Clinical characteristics of 11 patients with chronic lymphocytic leukemia with t (14;19) (q32;q13) / 中华血液学杂志

Objective: To analyze the clinicopathological characteristics of 11 cases of chronic lymphocytic leukemia (CLL) with t (14;19) (q32;q13) . Methods: The case data of 11 patients with CLL with t (14;19) (q32;q13) in the chromosome karyotype analysis results of the Blood Diseases Hospital, Chinese Academy of Medical Sciences from January 1, 2018, to July 30, 2022, were retrospectively analyzed. Results: In all 11 patients, t (14;19) (q32;q13) involved IGH::BCL3 gene rearrangement, and most of them were accompanied by +12 or complex karyotype. An immunophenotypic score of 4-5 was found in 7 patients and 3 in 4 cases. We demonstrated that CLLs with t (14;19) (q32;q13) had a mutational pattern with recurrent mutations in NOTCH1 (3/7), FBXW7 (3/7), and KMT2D (2/7). The very-high-risk, high-risk, intermediate-risk, and low-risk groups consisted of 1, 1, 6, and 3 cases, respectively. Two patients died, 8 survived, and 2 were lost in follow-up. Four patients had disease progression or relapse during treatment. The median time to the first therapy was 1 month. Conclusion: t (14;19) (q32;q13), involving IGH::BCL3 gene rearrangement, is a rare recurrent cytogenetic abnormality in CLL, which is associated with a poor prognosis.

Construction and Identification of Leukemia Cell Line Stably Expressing CD123 and CLL-1 / 中国实验血液学杂志

OBJECTIVE@#To construct an acute myeloid leukemia cell line stably expressing CD123-CLL1 so as to provide an "in vitro" model for studying the role of CD123 and CLL-1 in leukemia and the treatment targeting CD123 and CLL-1.@*METHODS@#The recombinant plasmid of lentivirus was constructed by synthesizing CD123 and CLL-1 sequences and PCR homologous recombination. The lentivirus vector was packaged by three-plasmid packaging system. After collecting the supernatant of lentivirus, the virus titer was determined by quantitative PCR. K562 leukemia cells were collected and transtected with virus supernatant. Leukemia cell line stably expressing the target gene were screened by purinomycin. The expression levels of CD123 and CLL-1 were detected by RT-PCR and flow cytometry.@*RESULTS@#The lentiviral vector was successfully constructed, and identified by agarose gel electrophoresis and gene sequencing, then the virus titer of the supernatant was up to 5.81×10@*CONCLUSION@#Lentiviral vector expressing CD123-CLL1 has been successfully constructed, and K562 leukemia cell line stably expressing CD123 and CLL-1 has been successfully obtained.

Ofatumumab monoclonal antibody affinity maturation through in silico modeling

Background: Ofatumumab, an anti-CD20 mAb, was approved in 2009 for the treatment of chronic lymphocytic leukemia. This mAb acts through immune-mediated mechanisms, in particular complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity by natural killer cells as well as antibody-dependent phagocytosis by macrophages. Apoptosis induction is another mechanism of this antibody. Computational docking is the method of predicting the conformation of an antibody-antigen from its separated elements. Validation of the designed antibodies is carried out by docking tools. Increased affinity enhances the biological action of the antibody, which in turn improves the therapeutic effects. Furthermore, the increased antibody affinity can reduce the therapeutic dose of the antibody, resulting in lower toxicity and handling cost

Methods: Considering the importance of this issue, using in silico analysis such as docking and molecular dynamics, we aimed to find the important amino acids of the Ofatumumab antibody and then replaced these amino acids with others to improve antibody-binding affinity. Finally, we examined the binding affinity of antibody variants to antigen

Results: Our findings showed that variant 3 mutations have improved the characteristics of antibody binding compared to normal Ofatumumab antibodies. Conclusion: The designed anti- CD20 antibodies showed potentiality for improved affinity in comparison to commercial Ofatumumab

Telomere length analysis in monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia Binet A

Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic clinical entity characterized by the proliferation of monoclonal B cells not meeting the diagnosis criteria for chronic lymphocytic leukemia (CLL). MBL may precede the development of CLL, but the molecular mechanisms responsible for disease progression and evolution are not completely known. Telomeres are usually short in CLL and their attrition may contribute to disease evolution. Here, we determined the telomere lengths of CD5+CD19+ cells in MBL, CLL, and healthy volunteers. Twenty-one CLL patients, 11 subjects with high-count MBL, and 6 with low-count MBL were enrolled. Two hundred and sixty-one healthy volunteers aged 0 to 88 years were studied as controls. After diagnosis confirmation, a flow cytometry CD19+CD5+-based cell sorting was performed for the study groups. Telomere length was determined by qPCR. Telomere length was similar in the 3 study groups but shorter in these groups compared to normal age-matched subjects that had been enrolled in a previous study from our group. These findings suggest that telomere shortening is an early event in CLL leukemogenesis.

Frequency of monoclonal B-cell lymphocytosis in relatives of patients with chronic lymphocytic leukemia / Frecuencia de linfocitosis monoclonal de células B en familiares de pacientes con leucemia linfoide crónica

Introduction: monoclonal B-cell lymphocytosis is a symptom free condition characterized by the circulation of small clonal population of B lymphocytes in peripheral blood (less than 5x10(9)/L) expressing an immunophenotype similar to chronic lymphocytic leukemia. Different studies based on big hospital series have manifested a higher risk in subjects with monoclonal B-cell lymphocytosis to progress to a chronic lymphocytic leukemia. The behavior of this hematologic entity is unknown therefore its frequency in sporadic chronic lymphocytic leukemia patient relatives was determined. Methods: transversal descriptive study, 8 color flow cytometry was performed using two of the tubes of the Euro Flow recommended panel, with modifications, for the diagnose of chronic lymphoproliferative disorders of B lymphocytes; besides, a fluorescence in situ hybridization was performed. univariate and bivariate analyses of the information were performed. Results: monoclonal B-cell lymphocytosis frequency found in 51 analyzed relatives was 2%, it was a female participant, 59 years old, with a total leukocyte count of 7.7x109/L and a B lymphocyte count of 0.124x10(9)/L; from these, 0.04x10(9)/L were clonal cells with restrictions of the kappa light chain. Rearrangements of the IGH gene (14q32) were found. Conclusion: monoclonal B-cell lymphocytosis was detected in one relative of a patient with sporadic chronic lymphocytic leukemia in a frequency similar to the one reported in general population.

Introducción: La linfocitosis monoclonal de células B es una condición asintomática que se caracteriza por la circulación de pequeñas poblaciones clonales de linfocitos B en sangre periférica (menos de 5x10(9)/L) que expresan un inmunofenotipo similar al de la leucemia linfoide cónica. Diferentes estudios basados en grandes series hospitalarias, han puesto de manifiesto un riesgo más elevado de los sujetos con linfocitosis monoclonal de células B de progresar a una leucemia linfoide crónica. En Colombia se desconoce el comportamiento de esta entidad hematológica, por tal razón se determinó su frecuencia en familiares de pacientes con leucemia linfoide crónica esporádica. Métodos: Estudio descriptivo transversal, se realizó citometría de flujo de 8 colores utilizando dos de los tubos del panel recomendado por Euro Flow para el diagnóstico de enfermedades linfoproliferativas crónicas de linfocitos B con modificaciones, además se hizo hibridación fluorescente in situ. Se realizó análisis univariado y bivariado. Resultados: La frecuencia de linfocitosis monoclonal de células B encontrada en los 51 familiares analizados fue del 2%, se trató de un participante del sexo femenino y 59 años de edad, con un recuento total de leucocitos de 7,7x10(9)/L y un recuento de linfocitos B de 0,124x109/L; de estos 0,04x10(9)/L eran células clonales con restricción de la cadena ligera kappa. Se encontraron reordenamientos del gen IGH (14q32). Conclusión: Se detectó linfocitosis monoclonal de células B en un familiar de paciente con leucemia linfoide cónica esporádica en una frecuencia similar a la informada en la población general.

Clinico-pathological impact of cytogenetic subgroups in B-cell chronic lymphocytic leukemia: Experience from India.

BACKGROUND: The present study of 238 B‑cell Chronic Lymphocytic Leukemia (B‑CLL) patients were undertaken to seek the prevalence and to evaluate clinico‑pathological significance of recurrent genetic abnormalities such as del(13q14.3), trisomy 12, del(11q22.3) (ATM), TP53 deletion, del(6q21) and IgH translocation/deletion. MATERIALS AND METHODS: We applied interphase – fluorescence in situ hybridization (FISH) on total 238 cases of B‑CLL. RESULTS: Our study disclosed 69% of patients with genetic aberrations such as 13q deletion (63%), trisomy 12 (28%), 11q deletion (18%), 6q21 deletion (11%) with comparatively higher frequency of TP53 deletion (22%). Deletion 13q displayed as a most frequent sole abnormality. In group with coexistence of ≥2 aberrations, 13q deletion was a major clone indicating del(13q) as a primary event followed by 11q deletion, TP53 deletion, trisomy 12, 6q deletion as secondary progressive events. In comparison with del(13q), trisomy 12, group with coexistence of ≥2 aberrations associated with poor risk factors such as hyperleukocytosis, advanced stage, and multiple nodes involvement. In a separate study of 116 patients, analysis of IgH abnormalities revealed either partial deletion (24%) or translocation (5%) and were associated with del(13q), trisomy 12, TP53 and ATM deletion. Two of 7 cases had t(14;18), one case had t(8;14), and four cases had other variant IgH translocation t(?;14). CONCLUSION: Detail characterization and clinical impact are necessary to ensure that IgH translocation positive CLL is a distinct pathological entity. Our data suggests that CLL with various cytogenetic subsets, group with coexistence of ≥2 aberrations seems to be a complex cytogenetic subset, needs more attention to understand biological significance and to seek clinical impact for better management of disease.

Recent advances in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) was largely considered to be a disease of slow progression, standard treatment with Chlorambucil and having almost similar prognosis. With the introduction of molecular methods for understanding the disease pathophysiology in CLL there has been a remarkable change in the approach towards the disease. The variation in B-cell receptor response and immunoglobulin heavy chain variable region (IGHV) mutation, genetic aberration and defect in apoptosis and proliferation has had an impact on therapy initiation and prognosis. Early diagnosis of molecular variant is therefore necessary in CLL.

Patogénesis de la leucemia linfática crónica / Pathogenesis of the chronic lymphocytic leukemia

La leucemia linfática crónica (LLC) es la leucemia de mayor prevalencia en adultos mayores. Se caracteriza por la acumulación progresiva de linfocitos B con morfología madura y un fenotipo particular con expresión de CD5, CD23 y bajos niveles de inmunoglobulina en la membrana. El linfocito leucémico en LLC presenta numerosas aberraciones cromosómicas, pero no se ha podido atribuir a una mutación o deleción particular la responsabilidad de la transformación maligna. Las alteraciones epigenéticas también juegan un papel en LLC, en particular la baja o nula expresión de ciertos microARN que controlan la transcripción de genes anti-apoptóticos. La inmunoglobulina clonal en LLC representa una molécula clave para entender la patología. Alrededor del 30% de los pacientes expresan inmunoglobulinas que reconocen autoantígenos intracelulares que se exponen en las células apoptóticas. En estos casos, la estimulación a través del receptor antigénico sería la responsable de la iniciación y/o progresión leucémica. Tradicionalmente se consideró a la LLC como una patología causada por defectos en la maquinaria apoptótica. En años recientes se demostró que las células leucémicas proliferan en forma activa en los tejidos linfáticos, donde se encuentran en íntimo contacto con linfocitos T, células estromales y de estirpe mieloide. Este microambiente particular provee a las células LLC de señales de supervivencia y activación a través de factores solubles y contacto celular. Uno de los objetivos terapeúticos actuales es lograr compuestos que rompan la interacción de las células LLC con su microambiente para interferir con estas señales de supervivencia. En esta revisión se discuten los aportes realizados desde la investigación básica para entender la etiopatología de la LLC.

Chronic lymphocytic leukemia (CLL) is the commonest leukemia in elderly. It is characterized by the progressive accumulation of B lymphocytes, with a mature morphology and a particular phenotype, expressing CD5, CD23 and low levels of surface immunoglobulin. Although the leukemic lymphocyte in CLL presents a variety of chromosomic aberrations, none of them was demonstrated to be responsible for the malignant transformation. Epigenetic alterations have also a place in CLL, particularly the low or absent expression of a number of microRNA that normally control the transcription of anti-apoptotic genes. Around 30% of CLL cases express clonal immunoglobulin that recognizes intracellular autoantigens which are exposed in apoptotic cells. In these cases, stimulation through the antigenic receptor would be responsible for the initiation and/or progression of the disease. The traditional point of view considered CLL as a pathology caused by defects in the apoptotic machinery. However, in recent years it was demonstrated that leucemic cells actively proliferate in lymphoid tissues, where they are found in intimate contact with T lymphocytes, myeloid and stromal cells. This particular microenvironment provides CLL cells with survival and activation signals through the release of soluble factors and cell contact interactions. Today, one of the therapeutic goals in CLL is the development of agents capable of disturbing the interaction of leukemic cells with their mileu in order to interfere with pro-survival signals. This review discusses the novel evidence from basic research directed to understand the etiopathology of CLL.

Aspectos epidemiológicos, biotipologia e evolução do tratamento da leucemia linfocítica aguda na infância e adolescência no Rio Grande do Sul / Epidemiologic aspects, biotypology and evolution of acute lymphocytic leukemia in childhood and adolescence in Rio Grande do Sul

A leucemia linfocítica aguda na infância e adolescência é umaneoplasia de precursores linfoides de natureza heterogênea. NoBrasil, os estudos cooperativos foram iniciados em 1980. Nasequência destes estudos foram observadas sobrevidas livre deeventos de 50%, 58% e 70% nos protocolos 80, 82 e 85 respectivamente.Neste trabalho foram avaliados 1.472 pacientes comLLA, 56,59% masculinos e 43,41% femininos, com idades entre 0e 20 anos, média de 7,40 anos, no período de 1980 a 2008 provenientesdo RS. Os dados foram colhidos dos prontuários dos pacientesdas principais instituições hospitalares que assistemneoplasias hematológicas pediátricas. Neste estudo, 487 pacientes(39,40%) foram registrados nos protocolos do GBTLI; 678(54,85%) receberam tratamento baseados nos regimes do grupoBFM e 71 (5,75%) por outros regimes. A sobrevida livre de eventosdos pacientes protocolados foi significativamente superiorcomparada aos não protocolados, 62,41% ± 2,43% e 53,86% ±2,04% respectivamente, em cinco anos. Pacientes com idade de 15a 19 anos tiveram um índice de SLE de 37,98% ± 4,72% em cincoanos, inferior quando comparado aos de 0 a 4 anos e 5 a 9 anosrespectivamente: 62,78% ± 2,28% e 62,43% ± 2,84%. Foi observada,na população estudada, uma SG de 63,73% ± 1,49% e SLEde 57,27% ± 1,57%. A incidência da LLA com progenitores Bseguiu o padrão observado em países desenvolvidos com um picode frequência absoluta entre as idades de 2 a 4 anos. Houve diferençasignificativa entre a população da região urbana ou rural:SLE em cinco anos de 61,76% ± 1,76% e 49,81% ± 4,28% respectivamente.A SLE e a SG em lactentes e portadores de síndrome deDown foi inferior aos resultados obtidos em instituições dos paísesdesenvolvidos.

Acute lymphocytic leukemia (ALL) in childhood andadolescence is a neoplastic disease of varied lymphoid precursors.In Brazil, cooperative studies on the treatment of ALL started in1980. According to these studies, the event free survival (EFS)was 50%, 58% and 70% in the protocols of 1980, 1982 and 1985,respectively. In this work, 1472 ALL patients were evaluated;56.59% were male and 43.41% were female with ages that rangedbetween 0 and 20 years old (mean age of 7.4 years old). Data wascollected from the records of patients with hematologic neoplasiasin medical institutions that offered treatment for pediatricneoplasias in the period from 1980 to 2008. In this study, 487patients (39.40%) were registered in the GBTLI protocol; 678(54.85%) received treatment based on the BFM group regimenand 71 (5.75%) were treated according to other regimens. TheEFS at five years of the patients on the GBTLI protocol wassignificantly higher than those who were not on this protocol(62.41% ± 2.43% and 53.86% ± 2.04%, respectively). In respectto the age range, the patients who were between 15 and 20 yearsold had an EFS of 37.98% ± 4.72% at five years, which is lowerthan the rate for 0 to 4-year-old and 5 to 9-year-old patients(62.78% ± 2.28% and 62.543± 2.84%, respectively). An overallsurvival of 63.73% ± 1.49% and EFS of 57.27% ± 1.57% wereobserved in the studied population. Epidemiologically, theincidence of ALL in B progenitors followed the pattern observedin developed countries with an absolute frequency peak in the agerange of 2 to 4 year olds. The outcome was better for patientsfrom urban areas compared to those from rural areas. EFS andoverall survival in infant and Down syndrome patients were worsethan the results obtained in developed countries.

miRNA expression profiles in chronic lymphocytic and acute lymphocytic leukemia

MicroRNAs (miRNAs) are a class of small endogenous RNAs that play important regulatory roles by targeting mRNAs for cleavage or translational repression. miRNAs act in diverse biological processes including development, cell growth, apoptosis, and hematopoiesis, suggesting their association with cancer. We determined the miRNA expression profile of chronic and acute lymphocytic leukemias (CLL and ALL) using the TaqMan® MicroRNA Assays Human Panel (Applied Biosystems). Pooled leukemia samples were compared to pooled CD19+ samples from healthy individuals (calibrator) by the 2-DD Ct method. Total RNA input was normalized based on the Ct values obtained for hsa-miR-30b. The five most highly expressed miRNAs were miR-128b, miR-204, miR-218, miR-331, and miR-181b-1 in ALL, and miR-331, miR-29a, miR-195, miR-34a, and miR-29c in CLL. To our knowledge, this is the first report associating miR-128b, miR-204 and miR-331 to hematological malignancies. The miR-17-92 cluster was also found to be up-regulated in ALL, as previously reported for some types of lymphomas. The differences observed in gene expression levels were validated for miR-331 and miR-128b in ALL and CD19+ samples. These miRNAs were up-regulated in ALL, in agreement with our initial results. A brief target analysis was performed for miR-331. One of its putative targets, SOCS1, promotes STAT activation, which is a known mediator of cell proliferation and survival, suggesting the possibility of an association between miR-331 and these processes. This initial screening provided information on miRNA differentially expressed in normal and malignant B-cells that could suggest the potential roles of these miRNAs in hematopoiesis and leukemogenesis.

ZAP-70: un nuevo factor pronóstico en la leucemia linfoide crónica / ZAP-70: a new prognostic factor in chronic lymphocytic leukemia

En la leucemia linfoide crónica de tipo B (LLC-B) se han planteado diferentes factores pronósticos para predecir la evolución de la enfermedad. En fecha reciente se ha añadido un nuevo factor pronóstico determinado por la expresión de una proteina de 70 Kda que se asocia con la cadena Z de receptor de las células T, y que se representa por la abreviatura ZAP-70. Esta proteína no se expresa en los linfocitos B normales, pero sí en los de un subgrupo de LLC-B que no tiene mutaciones en los genes de la región variable de la cadena pesada de las inmunoglobulinas (IgVH). Estudios recientes sugieren que la expresión de esta proteína en los linfocitos leucémicos podría contribuir a la evolución más agresiva que pueden tener las LLC-B sin mutaciones en los genes IgVH. Se ha señalado que la determinación de la ZAP-70 puede proporcionar un indicador pronóstico más simple que la caracterización del estado mutacional de los genes IgVH

Leucemia linfoide crónica - B: aspectos inmunitarios y moleculares / Lymphoid leukemia: inmune and molecular aspects

La leucemia linfoide crónica-B representa la leucemia humana más común en los países occidentales y está caracterizada por la proliferación y acúmulo delinfocitos B monoclonales CD5 + en sangre periférica, médula ósea, ganglios linfáticos y órganos relacionados, que morfológicamente tienen apariencia madura, pero que son biológicamente inmaduros. El curso de la enfermedad está determinado por una profunda disregulación inmune con hipogammaglobulinemia progresiva y una disrupción en la interacción entre las células B y T, así como fenómenos de autoinmunidad. Es el prototipo de enfermedad maligna humana que involucra defectos de la muerte celular programada o apoptosis. En esta enfermedad las translocaciones cromosómicas son raras y las aberraciones genéticas más frecuentes son las deleciones 13q14,11q y la trisomía 12. A pesar de los avances logrados en las técnicas moleculares, aún no se ha podido identificar un oncogen asociado con la patogénesis de este tipo de leucemia, pero los hallazgos citogenéticos y moleculares suministran importante información diagnóstica, clínica y pronóstica, lo cual puede contribuir a decisiones en cuanto al tratamiento y seguimiento de los pacientes con esta enfermedad

Análisis de factores pronósticos en leucemia linfática crónica. Valor predictivo del inmunofenotipo, el CD23 soluble y la morfología / Predictive factors in chronic lymphocytic leukemia. Value of immunophenotype, SCD23 and morphology

En LLC se reconocen factores pronósticos útiles como la duplicación linfocitaria, el estadio clínico y el patrón de infiltración medular. Otros, como el porcentaje de células CD38+, están en estudio y requieren confirmación. El objetivo del presente trabajo fue evaluar si existe asociación entre morfología, inmunofenotipo linfocitario, CD23 soluble (SL) y sobrevida libre de eventos (SLE). Se evaluaron prospectivamente 36 pacientes sin tratamiento. Se determinaron: morfología típica, mixta y LLC-PL; inmunofenotipo linfocitario (score de Matutes); niveles plasmáticos de CD23 SL; estadio clínico, duplicación linfocitaria; ß2 microglobulina y alteraciones citogenéticas. Se consideró evento: progresión de enfermedad (necesidad de tratamiento, evolución a estadios avanzados, desarrollo de organomegalia voluminosa) y muerte por enfermedad. Mediana de seguimiento 24 meses. Resultados: estadio 0: 11/36, SLE 80 por ciento; I: 10/36 SLE 90 por ciento; II: 13/36: III y IV: 2/36. SLE >= II 37 por ciento. p= 0.023. Duplicación linfocitaria: <12m 7/31, >12m 24/31. SLE 28 por ciento vs 80 por ciento p<0.001. Citogenético: normal 13/28; anormal 15/28. SLE 92 por ciento vs 54 por ciento p=0.053. +12 positiva 7/30, negativa 23/30. SLE 65 por ciento vs 66 por ciento. ß2 microglobulina normal 9/35, elevada 26/35; SLE 100 por ciento vs 53 por ciento p=0.006. D23 SL < 350 Ul/ml 15/32, > 350 Ul/ml 17/32. SLE 92 por ciento vs 53 por ciento p=0.005. Inmunofenotipo: Score 5: 15/36, Score 4: 19/36, SLE 64 por ciento. Score 3: 2/36. p=0.516. Morfología típica 17/35, mixta 17/35. SLE 81 por ciento vs. 57 por ciento p=0.099. LLC-PL 1/35. El CD 23 SL resultó adecuado para predecir SLE, particularmente útil en estadios iniciales sin otros marcadores de actividad. La morfología y el fenotipo linfocitario, dos variables accesibles, no fueron útiles para el propósito del estudio.

Mutation analysis of IgVH gene in B-cell chronic lymphocytic leukemia / 华中科技大学学报（医学）（英德文版）

The variable heavy chain region (VH) genes of 3 untreated patients with B-cell chronic lymphocytic leukemia (B-CLL) were cloned and analyzed. The VH family used was VH3-11, VH3-72 and VH3-33. More than 2% difference from the corresponding germline gene was detected in all the 3 obtained potential functional genes (average 16.7). Mutation pattern analysis indicated evidence of antigen selective pressure observed in 1 of 3 cases. Our findings suggested that the tumor cells originate from post-GC cells.

Detecçäo de monoclonalidade em linfócitos do sangue periférico de pacientes portadores de leucemia linfocítica crônica pela reaçäo em cadeia da polimerase / Detection of monoclonicity in peripheric blood lymphocytes in patients with chronic lymphocytic leukemia by polymerase chain reaction

O rearranjo gênico da cadeia pesada de imunoglobulina é um fenômeno que ocorre precocemente durante a ontogênese do sistema linfóide B, permitindo a aproximaçäo da regiäo variável (VH) da regiäo juncional (JH, as quais flanqueiam a regiäo de diversidade (DH), de tal modo que o fragmento (VHDHJH, originado desse rearranjo torna-se acessível à amplificaçäo pela reaçäo em cadeia da polimerase (PCR). A partir de linfócitos de sangue periférico de 7 pacientes portadores de LLC, utilizando 2 "primers" complementares a sítios conservados das regiöes VH e JH, foi amplificado um fragmento que após eletroforese em gel de poliacrilamida a 12,5 por cento e coloraçäo pela prata, mostrou ser monoclonal. A presença dessa banda monoclonal foi mantida em diluiçöes sequenciais, as quais envolveram a mistura do DNA tumoral com DNA normal, até inclusive o nível de 1 por cento de DNA tumoral. A técnica da PCR revelada pela prata, mostrou-se sensível na detecçäo de monoclonalidade em pacientes portadores de LLC, sem necessidade do uso de sondas.