Single cell transcriptome analysis reveals disease-defining T cell subsets in the tumor microenvironment of classic Hodgkin lymphoma

Hodgkin lymphoma is characterized by an extensively dominant tumor microenvironment (TME) composed of different types of noncancerous immune cells with rare malignant cells. Characterization of the cellular components and their spatial relationship is crucial to understanding cross-talk and therapeutic targeting in the TME. We performed single-cell RNA sequencing of more than 127,000 cells from 22 Hodgkin lymphoma tissue specimens and 5 reactive lymph nodes, profiling for the first time the phenotype of the Hodgkin lymphoma–specific immune microenvironment at single-cell resolution. Single-cell expression profiling identified a novel Hodgkin lymphoma–associated subset of T cells with prominent expression of the inhibitory receptor LAG3, and functional analyses established this LAG3+ T-cell population as a mediator of immunosuppression. Multiplexed spatial assessment of immune cells in the microenvironment also revealed increased LAG3+ T cells in the direct vicinity of MHC class II–deficient tumor cells. Our findings provide novel insights into TME biology and suggest new approaches to immune-checkpoint targeting in Hodgkin lymphoma. SIGNIFICANCE: We provide detailed functional and spatial characteristics of immune cells in classic Hodgkin lymphoma at single-cell resolution. Specifically, we identified a regulatory T-cell–like immunosuppressive subset of LAG3+ T cells contributing to the immune-escape phenotype. Our insights aid in the development of novel biomarkers and combination treatment strategies targeting immune checkpoints

Genome-Wide Discovery of Somatic Regulatory Variants in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer originating from mature B-cells. Prognosis is strongly associated with molecular subgroup, although the driver mutations that distinguish the two main subgroups remain poorly defined. Through an integrative analysis of whole genomes, exomes, and transcriptomes, we have uncovered genes and non-coding loci that are commonly mutated in DLBCL. Our analysis has identified novel cis-regulatory sites, and implicates recurrent mutations in the 3′ UTR of NFKBIZ as a novel mechanism of oncogene deregulation and NF-κB pathway activation in the activated B-cell (ABC) subgroup. Small amplifications associated with over-expression of FCGR2B (the Fcγ receptor protein IIB), primarily in the germinal centre B-cell (GCB) subgroup, correlate with poor patient outcomes suggestive of a novel oncogene. These results expand the list of subgroup driver mutations that may facilitate implementation of improved diagnostic assays and could offer new avenues for the development of targeted therapeutics.&nbsp

Activation induced cytidine deaminase expression in lymphocyte predominant Hodgkin lymphoma

Background: The lymphocytic and histiocytic (L&H) cells of lymphocyte predominant Hodgkin lymphoma (HL) originate from germinal centre B cells and carry mutated V gene rearrangements, usually with intraclonal diversity. It is unclear whether intraclonal V gene diversification by somatic hypermutation, which is strictly dependent on the enzyme activation induced cytidine deaminase (AID), is restricted to the early phase of lymphoma clone expansion and later silenced, or whether it remains active throughout malignant proliferation. Aims: To analyse whether AID is expressed in L&H cells as an indicator of active somatic hypermutation in the tumour cells. Methods: L&H cells from lymphocyte predominant HL cases and centroblasts from lymphadenites were micromanipulated and analysed for AID expression by quantitative real time polymerase chain reaction. Results: The AID transcription level was higher than background in three of the six lymphocyte predominant HL cases, although it was lower than that seen in centroblasts. Conclusions: Somatic hypermutation may remain active in L&H cells in a considerable proportion of cases, increasing the risk of acquiring further transforming mutations

Epstein-Barr virus (EBV)-positive lymphoproliferations in post-transplant patients show immunoglobulin V gene mutation patterns suggesting interference of EBV with normal B cell differentiation processes

In a model for persistent infection, Epstein-Barr virus (EBV) uses the germinal center (GC) reaction to establish persistence in memory B cells. To study whether EBV adopts to normal B cell differentiation processes also in EBV-associated lymphoproliferative diseases, we micromanipulated EBV(+) cells from biopsies of five patients with post-transplantation lymphoproliferative disease (PTLD) and one unusual Hodgkin lymphoma with many small EBV(+) cells, and analyzed rearranged V genes of single cells. In all cases clonal expansions of EBV(+) B cells were identified. The vast majority of these clones carried mutated V gene rearrangements and a fraction of clones showed ongoing hypermutation. Hence, PTLD likely derive from GC and/or post-GC B cells. In two clones hypermutation occurred in the absence of follicular dendritic and CD4(+) T cells, important interaction partners of normal GC B cells. Furthermore, in one case sustained somatic hypermutation occurred without expression of a functional antigen receptor. Hence, EBV(+) B cells in PTLD can retain or acquire features of GC B cells in an unphysiological setting and may continue to undergo somatic hypermutation uncoupled from normal selection processes, suggesting that EBV interferes with normal B cell differentiation and selection processes in PTL

Basiswissen Sicherheitstests: Aus- und Weiterbildung zum ISTQB® Advanced Level Specialist - Certified Security Tester

Die Sicherheit von IT-Systemen ist heute eine der wichtigsten Qualitätseigenschaften. Wie für andere Eigenschaften gilt auch hier das Ziel, fortwährend sicherzustellen, dass ein IT-System den nötigen Sicherheitsanforderungen genügt, dass diese in einem Kontext effektiv sind und etwaige Fehlerzustände in Form von Sicherheitsproblemen bekannt sind. Die Autoren geben einen fundierten, praxisorientierten Überblick über die technischen, organisatorischen, prozessoralen, aber auch menschlichen Aspekte des Sicherheitstestens und vermitteln das notwendige Praxiswissen, um für IT-Anwendungen die Sicherheit zu erreichen, die für eine wirtschaftlich sinnvolle und regulationskonforme Inbetriebnahme von Softwaresystemen notwendig ist