Biphenotypic acute leukemia with t(15;17).

Biphenotypic acute leukemias (BAL) represent 5% of all acute leukemias. The most frequent cytogenetic abnormalities described are Philadelphia chromosome and 11q23 involvement. Here we report a BAL case, with blasts showing lymphoblast morphology and positivity for myeloperoxidase (in 6% of the blast cells). Immunophenotype revealed the compromise of myeloid and B-lymphoid lineages. Cytogenetic analysis showed the t(15;17) and 8 trisomy. PML/RARa rearrangement was detected by fluorescent in situ hybridization (FISH) on interphase nuclei while PML/RARa fusion transcript was detected in the bone marrow and peripheral blood by molecular biology studies (RT-PCR). This report describes a BAL case with an unfrequent cytogenetic abnormality, and highlights the importance of correlating the results of multiple diagnostic methods in order to establish a correct diagnosis and treatment in BAL patients.

Nonhepatosplenic gamma delta T-cell lymphoma with initial testicular compromise.

We report here a case of nonhepatosplenic gammadelta T-cell lymphoma with undescribed initial localization in testis, without hepatosplenomegaly or adenopathies, and subsequent development in the maxillary sinus. The maxillar mass biopsy revealed a T-cell infiltration, and its immunologic characterization by flow cytometry showed a gammadelta T-cell phenotype (CD45+, CD3+, CD2+, TCR gammadelta+), without expression of CD7, CD5, CD1a, TdT, CD4, CD8, TCR alphabeta, or NK antigens (CD16, CD56, and CD57). Clonal gamma-chain gene rearrangement by polymerase chain reaction (PCR) was detected in testicular and maxillar biopsies. Epstein-Barr virus type 1 (EBV) sequences were detected by molecular biology in the biopsy material, suggesting that this oncogenic virus may play a role in the genesis of the clonal expansion of gammadelta T-cells. The patient was initially treated with standard chemotherapeutic protocols, with poor response and aggressive course.

[Detection of minimal residual disease in acute leukemias by flow cytometry]. / Detección de enfermedad mínima residual en leucemias agudas por citometría de flujo.

Detection of minimal residual disease in acute leukemias by flow cytometry has become an interesting tool for the analysis of minimal residual disease in acute leukemias. Some complementary studies can be used for this purpose such as conventional cytogenetics, FISH and molecular biology (PCR and Southern Blot). Flow cytometry study can detect smoldering blast cells in patients with acute leukemias who appear to be in complete remission by conventional morphologic criteria (< 5% of blast cells in bone marrow aspirate sample). This method can recognize 1 blast in 10(-4) mononuclear bone marrow cells considering the characteristics of immunophenotype at diagnosis (aberrant, asynchronous and overexpressed phenotypes) or using the analysis cell maturation to identify normal and abnormal patterns. These differences can be distinguished when the cells occupy the 'empty spaces' where no normal cells are evident. The principal objective of detecting low levels of tumor cells is to obtain more information about the efficacy of the treatment in order to: 1) design adapted post-remission protocols for high risk patients, 2) predict relapses previous to the clinical manifestations, 3) study the quality of stem cells harvested for autologous bone marrow transplantation.

Detección de enfermedad mínima residual en leucemias agudas por citometría de flujo. / [Detection of minimal residual disease in acute leukemias by flow cytometry]

Detection of minimal residual disease in acute leukemias by flow cytometry has become an interesting tool for the analysis of minimal residual disease in acute leukemias. Some complementary studies can be used for this purpose such as conventional cytogenetics, FISH and molecular biology (PCR and Southern Blot). Flow cytometry study can detect smoldering blast cells in patients with acute leukemias who appear to be in complete remission by conventional morphologic criteria (< 5

of blast cells in bone marrow aspirate sample). This method can recognize 1 blast in 10(-4) mononuclear bone marrow cells considering the characteristics of immunophenotype at diagnosis (aberrant, asynchronous and overexpressed phenotypes) or using the analysis cell maturation to identify normal and abnormal patterns. These differences can be distinguished when the cells occupy the empty spaces where no normal cells are evident. The principal objective of detecting low levels of tumor cells is to obtain more information about the efficacy of the treatment in order to: 1) design adapted post-remission protocols for high risk patients, 2) predict relapses previous to the clinical manifestations, 3) study the quality of stem cells harvested for autologous bone marrow transplantation.

Trilineage phenotypic compromise in acute leukemia.

The expression of three lineage specific antigens in the leukemic blasts is extremely infrequent. We here report a case of triphenotypic acute leukemia with involvement of the myeloid and B and T lineages. The morphology of the blasts showed promyelocytic features with agranular cytoplasm, suggesting a M3-variant of AML. The blasts were positive for myeloperoxidase PAS and Sudan Black. Immunophenotype and cytogenetics did not confirm M3-AML diagnosis, showing a trilineage compromise (myeloid and T and B lymphoid markers) and the cytogenetic alterations +8 and +11, respectively. This report highlights the importance of correlating the results of multiple diagnostic methods in order to establish a correct diagnosis of mixed lineage acute leukemias, and allows evaluation of the prognostic importance of this subgroup of patients.

Promyelocytic blast crisis of chronic myelogenous leukaemia with translocations (9;22) and (15;17).

The promyelocytic blast crisis is a rare form of transformation during the evolution of chronic myeloid leukaemia (CML). We report a case of promyelocytic blast crisis with t(15;17) in addition to t(9;22). The morphology and immunophenotype of the blasts were similar to those seen in acute promyelocytic leukaemia (APL). The t(15;17) was confirmed by FISH. The patient had evidence of coagulopathy with clinical and laboratory findings of disseminated intravascular coagulation (DIC). This report highlights the importance of correlating the results of multiple diagnostic methods in order to establish a correct diagnosis of the promyelocytic blast crisis of CML.

Growth hormone inhibits normal B-cell differentiation and neutrophils' chemotaxis in vitro.

In acromegalic patients we have previously described a low ability of B-lymphocytes to differentiate into plasma cells under PWM stimulation, and a decreased chemotaxis of polymorphonuclear leukocytes (PMN) towards N-formylmethionylphenilalanine (FMP). In this study we examined the effect of exogenous GH over these immune functions in normal cells. PMN were purified by dextran sedimentation, incubated with recombinant human GH (0 to 20 ng/ml) and subjected to stimulation with FMP. PBMC were cultured with or without PWM, in the presence of GH (between 0 and 100 ng/ml). Plasma cells were determined as hemolysis plaque forming cells and also by immunofluorescence. GH, in a dose-dependent way, decreased directed migration of PMN (5 ng/ml: 1.787 +/- 148 microns; 10 ng/ml: 1.581 +/- 221 microns; 20 ng/ml: 1.569 +/- 149 microns, all as mean +/- S.E.M.), when compared to similar values of untreated PMN (0 ng/ml 2.085 +/- 139 microns). GH treatment did not modify spontaneous migration. Net migration showed the same pattern as directed migration. GH decreased dose-dependently the PWM-driven differentiation of B-lymphocytes into plasma cells to 60% of the basal level. Although not significantly, GH tended to increase spontaneous B-cell differentiation. These results could account for the already described defect in B-cell differentiation and PWN chemotaxis in acromegaly, emphasizing the relationship between the endocrine and immune systems.