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Biomedical subjects

M S Pombo-de-Oliveira

Publications and source records attributed to M S Pombo-de-Oliveira.

12 recordsLinked to original sources
PubMed2006

Cutaneous T-cell lymphoma with HTLV-I infection: clinical overlap with adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a malignant proliferation of mature helper T lymphocytes,(1) and is caused by human T-lymphotropic virus type I (HTLV-I);(2) an HTLV-I infection endemic in the Caribbean, south-western Japan, South America and Africa.(3,4) Seroepidemiological studies suggest that it is also endemic in Brazil.(5) Although carriers of HTLV-I show polyclonal integration of virus in T lymphocytes, only patients with ATLL of various subtypes show monoclonal integration of HTLV-I in tumor cells.(6,7) Cutaneous T-cell lymphomas (CTCL) are a group of primary cutaneous lymphoproliferative diseases(8) with unknown etiology.(9) The two most common presentations of CTCL are mycosis fungoides (MF) and Sézary syndrome (SS).(10-13) However, both CTCL categories can easily resemble ATLL. Therefore, in HTLV-I endemic areas, differentiation between ATLL and CTCL must be performed, as they have different prognoses and treatment approaches.(14).

Adult↗
PubMed2006

Cytosine arabinoside-metabolizing enzyme genes are underexpressed in children with MLL gene-rearranged acute lymphoblastic leukemia.

Infant acute lymphoblastic leukemia (IALL) is characterized by mixed lineage leukemia (MLL) gene rearrangements, unique gene expression profiles, poor prognosis, and drug resistance. One exception is cytosine arabinoside (Ara-C) to which IALL cells seem to be more sensitive. We quantified mRNA expression of Ara-C key enzymes in leukemic lymphoblasts from 64 Brazilian ALL children, 15 of them presenting MLL gene rearrangement, and correlated it with clinical and biological features. The diagnosis was based on morphological criteria and immunophenotyping using monoclonal antibodies. MLL gene rearrangements were detected by conventional cytogenetic analysis, RT-PCR and/or fluorescence in situ hybridization. The DCK and HENT1 expression levels were determined by real-time quantitative PCR using SYBR Green I. Relative quantification was made by the standard curve method. The results were analyzed by Mann-Whitney and Fisher exact tests. A P value of <or=0.05 was considered to be statistically significant. DCK and HENT1 expression levels were significantly lower in children with MLL gene-rearranged ALL compared to children with MLL germ line ALL (P = 0.0003 and 0.03, respectively). Our results differ from previous ones concerning HENT1 mRNA expression that observed a higher expression level in MLL gene-rearranged leukemias. In conclusion, the expression of the genes related to Ara-C metabolism was lower in MLL-positive children in the sample studied, suggesting the presence of population differences in the expression profile of these genes especially for HENT1.

Antimetabolites, Antineoplastic↗
PubMed2001

Adult T-cell leukemia/lymphoma and cluster of HTLV-I associated diseases in Brazilian settings.

We studied the transmission routes of human T-cell lymphotropic virus type I (HTLV-I) within families of 82 Brazilian patients diagnosed with adult T-cell leukaemia/lymphoma (ATL). Diagnosis of ATL in 43 male and 39 female patients was based on clinical and laboratory criteria of T-cell malignancy and detection of HTLV-I monoclonal integration. Samples were tested for HTLV antibodies and infection was confirmed as HTLV-I by Western Blot and/or polymerase chain reaction (PCR) assays. Overall 26/37 (70%) of mothers, 24/37 (65%) of wives, 8/22 (36%) of husbands, 34/112 (30%) of siblings and 10/82 (12%) offspring were HTLV-I infected. In 11 ATL patients, mothers were repeatedly HTLV-I seronegative, but HTLV-I pol or tax sequences were detected in 2 out of 6 cases tested by PCR. ATL patients with seronegative mothers related the following risk factors for HTLV-I infection: 6 were breast-fed by surrogate mothers with unknown HTLV-I status, 4 had a sexually promiscuous behaviour and 1 had multiple blood transfusions at a young age. Familial aggregation of ATL and other HTLV-I associated diseases such as HTLV-I myelopathy (HAM/TSP) and or uveitis, ATL in sibling pairs or in multiple generations was seen in 9 families. There were 6 families with ATL and TSP sibling pairs. In 3 families at least one parent had died with lymphoma or presenting neurological diseases and 2 offspring with ATL. Further to the extent of vertical and horizontal transmission of HTLV-I infection within ATL families, our results demonstrate that mothers who provide surrogate breast-milk appear to be an important source of HTLV-I transmission and ATL development in Brazil.

Brazil↗
PubMed2000

Clinicopathological studies of a patient with adult T-cell leukemia and pseudogynecomasty.

We present a rare case of adult T cell leukemia/lymphoma (ATL) in which leukemic T cells expressed CD4 and CD25 surface antigens and infiltrated mammary glands during clinical course of the disease. A 40-year-old male was admitted with long-standing skin lesions and leukocytosis. Peripheral blood lymphocytes were highly pleomorphic and presented CD2, CD4, CD25, CD38 membrane surface antigens. The patient proved to be seropositive for human T-cell lymphotropic virus type I (HTLV-I) antibodies. Monoclonal expansion of lymphoid cells integrated with HTLV-I genome was observed, and the diagnosis of ATL chronic type was made. He underwent a chemotherapy regimen, and skin lesions and leukocytosis improved markedly. He progressed with an indolent clinical course of ATL, when he was admitted with bilateral hyperplasia of breast, recurrent skin lesions, and leukocytosis. Breast biopsy revealed bilateral gynecomasty, extensive leukemic infiltration of typical ATL cells in the mammary glands, and the presence of mammary epithelial cells productively infected with HTLV-I. This is the first report describing invasion of the mammary tissue with HTLV-I-transformed T-cells and HTLV-I-associated breast disease.

Breast↗
PubMed2000

TEL-AML1 fusion gene frequency in paediatric acute lymphoblastic leukaemia in Brazil.

We analysed 67 samples from Brazilian children of diverse ethnic origins with acute lymphoblastic leukaemia (ALL) for the presence of the TEL-AML1 fusion gene transcripts using reverse transcription polymerase chain reaction (RT-PCR). All 12 positive cases (20% of the 60 B-cell precursor ALL) had common (CD10+) ALL with a mean age of 4 years (range 1-10 years). We conclude that the frequency, age, distribution and clinical features of the TEL-AML1 fusion gene-positive ALL is similar in the diverse ethnic backgrounds of the Brazilian children to that in other countries with predominantly white Caucasian or oriental ethnicity. Apparent exceptions to this generality are discussed.

Black People↗
PubMed1999

An inverse correlation of HTLV-I viral load in CSF and intrathecal synthesis of HTLV-I antibodies in TSP/HAM.

The authors measured human T-cell lymphotrophic virus type I (HTLV-I) proviral load and intrathecal synthesis of antibodies to HTLV-I in CSF of 13 Brazilian patients with tropical spastic paraparesis/ HTLV-I-associated myelopathy (HAM). The authors also measured HTLV-I proviral load in peripheral blood mononuclear cells of five of these patients and found that it was 10- to 100-fold higher than that in CSF cells. The combination of HTLV-I proviral load and intrathecal synthesis of antibodies to HTLV-I appears to be a useful marker of disease progression. Patients with high viral load and no intrathecal synthesis of antibodies to HTLV-I had more rapidly progressing, serious clinical disease.

Adult↗
PubMed1997

Monoclonal origin of concordant T-cell malignancy in identical twins.

Acute leukemia has a high concordance rate in young identical twins and in infants this is known, from molecular analysis, to reflect an in utero origin in one twin followed by prenatal metastasis to the other twin via intraplacental anastomoses. The situation in older twins with leukemia has been less clear. We describe a pair of identical twins who were diagnosed with a T-cell malignancy at 9 and 11 years of age, one with T-cell non-Hodgkin's lymphoma and the other with T-cell acute lymphoblastic leukemia. Leukemic cells from the twins shared the same TCR beta gene rearrangement with an identical 11 bp N region. The most plausible interpretation of this result is that these malignancies were initiated in one twin fetus in utero, in a single T-lineage cell that had stable bi-allelic TCR beta rearrangements. Progeny of this cell then spread to the other twin before birth via shared placental vasculature. This was then followed by a 9- and 11-year preleukemic latent period before clinical disease manifestation as leukemia or lymphoma. This result has considerable implications for the etiology and natural history of pediatric leukemia.

Alleles↗
PubMed1996

Adult T-cell leukemia (ATL) with an unusual immunophenotype and a high cellular proliferation rate.

A patient with adult T-cell leukemia (ATL) characterized by a suppressor phenotype is reported. A 52-year-old mulatto male presented with symptoms and signs of hypercalcemia. His laboratory finding disclosed a peripheral blood specimen with abnormal cells characterized by a rather pleomorphic morphology and polylobated nucleous typical of ATL cells. Serum calcium and LDH were 18.2 mg/dl and 1373 IU, respectively. The phenotype of these cells was CD2+, CD4-, CD8+, CD28+ associated with the expression of activated antigens such as CD25, CD38, CD71 and CD30. Ki-67 positive were found in 20% of cells. The argyrophilic stain for nuclear organizer regions (AgNORs) was shown one cluster in 35% of abnormal cells. The serum antibodies were positive against human T-cell lymphotropic virus type I (HTLV-I) and clinical features were compatible with the diagnosis of ATL acute type. The combination therapy with cyclophosphamide, vincristine, prednisone decreased the number of leukemic cells but the clinical course was aggressive. He only responded transiently to treatment and died of multiorgan failure due to uncontrollable septicemia two weeks after admission.

Adult↗
PubMed1994

CD44 expression in T-cell lymphoblastic leukemia.

1. CD44 is an adhesion molecule expressed by B and T lymphocytes that mediates cell attachment to extracellular matrix components and specific cell surface ligands. In normal process of T-cell development, CD44 can be implicated in homing of bone marrow-derived T-cell precursors into the thymus. In hematopoietic malignancies, CD44 and other adhesion molecules can mediate the behavior of neoplastic cells such as metastatic migration. In the leukemic process, CD44 expression is correlated with increased numbers of circulating blasts and it is present at other sites such as the central nervous system. 2. In the present study, CD44 was investigated in lymphoblasts from 30 patients with T-cell lymphoblastic leukemia (T-ALL) and in peripheral lymphocytes from 10 healthy individuals. CD44 expression was detected in 23 (77%) of T-ALL cases studied and was correlated with clinical features such as mediastinal mass, adenomegaly, and infiltration of the central nervous system and other organs. Interestingly, CD44 expression in patients with tumor infiltration was higher than in patients with no tumor infiltration. 3. These data suggest that CD44 may be regarded as an additional marker for tumor expansion in T-cell leukemias.

Adolescent↗
PubMed1990

The significance of phenotyping leukemias using monoclonal antibodies.

1. Acute leukemias have been defined as major types of lymphoblastic and myeloblastic leukemias according to morphological and cytochemical criteria. 2. The technical improvements and standardization of immunofluorescence and immunocytology staining methods have provided new insights for classifying these disorders on the basis of monoclonal antibodies. 3. The scheme used to describe normal lymphoid and myeloid differentiation, when also used to describe their malignant counterparts, provides a well-established model for the immunological classification of acute leukemias. 4. In this review article, we suggest some guidelines for performing a series of cytochemical reactions using immunological markers to ensure a reliable diagnosis of acute leukemia.

Antibodies, Monoclonal↗