AIDS-related lymphoma in Brazil - Histopathology, immunophenotype, and association with Epstein-Barr virus

The occurrence of malignant lymphoma is an increasingly important cause of morbidity and mortality in AIDS patients. The incidence of AIDS-related lymphoma in some developing countries such as Brazil is increasing as the survival of HIV infection has improved. Although there is a clear association between several types of immunodeficiency related lymphomas and Epstein-Barr virus (EBV), the association of EBV infection in AIDS-related lymphoma in Brazil, where the incidence of AIDS is high, is unknown. Formalin-fixed, paraffin-embedded tissue from 24 cases of AIDS-related lymphoma in Brazil were analyzed for morphologic classification, immunophenotype, and EBV association using in situ hybridization studies with an EBV-EBER1 biotinylated probe. Twenty cases of AIDS-related lymphoma were classified as non-Hodgkin's lymphoma and four cases were Hodgkin's disease. Eleven non-Hodgkin's lymphomas were classified as diffuse large cell type, five cases were small non-cleaved cell, Burkitt-type, and four cases were large cell immunoblastic non-Hodgkin's lymphoma. Eighteen cases were of B-cell phenotype; one was a T-cell lymphoma, and one was classified as null. Epstein-Barr virus (EBV) was demonstrated in the majority of tumor cells of 11 of 20 (55%) of the cases non-Hodgkin's lymphomas and in 3 of 4 (75%) cases of Hodgkin's disease. AIDS-related lymphomas in Brazil are usually of large cell/immunoblastic type, but Hodgkin's disease is also seen. Both non-Hodgkin's lymphoma and Hodgkin's disease are often associated with EBV infection. The non-Hodgkin's lymphoma is predominantly of B-cell phenotype.

Imunorreatividade da p53 associada à ausência de mutações no gene TP53 em linfomas caninos

Sabendo-se da influência das mutações no gene TP53 no desenvolvimento das neoplasias e da discrepância entre os resultados obtidos pelas técnicas de sequenciamento e imunoistoquímica, esta pesquisa teve como objetivo relacionar a sequência do TP53 com a imunorreatividade da p53. Foram obtidas amostras de linfoma de 12 cães. O diagnóstico histopatológico foi determinado pela classificação de Kiel. O imunofenótipo e a imunomarcação da p53 foram determinados por imunoistoquímica. Para reação com a p53, utilizou-se anticorpo policlonal anti-p53 (CM1) na diluição de 1:500. A região do gene TP53 compreendida entre os exons quatro e nove foi amplificada por PCR e submetida ao sequenciamento. Apesar dos resultados obtidos pela imunoistoquímica, nenhuma mutação foi encontrada nas sequências analisadas. Conclui-se que a imunorreatividade da p53 pela imunoistoquímica não pode ser atribuída à presença de mutações no domínio central do gene TP53.

Immunohistochemistry of small blue round cell tumors

Small blue round cell tumors (SBRCTs) are a set of malignancies that have a particular proclivity for the pediatric age group. These tumors are notoriously difficult to distinguish by histologic evaluation alone, and in recent years a number of new immunohistochemical markers have emerged that can aid in the correct categorization of these lesions. Myogenin, a muscle-restricted nuclear transcription factor, has been demonstrated to be a highly sensitive and specific marker of rhabdomyosarcoma, and is superior to previous markers such as myoglobin, muscle actins, and desmin. The FlI-1 gene product is expressed as part of the EWS/FLI-1 novel chimeric protein that results from the t(11;22)(q24;q12) translocation that occurs in approximately two-thirds of cases of PNET/Ewings sarcoma. Immunohistochemical detection of the FLI-1 gene product can thus complement detection of CD99/MIC2 for the positive identification of PNET/Ewings sarcoma. Markers of neuroblastoma include neural markers, such as chromogranin A, neurofilaments, and synaptophysin. Desmoplastic small round cell tumor (DSRCT) is a tumor with an unusual immunophenotype, including co-expression of cytokeratin, vimentin, and desmin; recent studies have also documented the use of antibodies to the WT-1 gene product as a marker of the chimeric EWS/WT-1 protein formed as a result of the t(11;22)(p13;q12) translocation that characterizes this unique tumor. In summary, there now exists a panel of antibodies defining immunohistochemical markers of individual SBRCTs that can identify rhabdomyosarcoma, PNET/Ewings sarcoma, neuroblastoma, and DSRCT with high sensitivity and specificity.

Uncaria tomentosa Aqueous-ethanol Extract Triggers an Immunomodulation toward a Th2 Cytokine Profile

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

COORDINATE EXPRESSION OF CYTOKERATIN-7 AND CYTOKERATIN-20 DEFINES UNIQUE SUBSETS OF CARCINOMAS

We tested the hypothesis that the coordinate expression of cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20) could distinguish among carcinomas arising from different primary sites. A total of 384 cases of carcinomas primary to various organs, as well as 16 cases of malignant mesothelioma, were evaluated using commercially available monoclonal antibodies and an avidin-biotin immunoperoxidase technique. The subset of tumors strongly expressing both CK 7 and CK 20 included virtually all bladder transitional cell carcinomas and the majority of pancreatic adenocarcinomas; the tumors negative for both CK 7 and CK 20 were largely restricted to hepatocellular, prostate, and renal cell carcinomas in addition to squamous cell and neuroendocrine carcinomas of lung. The CK 7-/CK 20+ immunophenotype, however, was highly characteristic of adenocarcinomas of colorectal origin, whereas CK 7+/CK 20- immunophenotype was typically seen in the vast majority of carcinomas arising from other sites, including ovary, endometrium, breast, and lung, as well as malignant mesothelioma. Gastric carcinomas were the most heterogeneous subgroup with respect to CK 7/CK 20 immunophenotype. In the subset of mucinous tumors, striking immunophenotypic differences were noted among those primary to the breast (CK 7+/CK 20-), gastrointestinal tract (CK 7-/CK 20+), and ovary (CK 7+/CK 20+). In all cases investigated, this CK immunophenotype was invariant in metastatic vs. primary tumors. It is concluded that, in the appropriate clinical setting, the CK 7/CK 20 immunophenotype of carcinomas is a valuable diagnostic marker in the determination of primary site of origin.

Nasal T-cell lymphoma presenting as midline lethal granuloma. Characterization of three cases by clinical markers of lymphomas

The authors report on three cases of so-called midline granuloma submitted to clinicopathologic and immunophenotype studies. The histopathologic features detected were necrosis, vasculitis and an atypical lymphohistiocytic infiltrate. Immunophenotype studies using monoclonal antibodies showed evidence leading to the diagnosis of nasal T cell lymphoma or lymphomatoid granulomatosis. Two of the patients with the presence of progressive or large cells died within 24 months, indicating that the size of the atypical lymphoid cells may be of prognostic significance.

Hodgkin disease in adult and juvenile groups from two different geographic regions in Brazil: Characterization of clinicopathologic aspects and relationship with Epstein-Barr virus infection

We analyzed clinicopathologic data, immunophenotype, and Epstein-Barr virus (EBV) status in 96 cases of Hodgkin disease (HD) in juveniles (younger than 20 years) and adults (20 years or older) from 2 distinctive states in Brazil. We studied 34 juvenile (group 1) and 16 adult (group 2) cases from Ceara and 31 juvenile (group 3) and 15 adult (group 4) cases from São Paulo. Ceara has a socioeconomic profile similar to a developing country; São Paulo is in better economic condition. Mixed cellularity (MC) was the major histologic subtype among groups 1 (22 [65%]), 3 (21 [68%]), and 4 (7 [47%]); nodular sclerosis (NS) was more frequent in group 2 (8 [50%]). EBV infection was observed in 61 cases (64%), including the following (among others): group 1, MC, 22 (65%) and NS, 4 (12%); group 2, NS, 3 (19%) and MC, 2 (12%); group 3, MC, 16 (52%) and NS, 1 (3%); and group 4, MC, 7 (47%). There was predominance of EBV+ HD cases in group 1 compared with group 3. HD in Brazilian patients is highly associated with EBV infection, but geographic differences reflect histologic subtypes and age distribution.

Diferenciação hepatocítica de células-tronco mesenquimais da medula óssea humana

Some recent articles have reported that mesenchymal stem cells (MSCs) can be induced to express hepatocyte markers by transplanting them into animal models of liver damage, or by in vitro culture with growth factors and cytokines. In this study, the aim is to evaluate the behavior of MSCs subjected to induction of hepatocyte differentiation. The MSCs were isolated from the bone marrow of 4 normal donors, characterized and subjected to both in vitro and in vivo induction of hepatocyte differentiation. The in vitro induced cells showed morphological changes, acquiring hepatocyte-like features. However, the immunophenotype of these cells was not modified. The induced cells exhibited no increase in albumin, cytokeratin 18 or cytokeratin 19 transcripts, when analyzed by real-time RT-PCR. The expression of albumin, cytokeratin 18 and alpha fetoprotein was also unchanged, according to immunofluorescence tests. In vivo, the MSC demonstrated a potential to migrate to damaged liver tissue in immunodeficient mice. Taken together, the results suggest that bone marrow MSCs are incapable of in vitro differentiation into hepatocytes by the approach used here, but are capable of homing to damaged hepatic tissue in vivo, suggesting a role for them in the repair of the liver. This contribution to tissue repair could be associated with a paracrine effect exerted by these cells.

Proliferação celular nos linfomas caninos

Lymphoma studies deals with morphological classification and immunophenotypic features and they have to be amplified for cellular kinetics evaluation. This evaluation can only be safely made, when the proliferative index are evaluated. In men the proliferation index have, most of the time, important influence in the neoplasia prognosis and treatment In this work it was used 40 canine lymphomas that were classified according to Kiel methods and immunophenotype was achieved with CD3 (T lymphocyte) and CD79a (B lymphocyte). Cellular proliferation was evaluated by AgNORs and Ki-67 (MIB-1) According to Kiel classification system, high grade lymphomas were more frequent and T and B lymphoma showed the same frequency.When cellular proliferation was evaluated, there was a significant difference between high grade and low grade lymphomas by AgNOR and Ki-67 (MIB-1) methods, but did not differ when comparing immunophenotype. Among high grade malignancy lymphomas the NORs medium number per cell nucleoli was 1.37± 0.32 and in low grade was 0.98± 0.36, concerning Ki-67 the positive cellular percentual was 43.19% ± 19.01, e 14.09% ± 11.74 in high and low grade, respectively.

Intravascular lymphomatosis in the central nervous system of dogs: Immunohistochemical investigation in two cases

We report here two postmortem cases of dogs with intravascular lymphomatosis affecting the central nervous system. Intravascular lymphomatosis is represented by an exclusively intravascular proliferation of neoplastic lymphoid cells. To characterize the origin of the neoplastic cells, we have proceeded with immunohistochemical analysis to identify B and T lymphocytes and endothelial cells. The results showed predominance of cells from the T cell lineage, and no evidence of B cell origin was found. Few cells from one dog also exhibited cytoplasmatic staining for vimentin and Von Willebrand factor. Although in one case some immunophenotype diversity was observed, the massive presence of CD3 positive cells confirmed these neoplasms as intravascular lymphomatosis of T cell origin.

Immunophenotyping of thymic lymphoma in a Nelore cow

Thymic lymphoma is a malignant lymphoid neoplasm that affects several species, including cattle. This type of neoplasia can lead to death due to malignant cell infiltration in different organs. The classification of this neoplasm may predict prognosis and response to treatment. Immunophenotyping is one of the ways to perform this classification. There are reports about the performance of immunohistochemistry (IHC) to classify thymic lymphoma only in taurine cattle, therefore the aim of this report is to describe the immunophenotype of a thymic lymphoma in a Nelore cow. Immunostaining was performed with monoclonal antibodies (CD79, CD4 and CD8). The tumor cells showed positive staining only for CD8 T lymphocytes, coinciding with the disease progression, since the T lymphoma type is more aggressive.

Concentração sérica e imunomarcação do fator de crescimento do endotélio vascular no prognóstico dos linfomas caninos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de anticorpos monoclonais murinos dirigidos contra antígenos de células-tronco adulta de origem humana e de coelho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise mutacional do gene supressor de tumor TP53 e imunorreatividade da p53 em linfomas caninos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo clínico e imunopatológico da infecção experimental em cães com a amostra Jaboticabal de Ehrlichia canis na fase aguda e após o tratamento: expreção de citocinas no baço e sangue e de subpopulações de células imunes no baço

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)