lymphome : Neuigkeiten und offene Fragen.

The 5th edition of the WHO classification (WHO-HAEM5) and the International Consensus Classification (ICC) show a broad consensus in the categorization of aggressive, large B­cell lymphomas with expected minor impact only on the daily diagnostic routine. The changes compared to the 2017 revised WHO-HAEM4R are moderate and include updated names of entities, sharpened diagnostic criteria, and upgrades from provisional to definite entities. The definition of the most common aggressive B­cell lymphoma, diffuse large B­cell lymphoma (DLBCL), not otherwise specified (NOS), remains unchanged, and both classifications strongly encourage subtyping into germinal center B­like (GCB) or the activated B­like (ABC or non-GCB) DLBCL. DLBCL, NOS, should be separated from other large B­cell lymphomas including large B­cell lymphoma with IRF4 rearrangement (upgraded to a definite entity in both classifications) and large-cell/high-grade B­cell lymphomas with 11q aberration. Aggressive B­cell lymphomas with MYC and BCL2 rearrangements form a molecularly distinct group and are listed as definite entities in both classifications. This is in contrast to the more heterogeneous group of aggressive B­cell lymphomas with MYC and BCL6 rearrangements that are recognized as a provisional entity in the ICC, while they fall into the DLBCL, NOS, or the HGBL, NOS, groups in the WHO-HAEM5.

Ectopic Salivary Gland - A Possible Differential Diagnosis of a Branchial Cleft Cyst.

Background: Branchial cleft cysts or fistulae are common in pediatric surgical pathology and are cured by surgery. Lesions in this area may not show the classical features of a cyst or duct lined by squamous or respiratory epithelium and other differential diagnoses should be considered. Case report: A seven-year-old otherwise healthy boy presented with bilateral swelling of the lower neck and reported intermittent secretion of clear fluid on the right side. Excision of the right sided lesion revealed an ectopic salivary gland, the excision of the left showed only subtle fibrosis. Conclusion: Ectopic salivary glands may occur in the distribution of branchial cleft remnants. Clear fluid drainage (saliva) may be a clinical clue that these are not branchial cleft cremnants.

The pulmonary vasculature in lethal COVID-19 and idiopathic pulmonary fibrosis at single-cell resolution.

AIMS: Severe acute respiratory syndrome coronavirus-2 infection causes COVID-19, which in severe cases evokes life-threatening acute respiratory distress syndrome (ARDS). Transcriptome signatures and the functional relevance of non-vascular cell types (e.g. immune and epithelial cells) in COVID-19 are becoming increasingly evident. However, despite its known contribution to vascular inflammation, recruitment/invasion of immune cells, vascular leakage, and perturbed haemostasis in the lungs of severe COVID-19 patients, an in-depth interrogation of the endothelial cell (EC) compartment in lethal COVID-19 is lacking. Moreover, progressive fibrotic lung disease represents one of the complications of COVID-19 pneumonia and ARDS. Analogous features between idiopathic pulmonary fibrosis (IPF) and COVID-19 suggest partial similarities in their pathophysiology, yet, a head-to-head comparison of pulmonary cell transcriptomes between both conditions has not been implemented to date. METHODS AND RESULTS: We performed single-nucleus RNA-sequencing on frozen lungs from 7 deceased COVID-19 patients, 6 IPF explant lungs, and 12 controls. The vascular fraction, comprising 38 794 nuclei, could be subclustered into 14 distinct EC subtypes. Non-vascular cell types, comprising 137 746 nuclei, were subclustered and used for EC-interactome analyses. Pulmonary ECs of deceased COVID-19 patients showed an enrichment of genes involved in cellular stress, as well as signatures suggestive of dampened immunomodulation and impaired vessel wall integrity. In addition, increased abundance of a population of systemic capillary and venous ECs was identified in COVID-19 and IPF. COVID-19 systemic ECs closely resembled their IPF counterparts, and a set of 30 genes was found congruently enriched in systemic ECs across studies. Receptor-ligand interaction analysis of ECs with non-vascular cell types in the pulmonary micro-environment revealed numerous previously unknown interactions specifically enriched/depleted in COVID-19 and/or IPF. CONCLUSIONS: This study uncovered novel insights into the abundance, expression patterns, and interactomes of EC subtypes in COVID-19 and IPF, relevant for future investigations into the progression and treatment of both lethal conditions.

A Case Study of Zoonotic Chlamydia abortus Infection: Diagnostic Challenges From Clinical and Microbiological Perspectives.

Chlamydia abortus is the most common causative agent of abortion in small ruminants, but it is poorly recognized as a human pathogen. In most published case studies, diagnosis remained difficult and often resulted in delayed initiation of therapy. In this case study of severe C abortus infection in a pregnant farmer from Switzerland, we highlight the clinical and microbiological diagnostic challenges and provide evidence of a zoonotic epidemiological link.

[Differential diagnosis of reactive cytopenias]. / Differenzialdiagnose reaktiver Zytopenien.

Reactive cytopenias are a frequent cause for bone marrow investigations, including bone marrow trephine biopsies, especially if clinical examination and laboratory analyses (e.g., detection of substrate deficiencies) cannot provide a sufficient explanation. The evaluation of such biopsies is primarily concerned with the exclusion of diseases that displace the normal hematopoiesis (infiltrates of acute leukemias or lymphomas and metastases), the exclusion of a myelodysplastic syndrome that classically results in ineffective hematopoiesis, or the detection of specific diseases, particularly infectious or histiocytic diseases (e.g., hemophagocytic lymphohistiocytosis).In this review, we describe characteristic morphologic changes of reactive cytopenias, focus on specific infectious and noninfectious clinical pictures, and distinguish them from malignant changes, especially myelodysplastic syndrome and underlying leukemia of large granular T lymphocytes. Drug-induced changes in hematopoiesis are described in another article in this issue.

Tumor Microenvironment in Acute Myeloid Leukemia: Adjusting Niches.

Acute myeloid leukemias (AML) comprise a wide array of different entities, which have in common a rapid expansion of myeloid blast cells leading to displacement of normal hematopoietic cells and also disruption of the microenvironment in the bone marrow niches. Based on an insight into the complex cellular interactions in the bone marrow niches in non-neoplastic conditions in general, this review delineates the complex relationship between leukemic cells and reactive cells of the tumor microenvironment (TME) in AML. A special focus is directed on niche cells and various T-cell subsets as these also provide a potential therapeutic rationale considering e.g. immunomodulation. The TME of AML on the one hand plays a vital role for sustaining and promoting leukemogenesis but - on the other hand - it also has adverse effects on abnormal blasts developing into overt leukemia hindering their proliferation and potentially removing such cells. Thus, leukemic cells need to and develop strategies in order to manipulate the TME. Interference with those strategies might be of particular therapeutic potential since mechanisms of resistance related to tumor cell plasticity do not apply to it.

Mutational landscape of marginal zone B-cell lymphomas of various origin: organotypic alterations and diagnostic potential for assignment of organ origin.

This meta-analysis aims to concisely summarize the genetic landscape of splenic, nodal and extranodal marginal zone lymphomas (MZL) in the dura mater, salivary glands, thyroid, ocular adnexa, lung, stomach and skin with respect to somatic variants. A systematic PubMed search for sequencing studies of MZL was executed. All somatic mutations of the organs mentioned above were combined, uniformly annotated, and a dataset containing 25 publications comprising 6016 variants from 1663 patients was created. In splenic MZL, KLF2 (18%, 103/567) and NOTCH2 (16%, 118/725) were the most frequently mutated genes. Pulmonary and nodal MZL displayed recurrent mutations in chromatin-modifier-encoding genes, especially KMT2D (25%, 13/51, and 20%, 20/98, respectively). In contrast, ocular adnexal, gastric, and dura mater MZL had mutations in genes encoding for NF-κB pathway compounds, in particular TNFAIP3, with 39% (113/293), 15% (8/55), and 45% (5/11), respectively. Cutaneous MZL frequently had FAS mutations (63%, 24/38), while MZL of the thyroid had a higher prevalence for TET2 variants (61%, 11/18). Finally, TBL1XR1 (24%, 14/58) was the most commonly mutated gene in MZL of the salivary glands. Mutations of distinct genes show origin-preferential distribution among nodal and splenic MZL as well as extranodal MZL at/from different anatomic locations. Recognition of such mutational distribution patterns may help assigning MZL origin in difficult cases and possibly pave the way for novel more tailored treatment concepts.

[Intrauterine fetal demise in extensive SARS-CoV-2-associated placental maternal vascular malperfusion in the setting of SARS-CoV-2 placentitis (severe acute respiratory syndrome coronavirus 2)]. / Intrauteriner Fruchttod bei massiver SARS-CoV-2-assoziierter ("severe acute respiratory syndrome coronavirus 2") plazentarer maternaler Malperfusion im Rahmen einer SARS-CoV-2-Plazentitis.

We report a case of a placenta with extensive maternal vascular malperfusion and chronic histiocytic intervillositis corresponding to SARS-CoV­2 placentitis in the context of fetal demise at 31 weeks of gestation. Placental swamp and PCR of the placental parenchyma, umbilical cord and amnion-chorion membrane showed SARS-CoV-2- and B­betacoronavirus-specific RNA. Maternal vascular malperfusion has been described in cases of SARS-CoV­2 infection; however, the manifested severity of this case in the setting of a severe SARS-CoV­2 placentitis is rare. It emphasizes the need of a maternal prophylactic anticoagulation.