[Myelodysplastic syndromes. Epidemiology, molecular and morphological characteristics and risk stratification]. / Myelodysplastische Syndrome. Epidemiologie, molekulare und morphologische Merkmale, Risikostratifizierung.

Myelodysplastic syndromes (MDS) comprise a spectrum of clonal stem cell disorders which are currently defined according to the classification scheme of the revised 2008 WHO classification but which may be further refined in the future. The clinical presentation is often characterized by unexplained isolated or multiple peripheral blood cytopenias resulting in anemia, bleeding events or increased susceptibility to infections. The generally hypercellular, but rarely hypocellular and occasionally fibrotic bone marrow shows dysplastic features in ≥ 10 % of cells of at least one of the hematopoietic lineages. These features and enhanced apoptosis, stem cell senescence and immunologic dysregulation result in ineffective hematopoiesis. Diagnostics in MDS relies on complementary consideration of hematological, morphological and cytogenetic/molecular parameters. Methods include marrow and peripheral blood cytology, cytogenetics, fluorescence in situ hybridization (FISH), trephine bone marrow biopsy examination, immunophenotyping and the evaluation of molecular markers by established and new techniques. Mutations affecting growth factor receptors, cell cycle and apoptosis regulators, intracellular signaling, transcription factors, epigenetic regulation and the splicosome are involved in MDS pathogenesis and progression.

Gamma/delta T cell clones and natural killer cell clones mediate distinct patterns of non-major histocompatibility complex-restricted cytolysis.

Non-MHC-restricted killer cells are cytotoxic lymphocytes that can mediate cytolysis of most tumor targets without apparent selectivity and restriction by the MHC, particularly when activated with IL-2. These effector cells include predominantly NK cells and T cells expressing the TCR-gamma/delta. We found that TCR-gamma/delta-1+, delta TSC1-, BB3+, Ti gamma A+ T cell clones mediate a characteristic cytolytic pattern of non-MHC-restricted cytolysis that is markedly different from NK clones and alpha/beta T cell clones derived from the peripheral blood of the same normal individuals. The characteristic finding is that all BB3/Ti gamma A+ gamma/delta clones mediate strong cytolysis of Daudi cells but they do not lyse Raji cells. In contrast, NK clones from the same donors mediate strong cytolysis of both Daudi and Raji targets. Cytotoxicity by the gamma/delta clones on certain target cells such as Daudi and Molt 4 can be specifically inhibited by mAbs reactive against the TCR-gamma/delta. Therefore, the TCR-gamma/delta on these clones either directly recognizes target epitopes on some tumor targets or it is involved in the regulation of their cytotoxic function. The expression of TCR-gamma/delta products reacting with the BB3 and Ti gamma A mAbs reflects the usage of identical TCR-gamma/delta V region genes that appear to be associated with the characteristic pattern of non-MHC-restricted cytotoxicity displayed by this major subset of human peripheral blood gamma/delta cells.

Intraepithelial CD8-positive T lymphocytes predict survival for patients with serous stage III ovarian carcinomas: relevance of clonal selection of T lymphocytes.

BACKGROUND: The aim of this study was to investigate the prognostic effect of tumour-infiltrating lymphocytes (TILs) in serous stage III ovarian carcinoma to determine TIL clonality and to correlate this to Her2/neu expression. METHODS: Formalin-fixed and paraffin-embedded ovarian carcinomas were examined for CD20-, CD3-, CD4- and CD8-positive lymphocytes (n=100), and for Her2/neu-positive tumour cells (n=55/100) by immunohistochemistry. Clonality analysis was carried out by T-cell receptor gamma (TCRgamma) gene rearrangements (n=93/100). Statistical analyses included experimental and clinico-pathological variables, as well as disease-free (DFS) and overall (OS) survival. RESULTS: CD20-positive B lymphocytes were present in 57.7% (stromal)/33.0% (intraepithelial) and CD3-positive T lymphocytes in 99.0% (stromal)/90.2% (intraepithelial) of ovarian carcinomas. Intraepithelial CD3-positive T lymphocytes were correlated with improved DFS in optimally debulked patients (P=0.0402). Intraepithelial CD8-positive T lymphocytes were correlated with improved OS in all optimally debulked patients (P=0.0201) and in those undergoing paclitaxel/carboplatin therapy (P=0.0092). Finally, rarified and clonal TCRgamma gene rearrangements were detected in 37 out of 93 (39.8%) and 15 out of 93 (16.1%) cases, respectively. This was marginally associated with improved DFS (P=0.0873). Despite a significant correlation of HER2/neu status and intraepithelial CD8-positive lymphocytes (P=0.0264), this was non-directional (R=-0.257; P=0.0626). CONCLUSION: Improved survival of ovarian cancer patients is related to the infiltration, clonal selection and intraepithelial persistence of T lymphocytes.

Recognition by human V gamma 9/V delta 2 T cells of a GroEL homolog on Daudi Burkitt's lymphoma cells.

All human gamma delta T cells coexpressing the products of the variable (V) region T cell receptor (TCR) gene segments V gamma 9 and V delta 2 recognize antigens from mycobacterial extracts and Daudi cells. Exogenous and endogenous ligands on the cell surface, homologous to the groEL heat shock family, induced reactivities that resembled superantigen responses in this major subset of human peripheral blood gamma delta T cells. Stimulation of human V gamma 9/V delta 2 T cells is not restricted by human leukocyte antigens (HLA), including nonpolymorphic beta 2-microglobulin (beta 2M)-associated class Ib molecules. These data may be important for understanding the role of gamma delta T cells in autoimmunity and in responses to microorganisms and tumors.

Partial break in tolerance of NKG2A-/LIR-1- single KIR+ NK cells early in the course of HLA-matched, KIR-mismatched hematopoietic cell transplantation.

Natural killer (NK) cell subpopulations from 8 HLA-matched but killer cell immunoglobulin-like receptor (KIR)/HLA-ligand-mismatched patient-donor pairs were analyzed in the course of allogeneic hematopoietic stem cell transplantation (HCT). The patients' post-transplantation NKG2A-/LIR-1- NK cells, which expressed only inhibitory KIRs for which the patient had no HLA class I ligands, showed higher cytotoxic capacity than the NKG2A-/LIR-1- NK cells lacking any inhibitory KIRs that remained tolerant throughout the course of HCT. The NKG2A+ NK cell subpopulations displayed the highest levels of cytotoxic activation, which appeared to be significantly enhanced in comparison with that in allogeneic graft's donors. LIR-1- NK cells were much more frequent after HCT than LIR-1+ NK cells and LIR-1 expression on NKG2A+ or NKG2A- NK cells was associated with significantly lower cytotoxic activities. Thus NKG2A-/LIR-1- NK cells expressing only HLA-mismatched KIRs show a partial break in tolerance in the first year following HCT. The failure to exclude LIR-1+ cells within the NKG2A- NK cell subset in previous studies could explain the earlier conflicting results. Thus systemic immune activation in patients following HCT augments the GvL effect through both increasing overall NK cell activities and partially breaking tolerance of unlicensed NK cells.

Lymphokine-activated killer activity induced by in vivo interleukin 2 therapy: predominant role for lymphocytes with increased expression of CD2 and leu19 antigens but negative expression of CD16 antigens.

The phenotype and function of lymphocytes from cancer patients treated with repetitive weekly cycles of continuous i.v. infusions of recombinant interleukin 2 (IL-2) were examined. Peripheral blood lymphocytes (PBL) obtained after IL-2 therapy showed an increased percentage of cells bearing the CD16 and leu19 markers which are associated with natural killer cells. These PBL mediated significantly increased levels of IL-2-dependent lymphokine-activated killer (LAK) activity against the Daudi cell line. Depletion of CD16+ cells from PBL obtained after in vivo IL-2 caused only slight inhibition of their LAK activity or their proliferative response to IL-2 in vitro. This indicates that CD16+ cells are involved but play only a minor role in these responses. In contrast, depletion of leu19+ cells, from PBL activated in vivo with IL-2, virtually abrogated their LAK activity and their proliferative response to IL-2. Two-color flow cytometry studies showed that a leu19+/CD16- population was expanded by in vivo IL-2 therapy and was responsible for the majority of LAK activity by in vivo-activated PBL. Moreover, this CD16- population showed an increased density of leu19 and CD2 (E rosette receptor) antigens when compared to the resting PBL obtained prior to IL-2 treatment. These data show that the predominant population mediating in vitro LAK activity, induced by in vivo IL-2 therapy, consists of activated natural killer cells with a high density of leu19 and CD2 antigens but negative for the CD16 antigen.

Natural killer cells activated by interleukin 2 treatment in vivo respond to interleukin 2 primarily through the p75 receptor and maintain the p55 (TAC) negative phenotype.

Interleukin 2 (IL-2) induced activation of unstimulated resting natural killer (NK) cells or resting T-cells initially occurs following binding of IL-2 through the p75 receptor that is expressed primarily by these cells. However, this IL-2/p75 interaction induces TAC chain synthesis and formation of high affinity IL-2 receptor required for the proliferation of resting peripheral blood lymphocytes. In this study, we present data indicating that NK cells activated by in vivo IL-2 treatment, in contrast to resting NK cells, respond and proliferate to further IL-2 in vitro using primarily the p75 receptor with only a minor component of cells responding through the high affinity receptor. These in vivo activated NK cells minimally expressed the TAC chain and maintained this TAC negative phenotype while proliferating in response to IL-2. The primary involvement of the p75 receptor in the proliferative response of these cells to IL-2 was demonstrated by the need for concentrations of IL-2 higher than 44 pM to obtain a significant response and by the dramatic inhibition of this response by anti-p75 monoclonal antibody. Anti-TAC monoclonal antibody inhibited only the poor proliferation obtained at low doses of IL-2 suggesting a minor role for TAC and high affinity IL-2 receptors. This was in contrast to the partial inhibition of proliferation by anti-p75 or anti-TAC observed in unstimulated pretherapy peripheral blood lymphocytes suggesting that these cells respond to IL-2 through both high affinity receptors and intermediate affinity p75 receptors. The T-cells isolated from in vivo activated peripheral blood lymphocytes, despite expressing TAC, were not responsive to IL-2, suggesting that these cells express predominantly nonfunctional low affinity TAC receptors. NK cells activated by IL-2 in vivo represent a unique model system of IL-2 dependent cells that respond and proliferate to IL-2 essentially through the p75 IL-2 receptor.

Clonal evolution of malignant and non-malignant T cells carrying t(14;14) and t(X;14) in patients with ataxia telangiectasia.

People with ataxia telangiectasia (AT) are at a higher than normal risk of T cell leukaemia and often have either non-malignant or malignant T cells with chromosomal abnormalities, typically t(14;14), inversion 14 or more rarely t(X;14). This provides a chance to study the pre-leukaemic phase of the disease. T cells have been studied with either t(14;14)(q11;q32.1) or t(X;14)(q28;q11) from two AT sisters of which the latter developed T cell leukaemia. The telomeric breakpoint of the t(14;14) was cloned and found to occur at 14q32.1 where known tumour-associated breakpoints are located, but the patient remains asymptomatic for leukaemia. Analysis of T cell populations in both patients showed that the cells containing the translocation became oligoclonal with respect to T cell receptor beta rearrangement and complete T cell receptor beta clonality was only established in the patient with t(X;14) by onset of overt disease. Therefore in these chronic diseases, chromosomal translocations can precede T cell receptor rearrangement suggesting a role for these abnormalities as early events of malignant outgrowth.

T cell tumours of disparate phenotype in mice transgenic for Rbtn-2.

RBTN2 is a LIM domain protein which can be activated by the translocation t(11;14)(p13;q11) in childhood T cell acute leukaemia. Transgenic mice were examined in which rbtn2 protein is expressed in the T cell lineage. An average of 72% of these mice developed T cell tumours before 18 months of age, compared with 9% in transgenic mice expressing the related gene Rbtn-1. Rbtn2-induced tumours first appeared at 5 months of age and were clonal. They displayed a range of phenotypes, the most notable being CD3/CD45R double-positive cells. Tumours expressing either T cell receptor alpha/beta or gamma/delta heterodimers were found. Thus rbtn2 can promote tumours within a range of T cell types and maturities. The latency period before tumour development indicates that secondary events must occur before the onset of overt malignancy.

The chromosomal translocation t(X;14)(q28;q11) in T-cell pro-lymphocytic leukaemia breaks within one gene and activates another.

Chromosomal translocation t(X;14)(q28;q11) has been observed in patients with pro-lymphocytic T-cell leukaemia (T-PLL). In two cases of T-PLL, one of which was associated with Ataxia telangiectasia (AT), the chromosomal break occurred in two different introns of a gene c6.1A, located at the Xq28 locus. Fusion transcripts, consisting of 5' sequences of c6.1A and the TCR alpha constant (C) region, were expressed at high levels in the leukaemic cells from both patients, but in only one case did this fusion generate an in-frame c6.1A-C alpha mRNA. However, the breaks within c6.1A seem to affect another gene, c6.1B, which is transcribed from the same CpG rich island as c6.1A but in the opposite transcriptional orientation. The c6.1B gene is not damaged by the translocation but is transcribed in both T-PLL cases. Furthermore, c6.1B may lack protein coding capacity and thus this translocation might result in a novel mechanism in tumorigenesis. In any event, this is the first cloned gene which is implicated in pathogenesis of chronic/pro-lymphocytic leukaemia of the T-cell lineage.

T-cell acute lymphoblastic lymphoma induced in transgenic mice by the RBTN1 and RBTN2 LIM-domain genes.

Two members of the RBTN gene family, RBTN1/Ttg-1 and RBTN2/Ttg-2, were found by their association with T-cell tumour-specific chromosomal translocations and are thought to be involved in the aetiology of such T-cell tumours. Here a transgenic mouse model is described in which T-cell tumours are induced by the presence of RBTN1 and RBTN2 transgenes that direct expression in thymus-derived cells. The latency period for lymphoid tumour appearance is variable, and tumours occur in a small proportion of transgenic animals that develop T-cell acute lymphoblastic malignancies. No significant increase in the rate of tumour development was observed in RBTN1 transgenic mice infected with Moloney murine leukaemia virus, nor did tumours arise in mice bearing a construct in which RBTN1 was expressed from the insulin transcriptional promoter. These data, which provide formal proof of the oncogenic activity of these genes, suggest that aberrant expression of transcription factor genes, such as RBTN1 and RBTN2, functions in tumour aetiology by disturbing some aspect of T-cell differentiation.

Innate T-cell immunity in HIV infection: the role of Vgamma9Vdelta2 T lymphocytes.

There is growing interest in the use of innate immune reactions in the therapy and prophylaxis of various diseases. Natural T (NT) lymphocytes that recognize infected cells or microbial compounds without the classical genetic restriction by polymorphic MHC molecules are crucial components of innate immunity. NT cells bearing the Vgamma9Vdelta2 T-cell receptor (TCR) are broadly reactive against intracellular pathogens, can lyse human immunodeficiency virus (HIV) infected cells, and release cytokines capable of regulating HIV replication. The potent antiviral activities of Vgamma9Vdelta2 T cells may help to contain viral spread during acute HIV infection and/or to prevent the establishment of viral persistence. Substantial changes in the composition and function of circulating gammadelta T-cell pools occur in HIV-infected patients. These changes a) may contribute to the etiopathogenesis of opportunistic infections and neoplasms, and b) are partly reversed by highly active anti-retroviral therapy (HAART). In addition to direct antiviral activities, activated gammadelta T cells influence dendritic cell maturation and the adaptive alphabeta T-cell response. Vgamma9Vdelta2 T cells can be stimulated in vivo and in vitro by various nonpeptidic antigens (NpAgs) and recent animal experimental data suggest that activated Vgamma9Vdelta2 T cells may help to control SIV replication. Currently, NpAgs are being assessed as potential therapeutic agents in AIDS, tuberculosis and certain cancers susceptible to Vgamma9Vdelta2 T-cell effector mechanisms.

The cellular immunotherapy of cancer: current and potential uses of interleukin-2.

The potential for immune-mediated destruction of neoplasms was suggested nearly one century ago. Despite this, no "magic bullet" has yet been identified. Nevertheless, the physiology of cell-mediated immune reactions has been well characterized in molecular, cellular, and clinical studies of allograft and microbial immunity. Extensive studies performed in laboratory animal models have documented the in vitro and in vivo destruction of various neoplastic tissues by immune cells. This destruction can be directed against autologous, syngeneic, or allogeneic tumors in several systems with varying degrees of "tumor specificity". Two approaches exist towards utilizing these immune reaction in vivo. The first involves providing the tumor bearer with immunostimulatory agents, either specific or nonspecific, designed to activate and amplify the destructive potential of the individual's endogenous immune cells able to recognize and destroy autologous tumor. The second approach provides immune cells with antitumor capacity to a tumor-bearing individual, these cells having been activated exogenously. A number of successful regimens involving these two approaches, and combinations of them, have been delineated in animal tumor models. These experimental studies lay a strong foundation for initiating clinical trials of these concepts for patients with cancer. This review summarizes the diverse experimental studies in animals leading to clinical trials, presents recent data from ongoing clinical trials directly testing the potential for cellular immunotherapy, and then presents some of the major challenges facing further development and application of this potential therapeutic approach.

Rapid expression cloning of human immunoglobulin Fab fragments for the analysis of antigen specificity of B cell lymphomas and anti-idiotype lymphoma vaccination.

An expression system for rapid and standardized production of human recombinant immunoglobulin Fab fragments in E. coli was developed. Functional folding of the Fab fragments was accomplished by the dicistronic expression vector pFab.gammakappa containing specialized leader sequences to direct the immunoglobulin heavy and light chains to the periplasmic bacterial space. A C-terminal hexahistidine tag of the Fd chain facilitated metal affinity chromatography and purification to homogeneity as assessed by SDS PAGE and silver staining. Specific antigen recognition by a hybridoma-derived Fab fragment was indistinguishable from that of the corresponding monoclonal antibody. This protocol may be useful for analysis of the antigen specificity of human B cells and for convenient production of lymphoma-derived idiotype protein for vaccination strategies. To obtain unmodified immunoglobulin cDNA sequences from small human biopsies for insertion into pFab.gammakappa, oligo(dG)-tailed cDNA was amplified with an oligo(dC)- and nested mu or kappa constant region-specific primers. Using single sets of primers for each class of immunoglobulin transcripts, the products of this anchored PCR reflected the relative abundance of the starting cell population and permitted reliable identification of clonal, lymphoma-derived sequences for subsequent expression cloning.

Specific recognition of human leukemic cells by allogeneic T cell lines.

Clinical and experimental data suggest a role for the immune response in preventing leukemic relapses following allogeneic bone marrow transplantation the graft-versus-leukemia (GVL) effect. In the context of an allogeneic BMT, a number of different immune mechanisms mediated by donor cells may be responsible for the GVL effect. We have approached this question by using limiting dilution cultures of alloactivated human lymphocytes to analyze the in vitro allogeneic cytolytic response against fresh allogeneic leukemia. Initial results in the limiting dilution assays with split culture analyses demonstrated frequent alloreactive cytolytic T lymphocyte precursors that destroyed remission peripheral blood lymphocytes and leukemic cells from the allogeneic leukemic patient. These assays also demonstrated frequent lymphokine-activated killer (LAK) cell precursors that lysed both the LAK sensitive Daudi line and the allogeneic leukemia. In these experiments, isolated cultures also showed cytolytic activity directed against the allogeneic leukemic blasts without activity against remission PBL, or the LAK-sensitive Daudi cell line. Two T cell lines (ABL1 and ABL2) isolated from an LDA, demonstrated this form of specificity, mediating destruction specifically against the allogeneic acute lymphoblastic leukemic cells. Both cell lines ABL1 and ABL2 were CD3+, TCR alpha beta +, and CD4+. These 2 cell lines mediated little or no cytotoxicity against a large panel of other targets tested (natural killer sensitive and resistant cell lines, allogeneic PBL, and allogeneic fresh leukemic blasts). Antibody-blocking experiments revealed a role for the CD3-TCR receptor of both cell lines in lysis of leukemic cells; the CD4 and MHC class II molecules were clearly involved in the lysis by the ABL1 cell line. Specificity of recognition for the allogeneic leukemic blasts was further confirmed by unlabeled target competitive inhibition studies. The mechanism of the preferential lysis of leukemia by the alloactivated T cell lines described in this paper remains uncertain. Nevertheless, these leukemic-specific populations provide a means by which the human GVL effect may be further studied in vitro.

Evidence of clonality in chronic neutrophilic leukaemia.

BACKGROUND: Chronic neutrophilic leukaemia (CNL) is a rare myeloproliferative disorder of elderly patients characterised by sustained neutrophilia and splenomegaly. The diagnosis of CNL requires the exclusion of BCR/ABL positive chronic myelogenous leukaemia (CML) and of leukaemoid reactions (LRs). The differentiation between CNL and LR is problematic because both conditions share similar morphological features; it is also important because patients with CNL generally have a poor prognosis. AIMS: To determine whether CNL and LR could be distinguished on the basis of different clonality patterns. METHODS: Blood samples from 52 women were studied using the human androgen receptor gene assay (HUMARA). RESULTS: Monoclonality was found in the neutrophils in all 17 patients with different myeloproliferative syndromes (MPSs), including those with CNL. In four of the patients with CNL, autologous T cells were also monoclonal, suggesting that they belonged to the neoplastic clone. This finding was in contrast to other MPSs in which T cells were almost always polyclonal. Of nine patients with clinically suspected LR, the neutrophils of five were polyclonal, whereas three patients had monoclonal neutrophils, suggesting that they might be in the process of developing an MPS. Among 26 healthy blood donors, 20 had polyclonal neutrophils and five showed skewed clonality patterns. One case of LR and one normal blood donor were scored "not informative" at the HUMARA locus. CONCLUSIONS: Clonality studies of blood neutrophils using HUMARA aid in distinguishing female patients with monoclonal CNL from those with LR. For the diagnosis of CNL, monoclonality of the neutrophils should be demonstrated whenever possible.

In vitro fertilization and intracytoplasmic sperm injection pregnancies after successful transport of oocytes by airplane.

OBJECTIVE: To determine the feasibility of a transport IVF program involving air transportation of oocytes. DESIGN: Prospective cohort study. SETTING: Regional hospital (Hôpital de Chicoutimi) and University Infertility Center (McGill Reproductive Center, Montreal). PATIENT(S): The first series of patients referred for IVF or IVF and ICSI, for a variety of indications, who opted for inclusion in the transport IVF program. INTERVENTION(S): The IVF-ET with ovarian stimulation and oocyte collection at the peripheral unit and transport of the oocytes by airplane to the McGill Reproductive Center where IVF or ICSI was performed. MAIN OUTCOME MEASURE(S): Clinical pregnancy. RESULT(S): Seven couples, in the first series, underwent nine cycles of transport IVF treatment. Two also underwent ICSI. There were two clinical pregnancies. CONCLUSION(S): Transport IVF using air travel is possible and opens the possibility for this type of program to be implemented in large countries with scattered populations, such as the United States, Canada, and Australia.

Unexplained infertility: evaluation of treatment with clomiphene citrate and human chorionic gonadotropin.

A double-blind, randomized, prospective therapeutic trial was conducted in 148 couples with unexplained infertility. Treatment consisted of 4 consecutive months of placebo or clomiphene citrate (CC) (100 mg) by mouth on cycle days 5 to 9, and placebo or human chorionic gonadotropin (hCG) (5,000 IU) intramuscularly on cycle days 19, 22, 25, and 28. There were 14 pregnancies during the trial and 39 pregnancies during observation before and after the trial. Placebo treatment resulted in no pregnancies over 4 months. Clomiphene citrate was significantly better than placebo (P less than 0.04), with a pregnancy rate of 19% over the course of 4 months. The pregnancy rate with hCG either alone (11%) or in combination with CC (7.6%), was not significantly better than placebo. Treatment-independent pregnancies, defined as those before treatment (but after enrollment), or more than 1 month after therapy, occurred in 16% of the couples, with a mean time to conception of 8.8 months. As part of their follow-up, 39 of the study couples subsequently underwent in vitro fertilization (IVF), and 43% were found to have a previously unrecognized male factor or fertilization defect. A pregnancy rate of 16% was achieved after a mean of 1.1 cycles in these 39 couples. The authors conclude that CC is useful in treating unexplained infertility and is a reasonable initial therapy. For couples who fail to conceive, IVF may be diagnostic as well as therapeutic.

Novel molecular and cellular strategies in cancer therapy.

Tumor initiation and progression results from several subsequent mutations in genes that control cellular proliferation and differentiation. Neoplasia may lead to the expression of antigens that may be derived from such oncogenes or the activation of other cellular or viral genes that may represent tumor associated antigens. This review summarizes the present understanding of these mechanisms in an effort to design new therapeutic strategies.