Functional Analysis of Aberrantly Spliced Caspase8 Variants in Adult T-Cell Leukemia Cells.

The genetic and molecular alterations responsible for leukemogenesis and progression of HTLV-infected adult T-cell leukemia (ATL) have not been fully clarified. Previously, we reported that various genes are not only overexpressed but also abnormally spliced in ATL cells. Here, we identified various CASP8 transcript variants in PBMCs from a smoldering-type ATL patient, which encode aberrant truncated caspase 8 (Casp8) isoforms. Among those, we focus on the three transcript variants, CASP8L (including the first 136 bp of the intron 8 between exon 8 and exon 9), CASP8-ΔE4 (without the exon 4), and CASP8-ΔE7 (without the exon 7), because they encode isoforms, Casp8L, Casp8-ΔE4, and Casp8-ΔE7, respectively, without the C-terminal catalytic domains. In this study, we conducted in vitro characterization and functional analysis of those mutant Casp8 isoforms to clarify their changed functions compared with the wild-type (WT)-Casp8. We demonstrated that these abnormal Casp8 isoforms showed lower ability to induce apoptosis than WT-Casp8 due to their dominant-negative interactions with WT-Casp8, which impair WT-Casp8 homodimerization that is essential for induction of apoptosis. Moreover, Casp8L and Casp8-ΔE7, which have only two death-effector domains, significantly activated NFκB by forming filament-like structures, which probably function as scaffolds for the IKK complex formation. In view of increasing levels of these abnormal CASP8 transcripts in primary PBMCs from HTLV-1 carriers and patients with ATL, we propose a possibility that overexpression of those Casp8 mutants, with lower proapoptotic activities and higher NFκB-activating functions than WT-Casp8, may be one of the molecular abnormalities causing malignant transformation and growth of ATL cells. IMPLICATIONS: We describe naturally occurring CASP8 transcription variants in PBMCs from patients with ATL, which encode truncated Casp8-mutant isoforms with lower proapoptotic activities and higher NFκB-activating functions compared with WT-Casp8.

Paraneoplastic autoimmune multiorgan syndrome (paraneoplastic pemphigus) with unusual manifestations and without detectable autoantibodies.

We describe a patient with paraneoplastic autoimmune multiorgan syndrome (PAMS) secondary to a lymphoblastic T- cell lymphoma who presented with a lichenoid dermatitis and vitiligo, later developing bronchiolitis obliterans and autoimmune hepatitis. Notably, he had no detectable autoantibodies. The development of vitiligo and autoimmune hepatic involvement probably indicate a role for cytotoxic T- cell lymphocytes in the pathogenesis of this syndrome.

Spontaneous chronic T-cell leukemia in a male rhesus macaque ( Macaca mulatta).

Blood smears from a 24-year-old male rhesus macaque ( Macaca mulatta) used for cognitive function studies were evaluated. The macaque had an 8-month history of gradual weight loss and increasing lymphocytosis. Most of the lymphocytes present were small to medium and had a mature morphology. Based on the degree and duration of the lymphocytosis, and the appearance of the lymphocytes, a diagnosis of chronic lymphocytic leukemia was made. The animal tested negative for 4 viral diseases that are commonly associated with lymphoproliferative disorders in Old World monkeys. Over the course of 12 months, the lymphocytosis progressed from 18.4 to 384 × 103 lymphocytes/µl (reference range: 0.8-17 × 103 cells/µl), and euthanasia was elected. On histologic examination, cluster of differentiation (CD)3- and CD8-positive, CD79-negative neoplastic cells comprised 40-60% of the bone marrow, diffusely obscured the normal splenic architecture, and were present in the vascular channels in other organs. Findings were characteristic of T-cell lymphocytic leukemia. Naturally occurring T-cell lymphocytic leukemia has been rarely reported in rhesus macaques and, to the authors' knowledge, never in males. A persistent lymphocytosis characterized by a monomorphic population of CD3- and CD8-positive cytotoxic T-lymphocytes and the presence of neoplastic cells in the bone marrow led to a diagnosis in the current case.

Novel single-platform multiparameter FCM analysis of apoptosis: Significant differences between wash and no-wash procedure.

FCM is a generally accepted tool to analyze apoptosis. Unfortunately, the cell preparation of all commercial kits available includes cell washing known to cause cell loss which is most likely to affect apoptotic cells in particular. To address this, we developed a seven-color single-platform no-wash analysis technique and compared the results with those from an analogous procedure including cell washing. A five-color mAb cocktail was employed to address target cells by surface labeling, Yo-PRO-1® and DAPI were used to discriminate apoptotic and necrotic from viable cells. Cells were quantified on the basis of internal-standard fluorescent beads. Jurkat cells ACC 282 treated with camptothecin were employed to establish the staining procedure, which was then applied to blood cells collected by extracorporeal apheresis and treated with UV irradiation. Data evaluation showed that although each method by itself was highly reproducible (R(2) = 0.973), the numbers of apoptotic cells detected with the no-wash procedure were significantly higher than those obtained after cell washing (P = 6.6 E(-5), Wilcoxon Test). In addition, the observed differences increased with higher cell numbers (Bland and Altmann). We conclude that the described test is a feasible and reliable tool for apoptosis measurement and it provides results that are definitely closer to the truth than those obtained from kits that require cell washing.

El virus linfotropico HTLV-1: un problema emergente en Bolivia / The lymphotropic HTLV-1 virus: an emergent problem in Bolivia

En los últimos años nos hemos venido preguntando, ¿ existen nuevas enfermedades o simplemente estamos redescubriendo algunas? Esto lleva a la necesidadde generar el término de Enfermedades Emergentes, refiriéndonos a aquellas enfermedades nuevas opreviamente descritas que se hacen importantes porsu incidencia creciente.1Tajima y Sonoda, han planteado un nuevo enfoque en el conocimiento de ciertas enfermedades que hanafectado al ser humano desde épocas antiguas, denominando a esta disciplina etnoepidemiología. 2,3Una entidad digna de estos estudios es el Virus Linfotrófico Humano Tipo 1 (HTLV-1), ya que su descubrimiento en varias partes del mundo, apoya la hipótesis de la migración de los pueblos, portadores de este virus, a través del Estrecho de Bering, llegando hasta las más remotas regiones del sur del continente americano, sin descartar la posibilidad de otras migraciones posteriores por vía marítima

Activation of complement system in adult T-cell leukemia (ATL) occurs mainly through lectin pathway: a serum proteomic approach using mass spectrometry.

Adult T-cell leukemia (ATL) is a fatal malignancy caused by infection with human T lymphotropic virus type-1 (HTLV-1). To search for a new biomarker of ATL, we analyzed sera from ATL patients using ProteinChip arrays. The spectral comparison of ATL patients with HTLV-1 carriers and healthy volunteers showed that the intensities of five peaks (1779, 1866, 2022, 4467, and 8930 m/z) were significantly increased in ATL, while those of four peaks (4067, 4151, 8130, and 8597 m/z) were decreased. From these differentially expressed peaks, we chose peaks of 1779, 1866, and 2022 m/z as biomarker candidates of ATL. MS/MS ion search using tandem mass spectrometry and immunoprecipitation assay using anti-C3 antibody showed that factors derived from these candidate peaks were identified as C3f, which is a component of the complement system and a fragment of complement C3. These results indicate that the complement system was activated in ATL. Further analysis of markers specific to the activation pathways (classical, alternative, and lectin pathways) in the complement system showed that the serum concentration of the marker of the lectin pathway was significantly higher in ATL patients. These results suggest that activation of the complement system in ATL occurs mainly through the lectin pathway.

Long-term T-cell reconstitution after hematopoietic stem-cell transplantation in primary T-cell-immunodeficient patients is associated with myeloid chimerism and possibly the primary disease phenotype.

We studied T-cell reconstitution in 31 primary T-cell-immunodeficient patients who had undergone hematopoietic stem-cell transplantation (HSCT) over 10 years previously. In 19 patients, there was no evidence of myeloid chimerism because little or no myeloablation had been performed. Given this context, we sought factors associated with good long-term T-cell reconstitution. We found that all patients having undergone full myeloablation had donor myeloid cells and persistent thymopoiesis, as evidenced by the presence of naive T cells carrying T-cell receptor excision circles (TRECs). In 9 patients with host myeloid chimerism, sustained thymic output was also observed and appeared to be associated with gammac deficiency. It is therefore possible that the complete absence of thymic progenitors characterizing this condition created a more favorable environment for thymic seeding by a population of early progenitor cells with the potential for self-renewal, thus enabling long-term (> 10 years) T-cell production.

Mature T-cell leukemias.

Mature T-cell and NK-cell leukemias are a group of relatively uncommon neoplasms derived from mature or postthymic T-cells accounting for a relatively small percentage of lymphoid malignancies. The recent availability of modern immunophenotypic and molecular tools has allowed a better distinction of these disorders from their B-cell counterparts. Similarly, identification of recurrent cytogenetic abnormalities, as well as plausible mechanisms through which these molecular events influence cellular signaling pathways, have created further insight into the pathogenesis of these disorders. Furthermore, the availability of new agents such as alemtuzumab has generated significant interest in devising specific therapeutic strategies for these malignancies. Herein, we review the clinical and pathological features of mature T-cell leukemias.

Nonmyeloablative peripheral blood stem cell transplant for T-cell prolymphocytic leukaemia complicated by fulminant haemolysis and acute renal failure at engraftment secondary to minor ABO incompatibility.

We present a 54-year-old man who underwent human leucocyte antigen-identical sibling nonmyeloablative peripheral blood stem cell transplant for primary refractory T-cell prolymphocytic leukaemia (T-PLL). His clinical course was complicated by fulminant haemolysis and acute renal failure at the time of engraftment because of minor ABO incompatibility between the donor and the recipient. This case highlights the curative potential of nonmyeloablative transplantation for T-PLL as well as the potential severity of immune haemolysis secondary to minor ABO incompatibility.

T-cell large granular lymphocytic leukemia and hereditary hemochromatosis: a fortuitous association?

We describe a patient with hereditary hemochromatosis (homozygous for C282Y mutation) and neutropenia who was found to have underlying T-cell large granular lymphocytic (T-LGL) leukemia. The diagnosis was confirmed by demonstrating T-cell receptor (TCR) gene rearrangement by polymerase chain reaction (PCR). Multiple quantitative and qualitative defects have been described for the T cells of patients with hemochromatosis. Although the association between the two may be fortuitous, this case report raises the possibility that the T cells in these patients may be susceptible to leukemic transformation as well.

[Unclassified mature T cell leukemia with cerebriform nuclei].

A 53 year-old male visited our hospital for evaluation of his leukocytosis, which was first diagnosed more than 6 years previously. He was asymptomatic and there were no remarkable findings on physical and laboratory examinations except for the lymphocytosis. Abnormal lymphocytes with deep folded nuclei were seen on light microscopy, whose phenotype was CD3+, CD4-, CD8-, CD7-, CD16 , CD56-, CD45RO+ and CD45RA- . Electron microscopy revealed 'cerebriform nuclei' which were characteristic of Sézary cells. Adult T cell leukemia (ATL) and Sézary syndrome (SS) were ruled out because of the negative HTLV-1 test and the absence of skin lesions, respectively. T-prolymphocytic leukemia (T-PLL), which is characterized by a marked increase in leukocytes having a CD7-phenotype and a progressive fatal course, was also excluded. Recently, the TCL1 onco-protein has been shown to be overexpressed in progressive T-PLL but not in other mature T cell leukemias including Sézary syndrome. Peripheral mononuclear cells in the present patient did not overexpress TCL1. In its morphology and phenotypes, our case resembled 'Sézary cell leukemia (SCL)' but the clinical course was much more indolent. This case did not match any of the mature T cell leukemias defined in the WHO classification.

Expression of the Tpl2/Cot oncogene in human T-cell neoplasias.

BACKGROUND: Tpl2/Cot oncogene has been identified in murine T-cell lymphomas as a target of MoMuLV insertion. Animal and tissue culture studies have shown that Tpl2/Cot is involved in interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) production by T-cells contributing to T-cell proliferation. In the present report we examined a series of 12 adult patients with various T-cell malignancies, all with predominant leukemic expression in the periphery, for the expression of Tpl2/Cot oncogene in order to determine a possible involvement of Tpl2/Cot in the pathogenesis of these neoplasms. RESULTS: Our results showed that Tpl2/Cot was overexpressed in all four patients with Large Granular Lymphocyte proliferative disorders (LGL-PDs) but in none of the remaining eight patients with other T-cell neoplasias. Interestingly, three of the LGL-PD patients displayed neutropenia, one in association with sarcoidosis. Serum TNF-alpha levels were increased in all Tpl2/Cot overexpressing patients while serum IL-2 was undetectable in all subjects studied. Genomic DNA analysis revealed no DNA amplification at the Tpl2/Cot locus in any of the samples analyzed. CONCLUSIONS: We conclude that Tpl2/Cot, a gene extensively studied in animal and tissue culture T-cell models may be also involved in the development of human LGL-PD and may have a role in the pathogenesis of immune manifestations associated with these diseases. This is the first report implicating Tpl2/Cot in human T-cell neoplasias and provides a novel molecular event in the development of LGL-PDs.

Near-triploidy and near-tetraploidy in hematological malignancies and mutation of the p53 gene.

Hyperdiploidy of > or =58 chromosomes is reported in 0.5-3% of hematological malignancies, but reports of near-triploidy (58-80 chromosomes) and near-tetraploidy (81-103 chromosomes), are few. We examined these chromosome abnormalities and analyzed the relationship with the mutation of the p53 gene. Thirty-one of 979 adult patients (3.2%) with hematological malignancies were identified as having near-triploid or near-tetraploid (tri-/tetraploid) chromosomes. These included 11 with B-cell neoplasms, seven with Hodgkin's lymphoma, five with T-cell neoplasms, four with myelodysplastic syndromes and four with acute myeloid leukemias. All patients had concurrent complex chromosome aberrations. Deletion of one allele of the p53 gene was found in two patients and a point mutation of the p53 gene was detected in five patients. Although abnormalities of the p53 gene have been reported in about 10% of hematological malignancies, these were found in seven of 31 (23%) patients with tri-/tetraploidy. These findings suggest that the abnormality of the p53 gene may be closely related with tri-/tetraploidy. The four myelodysplastic syndrome (MDS) patients with tri-/tetraploidy had a significantly worse prognosis than those with diploid cytogenetics (n = 35; P < 0.002). In B-cell neoplasms (n = 3), triploidy was associated with a worse prognosis than tetraploidy (n = 8) and diploidy (n = 130; P < 0.02).

Use of a chimeric synthetic peptide from the core p19 protein and the envelope gp46 glycoprotein in the immunodiagnosis of HTLV-II virus infection.

A chimeric synthetic peptide incorporating immunodominant epitope of the p19 gag protein (116-134) and the gp46 env protein (178-200) of HTLV-II virus, separated by two glycine residues, was synthesized by conventional solid-phase peptide synthesis. The antigenic activity of this peptide was evaluated by Ultramicro Enzyme-linked immunosorbent assay (UMELISA) by using panels of anti-HTLV-II positive sera (n = 9), anti-HTLV-I/II positive sera (n = 2), HTLV-positive (untypeable) serum samples (n = 1),and anti-HTLV-I positive sera (n = 14), while specificity was evaluated with samples from healthy blood donors (n = 20). The efficacy of the chimeric peptide in solid-phase immunoassays was compared with the monomeric peptides. Data demonstrated that the chimeric peptide was the most reactive because it detected antibodies to virus efficiently. This may be related to peptide adsorption to the solid surface and epitope accessibility to the antibodies. The results indicate that chimeric peptide as coating antigen is very useful for the immunodiagnosis of HTLV-II infection.

Significance of HTLV-1 proviral load quantification by real-time PCR as a surrogate marker for HTLV-1-infected cell count.

We developed a real-time (RT) PCR quantitative assay to measure the level of the integrated viral genome of HTLV-1 in host peripheral blood-mononuclear cells (PB-MNC) from healthy carriers and patients with adult T-cell leukemia (ATL). All of the clinical specimens were serologically and molecularly characterized by enzyme-linked immunosorbent assay (ELISA) and Southern blot hybridization (SBH) analyses. The assay system for quantifying the proviral copy level was sensitive, accurate, and reproducible over a wide range of density from 100 to 0.1% with a coefficient of variation (%) of 4.5 to 9.6. The proviral load of the healthy carriers and patients with ATL was 301 +/- 339 copies per 10(4) MNC (3 +/- 3.4%) on average and varied depending on the ATL cell number and the SBH band-status of single or multiple bands. In ATL cases with multiple bands detected by SBH analysis, their ATL cells were shown to harbor multiple copies within one ATL cell, so that the corrected copy number interpolated by the band number in SBH was closely equivalent to the expected ATL cell number in PB, corresponding to the virus-infected cell burden. The proviral load in healthy carriers ranged from 0.1 to 15% of PB-MNC, and, in combination with the fraction (%) of ATL-like flower cells defined by PB smear morphology, enabled carriers to be subgrouped into three categories. This result indicates that the detection of proviral load by(RT) PCR is sufficient and relevant to monitor the infected cell number in the PB and to evaluate the HTLV-1 pathologic status.

T-cell prolymphocytic leukemia with hemorrhagic gastrointestinal involvement and a new chromosomal abnormality.

We report a case of T-cell prolymphocytic leukemia in a 56-year-old woman who exhibited hemorrhaging with gastric involvement as the first manifestation. This patient's condition was diagnosed as T-cell prolymphocytic leukemia based on the findings of lymphocytosis, abnormal immunophenotype, hepatosplenomegaly, lymphadenopathy, and cutaneous involvement. Endoscopic examination of the upper gastrointestinal tract revealed hemorrhage from a gastric lesion with histological involvement. Cytogenetic analysis revealed chromosomal abnormalities, 46,XX,der(1), add(1)(p36), that have not previously been described in T-cell prolymphocytic leukemia. In spite of a transient response to chemotherapy, the patient died 15 months after onset of the disease.

Matrix metalloproteinase-9 and vascular endothelial growth factor: a possible link in adult T-cell leukaemia cell invasion.

Plasma from a total of 57 patients with adult T-cell leukaemia (ATL) (acute ATL, 39 patients; lymphoma ATL, one patient; chronic ATL, 15 patients; smouldering ATL, two patients) and 20 healthy controls was analysed for the presence of type IV gelatinase activity with clinical features. A significant elevation of plasma matrix metalloproteinase-9 (MMP-9) was observed in some ATL patients, particularly in the patients with malignant cell infiltration. MMP-9 was found to be secreted into the conditioned medium from all ATL cell lines examined. Moreover, the corresponding mRNA was detectable both in all ATL cell lines examined and in the majority of primary acute ATL cells, indicating that ATL cells are capable of synthesizing and secreting MMP-9. We previously demonstrated that a high incidence of ATL cell infiltration was closely related to a high plasma level of vascular endothelial growth factor (VEGF) produced by ATL cells themselves. This present study showed that the presence of increased plasma MMP-9 was closely associated with elevated plasma VEGF in ATL patients. Furthermore, we showed that both increased plasma MMP-9 and VEGF were significantly related to high ATL cell infiltration. All these findings strongly suggest that MMP-9 and VEGF act co-operatively in the process of ATL cell invasion.