B cell chronic lymphocytic leukemia (B-CLL) is a hematologic neoplasm characterised by the proliferation and accumulation of sIgM+/D+ B cells that fail to progress to the final stages of B cell development. The malignant cells in B-CLL also express the pan-T cell antigen CD5, suggesting that CLL is a malignancy of the CD5+ subset of B cells. Additional characteristics of the malignant clone include a low proliferative index, enhanced in vivo survival and constitutive expression of the anti-apoptosis oncoprotein bcl-2. The behaviour of leukemic CD5 B cells in vitro contrasts their arrested in vivo state. That is, despite the majority of cells being arrested in the G0 phase of the cell cycle, the leukemic B cells are not irreversibly frozen as they can be induced to differentiate to Ig-secreting cells under appropriate in vitro conditions. Furthermore, leukemic CD5 B cells rapidly undergo death by apoptosis following in vitro culture. This thesis describes the requirements for in vitro activation of leukemic CD5+ B cells, the characterisation of the events involved in apoptosis of these cells as well as the identification of various growth factors capable of modulating these events. Stimulation of unfractionated peripheral blood lymphocytes (PBLs) from three patients with B-CLL with the phorbol ester PMA and the mitogens PHA and PWM resulted in significant increases in cell proliferation, RNA synthesis and 1gM secretion when compared to unstimulated cell populations. PMA was the most potent inducer of 1gM secretion and this occurred irrespective of the presence of residual T cells. PMA-induced proliferation and RNA synthesis were also independent of T cells. However, in the presence of T cells, these parameters of cellular activation were enhanced during in vitro culture. Thus, the inductive ability of PMA on leukemic CD5 B cells was independent of T cells. In contrast, activation and differentiation of the leukemic CD5 B cells into 1gM-secreting cells following culture with mitogens did not occur in the absence of T cells. Interestingly, co-stimulation of leukemic CD5+ B cells with PMA and anti-Ig induced cellular responses that exceeded those induced by either activator alone. Thus, leukemic CD5+ B cells from patients with B-CLL can be activated in vitro and differentiate in response to stimulation via both T cell-dependent and T cell-independent mechanisms. Apoptotic cell death was characterised in purified leukemic CD5 B cells obtained from six B-CLL patients. All leukemic CD5 B cell populations entered an apoptotic pathway in vitro as evidenced by a reduction in cell size, loss of cell viability and fragmentation of DNA into multimers of -180 base pairs. Following 24 hours of in vitro culture 24.0±16% of DNA was fragmented. After 8 days, the majority of DNA was fragmented, and fewer than 10% of cultured cells were viable. Examination of bcl-2 expression in the malignant B cells by flow cytometry revealed a unimodal pattern of expression in greater than 85% of cells from each B-CLL patient prior to culture. During in vitro culture, bcl-2 expression became bimodal such that the B cells displayed a bcl-2hjgh and bcl-2iow phenotype. The level of expression by the bCl2hjgh cells was similar to that observed prior to in vitro culture, indicating that bcl-2 is down-regulated in apoptosing cells. Interestingly, despite this downregulation, the overall number of cells positive for bcl-2 remained constant. This suggests that the enhanced survival of leukemic CD5+ B cells in vivo is mediated by the sustained expression of bcl-2 and that additional mechanisms exist capable of overriding the protective effect of bcl-2 when bcl-2 is present at reduced levels. Leukemic B cell apoptosis has previously been reported to be delayed or prevented by IL-4, IFN-y and IFN-a. These results were confirmed in this study where it was found that culture of leukemic CD5 B cells with IL-4 or IFN-y enhanced cell viability and delayed apoptosis in 6/6 and 5/6 populations of leukemic B cells, respectively. This function was also found to be shared by IL-2, IL-6, IL-13 and TNF-a as these cytokines enhanced cell viability and delayed apoptosis in some of the cell populations examined at a level similar to that observed for IL-4 and IFN-y. These cytokines may mediate their effect via the expression of bcl2 as culture in the presence of IL-2, IL-4, IL-6, IL-13, IFN-y or TNF-a resulted in a higher percentage of cells displaying the bcl-2high phenotype, compared to unstimulated cells. Taken together, these results suggest that autocrine and/or paracrine growth loops may play a role in the pathogenesis of B-CLL and that cytokines that prevent apoptosis in vitro may be targets for treatment of this B cell malignancy.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Includes bibliographical references (leaves 87-101) Also available in print.

Class of 2012 Abstract / Specific Aims: The objectives of this study were to determine the financial impact and mortality of CLL and Richter’s transformation in CLL in the inpatient setting in the payer’s perspective, the common diagnoses at discharge for patients with CLL, and to compare demographics, hospital characteristics, and co-morbidities for CLL cases versus Richter’s only cases. Methods: This study was a retrospective cohort of inpatient hospital charges and mortality of CLL patients and CLL patients with Richter’s transformation in the United States in the perspective of the payer. Using weighted statistical methods, results of this investigation yielded nationally-representative findings. The hospital charges were analyzed with a gamma regression with log link, and mortality was analyzed with a generalized linear regression. Main Results: There were total of 391,287 cases and 7% (27,259) were Richter’s cases. The overall hospital charges for CLL and CLL patients with Richter’s transformation from 2005 to 2009 were $38,735 (±58859) per case and $53,118 (±77993) per case, respectively. The mortality was 6.3% (24,520 deaths) overall and 9.1% mortality (2,485 deaths) for Richter’s transformation patients. The significant predictors (p < 0.05) that were associated with an increase the hospital charges for Richter’s patients was sepsis while sepsis and weight loss were associated with an increase in mortality. Conclusions This study adds to the few studies published to show the impact of CLL and Richter’s. However, due to the limitation on pharmacotherapies, it was not possible to determine therapeutic cost drivers for these cases. Future studies are warranted to determine the cost of therapies associated to the different stages of CLL.

No description available.

<p>Chronic lymphocytic leukemia (CLL) cells are considered to be derived from antigen-exposed B cells. To further explore the antigen-driven selection behind the leukemogenesis of CLL, we performed immunoglobulin (Ig) specificity screening of 7 CLL cell lines and 23 primary CLL clones from patient peripheral blood. We also included a recombinant monovalent monoclonal antibody (mAb) belonging to a subset of CLL cases with identical or semiidentical heavy chain complementarity determining region 3 (HCDR3) of the IGHV3-21 gene rearrangement. We found CLL mAb specificities against vimentin, filamin B, cofilin-1, proline-rich acidic protein 1, cardiolipin, oxidized low density lipoprotein and Streptococcus pneumoniae polysaccarides. These molecules are functionally associated with microbial infection and/or apoptotic cell removal. An antigen-driven selection would therefore imply that CLL B cell precursors are involved in the elimination and scavenging of pathogens and apoptotic cells, which could trigger the development of the disease.</p><p>The limited in vitro survival of CLL cells makes Epstein-Barr virus (EBV) immortalization of CLL cells a useful experimental model for studies on antibody-specificity screening. Considering the intricate procedure of EBV transformation of CLL cells and the many false cell lines used worldwide, we also wanted to characterize and evaluate the authentic origin of several previously established CLL cell lines and their normal lymphoblastoid counterparts. Three of the CLL cell lines tested were truly authentic (I83-E95, CLL-HG3 and CII), two had features of a biclonal Ig expression (232B4 and WaC3CD5+), one was only tentatively verified (PGA-1), whereas one cell line could not be verified (EHEB) due to lack of original patient cells for comparison. Two of the presumed normal lymphoblastoid cell lines tested were shown to be a neoplastic CLL clone. This study emphasizes the importance of proper cell line authentication and we will continue to verify additional cell lines not yet proven authentic.</p><p>In conclusion, we provide evidence for natural Ab production by CLL cells and suggest that these cells might be derived from B cell precursors involved in the innate immunity and, thus, providing a first-line-defence against pathogens and in elimination of apoptotic cells.</p>

Previously a t(2;14)(p13;q32) translocation was characterized in four unusually aggressive cases of B cell chronic lymphocytic leukemia (B-CLL). A gene located near the 2p13 breakpoint, B cell lymphoma/leukemia 11A (BCL11A), was shown to overexpress 3 isoforms (BCL11A-XL, L and S). Bcl11a knockout mice are severely impaired in B cell development at the early (pro-B) stage. I have further characterized BCL11A, focusing on the most abundant and evolutionarily conserved isoform, BCL11A-XL (XL). I demonstrated that XL resides in the nuclear matrix, is modified by ubiquitination, and is destabilized by B cell antigen receptor ligation. I identified domains within XL required for its localization within nuclear paraspeckles and for its transcriptional repression. While BCL11A-XL represses model promoters in non-B cells, its biologically relevant targets in B lymphocytes were unknown. I have identified and confirmed a number of XL targets which are both up- and down-regulated by XL over-expression in B cell lines. A number of these genes have been implicated in B cell function, including the V(D)J recombination activating (RAG) genes. Both RAG1 and RAG2 transcripts were up-regulated by XL. XL binds to the RAG1 promoter and RAG enhancer (Erag) in vivo as well as in vitro. Unexpectedly, XL repressed RAG1 transcription in non-B cells, indicating that additional B cell-specific factors are required for activation. Overexpression of XL in a V(D)J recombination-competent pre-B cell line markedly induced RAG expression and VDJ recombination. IRF4 and IRF8, transcription factors previously shown to be required for early B cell development, were also induced by BCL11A-XL. I propose that the early B cell progenitor block in Bcl11a knockout mice is, at least in part, a direct result of BCL11A-XL regulation of V(D)J recombination. Further experiments are required to establish how other XL targets promote B cell lineage development and how malignant transformation such as in B-CLL may corrupt BCL11A function.

Made available in DSpace on 2014-06-11T19:23:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-04-01Bitstream added on 2014-06-13T19:29:04Z : No. of bitstreams: 1 duarte_pd_me_botfm.pdf: 611993 bytes, checksum: ccf0323dc58e760455c77b8af2abcf44 (MD5) / Fundação para o Desenvolvimento Médico e Hospitalar (Famesp) / Fundação Amaral Carvalho / Leucemia Linfóide Crônica (LLC) é uma neoplasia maligna de linfócitos B maduros com aspecto monomórfico, que se acumulam em tecidos linfóides secundários, medula óssea e sangue periférico. O diagnóstico é realizado com base em achados clínico-morfológicos e imunofenotípicos. Os pacientes com LLC são estratificados conforme o estadiamento clínico para definição de terapêutica; atualmente a descoberta de marcadores prognósticos, como ZAP-70, trouxe novas perspectivas ao tratamento, principalmente no estádio precoce. Os objetivos deste estudo foram: avaliar a eficácia da pesquisa da ZAP-70 em biópsia de medula óssea (BMO) e em inclusão do coágulo, utilizando-se a técnica de imuno-histoquímica; avaliar possíveis correlações deste marcador na BMO com evolução clínica e risco de progressão; correlacionar a imuno-expressão da ZAP- 70 com o arcabouço reticulinico das BMO; avaliar se este arcabouço possui correlação com o prognostico da doença e, por fim, traçar um perfil epidemiológico dos pacientes com LLC atendidos no Hospital das Clinicas da Faculdade de Medicina de Botucatu (FMB). Foram selecionados 153 pacientes com LLC, atendidos no ambulatório do Serviço de Hematologia da FMB-UNESP, de 1980 a 2008, e 9 pacientes assistidos no Serviço de Onco-Hematologia do Hospital Amaral Carvalho-Jaú, no período de 2000 a 2008, com o mesmo diagnóstico, perfazendo 162 casos. Destes, 79 possuíam prontuários que foram revisados, bem como dados morfológicos da BMO e AMO. Foi realizada a pesquisa da ZAP- 70 pela técnica de imuno-histoquímica nas amostras parafinadas de BMO e inclusão do coágulo. Observou-se que 55,7% dos pacientes eram do sexo masculino; 86,1% de etnia branca; a mediana de idade foi 65 anos; relação homem:mulher de 1,2:1. 40,5% dos pacientes tiveram diagnóstico por achado incidental e 73,4%, já com adenopatia secundária à admissão. 17,2%... / Chronic lymphocytic leukemia (CLL) is a malignant neoplasm consisting of mature monomorphic B lymphocytes that accumulate in secondary lymphoid tissues, bone marrow and peripheral blood. Diagnosis is based on clinical, morphological and immunophenotypic findings. CLL patients are categorized according to clinical aspects for treatment management and currently, certain tools, such as prognostic marker ZAP- 70, have determined new treatment perspectives, especially for patients in early stages. The study aimed to evaluate the efficiency of ZAP-70 investigation in bone marrow biopsies (BMBs) and inclusion coagulate using immunohistochemistry; identify possible correlations of this marker in clinical evolution and risk of progression; correlate the immunoexpression of ZAP-70 with BMB reticulin network; evaluate whether this network correlates with disease prognosis and; outline an epidemiological profile of patients with CLL attended in the Clinics Hospital of Botucatu Faculty of Medicine (FMB). The sample consisted of 153 CLL patients attended at hematology outpatient clinic of the FMB-UNESP, from 1980 to 2008, and 9 CLL patients attended at the oncohematology service of the Amaral Carvalho Hospital, Jaú, from 2000 to 2008, totaling 162 cases. In 79 cases, medical records including BMB and bone marrow aspirate (BMA) morphological data were reviewed. Immunohistochemistry for ZAP-70 was conducted on paraffinated samples of BMB and inclusion coagulate. Observation revealed that: 55.7% were male, 86.1% white, with a median age of 65 years-old; 40.5% of cases were diagnosed by incidental findings in routine blood smears; 73.4% were diagnosed with peripheral adenomegaly on admission. 17.2% were diagnosed in the early stages and 15% of cases showed prolonged remission. BMB and BMA morphology revealed that 94.8% of patients presented increased cellularity... (Complete abstract click electronic access below)

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