Immunophenotypic Studies Research Articles

Диагностика врожденных дефектов иммунитета в многопрофильном стационаре: обзор клинических наблюдений

Inborn errors of immunity (IEI) are rare heterogeneous diseases with a wide range of clinical manifestations that makes its diagnosis difficult for practitioners of different specialties. The purpose of this research was to describe a series of clinical case reports of primary immunodeficiencies (PIDs) diagnosis using the TREC/KREC assay in a multidisciplinary hospital. In order to verify the diagnosis, TREC/KREC determination, immunophenotyping and molecular genetic studies were performed. Thirty-nine patients with alarming signs of PIDs were examined within a period of 18 months. Primary immunodeficiencies were identified in 6 (31.6%) children with congenital malformations, in 5 (50%) with resistant cytopenias and in 3 (30%) with severe infections. Syndromal IDs were diagnosed in 8 (57.1%), combined immunodeficiency in a single patient (7.1%), immune regulation defects in 2 (14.3%) and antibody formation disorders in 3 (21.5%). Abnormal TREC/KREC values were established in 9 (64.3%) patients with IEI at the early stages of diagnostic search. Thus, TREC/KREC assay is an effective method for IEI diagnosis within a multidisciplinary hospital.

Primary anaplastic T-cell lymphoma of the omentum presenting as small bowel obstruction and complicated with Massilia timonae infection: a case report

BackgroundAnaplastic large-cell lymphoma primarily involving the omentum is an extremely rare entity with variable clinical presentation. Owing to its rarity and nonspecific clinical manifestation, omental T-cell lymphoma is often diagnosed at a later stage, riddled with complications. While imaging modalities such as computed tomography scan can help a physician reach a diagnosis, cases that present with complications may require a multidisciplinary approach that combines surgical exploration along with consultation from Oncology.Case presentationWe hereby report a rare case of a 66-year-old African American male patient who presented to the emergency department with complaints of acute gastrointestinal obstruction. A computed tomography scan of the abdomen and pelvis revealed evidence of an internal hernia and surgical exploration revealed a hemorrhagic and infarcted omentum. Biopsies along with immunophenotypic studies confirmed the diagnosis of anaplastic T-cell lymphoma of the omentum complicated by Massilia timonae infection.ConclusionThe case highlights the significance of considering lymphoma, although rare, as a differential in a patient who presents with small bowel obstruction and the importance of investigating for malignancy for early diagnosis and treatment of primary omental lymphomas, before complications develop.

NEURONAL INJURY DRIVES GLIOBLASTOMA INITIATION

Abstract AIMS Glioblastoma (GBM), the most common primary brain malignancy in adults, remains incurable. Pervasive heterogeneity and plasticity underpin therapy resistance and lethal recurrence, suggesting that prevention or earlier intervention may be required. Improved understanding of GBM initiation is a prerequisite for achieving this goal. GBM frequently originates from neural stem cells (NSCs) of the subventricular zone, which, upon acquisition of mutations, migrate away from their niche and form tumours at distal sites through unknown mechanisms. Here, we explored GBM initiation and its microenvironment. METHOD We combined a murine somatic GBM model which faithfully recapitulates the human disease with PDX models and patient tissue datasets. We used immunohistochemistry, scRNA-sequencing, immuno-phenotyping, behavioural and survival studies and in vivo gain- and loss-of-function experiments in Sarm1-/- lines. RESULTS Time-course analysis of tumour development identified neuronal degeneration as an early event in GBM tumourigenesis, occurring preferentially in white matter, where we find mutated NSCs are immediately rerouted. Axonal loss was accompanied by a robust inflammatory response, marked by microglial and astrocytic activation. Neuronal degeneration played a causative role, in that transection injury of corpus callosum axons accelerated tumourigenesis and, conversely, GBM development was delayed in Sarm1-/- mice with impaired Wallerian degeneration, a major mode of neuronal death following injury. Consistently, terminal Sarm1-/- tumours were more diffuse, contained more immature tumour cells and were less immune-infiltrated than their WT counterparts. Strikingly, behavioural studies revealed that Sarm1-/- tumour-bearing mice also retained improved motor performance compared to WT mice, even at terminal disease stages. CONCLUSION Our work provides important insights into GBM development, identifying white matter injury as a key initiating event, elicited by early tumour cells and orchestrated by neuronal degeneration. It identifies Wallerian degeneration, a druggable pathway already in clinical trials for neurodegenerative diseases, as a therapeutic target for GBM, with the potential to extend survival and ameliorate cognition.

Immunophenotyping schizophrenia subtypes stratified by antipsychotic response

Immune dysfunction has been proposed to play a role in the pathophysiology behind the development and persistence of psychosis. Current immunophenotyping studies are limited by small sample sizes and the number of immune markers investigated. Pharmacological subtypes in schizophrenia based on antipsychotic response have been proposed, but few studies have investigated immunophenotypes in treatment-resistant schizophrenia. In this study, we perform comprehensive immunophenotyping on 196 subjects comprising 147 schizophrenia patients stratified by antipsychotic response (49 antipsychotic-responsive, 70 clozapine-responsive, 28 clozapine-resistant) and 49 healthy controls. We aim to identify significant immune cell populations associated with schizophrenia and increasing treatment resistance, as potential modulators of underlying psychosis and/or treatment response. Patients with schizophrenia were recruited and assessed on the Clinical Global Impression – Schizophrenia (CGI-SCH). Treatment response was defined as a rating of three (mild severity) or less on the CGI-SCH positive symptom item after at least 8 weeks of adequate antipsychotic or clozapine treatment. Peripheral blood mononuclear cells were collected and flow cytometry was performed to identify 66 immune cell populations. Differences in cell population proportions were compared between schizophrenia cases and controls, and across all 4 groups, with post-hoc pairwise comparisons. Mucosal-associated invariant T (MAIT) cells (specifically CD8 + and DN double-negative subsets), total, exhausted and memory CD8 + T cells, VD1 + ϒδ T cells, plasmablasts, IgG + B cells and conventional dendritic cells 2 (cDC2) were among the top cell populations downregulated in schizophrenia. We observed increased downregulation with increasing treatment resistance. Conversely, naïve and exhausted CD4 + T cells, CD4/CD8 ratio and CCR5 + CCR2 + HLA DR + Myeloid cells were found to be upregulated in schizophrenia — we observed increased upregulation with increasing treatment resistance. We show significant immunophenotypic differences between schizophrenia cases and healthy controls, and consistent trend differences across varying degrees of antipsychotic resistance. We also examined immune cell populations not previously reported in schizophrenia. Future studies may explore immune markers identified as potential biomarkers of treatment resistance, and clarify on the relationship between immunological changes and pharmacological subtypes in schizophrenia.

High concentration of estrogen resulted by COH may affect the secretion of pro-angiogenic factors in uNK cells by downregulating the expression of IL-11 in decidual stromal cells.

High serum estrogen concentrations after controlled ovarian hyperstimulation (COH) and fresh embryo transfers are associated with the increased risk of pregnancy complications resulting from aberrant placentation. Uterine natural killer (uNK) cells are important for establishment of pregnancy and normal placentation. It has been found that the proliferation and function of uNK cells are compromised by COH. However, the underlying role of high concentration of estrogen following COH in the abnormalities of uNK cells is poorly understood. Expression of cytokines and immunophenotype study of uNK was performed by flow cytometry analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to quantify RNA expression; Western blot was performed to quantify protein levels. The secretion level of pro-angiogenic factors in uNK cells is significantly reduced by co-culture with decidual stromal cells (DSCs) induced by high estrogen. It was discovered that COH and supraphysiologic levels of estrogen downregulated IL-11 in decidual tissue of mice. Additionally, we found that the downregulation of IL-11 is a major factor contributing to the downregulation of VEGF and PLGF in uNK cells. Moreover, we found that uNK cells may acquire IL-11Rα sequentially during differentiation and that only a portion of uNK cells are IL-11Rα positive. Lastly, we discovered that IL-11 may regulate VEGF and PLGF secretion in uNK cells via the ERK signaling pathway. These results suggested the downregulation of IL-11 expression in DSCs caused by high estrogen levels affects the secretion of pro-angiogenic factors in uNK cells, which provided an explanation for the pregnancy complications caused by COH.

A Case Series of Primary Cutaneous Sarcomatoid Carcinoma With Aberrant Smooth Muscle Actin Expression: A Clinicopathologic and Immunophenotypic Study.

Primary cutaneous sarcomatoid squamous cell carcinoma can show significant histologic overlap with other malignant spindle cell tumors, posing a diagnostic challenge. Even with a wide array of immunohistochemical markers, the exact line of differentiation can be a challenge to identify in some cases. The picture is further complicated by the aberrant expression of myofibroblastic markers [such as smooth muscle actin (SMA)] by these neoplasms, along with a concomitant loss of conventional epithelial markers. The histologic differential diagnoses of primary cutaneous sarcomatoid squamous cell carcinoma include desmoplastic melanoma, leiomyosarcoma, and spindle cell atypical fibroxanthoma/pleomorphic dermal sarcoma (AFX/PDS). A retrospective analysis of 16 cases of PCSSCCs with SMA expression, obtained from large academic institutions, was performed and is summarized below. The tumors were in the scalp (6 cases), arm (4 cases), leg (2 cases), face (2 cases), hand (1 case), and neck (1 case). Immunohistochemical studies were performed in all cases with the following antibodies: AE1/AE3, CAM 5.2, MNF-116, p63, p40, CK5/6, S-100, SOX10, SMA, desmin, calponin, H-caldesmon, CD10, CD68, CD163, and CD34. Histopathologically, all cases were classified as high-grade malignant poorly differentiated neoplasms. Tumors were characterized by an infiltrative neoplasm that involved the entire reticular dermis and, in 7 cases, the subcutaneous fat. Three cases were associated with a well-differentiated squamous cell component. The neoplasms were composed of atypical spindle and epithelioid cells arranged in long and intersecting fascicles. All neoplasms were positive for epithelial markers (at least 1 marker), and all cases were strongly positive for SMA. Our data emphasize the diagnostic utility of multiple epithelial markers as a first screening tool in the detection and workup of malignant cutaneous sarcomatoid neoplasms. Awareness of SMA expression in these tumors can complicate its diagnosis, and it is important to recognize this aberrant immunophenotype to facilitate definitive diagnosis and avoid misdiagnosis.

Peripheral T Cell Development and Immunophenotyping of Twins with Heterozygous FOXN1 Mutations.

The transcription factor FOXN1 plays an established role in thymic epithelial development to mediate selection of maturing thymocytes. Patients with heterozygous loss-of-function FOXN1 variants are associated with T cell lymphopenia at birth and low TCR excision circles that can ultimately recover. Although CD4+ T cell reconstitution in these patients is not completely understood, a lower proportion of naive T cells in adults has suggested a role for homeostatic proliferation. In this study, we present an immunophenotyping study of fraternal twins with low TCR excision circles at birth. Targeted primary immunodeficiency testing revealed a heterozygous variant of uncertain significance in FOXN1 (c.1205del, p.Pro402Leufs*148). We present the immune phenotypes of these two patients, as well as their father who carries the same FOXN1 variant, to demonstrate an evolving immune environment over time. While FOXN1 haploinsufficiency may contribute to thymic defects and T cell lymphopenia, we characterized the transcriptional activity and DNA binding of the heterozygous FOXN1 variant in 293T cells and found the FOXN1 variant to have different effects across several target genes. These data suggest multiple mechanisms for similar FOXN1 variants pathogenicity that may be mutation specific. Increased understanding of how these variants drive transcriptional regulation to impact immune cell populations will guide the potential need for therapeutics, risk for infection or autoimmunity over time, and help inform clinical decisions for other variants that might arise.

Bone Marrow Aspiration and Biopsy Findings in Patients with Hematological Disorders in a Tertiary Care Center from Eastern Nepal: An Institutional Experience

Background: Bone marrow study is an important study which is performed when the peripheral blood examination and other laboratory tests and clinical signs and symptoms are suggestive and sometimes inconclusive of both hematological neoplastic and non-neoplastic conditions. The aim of this study was to study about the indications of bone marrow to assess the diagnostic value and comparison of microscopic findings with immunophenotyping and molecular studies. Methods: A total of 102cases were analyzed retrospectively and prospectively from January 2022 to October 2023. All the bone marrow aspiration and trephine biopsy received at the laboratory during this period were included in the study and other cases were analyzed form medical record of the department. Results: Among the 102 cases, mean age of the patient was 48 years and majority were male patients. The age range was between 17-80 years. The male: female ratio was 1.25:1. Weakness was most common presenting complain. Acute leukemia was the most frequent diagnosis (24.5%) followed by myeloproliferative neoplasm (7.8%), primary aplastic anemia (6.9%), myelodysplastic syndrome (5.8%), megaloblastic anemia (4.9%) and plasma cell dyscrasia (3.9%), CLPD (2.9%), ITP (1.9%). Reactive marrow constituted 3.9% and few of the rare diagnosis included hypereosinophilia with PDGFRA mutation, Leishmaniasis etc. Conclusions: The study concludes the bone marrow aspirate and biopsy examination is still the gold standard technique for screening and definite diagnosis of hematological conditions. Immunophenotyping and molecular studies are important for treatment purpose and in case of cytomorphological dilemma.

Immunophenotypic but Not Genetic Changes Reclassify the Majority of Relapsed/Refractory Pediatric Cases of Early T-Cell Precursor Acute Lymphoblastic Leukemia.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) develops from very early cells with the potential for both T-cell and myeloid differentiation. The ambiguous nature of leukemic blasts in ETP-ALL may lead to immunophenotypic alterations at relapse. Here, we address immunophenotypic alterations and related classification issues, as well as genetic features of relapsed pediatric ETP-ALL. Between 2017 and 2022, 7518 patients were diagnosed with acute leukemia (AL). In addition to conventional immunophenotyping, karyotyping, and FISH studies, we performed next-generation sequencing of the T-cell receptor clonal repertoire and reverse transcription PCR and RNA sequencing for patients with ETP-ALL at both initial diagnosis and relapse. Among a total of 534 patients diagnosed with T-cell ALL (7.1%), 60 had ETP-ALL (11.2%). Ten patients with ETP-ALL experienced relapse or progression on therapy (16.7%), with a median time to event of 5 months (ranging from two weeks to 5 years). Most relapses were classified as AL of ambiguous lineage (n = 5) and acute myeloid leukemia (AML) (n = 4). Major genetic markers of leukemic cells remained unchanged at relapse. Of the patients with relapse, four had polyclonal leukemic populations and a relapse with AML or bilineal mixed-phenotype AL (MPAL). Three patients had clonal TRD rearrangements and relapse with AML, undifferentiated AL, or retention of the ETP-ALL phenotype. ETP-ALL relapse requires careful clinical and laboratory diagnosis. Treatment decisions should rely mainly on initial examination data, taking into account both immunophenotypic and molecular/genetic characteristics.

Renal B-lymphoblastic lymphoma with hematuria as the first symptom diagnosed in urine cytology: A case report and literature review.

Cytological examination of urine sediment is a helpful diagnostic tool for identifying renal involvement by hematological malignancies. We present the case of a 47-year-old man who was diagnosed with extranodal B-lymphoblastic lymphomas after presenting with gross hematuria as his first symptom. The presence of lymphoma cells in the urine led to a diagnosis confirmed through an immunophenotypic study using cell block sections of urine centrifuge sediment and core needle biopsy histology of the right renal pelvis mass. This case highlights the usefulness of a urine cytological study in diagnosing lymphoma involvement in the genitourinary tract. Furthermore, this paper reviews relevant literature on diagnosing lymphoma involvement from urine sediment.

Implementation of a roadmap for the comprehensive diagnosis, follow-up, and research of childhood leukemias in vulnerable regions of Mexico: results from the PRONAII Strategy.

The main objective of the National Project for Research and Incidence of Childhood Leukemias is to reduce early mortality rates for these neoplasms in the vulnerable regions of Mexico. This project was conducted in the states of Oaxaca, Puebla, and Tlaxcala. A key strategy of the project is the implementation of an effective roadmap to ensure that leukemia patients are the target of maximum benefit of interdisciplinary collaboration between researchers, clinicians, surveyors, and laboratories. This strategy guarantees the comprehensive management of diagnosis and follow-up samples of pediatric patients with leukemia, centralizing, managing, and analyzing the information collected. Additionally, it allows for a precise diagnosis and monitoring of the disease through immunophenotype and measurable residual disease (MRD) studies, enhancing research and supporting informed clinical decisions for the first time in these regions through a population-based study. This initiative has significantly improved the diagnostic capacity of leukemia in girls, boys, and adolescents in the regions of Oaxaca, Puebla, and Tlaxcala, providing comprehensive, high-quality care with full coverage in the region. Likewise, it has strengthened collaboration between health institutions, researchers, and professionals in the sector, which contributes to reducing the impact of the disease on the community.

Abstract 3988: Deep spatial immunophenotyping of lymphoid aggregates in pancreatic cancer using multi-omic integration of ultra high-plex proteomics and transcriptomics

Abstract The most well-described mechanism of immune evasion in PDAC is exclusion of immune cells by a desmoplastic stroma, but such immune exclusion is not uniform. Through single-nucleus RNA-seq and whole-transcriptome digital spatial profiling of patient tumors, we previously reported marked heterogeneity in the immune composition of PDAC. Here, we developed a novel multi-omics workflow integrating single cell spatial proteomics (96-plex, Akoya Phenocycler®-Fusion) and transcriptomics (990-plex, Nanostring CosMx) in primary patient PDAC tumors to systematically study spatial relationships and functional states of malignant, stromal, and immune cells. Consecutive sections from four independent tumors enabled whole slide proteomic assessment of >3.5M cells, and transcriptomic assessment of >200K cells. Strikingly, we observed an abundance of immune cell aggregates in all tissue sections, up to 57 within a 1 cm2 tumor section. Aggregates were diverse in composition with representation of myeloid cells, CD8+ T cells, and stromal cells, including fibroblasts and nerves. B/T lymphoid aggregates were well vascularized with co-localized CD31+CD34+ endothelial cells and appeared at various phases of maturation towards putative tertiary lymphoid structures (TLSs) containing CD38+ B cells, CD4+ T cells, and CD21+ follicular DCs. These tissues were enriched for interferon stimulated genes in T cells and type 1 interferon response signatures in malignant cells and cancer associated fibroblasts (CAFs) forming inflammatory multicellular hubs that have been associated with improved response to immune checkpoint blockade. Surprisingly, B cells, in addition to macrophages and CD8+ T cells, were major producers of interferon gamma (B cells: 13.7%, macrophages: 36.6%, CD8+ T cells: 12.1% of IFNG+ cells). Finally, to gain insight into the necessary factors for TLS formation in PDAC, we quantified the expression of chemokines and adhesion molecules associated with TLS initiation. Activated dendritic cells expressed CCL19 and CCL21, endothelial cells expressed CCL21, and in concert with inflammatory CAFs (iCAFs), CXCL12. Malignant cells expressed CXCL13 and CCL20 and displayed high levels of cell adhesion molecules ICAM1, VCAM1, and ICAM2. Together, our data suggests that the functions of lymphoid tissue organizer cells can be substituted by endothelial cells, dendritic cells, iCAFs, and, surprisingly, malignant cells. Our spatial immunophenotyping study of pancreatic cancer thus highlights the marked immune heterogeneity of the disease and suggests a central role for malignant and stromal cells in mediating diverse mechanisms of immune evasion and engagement. Functional studies will be conducted to investigate these mechanisms of tumor-immune crosstalk and identify novel immunotherapeutic vulnerabilities for this deadly disease. Citation Format: Dennis Gong, Jingyi Cao, Peter Wang, Niyati Jhaveri, Yue Hou, Bassem B. Cheikh, HaYeun Ji, Mark Gregory, Jason Reeves, Michael Patrick, Carina Shiau, Jennifer Su, Jimmy A. Guo, Joseph M. Beechem, Martin Hemberg, William L. Hwang, Ryan Park. Deep spatial immunophenotyping of lymphoid aggregates in pancreatic cancer using multi-omic integration of ultra high-plex proteomics and transcriptomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3988.

Abstract 2642: KEAP1 mutation in lung cancer cells leads to increased immunosuppressive capability

Abstract Considerable advances have been made in lung cancer therapies, but there is still an unmet clinical need to improve survival for lung cancer patients. Immunotherapies have improved survival, although only 20-30% of patients respond to these treatments. Interestingly, cancers with mutations in KEAP1, the negative regulator of the NRF2 cytoprotective pathway, are resistant to immune checkpoint inhibition and correlate with decreased immune cell infiltration. NRF2 is known for promoting an anti-inflammatory phenotype when activated in immune cells, but the study of NRF2 activation in cancer cells has not been adequately assessed. The overall objective of this study is to determine how lung cancer cells with constitutive NRF2 activity interact with the immune microenvironment to promote cancer progression and metastasis. To assess this, we generated CRISPR-edited mouse lung cancer cell lines (Lewis Lung Carcinoma/LL2) with knockouts (KO) of the KEAP1 and NFE2L2 genes. The transcriptomic profiles of 3 KEAP1 KO and 1 NRF2 KO cell lines were compared to the parental wildtype (WT) line using RNA-sequencing. On unsupervised hierarchical clustering of differentially expressed genes, the 3 KEAP1 KO cell lines clustered together and the NRF2 KO clustered with WT cells. Importantly, canonical NRF2 pathway-related genes were significantly increased in KEAP1 KO clones, but the same genes were either decreased or similar to WT in the NRF2 KO clone. We then used flow cytometry to evaluate immunosuppressive surface markers known to suppress T cell function when expressed on cancer cells. Importantly, PD-L1, CD155, CD80, and CD86 were increased in the KEAP1 KO lines compared to WT, but not in the NRF2 KO clone. In addition, the cytokine release profile was differentially regulated in the KEAP1 KO clones in a manner that could alter T cell recruitment and function. These results were also consistent with gene expression in the sequencing dataset. Finally, using an orthotopic allograft model, we completed a preliminary immunophenotyping study of lung tumors for WT, KEAP1 KO, and NRF2 KO cell lines. The activation status of CD8+ T cells and the ratio of CD8+/CD4+CD25+ T cells (a prognostic marker) were decreased in KEAP1 KO tumors. Taken together, these data suggest cancers with KEAP1 mutations may increase tumor growth through suppression of T cells. Citation Format: Christopher John Occhiuto, Karen T. Liby. KEAP1 mutation in lung cancer cells leads to increased immunosuppressive capability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2642.

An enigmatic cutaneous presentation of plasma cell granuloma- A rare case report

Plasma cell granuloma is a rare reactive tumour-like proliferations composed mainly of plasma cells, lymphocytes and innate immune cells like macrophages. Cutaneous plasma cell granuloma (CPCG) is extremely rare benign growth. A good immunophenotyping study is required to confirm the diagnosis. Surgical resection is the primary choice of treatment. We report a case of cutaneous plasma cell granuloma in an adult male.

P127 Sphingosine-1-Phosphate Receptor Blockade with Etrasimod alters Lymphocyte Trafficking in Crohn's Disease: Insights from High-Dimensional Phenotypic Mapping

Abstract Background The blockade of lymphocyte trafficking from the lymph nodes (LNs) towards the intestinal mucosa is an effective approach for the treatment of ulcerative colitis (UC). Etrasimod is an oral, once-daily (QD), selective sphingosine 1-phosphate (S1P)1,4,5 receptor (S1PR) modulator, which is currently also under investigation for Crohn’s disease (CD). The therapeutic mechanism of action of S1PR modulators in the context of inflammatory bowel disease (IBD) is not completely understood. It is hypothesized that both B and T- cell populations are affected by this treatment and are retained in the peripheral LNs, reducing circulating lymphocytes and resulting in fewer immune cells available to traffic in the gastrointestinal tract. Etrasimod has been reported to induce a partial and selective reduction of lymphocyte subsets in the blood of healthy subjects, but the direct effect of S1PR modulators on LN leukocytes has not been evaluated. The aim of this study was to investigate changes in leukocyte subpopulations in peripheral LNs and peripheral blood (PB) in response to S1PR inhibition with etrasimod in patients with CD. Methods CD patients with moderate to severe disease activity, participating in the Phase 2, double-blinded, non-placebo-controlled portion of the CULTIVATE trial, were eligible for this sub-study. At baseline and after 14 weeks of etrasimod induction treatment (2 or 3 mg/day), 10cc of PB and 4 ultrasound guided biopsy samples of an inguinal LN were obtained. The isolated peripheral blood mononuclear cells (PBMCs) and LN leukocyte populations, were analyzed at single cell level via high-dimensional immunophenotyping through mass cytometry (CyTOF) at both timepoints. Results We observed that in the LNs, the numbers/percentages of naïve, central and effector memory T-helper cells, as well as, of CD8+ naïve T-cells were increased after treatment with etrasimod. There was a decrease in the proportion of these cell populations in peripheral blood. Circulating naïve and memory B-cells were reduced, while these subsets where also slightly reduced in the LN compartment. Innate immune cell populations were not significantly altered. Conclusion Etrasimod induction treatment resulted in an increase of both naïve and central memory T-lymphocyte subsets in inguinal LNs, with a corresponding decrease in the periphery. The effect on the frequency of B-cells was not consistent in the LNs and PB, while innate immunotypes and T-regs, were not significantly affected. Despite the limited sample size, these selective effects were consistent with previously published PB immunophenotyping studies with etrasimod. This study was conducted as a collaboration between Amsterdam UMC and Pfizer.

What Does Atypical Chronic Lymphocytic Leukemia Really Mean? A Retrospective Morphological and Immunophenotypic Study.

Atypical chronic lymphocytic leukemia (CLL) is still defined according to morphological criteria. However, deviance from the typical surface immunological profile suggests an atypical immunological-based CLL. A large cohort of patients with CLL was retrospectively evaluated aiming at assessing morphological (FAB criteria), immunophenotypical (two or more discordances from the typical profile), and clinical-biological features of atypical CLL. Compared to typical cases, morphologically atypical CLL showed a greater percentage of unmutated IgVH and CD38 positivity, and a higher expression of CD20. Immunophenotypically atypical CLL was characterized by more advanced clinical stages, higher expression of CD20, higher rate of FMC7, CD79b and CD49d positivity, and by an intermediate-high expression of membrane surface immunoglobulin, compared to typical cases. When patients were categorized based on immunophenotypic and morphologic concordance or discordance, no difference emerged. Finally, morphological features better discriminated patients' prognosis in terms of time-to-first treatment, while concordant atypical cases showed overall a worse prognosis. Discordant cases by immunophenotype and/or morphology did not identify specific prognostic groups. Whether-in the era of molecular markers used as prognostic indicators-it does make sense to focus on morphology and immunophenotype features in CLL is still matter of debate needing further research.

Role of Angiogenesis and Endothelialmesenchymal Transition in Bone Marrow Fibrosis Associated with Haematopoietic Neoplasms: A Cross-sectional Immunohistochemical Analysis

Introduction: The bone marrow examination is an essential investigation in the diagnosis and management of many haematological disorders. The integration of all investigations, including peripheral blood analysis, bone marrow aspirate, and trephine biopsy findings, along with supplementary tests such as immunophenotyping, cytogenetic analysis, and molecular genetic studies, is crucial for arriving at a final diagnosis. Aim: To assess the presence of reticulin fibres in bone marrow biopsy sections in haematological malignancies, to evaluate the grade of BMF associated with haematological malignancies and to assess the role of angiogenesis using IHC markers in various haematological malignancies. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at the National Institute of Pathology, Safdarjung Hospital, New Delhi, India in 2009 for a duration of 18 months. Thirty-eight patients with a diagnosis of Acute Myeloid Leukaemia (AML), Acute Lymphoblastic Leukaemia (ALL), Chronic Myeloid Leukaemia (CML), and Chronic Lymphoproliferative Disorder (CLPD) were studied. Bone marrow biopsies were taken, fixed in 10% formalin, and decalcified in 10% Ethylene Diamine Tetraacetic Acid (EDTA). Routine paraffin embedding was performed, and serial sections of 4 µm were obtained on poly-L-lysine-coated slides for Immunohistochemistry (IHC) {Vimentin, Vascular Endothelial Growth Factor (VEGF), CD-34, Smooth Muscle Actin (SMA)}. The presence of reticulin fibres in the bone marrow biopsy sections was assessed using two special stains: Gomori’s Silver Impregnation and Masson’s Trichrome. Fibrosis was quantified according to the Baurmeister 0-4 grading system of Bone Marrow Fibrosis (BMF). Results: The results of the present study suggest that Endothelial to Mesenchymal Transition (EndMT) may play a role in the pathogenesis of BMF. Various grades of fibrosis were observed, with 15 cases (39.47%) in Grade 3, followed by 11 cases (28.95%) in Grade 2, 8 cases (21.05%) in Grade 1, and 4 cases (10.53%) in Grade 4. Conclusion: BMF was a significant finding even in the early stages of the majority of the lesions studied and was closely linked with angiogenesis. This study showed that angiogenesis plays an important role in the pathogenesis of haematological neoplasms and that VEGF is a prominent stimulus in the majority of these disorders. Additionally, this study suggests that EndMT has a possible role in the pathogenesis of BMF.Introduction: The bone marrow examination is an essential investigation in the diagnosis and management of many haematological disorders. The integration of all investigations, including peripheral blood analysis, bone marrow aspirate, and trephine biopsy findings, along with supplementary tests such as immunophenotyping, cytogenetic analysis, and molecular genetic studies, is crucial for arriving at a final diagnosis. Aim: To assess the presence of reticulin fibres in bone marrow biopsy sections in haematological malignancies, to evaluate the grade of BMF associated with haematological malignancies and to assess the role of angiogenesis using IHC markers in various haematological malignancies. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at the National Institute of Pathology, Safdarjung Hospital, New Delhi, India in 2009 for a duration of 18 months. Thirty-eight patients with a diagnosis of Acute Myeloid Leukaemia (AML), Acute Lymphoblastic Leukaemia (ALL), Chronic Myeloid Leukaemia (CML), and Chronic Lymphoproliferative Disorder (CLPD) were studied. Bone marrow biopsies were taken, fixed in 10% formalin, and decalcified in 10% Ethylene Diamine Tetraacetic Acid (EDTA). Routine paraffin embedding was performed, and serial sections of 4 µm were obtained on poly-L-lysine-coated slides for Immunohistochemistry (IHC) {Vimentin, Vascular Endothelial Growth Factor (VEGF), CD-34, Smooth Muscle Actin (SMA)}. The presence of reticulin fibres in the bone marrow biopsy sections was assessed using two special stains: Gomori’s Silver Impregnation and Masson’s Trichrome. Fibrosis was quantified according to the Baurmeister 0-4 grading system of Bone Marrow Fibrosis (BMF). Results: The results of the present study suggest that Endothelial to Mesenchymal Transition (EndMT) may play a role in the pathogenesis of BMF. Various grades of fibrosis were observed, with 15 cases (39.47%) in Grade 3, followed by 11 cases (28.95%) in Grade 2, 8 cases (21.05%) in Grade 1, and 4 cases (10.53%) in Grade 4. Conclusion: BMF was a significant finding even in the early stages of the majority of the lesions studied and was closely linked with angiogenesis. This study showed that angiogenesis plays an important role in the pathogenesis of haematological neoplasms and that VEGF is a prominent stimulus in the majority of these disorders. Additionally, this study suggests that EndMT has a possible role in the pathogenesis of BMF.

A profile of hematological malignancies diagnosed in a tertiary care center of Assam: Highlighting the experience from a resource constraint perspective

Background: Hematological disorders require a systematic approach, from clinical examination to a complete blood count, followed by a bone marrow study for diagnosis. To effectively plan, treat, and prognosticate, immunophenotyping and molecular studies are essential to incorporate. Aims and Objectives: The aim of our study is to understand the pattern of neoplastic hematological conditions encountered in Assam and share our experience during the diagnosis. Materials and Methods: This was a single-centered, observational study carried out for 18 months (January 2022–June 2023). A thorough hematological workout was done, including cytochemical staining and conventional polymerase chain reaction for the BCR-ABL transcript, after satisfying inclusion and exclusion criteria. The data were analyzed and correlated before arriving at the final diagnosis. Results: The total of 38 neoplastic cases confirmed by bone marrow study. Out of 38 cases, 14 were chronic myeloid leukemia, 10 were chronic, 4 were in the blastic phase, and BCR-ABL was positive in 13 cases. Two cases were pediatric, of which 1 was in the blastic phase. All 8 cases of plasma cell dyscrasia presented with anemia, bone lesions, and hypercalcemia. The acute leukemia category consisted of 4 acute myeloid leukemia cases, of which 1 was acute promyelocytic leukemia. A total of 10 acute lymphoblastic leukemia (ALL) cases, where 1 case was T-ALL and the rest was B-ALL. Two cases showed a subleukemic presentation in peripheral blood. Conclusion: The experience of pathologists and their meticulous approach can greatly aid in accurate diagnosis, but the immunophenotyping facility and molecular hematology setup can provide most of the relevant information for the best decision-making.

МНОЖЕСТВЕННАЯ МИЕЛОМА: ОСОБЕННОСТИ ТЕЧЕНИЯ И ОТВЕТА НА ТЕРАПИЮ У ПАЦИЕНТОВ РАЗНЫХ ВОЗРАСТНЫХ ГРУПП

Background: Multiple myeloma (MM) remains an incurable disease with the development of relapses, sometimes with an uncontrolled course leading to death regardless of the age of the patient. The use of new schemes and methods of treatment has not only significantly improved outcomes in younger MM patients but also improved the quality of life and survival in people over 65 years of age. Objective: to determine the clinical features of the course of the disease and response to therapy in patients of different age groups with newly diagnosed multiple myeloma. Material and Methods: An analysis of the data of 139 patients with newly diagnosed MM was carried out. The median follow-up was 25 months, with a maximum of 58 months. Patients were divided into study groups depending on age at the time of diagnosis: the first group - age up to 65 years (n=65); the second group - age from 65 years and older (n=74). The material of the study was clinical and anamnestic data, the results of laboratory blood tests: biochemical analysis and immunochemical analysis. All the patients underwent the whole body CT scan, diffusely weighted whole body MRI and bone marrow aspiration biopsy with immunophenotypic study. As an induction therapy, according to international recommendations, courses of chemotherapy were used using various regimens containing bortezomib, depending on age and comorbidity. Results. The MM variant with IgA secretion occurred 1.76 times more often in the first group (p=0.128). In the first group hypercalcemia was somewhat more common (2.4 times, p=0.099) and an excess of LDH levels (2.9 times, p=0.072). In contrast, the presence of infectious complications (by 1.2 times, p=0.392), excess of the level of β2-microglobulin > 3 mg/l (by 1.6 times, p=0.086) and kidney damage (by 1.45 times, p=0.037) were more common in the second group, and in the latter case the differences were statistically significant. Disease stage (p=0.0001), excess of β2 microglobulin level (p=0.004), excess of LDH level (p=0.03), presence of anemic syndrome (p=0.003), hypercalcemia (p=0.02), presence of infectious complications (p=0.01) at the time of diagnosis were predictors of worse survival in the general group of MM patients. Conclusion. The active use of new therapeutic strategies and regimens improves treatment outcomes not only in patients under 65 years of age, but also in older patients. New studies are needed to identify prognostic factors in individuals of different age groups in order to start personalized therapy and improve treatment outcomes.

Multi-Omics Analysis Reveals That TET2 Loss Epigenetically Primes Monocytes for Inflammatory Responses Via AP-1 Signaling

Loss of function mutations in TET2 are common in clonal hematopoiesis (CH) and myelodysplastic syndromes (MDS). Increased inflammation and stem cell capacity have been reported in Tet2 KO mouse models, but molecular mechanisms and cell type-specific contributions to explain this phenotype are lacking. To create models of CH-like TET2 deficiency, we transplanted Mx1-CRE Tet2 fl/fl (Tet2 KO) or Tet2 fl/fl (both CD45.1 +) in CD45.2 + recipientsfollowing radiation-free conditioning with ACK2 (anti-cKit) antibody injection. Six months post-transplant, we flow sorted CD45.1 +Tet2 KO and Tet2 fl/fl Lin -Sca-1 +cKit + (LSK) cells, granulocyte-monocyte progenitors (GMP), and monocytes for RNA and assay for transposase-accessible chromatin (ATAC) sequencing. Differential gene expression analysis identified 902 (468 up, 434 down) differentially expressed genes (DEGs) in LSK, 134 (95 up, 39 down) in GMP, and 474 (125 up, 349 down) in monocytes (p adj<0.05). Gene set enrichment analysis (GSEA) identified that the top Hallmark gene sets in Tet2 KOLSK cells were related to MYC targets, oxidative phosphorylation, and E2F targets. In contrast, GMP and monocytes were most enriched for IFN-alpha and gamma gene sets along with IL6/JAK/STAT3 signaling. ATACseq revealed increased accessibility of myeloid-related transcription factor (TF) binding motifs in Tet2 KOLSK cells (CEBPA, PU.1-IRF(ETS:IRF), and AP-1 TF FOSL2(bZIP)), while prediction of cis-regulating regions via GREAT identified downregulated peaks associated with stem cell maintenance and upregulated peaks associated with myeloid mediated immunity. Peaks upregulated in Tet2 KOGMP cells were enriched for the motifs recognized by CEBPE, ISRE(IRF)) and the AP-1 TF JUND, while upregulated peaks in monocytes were enriched for RUNX1 and CEBPA motifs, as well as AP-1 TF FOS::JUNB. GREAT analysis in GMPs identified cis-regulatory regions related to myeloid mediated immunity, while monocytes possessed those associated with biotic stimuli. To better dissect heterogeneity across primitive and mature cell types driven by TET2 loss, we performed scRNAseq on Tet2 KO and Tet2 WT wholebone marrow (WBM) and sorted LSK cells. We identified 18 transcriptionally distinct cell subsets in a combined analysis of WBM. Tet2 KOprogenitor and myeloid subsets were all enriched for gene sets related to IFN-alpha and gamma and immune signaling. Interestingly, primitive and cycling HSPCs were also enriched for MYC target and oxidative phosphorylation gene sets, while these were negatively enriched for GMP, monocyte progenitor, and monocyte Tet2 KO subsets. Further, the IL-6/JAK/STAT3 signaling gene set was enriched in later myeloid cell types, but not in early or cycling HSPCs. These observations led us to hypothesize that Tet2 KO BM cell populations have differentially enhanced phosphoprotein signaling responses to key cytokines. We used a 36-antibody mass cytometry panel to perform deep immunophenotyping and signaling response studies in Tet2 KO BM. FlowSOM analysis identified clusters corresponding to cKIT +CD34 + myeloid progenitors, a Ly6C +CD34 +cKIT + progenitor, and Ly6Chi monocyte clusters were enriched in Tet2 KO BM, while manual gating revealed expansion of LSK, MPP3, and monocytes. We found that activation of pSTAT3 and pSTAT1, in response to either IL-6 or IFNγ, respectively, were significantly higher in Tet2 KO Ly6Chi monocytes, while the more primitive Ly6C +CD34 +cKIT + progenitors demonstrated only an increased response to IFNγ at pSTAT1. Further, prolonged exposure to IL-6 in immortalized Tet2 KO Hoxb8-ER GMP-like cells led to significantly higher levels of pSTAT3 over 4 hours. Since AP-1 TFs are drivers of inflammation and were enriched in our ATACseq dataset, we tested the effects of an AP-1 inhibitor on the Tet2 KO Hoxb8-ER cells. We found that the AP-1 inhibitor T5224 dose dependently reduced the expansion of Tet2 KO Hoxb8 progenitor cells in base media and inhibited the IL-6 mediated expansion of Tet2 KO Hoxb8 cells. Our data show that TET2 loss rewires BM HSPCs towards an inflammatory, myeloid phenotype. Starting at the GMP stage, we see increases in phosphoprotein responses to IFNγ, and then the addition of hypersensitivity to IL-6 in monocytes. TET2 loss leads to an increase in accessible AP-1 motifs in Tet2 KO cells, while inhibition of AP-1 reduces fitness of cells, suggesting a possible therapeutic strategy for TET2-mutated myeloid malignancy.