Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
2.
Mod Pathol ; 30(8): 1100-1115, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28548121

RESUMO

Aggressive natural killer (NK)-cell leukemia/lymphoma is a systemic NK-cell neoplasm that preferentially affects Asians with a fulminant clinical course and is almost always associated with Epstein-Barr virus (EBV). The data on EBV-negative aggressive NK-cell leukemia/lymphoma are limited. Here we report a series of three patients (two Caucasians, one African-American) with EBV-negative aggressive NK-cell leukemia/lymphoma from a single institution, including a case diagnosed on post-mortem examination. Similar to EBV-positive aggressive NK-cell leukemia/lymphoma, our patients presented with constitutional symptoms and hepatosplenomegaly, and followed a highly aggressive clinical course. The disease involved peripheral blood, bone marrow, liver, spleen, and lymph node, and the neoplastic cells were pleomorphic with prominent azurophilic granules and demonstrated an atypical NK-cell phenotype. Lack of blood lymphocytosis (3 of 3), bone marrow interstitial infiltration (2 of 3), EBER negativity (3 of 3), and atypical phenotype including CD3 negativity by immunohistochemistry make an early recognition of the disease difficult. Ancillary studies revealed a complex karyotype (1 of 2), overexpression (3 of 3), and amplification (1 of 1) of c-MYC. The polycomb repressive complex 2 pathway-associated proteins EZH2 and H3K27me3 and immune checkpoint protein PD-L1 were overexpressed in three of three and two of three cases, respectively. Our findings indicate that the EBV-negative aggressive NK-cell leukemia/lymphoma shares similar clinicopathological features to the EBV-positive counterpart except for the high prevalence of Asian seen in EBV-positive cases. Overexpression of polycomb repressive complex 2 pathway-associated proteins and PD-L1 suggest potential therapeutic targets for this aggressive disease. Next-generation sequencing on two of three cases identified multiple genetic alterations but were negative for JAK-STAT pathway-associated gene mutations previously reported in EBV-positive NK/T-cell lymphoma, suggesting alternative molecular pathogenic mechanisms for EBV-negative aggressive NK-cell leukemia/lymphoma.


Assuntos
Leucemia Linfocítica Granular Grande/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
3.
Am J Clin Pathol ; 157(5): 701-708, 2022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-34698340

RESUMO

OBJECTIVES: Acute myeloid leukemia (AML) with t(8;16)(p11;p13) abnormalities is a rare, aggressive, and diagnostically challenging subtype that results in KAT6A-CREBBP gene fusion. METHODS: To investigate their immunophenotype and genomic features, we identified 5 cases of AML with t(8;16) through a retrospective review of the databases at Northwestern Memorial Hospital in Chicago, IL, and Washington University Medical Center, in St Louis, MO. RESULTS: In all, 4 of 5 cases were therapy related and 1 was possibly therapy related. The leukemic blasts showed distinctive features, including bright CD45 expression and remarkably high side scatter that overlapped with maturing myeloid elements, making the blasts difficult to identify on initial examination. They were positive for CD13, CD33, and CD64 and negative for CD34 and CD117. Next-generation sequencing profiling of 4 cases revealed pathogenic ASXL1 (2 cases), FLT3-tyrosine kinase domain (TKD) mutations (2 cases), and other pathogenic mutations. In 3 patients, t(8;16) was the sole cytogenetic abnormality; additional aberrations were found in 2 patients. Single nucleotide polymorphism microarray revealed 1 case with 7q deletion as a secondary clone. CONCLUSIONS: Our data highlight the distinctive immunophenotypic profile of AML with t(8;16), which, along with its unique morphology, often presents a diagnostic challenge. We showed that mutations of either ASXL1 or FLT3-TKD are seen in most cases of this leukemia.


Assuntos
Leucemia Mieloide Aguda , Aberrações Cromossômicas , Citometria de Fluxo/métodos , Humanos , Imunofenotipagem , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Mutação , Translocação Genética
4.
Immunology ; 133(4): 452-68, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21635248

RESUMO

Germinal centre (GC) reactions are central features of T-cell-driven B-cell responses, and the site where antibody-producing cells and memory B cells are generated. Within GCs, a range of complex cellular and molecular events occur which are critical for the generation of high affinity antibodies. These processes require exquisite regulation not only to ensure the production of desired antibodies, but to minimize unwanted autoreactive or low affinity antibodies. To assess whether T regulatory (Treg) cells participate in the control of GC responses, immunized mice were treated with an anti-glucocorticoid-induced tumour necrosis factor receptor-related protein (GITR) monoclonal antibody (mAb) to disrupt Treg-cell activity. In anti-GITR-treated mice, the GC B-cell pool was significantly larger compared with control-treated animals, with switched GC B cells composing an abnormally high proportion of the response. Dysregulated GCs were also observed regardless of strain, T helper type 1 or 2 polarizing antigens, and were also seen after anti-CD25 mAb treatment. Within the spleens of immunized mice, CXCR5(+) and CCR7(-) Treg cells were documented by flow cytometry and Foxp3(+) cells were found within GCs using immunohistology. Final studies demonstrated administration of either anti-transforming growth factor-ß or anti-interleukin-10 receptor blocking mAb to likewise result in dysregulated GCs, suggesting that generation of inducible Treg cells is important in controlling the GC response. Taken together, these findings indicate that Treg cells contribute to the overall size and quality of the humoral response by controlling homeostasis within GCs.


Assuntos
Centro Germinativo/imunologia , Linfócitos T Reguladores/imunologia , Animais , Centro Germinativo/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Linfócitos T Reguladores/citologia
5.
Cytometry B Clin Cytom ; 100(2): 142-155, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32319723

RESUMO

A peripheral blood flow cytometric assay for Sézary syndrome (SS) or circulating mycosis fungoides (MF) cells must be able to reliably identify, characterize, and enumerate T-cells with an immunophenotype that differs from non-neoplastic T-cells. Although it is also important to distinguish SS and MF from other subtypes of T-cell neoplasm, this usually requires information in addition to the immunophenotype, such as clinical and morphologic features. This article outlines the approach recommended by an international group with experience and expertise in this area. The following key points are discussed: (a) At a minimum, a flow cytometric assay for SS and MF should include the following six antibodies: CD3, CD4, CD7, CD8, CD26, and CD45. (b) An analysis template must reliably detect abnormal T-cells, even when they lack staining for CD3 or CD45, or demonstrate a phenotype that is not characteristic of normal T-cells. (c) Gating strategies to identify abnormal T-cells should be based on the identification of subsets with distinctly homogenous immunophenotypic properties that are different from those expected for normal T-cells. (d) The blood concentration of abnormal cells, based on any immunophenotypic abnormalities indicative of MF or SS, should be calculated by either direct enumeration or a dual-platform method, and reported.


Assuntos
Citometria de Fluxo , Micose Fungoide/patologia , Síndrome de Sézary/patologia , Neoplasias Cutâneas/patologia , Antígenos CD/análise , Humanos , Micose Fungoide/sangue , Síndrome de Sézary/sangue , Neoplasias Cutâneas/sangue , Linfócitos T/patologia
6.
Cytometry B Clin Cytom ; 100(2): 156-182, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33112044

RESUMO

Introducing a sensitive and specific peripheral blood flow cytometric assay for Sézary syndrome and mycosis fungoides (SS/MF) requires careful selection of assay design characteristics, and translation into a laboratory developed assay through development/optimization, validation, and continual quality monitoring. As outlined in a previous article in this series, the recommended design characteristics of this assay include at a minimum, evaluation of CD7, CD3, CD4, CD8, CD26, and CD45, analyzed simultaneously, requiring at least a 6 color flow cytometry system, with both quantitative and qualitative components. This article provides guidance from an international group of cytometry specialists in implementing an assay to those design specifications, outlining specific considerations, and best practices. Key points presented in detail are: (a) Pre-analytic components (reagents, specimen processing, and acquisition) must be optimized to: (i) identify and characterize an abnormal population of T-cells (qualitative component) and (ii) quantitate the abnormal population (semi/quasi-quantitative component). (b)Analytic components (instrument set-up/acquisition/analysis strategy and interpretation) must be optimized for the identification of SS/MF populations, which can vary widely in phenotype. Comparison with expert laboratories is strongly encouraged in order to establish competency. (c) Assay performance must be validated and documented through a validation plan and report, which covers both qualitative and semi/quasi-quantitative assay components (example template provided). (d) Ongoing assay-specific quality monitoring should be performed to ensure consistency.


Assuntos
Citometria de Fluxo , Micose Fungoide/patologia , Síndrome de Sézary/patologia , Neoplasias Cutâneas/patologia , Antígenos CD/análise , Humanos , Fenótipo , Controle de Qualidade
7.
ACS Cent Sci ; 6(8): 1341-1347, 2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32868999

RESUMO

Vaccines against COVID-19 have the potential to protect people before they are exposed to the infective form of the virus. However, because of the involvement of pathogenic immune processes in many severe presentations of COVID-19, eliciting an immune response with a vaccine must strike a delicate balance to achieve viral clearance without also inducing immune-mediated harm. This Outlook synthesizes current laboratory findings to define which parts of the immune system help with recovery from and protection against the virus and which can lead to adverse outcomes. To inform our understanding, we analyze research about the immune mechanisms implicated in SARS-CoV, from the 2003 outbreak, and SARS-CoV-2, the virus causing COVID-19. The impact of how innate immunity, humoral immunity, and cell-mediated immunity play a role in a harmful versus helpful response is discussed, establishing principles to guide the development and evaluation of a safe but effective COVID-19 vaccine. The principles derived include (i) targeting the appropriate specificity and effector function of the humoral response, (ii) eliciting a T cell response, especially a cytotoxic T cell response, to achieve safe, yet effective, immune protection from COVID-19, and (iii) monitoring for the possibility of acute lung injury during SARS-CoV-2 infection post-vaccination in preclinical and clinical studies. These principles can not only guide efforts toward a safe and effective COVID-19 vaccine, but also the development of effective vaccines for viral pandemics to come.

8.
Curr Opin Immunol ; 17(3): 298-302, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15886120

RESUMO

The germinal center (GC) is an important anatomical site for the development of high affinity antibodies during T-cell dependent B cell responses. Although the importance of the GC response to humoral immunity is well known, much remains to be elucidated about GC induction, maintenance and regulation. Recent studies examining the GC response in mice have identified key molecules expressed on follicular dendritic cells that support the differentiation of GC B cells, revealed essential chemokines that direct the organization of light and dark zones, and demonstrated potentially novel roles for TNF family members in the differentiation of GC B cells.


Assuntos
Linfócitos B/imunologia , Células Dendríticas Foliculares/metabolismo , Centro Germinativo/citologia , Centro Germinativo/imunologia , Animais , Diferenciação Celular , Regulação da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL
9.
Crit Rev Immunol ; 24(1): 39-65, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-14995913

RESUMO

The germinal center reaction is the foundation of T-cell-dependent humoral responses. Antigen-specific B cells recruited into germinal centers undergo a complex cellular program that allows for extensive expansion, isotype switching, somatic hypermutation, and differentiation into antibody-forming cells and memory cells. Importantly, the germinal center environment filters the repertoire of differentiating B cells such that high affinity variants are preferentially selected while low affinity or self-reactive clones are eliminated by apoptosis. The present article reviews the many processes that govern germinal center B-cell differentiation, as well as the cellular and molecular elements necessary to initiate and sustain a germinal center response. The major histologic features of the germinal center are also discussed, as well as the current dominant models of the germinal center reaction in humans and mice. Finally, a new model of murine B-cell differentiation is described on the basis of a multiparameter flow cytometric kinetic analysis of germinal center B cells.


Assuntos
Formação de Anticorpos/imunologia , Centro Germinativo/imunologia , Animais , Formação de Anticorpos/fisiologia , Antígenos/imunologia , Antígenos CD/imunologia , Antígenos de Superfície/imunologia , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/fisiologia , Linfócitos B/imunologia , Linfócitos B/fisiologia , Diferenciação Celular/imunologia , Diferenciação Celular/fisiologia , Citometria de Fluxo , Regulação da Expressão Gênica/imunologia , Centro Germinativo/citologia , Centro Germinativo/fisiologia , Haptenos/imunologia , Humanos , Camundongos , Camundongos Endogâmicos/imunologia , Modelos Imunológicos , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos B/fisiologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/fisiologia
10.
Am J Clin Pathol ; 143(2): 214-22, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25596247

RESUMO

OBJECTIVES: Nuclear overexpression of lymphoid enhancer-binding factor 1 (LEF1) assessed by immunohistochemistry has been shown to be highly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) among small B-cell lymphomas. The purpose of this study was to evaluate the utility of flow cytometric analysis of LEF1 in the diagnosis of CLL/SLL. METHODS: Normal peripheral blood was used to validate the test. Flow cytometric analysis of LEF1 was performed in 64 patient samples qualitatively and quantitatively by comparing the staining intensity and the ratios of the median fluorescence intensities (MFIs) of LEF1 in B cells of interest to the internal reference cell populations. The results were correlated with the pathologic diagnosis. RESULTS: Proper sample processing ensured sufficient separation of positive LEF1 staining in T cells from negative staining in normal B and natural killer (NK) cells. Qualitative analysis of patient samples showed that all 25 cases of CLL/SLL but none of the other small B-cell lymphomas were positive for LEF1. Using a B/NK MFI ratio of 1.5 and B/T MFI ratio of 0.45 separated CLL/SLL cases from non-CLL lymphomas. CONCLUSIONS: Flow cytometric analysis of LEF1 is sufficient to differentiate CLL/SLL from other small B-cell lymphomas and may serve as a useful tool in the diagnosis of CLL/SLL.


Assuntos
Biomarcadores Tumorais/análise , Citometria de Fluxo/métodos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Fator 1 de Ligação ao Facilitador Linfoide/biossíntese , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Fator 1 de Ligação ao Facilitador Linfoide/análise , Masculino , Pessoa de Meia-Idade
11.
Am J Clin Pathol ; 139(2): 231-41, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23355208

RESUMO

Clonal expansions of large granular lymphocytes (LGLs) have been identified in patients following stem cell transplants and may represent posttransplant LGL leukemias or reactive immune responses. To differentiate between these 2 possibilities, we assessed peripheral blood and bone marrow of patients with myeloma after autologous stem cell transplant. All patients examined shortly after autologous stem cell transplant had significant increases in the LGLs in the peripheral blood and bone marrow (71% of lymphocytes) as compared with controls (39%). This increase was detectable years after transplant. The LGLs had a reproducible immunophenotype of CD8+CD57+ T cells without phenotypic abnormalities in 19 of 20 patients. Sixty-five percent of the post-autologous stem cell transplant patients had clonal T-cell receptor gene rearrangements in the bone marrow, yet no patients had neutropenia or splenomegaly. Although the LGL expansions were clonal and persistent, the lack of clinical sequelae suggests the clonal LGL expansion is a reactive, potentially beneficial, immune response to autologous stem cell transplant.


Assuntos
Antígenos CD57/metabolismo , Linfócitos T CD8-Positivos/patologia , Leucemia Linfocítica Granular Grande/patologia , Linfocitose/patologia , Mieloma Múltiplo/patologia , Transplante de Células-Tronco , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Linfócitos T CD8-Positivos/imunologia , Proliferação de Células , Células Clonais/patologia , Citometria de Fluxo , Rearranjo Gênico do Linfócito T/genética , Humanos , Imunidade Inata/genética , Imunidade Inata/imunologia , Imunofenotipagem , Leucemia Linfocítica Granular Grande/imunologia , Mieloma Múltiplo/genética , Mieloma Múltiplo/terapia , Complicações Pós-Operatórias , Transplante Autólogo
12.
Am J Clin Pathol ; 138(4): 568-78, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23010712

RESUMO

Early posttransplant lymphoproliferative disorders (EPTLDs) represent the first changes in posttransplant lymphoproliferative disorders (PTLDs) morphologic spectrum. EPTLD data are available mostly from case reports and series that include other types of PTLD. Fifteen EPTLDs were reviewed retrospectively. Clinical data, histopathology, clonality, and Epstein- Barr virus (EBV) status were correlated with staining intensity to an antibody for phosphorylated S6 (pS6) ribosomal protein, a downstream effector of mammalian target of rapamycin (mTOR). Median time from transplantation to EPTLD was 50 months (range, 7-135 mo). EPTLDs involved tonsil and/or adenoids (n = 11) and lymph nodes (n = 4), all of which were nonclonal and EBV-encoded RNA-positive. Most (n = 11) were plasmacytic hyperplasia and florid follicular hyperplasia (n = 4). All regressed with reduced immunosuppression, and had increased pS6 staining compared with normal tonsil (P = .002, F test). EPTLDs developed later than previously reported, involved mostly tonsils/adenoids, were EBV-encoded RNA (EBER) positive, showed increased pS6, and had excellent clinical outcome with reduction of immunosuppression.


Assuntos
Transtornos Linfoproliferativos/etiologia , Transtornos Linfoproliferativos/patologia , Transplante de Órgãos/efeitos adversos , Serina-Treonina Quinases TOR/metabolismo , Adolescente , Criança , Células Clonais , Diagnóstico Precoce , Feminino , Humanos , Imunossupressores/uso terapêutico , Lactente , Tecido Linfoide/metabolismo , Tecido Linfoide/patologia , Tecido Linfoide/virologia , Transtornos Linfoproliferativos/tratamento farmacológico , Transtornos Linfoproliferativos/metabolismo , Masculino , Pessoa de Meia-Idade , Fosforilação , Complicações Pós-Operatórias , Proteínas de Ligação a RNA/metabolismo , Estudos Retrospectivos , Proteína S6 Ribossômica/metabolismo , Proteínas Ribossômicas/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/imunologia , Fatores de Tempo , Adulto Jovem
13.
J Immunol ; 177(4): 2072-9, 2006 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-16887965

RESUMO

Previous studies examining the primary germinal center (GC) response to SRBC in mice demonstrated a steady ratio of IgM(+) to isotype-switched GC B cells and a persistent population of GC B cells with a founder phenotype. These characteristics held true at the inductive, plateau, and dissociative phases of the GC response, suggesting a steady-state environment. To test whether these characteristics apply to the primary response of other T cell-dependent Ags, the present study examined the GC response after challenge with (4-hydroxy-3-nitrophenyl)acetyl (NP) in C57BL/6 mice. Multiparameter flow cytometric analysis was used to assess the phenotype of splenic NP-reactive cells at multiple time points after immunization. Results of these studies demonstrated the characteristics of the SRBC-induced GC reaction to be fully maintained in the NP response. In particular, there was a steady ratio of nonswitched to switched B cells, with the majority of NP-reactive GC B cells displaying IgM. In addition, a substantial frequency of B220(-) NP-binding cells was observed in the spleen at later time points after NP challenge. Although these cells were IgE(+), they were found to express both kappa and lambda L chains and display the high-affinity IgE Fc (FcepsilonRI) receptor, suggesting that this population is not of B cell origin. Adoptive transfer studies further demonstrated the B220(-) NP-binding subset to be derived from the myeloid lineage.


Assuntos
Subpopulações de Linfócitos B/imunologia , Epitopos de Linfócito B/imunologia , Centro Germinativo/imunologia , Haptenos/imunologia , Antígenos Comuns de Leucócito/metabolismo , Nitrofenóis/administração & dosagem , Nitrofenóis/imunologia , Animais , Subpopulações de Linfócitos B/metabolismo , Epitopos de Linfócito B/administração & dosagem , Feminino , Centro Germinativo/citologia , Centro Germinativo/metabolismo , Haptenos/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenilacetatos , Ligação Proteica/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA