IL-17-producing double-negative T cells are expanded in the peripheral blood, infiltrate the salivary gland and are partially resistant to corticosteroid therapy in patients with Sjögren's syndrome.

A small CD3+ T-cell population, that lacks both CD4 and CD8 molecules, defined as double negative (DN), is expanded in the peripheral blood of patients with systemic lupus erythematosus, produces IL-17 and accumulates in the kidney during lupus nephritis. Since IL-17 production is enhanced in salivary gland infiltrates of patients with primary Sjögren's syndrome (pSS), we aimed to investigate whether DN T cells may be involved in the pathogenesis of salivary gland damage. Fifteen patients with SS and 15 normal controls (NC) were enrolled. Peripheral blood mononuclear cells were stimulated with anti-CD3 antibody and cultured in presence or absence of dexamethasone (Dex). Phenotypic characterization was performed by flow cytometry in freshly isolated cells and after culture. Minor salivary glands (MSG) from pSS were processed for immunofluorescence staining. Total circulating DN T cells were increased in pSS compared to NC (4.7±0.4% vs 2.6±0.4%). NC and pSS freshly isolated DN T cells produce consistent amounts of IL-17 (67.7±5.6 in NC vs 69.2±3.3 in pSS). Notably, DN T cells were found in the pSS-MSG infiltrate. Dex was able to down-regulate IL-17 in vitro production in NC (29±2.6% vs 15.2±1.9% vs 13±1.6%) and pSS (49±4.8% vs 16±3.8% vs 10.2±0.8%) conventional Th17 cells and in DN T cells of NC (80±2.8% vs 3.8±2.1% vs 4.2±1.8%), but not of pSS (81±1.5% vs 85.4±0.8% vs 86.2±1.7%). DN T cells are expanded in pSS PB, produce IL-17 and infiltrate pSS MSG. In pSS, conventional Th17 cells are inhibited by Dex, but DN T cells appear to be resistant to this effect. Taken together, these data suggest a key role of this T-cell subset in the perpetuation of chronic sialoadenitis and eventually in pSS prognosis.

FLT3-targeted therapy restores GATA1 pathway function in NPM1/FLT3-ITD mutated acute myeloid leukaemia.

One-third of newly diagnosed adult acute myeloid leukaemia (AML) carry FLT3 mutations, which frequently occur together with nucleophosmin (NPM1) mutations and are associated with worse prognosis. FLT3 inhibitors are widely used in clinics with limitations due to drug resistance. AML cells carrying FLT3 mutations in both mouse models and patients present low expression of GATA1, a gene involved in haematopoietic changes preceding AML. Here, we show that FLT3 inhibition induces cellular responses and restores the GATA1 pathway and functions in NPM1/FLT3-ITD mutated AML, thus providing a new mechanism of action for this drug.

Myeloid sarcoma: clinico-pathologic, phenotypic and cytogenetic analysis of 92 adult patients.

Myeloid sarcoma (MS) is a rare neoplasm whose knowledge is largely based on case reports and/or technically dated contributions. Ninety-two MSs in adulthood with clinical data available were evaluated both morphologically and immunohistochemically. Seventy-four cases were also studied by fluorescent in situ hybridization on tissue sections and/or conventional karyotyping on bone marrow or peripheral blood. Histologically, 50% of the tumors were of the blastic type, 43.5% either monoblastic or myelomonocytic and 6.5% corresponded to different histotypes. CD68/KP1 was the most commonly expressed marker (100%), followed by myeloperoxidase (83.6%), CD117 (80.4%), CD99 (54.3%), CD68/PG-M1 (51%), CD34 (43.4%), terminal-deoxy-nucleotidyl-transferase (31.5%), CD56 (13%), CD61/linker for activation of T cells (2.2%), CD30 (2.2%) and CD4 (1.1%). Foci of plasmacytoid monocyte differentiation were observed in intestinal cases carrying inv16. Chromosomal aberrations were detected in about 54% of cases: monosomy 7(10.8%), trisomy 8(10.4%) and mixed lineage leukemia-splitting (8.5%) were the commonest abnormalities, whereas t(8;21) was rare (2.2%). The behavior was dramatic irrespective of presentation, age, sex, phenotype and cytogenetics. Most if not all, long survivors received bone-marrow transplantation. The present report expands the spectrum of our knowledge showing that MS has frequent monoblastic/myelomonocytic differentiation, displays distinctive phenotypic profile, carries chromosomal aberrations other than t(8;21), and requires supra-maximal therapy.

Sch proteins are localized on endoplasmic reticulum membranes and are redistributed after tyrosine kinase receptor activation.

The intracellular localization of Shc proteins was analyzed by immunofluorescence and immunoelectron microscopy in normal cells and cells expressing the epidermal growth factor receptor or the EGFR/erbB2 chimera. In unstimulated cells, the immunolabeling was localized in the central perinuclear area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane and endocytic structures, such as coated pits and endosomes, and with the peripheral cytosol. Receptor activation in cells expressing phosphorylation-defective mutants of Shc and erbB-2 kinase showed that receptor autophosphorylation, but not Shc phosphorylation, is required for redistribution of Shc proteins. The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein.

Quantitative assessment of minimal residual disease in acute myeloid leukemia carrying nucleophosmin (NPM1) gene mutations.

Mutations in exon 12 of the nucleophosmin (NPM1) gene occur in about 60% of adult AML with normal karyotype. By exploiting a specific feature of NPM1 mutants, that is insertion at residue 956 or deletion/insertion at residue 960, we developed highly sensitive, real-time quantitative (RQ) polymerase chain reaction (PCR) assays, either in DNA or RNA, that are specific for various NPM1 mutations. In all 13 AML patients carrying NPM1 mutations at diagnosis, cDNA RQ-PCR showed >30 000 copies of NPM1-mutated transcript. A small or no decrease in copies was observed in three patients showing partial or no response to induction therapy. The number of NPM1-mutated copies was markedly reduced in 10 patients achieving complete hematological remission (five cases: <100 copies; five cases: 580-5046 copies). In four patients studied at different time intervals, the number of NPM1 copies closely correlated with clinical status and predicted impending hematological relapse in two. Thus, reliable, sensitive RQ-PCR assays for NPM1 mutations can now monitor and quantify MRD in AML patients with normal karyotype and NPM1 gene mutations.

Simultaneous detection of NPM1 and FLT3-ITD mutations by capillary electrophoresis in acute myeloid leukemia.

Mutations in the Nucleophosmin (NPM1) gene have been recently described to occur in about one-third of acute myeloid leukemias (AML) and represent the most frequent genetic alteration currently known in this subset. These mutations generate an elongated NPM1 protein that localizes aberrantly in the cytoplasm. In analogy with Flt3 alterations, NPM1 mutations are mostly detectable in AML with normal karyotype and their recognition may be relevant to identify distinct response to treatment. Hence, in addition to conventional karyotyping and RT-PCR of fusion genes, combined analysis of both Flt3 and NPM1 mutations will be increasingly relevant in the genetic diagnosis work-up of AML. We developed a multiplex RT-PCR assay followed by capillary electrophoresis to simultaneously analyze NPM1 and Flt3 gene alterations (NFmPCR assay). The assay was validated in leukemic cell RNAs extracted from 38 AML patients, which had been previously characterized for Flt3 status by conventional RT-PCR. Direct sequencing of NPM1 RT-PCR products was carried out in 15 cases to verify results obtained by capillary electrophoresis. Both NPM1 sequencing and conventional RT-PCR Flt3 results showed 100% concordance with the results of the NFmPCR assay. We suggest that this assay may be introduced in routine analysis of genetic alterations in AML.

Cell line OCI/AML3 bears exon-12 NPM gene mutation-A and cytoplasmic expression of nucleophosmin.

We recently identified a new acute myeloid leukemia (AML) subtype characterized by mutations at exon-12 of the nucleophosmin (NPM) gene and aberrant cytoplasmic expression of NPM protein (NPMc+). NPMc+ AML accounts for about 35% of adult AML and it is associated with normal karyotype, wide morphological spectrum, CD34-negativity, high frequency of FLT3-ITD mutations and good response to induction therapy. In an attempt to identify a human cell line to serve as a model for the in vitro study of NPMc+ AML, we screened 79 myeloid cell lines for mutations at exon-12 of NPM. One of these cell lines, OCI/AML3, showed a TCTG duplication at exon-12 of NPM. This mutation corresponds to the type A, the NPM mutation most frequently observed in primary NPMc+ AML. OCI/AML3 cells also displayed typical phenotypic features of NPMc+ AML, that is, expression of macrophage markers and lack of CD34, and the immunocytochemical hallmark of this leukemia subtype, that is, the aberrant cytoplasmic expression of NPM. The OCI/AML3 cell line easily engrafts in NOD/SCID mice and maintains in the animals the typical features of NPMc+ AML, such as the NPM cytoplasmic expression. For all these reasons, the OCI/AML3 cell line represents a remarkable tool for biomolecular studies of NPMc+ AML.

A new variant anaplastic lymphoma kinase (ALK)-fusion protein (ATIC-ALK) in a case of ALK-positive anaplastic large cell lymphoma.

Anaplastic lymphoma kinase (ALK)-positive lymphomas ("ALKomas") constitute a distinct molecular and clinicopathological entity within the heterogeneous group of CD30-positive large cell lymphomas. In 80-85% of cases tumor cells express a Mr 80,000 hybrid protein comprising the nucleolar phosphoprotein nucleophosmin (NPM) and the ALK. We report here the cloning and expression of a novel ALK-fusion protein from an ALK-positive lymphoma. This case was selected for molecular investigation because of (a) the absence of NPM-ALK transcripts; (b) the atypical staining patterns for ALK (cytoplasm-restricted) and for NPM (nucleus-restricted); and (c) the presence of a Mr 96,000 ALK-protein differing in size from NPM-ALK. Nucleotide sequence analysis of ALK transcripts isolated by 5'-rapid amplification of cDNA ends revealed a chimeric mRNA corresponding to an ATIC-ALK in-frame fusion. ATIC is a bifunctional enzyme (5-aminoimidazole-4-carboxamide ribonucleotide transformylase and IMP cyclohydrolase enzymatic activities) that catalyzes the penultimate and final enzymatic activities of the purine nucleotide synthesis pathway. Expression of full-length ATIC-ALK cDNA in mouse fibroblasts revealed that the fusion protein (a) possesses constitutive tyrosine kinase activity; (b) forms stable complexes with the signaling proteins Grb2 and Shc; (c) induces tyrosine-phosphorylation of Shc; and (d) provokes oncogenic transformation. These findings point to fusion with ATIC as an alternative mechanism of ALK activation.

The acute promyelocytic leukaemia-associated PML gene is induced by interferon.

The PML protein concentrates within discrete nuclear structures known as nuclear bodies, also called NDs or PODs, which contain several proteins including the interferon (IFN)-inducible SP100 product. The function of these structures remains elusive. We and others have shown recently that they represent specific targets for adenovirus and herpes simplex virus. This prompted us to investigate whether PML, like SP100, might be induced by IFN and to explore the role of PML in viral infection. Here we report that PML mRNA levels increase rapidly in response to interferon treatment. This accumulation of PML transcripts is a primary IFN response since it does not require de novo protein synthesis. The IFN-induced activation of the PML gene is accompanied by enhanced protein expression as revealed by immunolabelling. Both the intensity of the staining and the number of labelled structures increased upon interferon exposure. To probe the role of PML in IFN action, we compared the antiviral state established by alpha-interferon in embryonic fibroblasts (EFs) derived from null mutant mice for PML and from wild-type control mice. The resistance to viral infection conferred by IFN-alpha was identical in both PML+/+ and PMLm/m fibroblasts indicating that PML is not an essential mediator of the antiviral effect of interferon. We also noted that DNA-binding factors are normally activated by IFN in PMLm/m cells.

Anaplastic large-cell lymphoma: clinical and prognostic evaluation of 90 adult patients.

PURPOSE: During the last few years, the application of CD30 monoclonal antibodies has led to the identification of a new lymphoma entity, termed anaplastic large cell lymphoma (ALCL). This tumor includes four distinct histologic subtypes, among which the Hodgkin's-like/Hodgkin's-related one (ALCL-HL) shares morphologic and phenotypic features with Hodgkin's disease (HD). PATIENTS AND METHODS: From September 1988 to October 1993, 90 ALCL patients were treated with third-generation chemotherapy regimens (either vincristine, cyclophosphamide, fluorouracil, cytarabine, doxorubicin, methotrexate with leucovorin, and prednisone [F-MACHOP] or methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin [MACOP-B]) during the course of an Italian multicentric randomized trial on high-grade non-Hodgkin's lymphomas (HG-NHL). In particular, 47 patients had ALCL of the common type (ALCL-CT) and 43 ALCL-HL. Null phenotype was the most common (39.8%), while T-cell, B-cell, and hybrid forms accounted for 35.5%, 22.2%, and 2.5%, respectively. RESULTS: Complete remission (CR) was achieved in 66 of 90 (73.5%) patients (33 of 47 [70%] with ALCL-CT and 33 of 43 [77%] with ALCL-HL). The majority of the patients in CR (56.5%) were alive and well at a median follow-up time of 38 months; no significant differences were observed between the two histologic groups, with the rate of complete responders being 49% and 65% in ALCL-CT and ALCL-HL, respectively. The probability of relapse-free survival (RFS), projected at 63 months, was 67% for ALCL-CT and 82% for ALCL-HL. The risk of lower CR and RFS rates was associated with the presence of bulky disease, advanced stage, and B symptoms. CONCLUSION: The data of the present study confirm that ALCL responds to third-generation chemotherapy regimens similarly to other aggressive malignant lymphomas in terms of both CR and RFS rates.

Immunological and molecular studies in a case of follicular lymphoma with an extra chromosome 12 and t(2;8) translocation.

Two sequential lymph node biopsies taken from a non-Hodgkin lymphoma patient revealed two karyotype abnormalities peculiar to B cell neoplasias: trisomy 12 and t(2;8)(p12;q24) translocation. The first was documented in all cells analyzed, while the second was present in 20% of the metaphases from the first biopsy and in 100% from the second. This suggests that the t(2;8) translocation arose as a secondary karyotypic change. In addition, although immunological characterization of the neoplastic cells disclosed a monoclonal B cell population that expressed immunoglobulin kappa light chains, as usually found in Burkitt's lymphoma with t(2;8) translocation, Southern blot analysis provided evidence of rearrangement in only one kappa chain allele.

Mouse models of NPM1-mutated acute myeloid leukemia: biological and clinical implications.

Acute myeloid leukemia (AML) carrying nucleophosmin (NPM1) mutations displays distinct biological and clinical features that led to its inclusion as a provisional disease entity in the 2008 World Health Organization (WHO) classification of myeloid neoplasms. Studies of the molecular mechanisms underlying the pathogenesis of NPM1-mutated AML have benefited greatly from several mouse models of this leukemia developed over the past few years. Immunocompromised mice xenografted with NPM1-mutated AML served as the first valuable tool for defining the biology of the disease in vivo. Subsequently, genetically engineered mouse models of the NPM1 mutation, including transgenic and knock-in alleles, allowed the generation of mice with a constant genotype and a reproducible phenotype. These models have been critical for investigating the nature of the molecular effects of these mutations, defining the function of leukemic stem cells in NPM1-mutated AML, identifying chemoresistant preleukemic hemopoietic stem cells and unraveling the key molecular events that cooperate with NPM1 mutations to induce AML in vivo. Moreover, they can serve as a platform for the discovery and validation of new antileukemic drugs in vivo. Advances derived from the analysis of these mouse models promise to greatly accelerate the development of new molecularly targeted therapies for patients with NPM1-mutated AML.

A novel patient-derived tumorgraft model with TRAF1-ALK anaplastic large-cell lymphoma translocation.

Although anaplastic large-cell lymphomas (ALCL) carrying anaplastic lymphoma kinase (ALK) have a relatively good prognosis, aggressive forms exist. We have identified a novel translocation, causing the fusion of the TRAF1 and ALK genes, in one patient who presented with a leukemic ALK+ ALCL (ALCL-11). To uncover the mechanisms leading to high-grade ALCL, we developed a human patient-derived tumorgraft (hPDT) line. Molecular characterization of primary and PDT cells demonstrated the activation of ALK and nuclear factor kB (NFkB) pathways. Genomic studies of ALCL-11 showed the TP53 loss and the in vivo subclonal expansion of lymphoma cells, lacking PRDM1/Blimp1 and carrying c-MYC gene amplification. The treatment with proteasome inhibitors of TRAF1-ALK cells led to the downregulation of p50/p52 and lymphoma growth inhibition. Moreover, a NFkB gene set classifier stratified ALCL in distinct subsets with different clinical outcome. Although a selective ALK inhibitor (CEP28122) resulted in a significant clinical response of hPDT mice, nevertheless the disease could not be eradicated. These data indicate that the activation of NFkB signaling contributes to the neoplastic phenotype of TRAF1-ALK ALCL. ALCL hPDTs are invaluable tools to validate the role of druggable molecules, predict therapeutic responses and implement patient specific therapies.

Histological and immunohistological analysis of human lymphomas.

Morphological and immunological characteristics of lymphoproliferative diseases are reviewed. In particular, a basic distinction is made between non-Hodgkin's lymphomas and Hodgkin's disease. As to the non-Hodgkin's lymphomas, emphasis is given to the problems of classification, technical approach, histogenesis, and prognosis. The authors adopt a version of the Kiel Classification modified to take account of new knowledge regarding T-cell lymphomas. The value of immunophenotyping in making an accurate distinction between the various categories is stressed; immunocytochemical detection of the growth fraction is also discussed and then proposed as a new prognostic tool. Finally, the criteria for differential diagnosis between non-Hodgkin's lymphomas, malignant histiocytosis, non-lymphoid large cell tumors, and atypical immune reactions are outlined.

Protein A-peroxidase conjugates for two-stage immunoenzyme staining of intracellular antigens in paraffin-embedded tissues.

Staphylococcal protein A conjugated to horseradish peroxidase was employed in an indirect immuno-staining technique to identify intracellular antigens in paraffin-embedded tissues. The sections were incubated with specific antisera and the antigen-IgG complexes demonstrated with protein A-peroxidase conjugate. Immunoglobulins, lysozyme and insulin were satisfactorily detected by this technique. A comparison of this method with the PAP, "labelled antigen" and peroxidase-labelled antibody sandwich techniques was made.

Description of a sequential staining procedure for double immunoenzymatic staining of pairs of antigens using monoclonal antibodies.

This paper describes a sequential staining procedure for double immunoenzymatic staining of pairs of antigens in frozen tissue sections and cell smears using monoclonal antibodies. This technique involves performance of an indirect immunoperoxidase sandwich (including development of the enzyme reaction) followed by an unlabelled immuno-alkaline phosphatase sandwich (the APAAP method). The two enzyme labels are revealed using DAB/H2O2 for peroxidase and naphthol AS-MX plus fast blue or fast red for alkaline phosphatase. When compared with a hapten-sandwich/biotin-avidin system, the sequential staining procedure proved to be simpler and more sensitive and was also more suitable for double immunoenzymatic staining when monoclonal antibodies were only available in small amounts. The sequential staining procedure is particularly useful for the identification of antigens distributed in different cell populations or in different sites (e.g., nucleus and cytoplasm or cell surface) of the same cell. In contrast, this method does not appear to be very suitable for demonstrating two antigens located in the same site (e.g., surface membrane) of the same cell for which purpose double immunofluorescence remains the first choice.

Expression of bcl-6 and CD10 in primary mediastinal large B-cell lymphoma: evidence for derivation from germinal center B cells?

Primary mediastinal large B-cell lymphomas (LBCLs) constitute a unique subtype of diffuse LBCLs, with distinct clinical, immunophenotypic, and morphologic features. These lymphomas are thought to originate from the thymus, and it has been hypothesized that they derive from a population of B lymphocytes normally present in the thymic medulla. Most diffuse LBCLs harbor somatic mutations in their immunoglobulin genes, suggesting that they have been exposed to the germinal center. To investigate the possible relationship of mediastinal LBCLs to germinal center B cells, we analyzed the expression of bcl-6 and CD10 in 19 mediastinal LBCLs, using an immunoperoxidase technique on formalin-fixed tissue. We found that 19 of 19 (100%) mediastinal LBCLs were bcl-6+ and 6 of 19 (32%) mediastinal LBCLs were CD10+. Because mediastinal LBCLs usually lack BCL-6 gene rearrangement or mutations, expression of bcl-6 and CD10 in these tumors tends to support a germinal center derivation.