<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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