Myocardial inflammatory cells in cardiac amyloidosis.

BACKGROUND: Immunoglobulin derived AL amyloidosis and transthyretin derived ATTR amyloidosis are the most common forms of cardiac amyloidosis. Both may present with cardiac arrhythmias, heart failure, and extracardiac symptoms. Disease outcome is often fatal. Recently, it was proposed that amyloid may cause cardiac inflammation. Here we tested the hypothesis that immune cell infiltration in cardiac tissue correlates with clinicopathological patient characteristics. PATIENTS AND METHODS: Myocardial biopsies from 157 patients with cardiac amyloidosis (46.5% AL, 53.3% ATTR) were immunohistochemically assessed for the presence and amount of T lymphocytes (CD3), macrophages (CD68) and neutrophils (MPO). Amyloid load, cardiomyocyte diameter, apoptosis (Caspase 3), necrosis (complement 9), and various clinical parameters were assessed and correlated with immune cell density. RESULTS: Myocardial tissue was infiltrated with T lymphocytes (CD3), macrophages (CD68) and neutrophils (MPO) with variable amounts. Significant correlations were found between the number of macrophages and NYHA class. No correlations were found between the presence and amount of T lymphocytes, neutrophils and clinicopathological patient characteristics. CONCLUSION: The significant correlation between cardiac macrophage density and heart failure points towards a significant role of macrophages in disease pathology.

From the midfacial destructive drama to the unfolding EBV story: a short history of EBV-positive NK-cell and T-cell lymphoproliferative diseases.

Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus that has been related to oncogenesis of lymphoid and epithelial malignancies. Although the mechanism of EBV infection of NK and T cells remains enigmatic, it plays a pathogenic role in various EBV+ NK-cell and T-cell lymphoproliferative diseases (LPDs), through promotion of cell activation pathways, inhibition of cell apoptotic pathways, behaving as oncogenes, interacting with host oncogenes or acting epigenetically. The study of NK-cell LPDs, previously hampered by the lack of immunophenotypical and genotypical criteria of NK cells, has become feasible with the recently accepted criteria. EBV+ NK- and T-cell LPDs are mostly of poor prognosis. This review delivers a short history from primeval to recent EBV+ NK- and T-cell LPDs in non-immunocompromised subjects, coupled with increasing interest, and work on the biological and oncogenic roles of EBV.

The genomic basis of childhood T-lineage acute lymphoblastic leukaemia.

T-lineage acute lymphoblastic leukaemia (T-ALL) is a high-risk tumour1 that has eluded comprehensive genomic characterization, which is partly due to the high frequency of noncoding genomic alterations that result in oncogene deregulation2,3. Here we report an integrated analysis of genome and transcriptome sequencing of tumour and remission samples from more than 1,300 uniformly treated children with T-ALL, coupled with epigenomic and single-cell analyses of malignant and normal T cell precursors. This approach identified 15 subtypes with distinct genomic drivers, gene expression patterns, developmental states and outcomes. Analyses of chromatin topology revealed multiple mechanisms of enhancer deregulation that involve enhancers and genes in a subtype-specific manner, thereby demonstrating widespread involvement of the noncoding genome. We show that the immunophenotypically described, high-risk entity of early T cell precursor ALL is superseded by a broader category of 'early T cell precursor-like' leukaemia. This category has a variable immunophenotype and diverse genomic alterations of a core set of genes that encode regulators of hematopoietic stem cell development. Using multivariable outcome models, we show that genetic subtypes, driver and concomitant genetic alterations independently predict treatment failure and survival. These findings provide a roadmap for the classification, risk stratification and mechanistic understanding of this disease.

Rare genetic variants provide a mechanistic basis for immune imbalance in IgG4-related disease.

Autoimmune diseases are commonly associated with a polygenic inheritance pattern. In rare instances, causal monogenic variants have been identified. The study by Liu et al. in this issue of the JCI provides an example of monogenic variants occurring in patients with IgG4-related disease (IgG4-RD). The authors investigated a familial cluster of IgG4-RD that consisted of an affected father and two daughters; the mother was unaffected. Genome sequencing of this quad identified a variant in IKZF1 (encoding IKAROS) and another variant in UBR4 (encoding E3 ubiquitin ligase). Both variants were present in the father and both daughters but absent in the unaffected mother. Using multidimensional profiling of immune cells and functional experiments in primary cells, the authors determined a molecular pathway contributing to T cell activation in IgG4-RD. Importantly, the characterization of these variants provides insights into pathogenic mechanisms in IgG4-RD and, potentially, other autoimmune diseases.

HER2 amplification subtype intrahepatic cholangiocarcinoma exhibits high mutation burden and T cell exhaustion microenvironment.

OBJECTIVE: This study aimed to establish a uniform standard for the interpretation of HER2 gene and protein statuses in intrahepatic cholangiocarcinoma (ICC). We also intended to explore the clinical pathological characteristics, molecular features, RNA expression and immune microenvironment of HER2-positive ICC. METHODS: We analyzed a cohort of 304 ICCs using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) to identify HER2 status. Comprehensive analyses of the clinicopathological, molecular genetic, and RNA expression characterizations of ICCs with varying HER2 statuses were performed using next-generation sequencing. We further investigated the tumor microenvironment of ICCs with different HER2 statuses using IHC and multiplex immunofluorescence staining. RESULTS: HER2/CEP17 ratio of ≥ 2.0 and HER2 copy number ≥ 4.0; or HER2 copy number ≥ 6.0 were setup as FISH positive criteria. Based on this criterion, 13 (4.27%, 13/304) samples were classified as having HER2 amplification. The agreement between FISH and IHC results in ICC was poor. HER2-amplified cases demonstrated a higher tumor mutational burden compared to non-amplified cases. No significant differences were observed in immune markers between the two groups. However, an increased density of CD8 + CTLA4 + and CD8 + FOXP3 + cells was identified in HER2 gene-amplified cases. CONCLUSION: FISH proves to be more appropriate as the gold standard for HER2 evaluation in ICC. HER2 gene-amplified ICCs exhibit poorer prognosis, higher mutational burden, and T cell exhaustion and immune suppressed microenvironment.

[Clinicopathological features of primary mucosal CD30-positive T-cell lymphoproliferative disorders].

Objective: To investigate the clinicopathological features and differential diagnosis of primary mucosal CD30-positive T-cell lymphoproliferative disorders (pmCD30+TLPD). Methods: Eight cases of pmCD30+TLPD diagnosed from 2013 to 2023 at the Department of Pathology, Beijing Friendship Hospital Affiliated to Capital Medical University and Beijing Ludaopei Hospital were retrospectively collected. The immunophenotype, EBV infection status and T-cell receptor (TCR) clonability of tumor cells were examined. The clinicopathological features were analyzed and related literatures were reviewed. Results: There were 5 females and 3 males, aged 28 to 73 years, without B symptoms, lack of trauma and autoimmune diseases. Seven cases occurred in oral mucosa and one in anal canal mucosa. Submucosal nodules with ulcerations were presented in all cases except one, which only submucosal nodule. Morphologically, there was different distribution of allotypic lymphocytes in inflammatory background. Four cases showed "kidney-shaped", "embryonic" and "horseshoe-shaped" cells, and one case resembled Hodgkin and Reed/Sternberg (HRS) cells. Allotypic lymphocytes expressed CD3 (7/8), CD4+/CD8-(7/8) and CD4-/CD8-(1/8). CD30 was uniformly strongly positive while ALK and CD56 were negative. In situ hybridization of EBER was negative in five cases (5/5). Clonal TCR gene rearrangement was positive in two cases. Four patients did not receive radiotherapy or chemotherapy. All the seven patients survived without disease except one died due to concurrent leukopenia. Conclusions: pmCD30+TLPD had a broad morphological spectrum and could be easily confused with primary cutaneous CD30+TLPD and systemic ALK-negative anaplastic large cell lymphoma involving mucosa, which may lead to misdiagnosis. Although the majority of the cases had a favorable prognosis, a few cases relapsed or progressed to lymphoma.

Mature B, T and NK-cell, plasma cell and histiocytic/dendritic cell neoplasms: classification according to the World Health Organization and International Consensus Classification.

In 2022, two updated classification systems for lymphoid neoplasms were published by the World Health Organization (WHO Classification of Haematolymphoid Tumours, 5th edition, referred to hereafter as WHO-HAEM5) and the International Consensus Conference (ICC) (Alaggio et al. in Leukemia 36(7):1720-1748, 2022; Campo et al. in Blood 140(11):1229-1253, 2022). Both classifications were conceived by both pathologists and clinicians with expertise in the field. The reasons for this have been reviewed previously (Arber et al. in Virchows Arch 482(1):1-9, 2023; Cree in Leukemia 36(7):1701-1702, 2022, Leukemia 36(11):2750, 2022). Given that both groups were using data-driven processes and consensus and used the revised 4th edition of the WHO Classification of Haematolymphoid Tumours (WHO-HAEM4R) as a starting point, it is not entirely surprising that the resulting classifications are quite similar. However, they are not identical and reflect preferences or approaches for certain unsettled areas as well as preferred terminology. In this review, we will compare nomenclature of the WHO-HAEM5 and ICC classifications, focusing on lymphoid neoplasms and lymphoproliferative disorders (LPDs).

Intraoral CD30+ T-Cell Lymphoproliferative Disorder with Lymphomatoid Papulosis Type C Features Mimics Lymphoma Histopathologically and Immunohistochemically.

BACKGROUND: Previous studies have shown that at least a of intraoral eosinophilic ulcer is best classified as a CD30 + T-cell lymphoproliferative disorder (LPD), with histopathology reminiscent of lymphomatoid papulosis (LyP) of the skin. Microscopically, a mixed population of inflammatory cells, often including eosinophils and varying numbers of atypical lymphoid cells, frequently expressing CD30, is typical for LyP, whose clinicopathological spectrum includes type A, B, C, D, E, and LyP with DUSP22/IRF4 rearrangement. To date, about 27 intraoral LyP cases have been reported. Of them, 7 cases were diagnosed as LyP type C, which is frequently confused with anaplastic large cell lymphoma (ALCL) on histopathology. METHODS: A 60-year-old male was referred for a one-month history of a tongue ulcer. RESULTS: Microscopy showed numerous subepithelial atypical large lymphoid cells, which expressed CD4 (with partial loss of CD3, CD5, and CD7), CD8 (few cells), CD30 (about 50%, in non-diffuse pattern with size variability), TIA-1, and Ki-67 (85%), without staining for CD56, ALK, LMP1, and EBER1/2, concerning for a diagnosis of ALCL. However, after three weeks, the lesion completely healed. CONCLUSION: We present here a rare case of intraoral CD30+ T-cell LPD that we believe is the oral counterpart of cutaneous LyP type C.

Ectopic pleural thymoma with T-cell lymphocytosis and bone metastasis: a case report.

BACKGROUND: The diagnostic complexities that arise in radiographic distinction between ectopic pleural thymoma and other thoracic neoplasms are substantial, with instances of co-occurring T-cell lymphocytosis and osseous metastasis being exceedingly rare. CASE PRESENTATION: A 51-year-old woman was admitted to our hospital with dyspnea and chest pain. Upon imaging examination, she was found to have diffuse and nodular pleural thickening on the left side, collapse of the left lung and a compression in the second thoracic vertebrae. All lesions showed significant 18F-FDG uptake on 18F-FDG PET/CT examination. Furthermore, she exhibited T-cell lymphocytosis in her peripheral blood, lymph nodes, and bone marrow. After ruling out malignant pleural mesothelioma (MPM), lung cancer with pleural metastasis, and T-cell lymphoma, the definitive diagnosis asserted was ectopic pleural thymoma with T-cell lymphocytosis and bone metastasis. CONCLUSION: Physicians need to expand their knowledge of the imaging features of ectopic pleural thymoma. Cases with T-cell lymphocytosis may exhibit increased aggressiveness and prone to bone metastasis.

PIK3CA inhibition in models of proliferative glomerulonephritis and lupus nephritis.

Proliferative glomerulonephritis is a severe condition that often leads to kidney failure. There is a significant lack of effective treatment for these disorders. Here, following the identification of a somatic PIK3CA gain-of-function mutation in podocytes of a patient, we demonstrate using multiple genetically engineered mouse models, single-cell RNA sequencing, and spatial transcriptomics the crucial role played by this pathway for proliferative glomerulonephritis development by promoting podocyte proliferation, dedifferentiation, and inflammation. Additionally, we show that alpelisib, a PI3Kα inhibitor, improves glomerular lesions and kidney function in different mouse models of proliferative glomerulonephritis and lupus nephritis by targeting podocytes. Surprisingly, we determined that pharmacological inhibition of PI3Kα affects B and T lymphocyte populations in lupus nephritis mouse models, with a decrease in the production of proinflammatory cytokines, autoantibodies, and glomerular complement deposition, which are all characteristic features of PI3Kδ inhibition, the primary PI3K isoform expressed in lymphocytes. Importantly, PI3Kα inhibition does not impact lymphocyte function under normal conditions. These findings were then confirmed in human lymphocytes isolated from patients with active lupus nephritis. In conclusion, we demonstrate the major role played by PI3Kα in proliferative glomerulonephritis and show that in this condition, alpelisib acts on both podocytes and the immune system.

[Interpretation of T-cell and NK-cell lymphoid proliferations and lymphomas in the 5th edition of the WHO classification of haematolymphoid tumours].

The 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumours used the hierarchical system to classify T-cell and NK-cell lymphoid proliferations and lymphomas (T/NK-LPD/LYM) based on research advances and clinicopathological characteristics of the diseases. In this edition of classification, tumour-like lesions were included, some tumors were added/deleted, the names or terms of certain diseases were refined, and the diagnostic criteria or subtypes of some diseases were revised. This group of diseases was reintegrated from non-clonal hyperplasia to highly aggressive lymphoma, which would further reflect the nature of T/NK-LPD/LYM and benefit to clinical application.

10× single-cell sequencing revealed cellular composition heterogeneity in cardiac myxoma with malignant glandular properties.

Cardiac myxoma is the most common primary cardiac tumor in adults. The histogenesis and cellular composition of myxoma are still unclear. This study aims to reveal the role of myxoma cell components and their gene expression in tumor development. We obtained single living cells by enzymatic digestion of tissues from 4 cases of surgically resected cardiac myxoma. Of course, there was 1 case of glandular myxoma and 3 cases of nonglandular myxoma. Then, 10× single-cell sequencing was performed. We identified 12 types and 11 types of cell populations in glandular myxoma and nonglandular myxoma, respectively. Heterogeneous epithelial cells are the main components of glandular myxoma. The similarities and differences in T cells in both glandular and nonglandular myxoma were analyzed by KEGG and GO. The most important finding was that there was active communication between T cells and epithelial cells. These results clarify the possible tissue occurrence and heterogeneity of cardiac myxoma and provide a theoretical basis and guidance for clinical diagnosis and treatment.

Null T-cell phenotype mycosis fungoides with aberrant CD20 and CD56 expression: A diagnostic dilemma.

Mycosis fungoides (MF) represents the most common type of primary cutaneous T-cell lymphoma. Recognition of MF variants with divergent immunophenotypes is important for accurate diagnosis and appropriate management, as they can be confused with other lymphoma subtypes. We present a case of a 49-year-old male previously diagnosed with a cutaneous lymphoproliferative disorder with an unusual NK/T-cell phenotype. He presented with a 10-year history of pelvic girdle rash involving the right hip and upper thigh. The lesions were characterized as atrophic patches concentrated in sun-protected areas and involving 10% of the body surface area. Shave biopsies revealed an atypical epidermotropic infiltrate composed of hyperchromatic small to medium-sized lymphocytes with perinuclear halos and "tagging" along the dermal-epidermal junction. The immunophenotype was unusual in that the neoplastic lymphocytes showed complete loss of pan T-cell antigens along with expression of CD56, cytotoxic markers, and weak CD20. All other B-cell markers were negative. The combination of clinical findings, in addition to the histopathologic and immunophenotypic profile, were diagnostic of null T-cell phenotype MF with aberrant expression of CD56 and CD20. Null T-cell phenotype MF is very uncommon, can be diagnostically challenging, and can mislead the diagnosis of aggressive lymphoma subtypes.

Fifth Edition of the World Health Organization Classification of Tumors of the Hematopoietic and Lymphoid Tissues: Mature T-Cell, NK-Cell, and Stroma-Derived Neoplasms of Lymphoid Tissues.

This review focuses on mature T cells, natural killer (NK) cells, and stroma-derived neoplasms in the fifth edition of the World Health Organization classification of hematolymphoid tumors, including changes from the revised fourth edition. Overall, information has expanded, primarily due to advancements in genomic understanding. The updated classification adopts a hierarchical format. The updated classification relies on a multidisciplinary approach, incorporating insights from a diverse group of pathologists, clinicians, and geneticists. Indolent NK-cell lymphoproliferative disorder of the gastrointestinal tract, Epstein-Barr virus-positive nodal T- and NK-cell lymphoma, and several stroma-derived neoplasms of lymphoid tissues have been newly introduced or included. The review also provides guidance on how the fifth edition of the World Health Organization classification of hematolymphoid tumors can be applied in routine clinical practice.

Spatial phenotyping of nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B-cell lymphoma.

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma with sparse tumor B-cells and a favorable prognosis. Variant growth patterns of NLPHL, however, often show advanced stage, progression to T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) and a worse prognosis. We studied the tumor microenvironment (TME) of NLPHL and THRLBCL using highplex imaging and spatial profiling at the single cell level. Our findings show distinct differences in TME composition and spatial configuration that differ among typical and variant NLPHL and THRLBCL. Typical NLPHL show abundant helper T-cell subsets, while THRLBCL show abundant cytotoxic T-cells and macrophages. Tumor B-cell size and content is lowest in typical NLPHL, followed by variant NLPHL, and highest in THRLBCL, whereas an opposite trend characterized TME B-cells. CD4/CD8 double-positive T-cells are seen in all NLPHL but not in the majority of THRLBCL and are spatially distant from LP-cells and TFH-rosettes. The differences in macrophage/monocyte content in distinguishing NLPHL pattern E from THRLBCL is further corroborated in independent cohorts of cases. Our results validate the current approach to classification and in addition provide novel insights that could be leveraged to refine clinical management for patients with this spectrum of lymphomas.