Multiple keukemic clones in acute leukemia of childhood

Summary Two abnormal karyotypes representing clonal populations have been demonstrated in three patients in the early stage of acute leukemia. The karyotypes were apparently unrelated in one patient, while in the other two, a relationship was conjectured. Both clones were present before therapy in two patients. Although a clone resistant to therapy was associated with relapse in one case, in two cases a clone has persisted in the lymphocyte culture during drug treatment with the patients in remission.     

Natural and chemotherapy-induced clonal evolution of tumors

Evolution and natural selection of tumoral clones in the process of transformation and the following carcinogenesis can be called natural clonal evolution. Its main driving factors are internal: genetic instability initiated by driver mutations and microenvironment, which enables selective pressure while forming the environment for cell transformation and their survival. We present our overview of contemporary research dealing with mechanisms of carcinogenesis in different localizations from precancerous pathologies to metastasis and relapse. It shows that natural clonal evolution establishes intratumoral heterogeneity and enables tumor progression. Tumors of monoclonal origin are of low-level intratumoral heterogeneity in the initial stages, and this increases with the size of the tumor. Tumors of polyclonal origin are of extremely high-level intratumoral heterogeneity in the initial stages and become more homogeneous when larger due to clonal expansion. In cases of chemotherapy-induced clonal evolution of a tumor, chemotherapy becomes the leading factor in treatment. The latest research shows that the impact of chemotherapy can radically increase the speed of clonal evolution and lead to new malignant and resistant clones that cause tumor metastasis. Another option of chemotherapy-induced clonal evolution is formation of a new dominant clone from a clone that was minor in the initial tumor and obtained free space due to elimination of sensitive clones by chemotherapy. As a result, in ~20% of cases, chemotherapy can stimulate metastasis and relapse of tumors due to clonal evolution. The conclusion of the overview formulates approaches to tumor treatment based on clonal evolution: in particular, precision therapy, prediction of metastasis stimulation in patients treated with chemotherapy, methods of genetic evaluation of chemotherapy efficiency and clonal-oriented treatment, and approaches to manipulating the clonal evolution of tumors are presented.     

Addressing heterogeneity of individual blood cancers: the need for single cell analysis

Cancer heterogeneity is a significant factor in response to treatment and escape leading to relapse. Within an individual cancer, especially blood cancers, there exists multiple subclones as well as distinct clonal expansions unrelated to the clinically detected, dominant clone. Over time, multiple subclones and clones undergo emergence, expansion, and extinction. Although sometimes this intra-clonal and inter-clonal heterogeneity can be detected and/or quantified in tests that measure aggregate populations of cells, frequently, such heterogeneity can only be detected using single cell analysis to determine its frequency and to detect minor clones that may subsequently emerge to become drug resistant and dominant. Most genetic/genomic tests look at the pooled tumor population as a whole rather than at its individual cellular components. Yet, minor clones and cancer stem cells are unlikely to be detected against the background of expanded major clones. Because selective pressures are likely to govern much of what is seen clinically, single cell analysis allows identification of otherwise cryptic compartments of the malignancy that may ultimately mediate progression and relapse. Single cell analysis can track intra- or inter-clonal heterogeneity and provide useful clinical information, often before changes in the disease are detectable in the clinic. To a very limited extent, single cell analysis has already found roles in clinical care. Because inter- and intra-clonal heterogeneity likely occurs more frequently than can be currently appreciated on a clinical level, future use of single cell analysis is likely to have profound clinical utility.     

Strong parasitoid-mediated selection in experimental populations of aphids

Clonal diversity in asexual populations may be maintained if different clones are favoured under different environmental conditions. For aphids, parasitoids are an important variable of the biotic environment. To test whether parasitoids can mediate selection among host clones, we used experimental populations consisting of 10 clones of the peach-potato aphid, Myzus persicae, and allowed them to evolve for several generations either without parasitoids or in the presence of two species of parasitoid wasps. In the absence of parasitoids, strong shifts in clonal frequencies occurred, mostly in favour of clones with high rates of increase. The parasitoid Diaeretiella rapae hardly affected aphid densities but changed the outcome of competition by favouring one entirely resistant clone and disfavouring a highly susceptible clone. Aphidius colemani, the more infective parasitoid, strongly reduced aphid densities and dramatically changed host clonal frequencies. The most resistant clone, not a successful clone without parasitoids, became totally dominant. These results highlight the potential of temporal or spatial variation in parasitoid densities to maintain clonal diversity in their aphid hosts.     

Clonal relationship of relapsing lymphoid neoplasms

Lymphomas encompass a broad spectrum of neoplasias. Traditionally it has been assumed that recurrent neoplasia, especially lymphoma, represents a relapse of the original clone. However, this concept has been challenged. Here we present an overview of novel perceptions regarding the clonal relationship of relapsing lymphoid neoplasms, i.e. precursor cell acute lymphoblastic lymphoma/leukemia (ALL), so called non-Hodgkin lymphomas (NHL) and classical Hodgkin lymphoma (cHL) and discuss the potential implications of these findings. In ALL, approximately 10% of "relapses" were found to be clonally unrelated to the original disease. In NHL, small series and case reports showed the occurrence of meta- or synchronous lymphoid malignancies, which were of different clonal origin. In cHL, there is evidence that both early and late "relapses" may constitute to a certain proportion a novel neoplasm of different clonal origin too. These findings warrant further investigations in order to verify and strengthen the existing data and might have important clinical implications because novel clonally unrelated lymphomas imitating relapses could possibly be treatable with less aggressive regimens compared to true recurrences.     

Clonal reproduction and patterns of genotypic diversity in Decodon verticillatus (Lythraceae)

Most perennial plants combine sexual reproduction with some form of clonal propagation. These mixed strategies may produce considerable variation among populations in levels of clonal diversity in response to ecological factors limiting one or other reproductive mode. Surveys of style morph frequencies in 163 populations of the eastern North American, clonal, tristylous aquatic, Decodon verticillatus (L.) Ell. (Lythraceae) suggested a wide range of clonal diversity among populations. Populations consisting of a single style morph were most common at the northern margin of the species' range and could have arisen through severe founder events followed by exclusive clonal propagation. Here, we test this hypothesis by comparing allozyme variation in populations monomorphic and polymorphic for style length located in Ontario and Michigan. Each of the four populations monomorphic for style length were fixed for a single three-locus allozyme genotype while the seven trimorphic and five dimorphic populations contained an average of 26 multilocus genotypes each. Measures of genotypic diversity were high in polymorphic populations (average D = 0.93 ± 0.02 standard error; D = 0.00 for all populations monomorphic for style length). Three of the populations monomorphic for style length were fixed for a heterozygous genotype at one of the loci surveyed, suggesting that each consists of a single clone. In contrast, genotype frequencies in polymorphic populations conformed to Hardy-Weinberg proportions indicative of sexual reproduction. The range of clonal diversity found in D. verticillatus is the largest reported for a clonal plant species, although the literature is too limited to determine whether this is truly unusual. Clonal diversity in D. verticillatus is likely to be regulated largely by ecological factors affecting seed production and establishment. However, genetically based sexual sterility also occurs in some populations.     

CFU-gm colony formation of peripheral blood and bone marrow in adult acute leukemia at presentation, during remission, and at relapse

Granulocyte/macrophage colony-forming unit (CFU-gm) formation was studied simultaneously in bone marrow and peripheral blood of 52 previously untreated adult patients with acute non-lymphocytic (ANLL) and 36 with acute lymphoblastic leukemia (ALL). They were followed during induction therapy at monthly intervals while in remission and in 19 ANLL and 22 ALL cases, until relapse. Patients showing a decreased colony number in the marrow but normal or increased colony numbers in the peripheral blood had a high probability of entering remission. Non-responding patients displayed an opposite pattern. The higher the degree of marrow repopulation with granulocytic progenitor cells after induction treatment, the longer remission duration and survival for ANLL patients and the longer survival for ALL patients. CFU-gm formation returned to normal in the early stages of complete remission, but then declined progressively. At ANLL and ALL relapse, colony growth was reduced markedly while cluster formation remained normal. The number of marrow colonies and clusters in ANLL were significantly higher at first and second relapse compared to the growth pattern at first presentation. A similar trend had been observed in ALL, suggesting a selection advantage.     

Expansion of a maternally derived monoclonal T cell population with CD3+/CD8+/T cell receptor-gamma/delta+ phenotype in a child with severe combined immunodeficiency.

The diagnosis of severe combined immunodeficiency complicated by chronic graft-vs-host disease affecting liver and skin in association with engraftment of maternal T cells was established in a 5-mo-old boy. Detailed immunologic and molecular genetic studies were performed because a unique T cell phenotype was identified on initial evaluation. A major proportion of the patient's peripheral T cells expressed a CD8+ and TCR-gamma/delta+ phenotype while CD4+ T cells were virtually absent. Southern blot analysis of cell subpopulations isolated by fluorescence activated cell sorting indicated that approximately 50% of CD8+/TCR-gamma/delta+ cells were clonally related. Immunophenotyping and -genotyping also identified a clonal TCR-gamma/delta+ cell population in the child's mother. Clonal identity of these T cell populations in mother and child was demonstrated by studies using a clonspecific TCR-delta probe generated by polymerase chain reaction as well DNA sequence analysis. HLA typing and DNA fingerprinting confirmed that the child had acquired this clone diaplacentally from the mother. According to immunohistology and DNA analysis the clone was found to be virtually absent in the liver tissue suggesting that this clonal T cell population plays a minor role, if any, in the pathogenesis of the liver abnormalities in the patient. In the mother the CD8+/TCR-gamma/delta+ clone spontaneously declined to a level around 1% of PBMC several months later and has remained at this level since. We conclude that 1) a clonal expansion of TCR-gamma/delta T cells, triggered by yet unknown stimuli, may occur in otherwise healthy individuals, 2) respective T cells are able to cross the placental barrier, and 3) in an microenvironment precluding rejection, i.e., in severely immunocompromised patients, these cells may persist and even represent a significant proportion of circulating T cells.     

Management of Ontario children with acute lymphoblastic leukemia by the Dana-Farber Cancer Institute protocols.

There is ample evidence of the value of intensive therapeutic strategies in the management of acute lymphoblastic leukemia (ALL), the commonest form of malignant disease in children. Such a program, devised at the Dana-Farber Cancer Institute (DFCI), Boston, and incorporating high-dose L-asparaginase, was adopted in 1984 by the Children''s Hospital at Chedoke-McMaster, Hamilton, Ont., and the Children''s Hospital of Western Ontario, London. We describe the experience of these institutions in the treatment of 82 children with ALL, 19 of whom were switched to the DFCI protocols while in continuing first remission with other treatment programs to complete a minimum of 2 years of maintenance therapy; the remaining 63 children, who had recently diagnosed disease, were consecutively enrolled in the DFCI protocols. Each child was assigned at diagnosis to a category of risk for relapse and treated accordingly. There were no remission induction failures or deaths due to induction therapy among the patients with newly diagnosed disease. There were no differences in total or event-free survival rates between the patients in Hamilton and those in London or between those whose protocols were switched and those who were treated from the beginning with the DFCI protocols. With a median follow-up interval of 144 weeks the total survival rate was 95% and the event-free survival rate 88%. For patients at standard risk of relapse the event-free survival rate was 100%, for those at high risk the rate was 82%, and for those at very high risk the rate was 67%. If infants (all of whom suffered a relapse) are excluded from the last category the rate was 89%. These results were achieved with moderate toxic effects (except for two deaths, one of which was due to a therapeutic misadventure) and suggest that the prospect for cure in children with ALL. may now approximate 80%, a degree of success that demands that consideration be given to reducing total therapy, at least for children with standard-risk disease. Further follow-up will determine whether these high event-free survival rates will stabilize and meet the criteria for cure.     

Local forest environment largely affects below-ground growth, clonal diversity and fine-scale spatial genetic structure in the temperate deciduous forest herb Paris quadrifolia

Paris quadrifolia (herb Paris) is a long-lived, clonal woodland herb that shows strong differences in local population size and shoot density along an environmental gradient of soil and light conditions. This environmentally based structuring may be mediated by differences in clonal growth and seedling recruitment through sexual reproduction. To study the interrelationship between environmental conditions and spatial patterns of clonal growth, the spatial genetic structure of four P. quadrifolia populations growing in strongly contrasting sites was determined. In the first place, plant excavations were performed in order to (i) determine differences in below-ground growth of genets, (ii) investigate connectedness of ramets and (iii) determine total genet size. Although no differences in internode length were found among sites, clones in moist sites were much smaller (genets usually consisted of 1-3 interconnected shoots, most of them flowering) than genets in dry sites, which consisted of up to 15 interconnected shoots, the majority of which were vegetative. Further, amplified fragment length polymorphism (AFLP) markers were used. Clonal diversity was higher in populations located in moist and productive ash-poplar forests compared to those found in drier and less productive mixed forest sites (G/N: 0.27 and 0.14 and Simpson's D: 0.84 and 0.75, respectively). Patterns of spatial population genetic structure under dry conditions revealed several large clones dominating the entire population, whereas in moist sites many small genets were observed. Nevertheless, strong spatial genetic structure of the genet population was observed. Our results clearly demonstrate that patterns of clonal diversity and growth form of P. quadrifolia differ among environments. Limited seedling recruitment and large clone sizes due to higher connectedness of ramets explain the low clonal diversity in dry sites. In moist sites, higher levels of clonal diversity and small clone sizes indicate repeated seedling recruitment, whereas strong spatial genetic structure suggests limited seed dispersal within populations.     

Acquired TET2 mutation in one patient with familial platelet disorder with predisposition to AML led to the development of pre‐leukaemic clone resulting in T2‐ALL and AML‐M0

Familial platelet disorder with predisposition to acute myeloid leukaemia (FPD/AML) is characterized by germline RUNX1 mutations, thrombocytopaenia, platelet dysfunction and a risk of developing acute myeloid and in rare cases lymphoid T leukaemia. Here, we focus on a case of a man with a familial history of RUNX1^R174Q mutation who developed at the age of 42 years a T2‐ALL and, 2 years after remission, an AML‐M0. Both AML‐M0 and T2‐ALL blast populations demonstrated a loss of 1p36.32‐23 and 17q11.2 regions as well as other small deletions, clonal rearrangements of both TCRγ and TCRδ and a presence of 18 variants at a frequency of more than 40%. Additional variants were identified only in T2‐ALL or in AML‐M0 evoking the existence of a common original clone, which gave rise to subclonal populations. Next generation sequencing (NGS) performed on peripheral blood‐derived CD34⁺ cells 5 years prior to T2‐ALL development revealed only the missense TET2^P1962T mutation at a frequency of 1%, which increases to more than 40% in fully transformed leukaemic T2‐ALL and AML‐M0 clones. This result suggests that TET2^P1962T mutation in association with germline RUNX1^R174Q mutation leads to amplification of a haematopoietic clone susceptible to acquire other transforming alterations.     

Genotypic diversity revealed by allozymes and oligonucleotide DNA fingerprinting in French populations of the aquatic macrophyte Sparganium erectum

The vast majority of perennial plants reproduce sexually and vegetatively at the same time. This may lead to important variation among clonal plant populations in their amount of genotypic diversity. In order to verify this assumption, we compare the clonal diversity of 10 natural populations of the aquatic clonal macrophyte Sparganium erectum in France. Diversity was quantified by DNA fingerprinting and allozyme electrophoresis for a sample of 10 shoots per population. Two DNA probes (CA)₈ and (TAA)₆ TA, were selected among 10 synthetic oligonucleotide probes containing simple repeat motifs. Both allozymes and DNA fingerprints revealed different amounts of diversity among populations. Five populations consist of a single genotype, whereas two populations were genetically highly diverse. In four of the monomorphic populations, absence of fingerprints diversity was combined with uniformly heterozygous allozyme loci, suggesting that each population was composed of a single clone. In the highly diverse populations, the level of clonal diversity combined with the allele segregation of the two allozyme loci Lap and Est suggests frequent seedling recruitment. The origin of new genotypes remains unclear but the absence of widespread genotypes together with the discrete distribution of Sparganium erectum populations implies that new genotypes are locally produced through sexual reproduction.     

Clonal diversity and structure of the invasive aquatic plant Eichhornia crassipes in China

The information on diversity and spatial distribution of clones of an invasive clonal plant is crucial for the understanding of its clonal structure and invasive history. In this paper, random amplified polymorphic DNA (RAPD) markers were used to explore the clonal diversity and clonal structure of Eichhornia crassipes (Mart.) Solms in natural populations, and their possible effects on the plant success as an invader are also discussed. Five populations covering the entire distribution area in China were studied, sampling 43 individuals per population at an interval of 1 m in a sampling plot. Twelve RAPD primers produced 69 reproducible bands, with 22 being polymorphic. Only five RAPD phenotypes (clones) were detected in these five populations, but each population consisted of at least three clones, contrary to the traditional expectations that E. crassipes populations should be monoclonal. The diversity of clones within populations is thought to be mainly resulted from multiple introductions by humans. The evenness of distribution of clones varied slightly and most clones were widespread, suggesting clonal growth is the predominant mode of regeneration in all the populations. A single clone dominated each population and this clone might be the first one introduced into China or the genotype with a higher phenotypic plasticity, which could survive and reproduce via clonal growth in various habitats. The clones in each population were highly intermixed, especially in river populations, suggesting this species has a guerilla clonal structure which can be facilitated by water current.     

Leukemic chromosome clone. I. Risk factor in the acute lymphatic leukemia of children]

As long as the aetiology of acute lymphatic leukaemia of children is not known its therapy is based on clinical experience. Among the values of experience those factors will play a part, the evidence of which during the ALL initial stage will be a risk for successful therapy and survival rate. This results in a choice of more aggressive variants of modern therapy schemes. In a cytogenetic study made in 35 children with ALL it was tested, whether even leukaemic chromosome clones will be a risk for the course of acute leukaemia. The duration of the first remission and survival rate were considered as criteria. The evidence of a leukaemic chromosome clone could be shown to be followed by a short survival rate, irrespective of the stage of the disease where the clone had been observed first. Thus, cytostatic therapy in those ALL patients who are affected with luekaemic chromosome aberration of stem line character should be aimed at the complete annihilation of the clone, irrespective of other remission criteria. The failure of blood and bone-marrow cultures as early as during the untreated initial stage indicated a primary cellular immuno-insufficiency. This combination of cell immuno-depression with high peripheral leukocytes connts and a primary mediastinal tumour or a generalizing lymphosarcoma respectively, was the highest risk up till now for the course of the disease. Judging from the duration of the first remission and the survival rates, the consecutive schemes of therapy did not differ in their effect on leukaemia with pathological stem lines. On the basis of the present study the impression could not be excluded that up till now long term survival rates could be attributed rather to individual manners of response than to the modern therapy scheme.     

Deep sequencing reveals clonal evolution patterns and mutation events associated with relapse in B-cell lymphomas

Background

Molecular mechanisms associated with frequent relapse of diffuse large B-cell lymphoma (DLBCL) are poorly defined. It is especially unclear how primary tumor clonal heterogeneity contributes to relapse. Here, we explore unique features of B-cell lymphomas - VDJ recombination and somatic hypermutation - to address this question.

Results

We performed high-throughput sequencing of rearranged VDJ junctions in 14 pairs of matched diagnosis-relapse tumors, among which 7 pairs were further characterized by exome sequencing. We identify two distinctive modes of clonal evolution of DLBCL relapse: an early-divergent mode in which clonally related diagnosis and relapse tumors diverged early and developed in parallel; and a late-divergent mode in which relapse tumors developed directly from diagnosis tumors with minor divergence. By examining mutation patterns in the context of phylogenetic information provided by VDJ junctions, we identified mutations in epigenetic modifiers such as KMT2D as potential early driving events in lymphomagenesis and immune escape alterations as relapse-associated events.

Conclusions

Altogether, our study for the first time provides important evidence that DLBCL relapse may result from multiple, distinct tumor evolutionary mechanisms, providing rationale for therapies for each mechanism. Moreover, this study highlights the urgent need to understand the driving roles of epigenetic modifier mutations in lymphomagenesis, and immune surveillance factor genetic lesions in relapse.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0432-0) contains supplementary material, which is available to authorized users.     

Effect of environmental stress on clonal structure of <Emphasis Type="Italic">Eucypris virens</Emphasis> (Crustacea,Ostracoda)

Environmental stress imposes strong natural selection on clonal populations, promoting evolutionary change in clonal structure. Environmental stress may also lead to reduction in population size, which together with clonal selection may reduce genotypic diversity of the local populations. We examined how clonal structure in wild-collected samples of two parthenogenetic populations of the freshwater ostracod Eucypris virens responded to hypersalinity and starvation, and the combination of the two stressors. We applied the stress treatments in a factorial design for one generation. When 60% of the individuals per experimental unit had died, post-experimental clonal structure was compared to that of the start of the experiment, which reflected the field conditions. We used five polymorphic allozyme loci as genotype markers. All stress treatments reduced survival compared to the control treatment. In the population “Rivalazzetto”, we observed a reduction of clonal richness in the control treatment, with the initially dominant clone maintaining dominance. This may have resulted from interclonal competition and clone-specific survival under the different laboratory conditions. Clonal richness remained high in the salinity treatment while it was reduced in the combined stress and starvation treatments. In the population “Fornovo”, clonal richness reduced in all treatments including control, while the salinity and combined stress treatment reduced clonal evenness. The clone dominating at the start of the experiment increased in frequency in all treatments, but the change in clonal structure during the experiment was more pronounced in this population. These results suggest that in some conditions an intermediate level of environmental stress may lessen the decline in genetic diversity by strong inter-clonal competition. Moreover, the variation in clonal structure among the stress treatments and distinct genetic backgrounds indicates that more general predictions of stress effects on clonal structure may be difficult.     

Viral impacts on total abundance and clonal composition of the harmful bloom-forming phytoplankton Heterosigma akashiwo

Recent observations that viruses are very abundant and biologically active components in marine ecosystems suggest that they probably influence various biogeochemical and ecological processes. In this study, the population dynamics of the harmful bloom-forming phytoplankton Heterosigma akashiwo (Raphidophyceae) and the infectious H. akashiwo viruses (HaV) were monitored in Hiroshima Bay, Japan, from May to July 1998. Concurrently, a number of H. akashiwo and HaV clones were isolated, and their virus susceptibilities and host ranges were determined through laboratory cross-reactivity tests. A sudden decrease in cell density of H. akashiwo was accompanied by a drastic increase in the abundance of HaV, suggesting that viruses contributed greatly to the disintegration of the H. akashiwo bloom as mortality agents. Despite the large quantity of infectious HaV, however, a significant proportion of H. akashiwo cells survived after the bloom disintegration. The viral susceptibility of H. akashiwo isolates demonstrated that the majority of these surviving cells were resistant to most of the HaV clones, whereas resistant cells were a minor component during the bloom period. Moreover, these resistant cells were displaced by susceptible cells, presumably due to viral infection. These results demonstrated that the properties of dominant cells within the H. akashiwo population change during the period when a bloom is terminated by viral infection, suggesting that viruses also play an important role in determining the clonal composition and maintaining the clonal diversity of H. akashiwo populations. Therefore, our data indicate that viral infection influences the total abundance and the clonal composition of one host algal species, suggesting that viruses are an important component in quantitatively and qualitatively controlling phytoplankton populations in natural marine environments.     

中国沙棘克隆生长对灌水强度的响应规律及其激素调控机制

关于中国沙棘克隆生长调节研究目前局限于外在机制,旨在探讨其克隆生长对灌水强度的响应规律及其激素调控的内在机制。结果表明:随着灌水强度的增大,分株生长、克隆繁殖、克隆扩散能力先升后降,IAA(吲哚-3-乙酸)、ZR(玉米素核苷)、GA_3(赤霉酸)含量及其与ABA(脱落酸)的比值先升后降而ABA含量先降后升。同时,分株生长、克隆繁殖、克隆扩散能力与IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA呈极显著或显著正相关,与ABA含量呈极显著负相关。灌水强度过小或过大,IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA低而ABA含量高,克隆生长潜力受到抑制,种群以分株小、数量少(分布稀疏)、扩散(水平根延伸和分枝)能力弱为特征,克隆生长格局倾向于"游击型"、种群早衰概率高;灌水强度适宜,IAA、ZR、GA_3含量以及IAA/ABA、ZR/ABA、GA_3/ABA高而ABA含量低,克隆生长潜力得以充分发挥,种群以分株大、数量多(分布密集)、扩散能力强为特征,克隆生长格局倾向于"聚集型"、种群稳定性高。随着灌水强度过小-适宜-过大的连续变化,中国沙棘通过改变激素状况调控克隆生长,从而形成与灌水强度相适应的克隆生长格局连续体"游击型-聚集型-游击型",种群稳定性呈"低-高-低"的连续变化过程。由此可见:灌水强度诱导内源激素发生改变,激素特征调控克隆生长格局,克隆生长格局决定种群稳定性。     

Analysis of the expression pattern of the BCL11B gene and its relatives in patients with T-cell acute lymphoblastic leukemia

Introduction

The development of Philadelphia chromosome (Ph) negative acute leukemia/myelodysplastic syndrome (MDS) in patients with Ph-positive chronic myeloid leukemia (CML) is very rare. The features of restrictive usage and absence of partial T cell clones have been found in patients with CML. However, the T-cell clonal evolution of Ph-negative malignancies during treatment for CML is still unknown.

Objective

To investigate the dynamic change of clonal proliferation of T cell receptor (TCR) Vα and Vβ subfamilies in one CML patient who developed Ph-negative acute lymphoblastic leukemia (ALL) after interferon and imatinib therapy.

Methods

The peripheral blood mononuclear cells (PBMC) samples were collected at the 3 time points (diagnosis of Ph-positive chronic phase (CP) CML, developing Ph-negative ALL and post inductive chemotherapy (CT) for Ph-negative ALL, respectively). The CDR3 size of TCR Vα and Vβ repertoire were detected by RT-PCR. The PCR products were further analyzed by genescan to identify T cell clonality.

Results

The CML patient who achieved complete cytogenetic remission (CCR) after 5 years of IFN-α therapy suddenly developed Ph-negative ALL 6 months following switch to imatinib therapy. The expression pattern and clonality of TCR Vα/Vβ T cells changed in different disease stages. The restrictive expression of Vα/Vβ subfamilies could be found in all three stages, and partial subfamily of T cells showed clonal proliferation. Additionally, there have been obvious differences in Vα/Vβ subfamily of T cells between the stages of Ph-positive CML-CP and Ph-negative ALL. The Vα10 and Vβ3 T cells evolved from oligoclonality to polyclonality, the Vβ13 T cells changed from bioclonality to polyclonality, when Ph-negative ALL developed.

Conclusions

Restrictive usage and clonal proliferation of different Vα/Vβ subfamily T cells between the stages of Ph-positive CP and Ph-negative ALL were detected in one patient. These changes may play a role in Ph- negative leukemogenesis.