Incidence and clinical significance of FLT3 and nucleophosmin mutation in childhood acute myeloid leukemia in Chile

Abstract Introduction Acute myeloid leukemia (AML) is a heterogeneous disease and approximately one-third of its carriers do not have evident genetic abnormalities. The mutation of specific molecular markers, such as fms-like tyrosine kinase 3 (FTL3) internal tandem duplication (ITD), FLT3 tyrosine kinase domain (TKD) and nucleophosmin (NPM1), are associated with an adverse and favorable prognosis, respectively. Objective The objective was to determine the prevalence of FLT3/ITD and NPM1 in Chilean patients and their association with clinical data and prognosis. Method and Results Two hundred and thirty-two children were studied between 2011 and 2017, the median being 8.6 years (ranging from 1 to 18 months). Acute promyelocytic leukemia (APL) was diagnosed in 29%. The FLT3/ITD-mutated in non-promyelocytic AML was at 10% (14/133) and the FLT3/TKD, at 3.7% (2/54). In APL, it was at 25.4% (16/63). In non-promyelocytic AML, the FLT3/ITD-mutated was associated with a high leucocyte count, the median being 28.5 x mm3 (n= 14) versus 19.4 x mm3 (n= 119), (p= 0.25), in non-mutated cases. In APL, the median was 33.6 x mm3 (n= 15) versus 2.8 x mm3 (n= 47), (p < 0.001). The five-year overall survival (OS) in non-promyelocytic AML with non-mutated and mutated FLT3/ITD were 62.7% and 21.4%, respectively, (p < 0.001); the 5-year event-free survival (EFS) were 79.5% and 50%, respectively, (p < 0.01). The five-year OS in APL with non-mutated and mutated FLT3/ITD was 84.7% and 62.5%, respectively, (p= 0.05); the 5-year EFS was 84.7% and 68.8%, respectively, (p= 0.122). The NPM1 mutation was observed in 3.2% (5/155), all non-promyelocytic AML with the normal karyotype. Conclusion The FLT3/ITD mutation was observed more frequently in APL and associated with a higher white cell count at diagnosis. However, the most important finding was that the FLT3/ITD mutation was associated with a shorter survival in non-promyelocytic AML.

Overall survival in Chilean patients with lymphoma and human immunodeficiency virus: A retrospective cohort study

ABSTRACT Introduction: People living with human immunodeficiency virus (PLWH) still face high morbidity and mortality resulting from lymphoma. Aim: To describe a population of PLWH and lymphoma in a Chilean public hospital and compare the overall survival (OS) with a previously reported cohort from the same institution. Methods: Retrospective single-center cohort study. All the patients diagnosed between 2010 and 2017 were included. Demographic and clinical variables were obtained from medical records. The overall survival (OS) was estimated in treated patients from diagnosis until death or October 2020. The OS was then compared with a cohort of patients diagnosed between 1992 and 2008. Main Results: Eighty-four patients were included. The most common histological types were Burkitt's lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), Hodgkin's lymphoma (HL) and plasmablastic lymphoma (PBL) at 31%, 27%, 21% and 14%, respectively. The three-year OS for the whole cohort of BL, DLBCL, HL and PBL was 58.9%, 65.2%, 47.4%, 76.4% and 50%, respectively. Compared to the cohort of 1992 to 2008, a global increase in the OS was found after excluding HL and adjusting for age and clinical stage (HR 0.38, p = 0.002). However, when the main types were analyzed individually, the increase in the OS was statistically significant only in DLBCL (HR 0.29, p = 0.007). Most patients with DLBCL received CHOP chemotherapy, as in the previous cohort. Conclusion: The OS has improved in this population, despite no major changes in chemotherapy regimens, mainly due to the universal access to antiretroviral therapy.

Características clínicas y epidemiológicas de las neoplasias mieloproliferativas Philadelphia negativas en el sistema público de salud de Chile

Background: Philadelphia-negative myeloproliferative neoplasms (Ph-MPN) are chronic hematological disorders characterized by the overproduction of one or more mature myeloid blood cell lineages. Classical Ph-MPN are polycythemia vera (PV), essential thrombocytopenia (ET) and primary myelofibrosis (PMF). Aim: To assess the epidemiological, clinical and diagnostic characteristics of Ph-MPN in Chile. Material and Methods: Retrospective review of medical records of all patients referred as MPN from 2012 to 2017. Patients with (9;21) translocation were excluded. Results: Data of 462 cases with a median age of 69 years from 10 public hospitals was reviewed. ET was the most frequently Ph-MNP found. The incidence of Ph-MPN was 1.5 x 100.000 cases. The JAK2 V617F mutation study was performed in 96% of patients and only 30% had a bone marrow biopsy. Thrombotic events were observed in 29% of patients. Bleeding events were observed in 7%. Five-year overall survival was 87%. Conclusions: ET is the most frequent Ph-MPN. The mean incidence was lower than reported in the literature, in part because of a sub diagnosis.

Quimioterapia intensiva asociada a imatinib en leucemia linfoblástica aguda del adulto, Philadelphia positivo. Experiencia en un hospital público / Intensive chemotherapy with tyrosine kinase inhibitors in philadelphia-positive acute lymphoblastic leukemia

Background: Before the advent of tyrosine kinase inhibitors (TKIs), patients with Philadelphia-positive Acute Lymphoblastic Leukemia (Ph+ALL) had a poor prognosis. The association of TKIs to intensive chemotherapy (CT) improved outcome. Aim: To evaluate results of an intensive CT protocol including TKI in a public hospital in Santiago, Chile. Material and Methods: All patients with Ph+ALL diagnosed between January 2010 and February 2019, and who met inclusion criteria for intensive CT, received the Ph+ALL national protocol in association with imatinib and were included in this analysis. Results: Thirty-five patients aged 15 to 59 years received treatment. Complete response (CR) was obtained in 97%. Measurable residual disease (MRD) was negative in 61% (19/31 evaluable cases) during follow-up, and 55% (16/29) were MRD (-) before three months. Relapse was observed in 13 cases. Three patients underwent allogeneic hematopoietic stem cell transplant (HSCT), two in CR1. The overall survival (OS) and event-free survival (EFS) at three years were 52 and 34%, respectively. In patients who achieved MRD negativity before three months, no statistically significant differences in OS (64 and 42% respectively, p = 0.15) or EFS (35 and 32% respectively, p = 0.37) were observed. Conclusions: The prognosis of Ph+ALL improved with the association of imatinib to intensive CT. MRD-negative status before three months in this series was not significantly associated with better outcomes. Our series suggests that the Ph+ALL national protocol associated to TKI is a therapeutic alternative with high CR and aceptable MRD (-) rates.

Leucemia/linfoma T del adulto HTLV1, un desafío para el clínico / Leukemia / Lymphoma T Of The Adult HTLV1, A Challenge For The Clinic

La leucemia / linfoma de células T en adultos (LLTA) es una enfermedad agresiva de células T maduras activadas causada por el virus linfotrópico de células T humano tipo 1 (HTLV-1). ATL tiene un mal pronóstico debido a la quimiorresistencia intrínseca y la inmunosupresión severa. Las formas agresivas de LLTA, aguda y linfoma, se tratan con quimioterapia asociada con agentes antirretrovirales (AZT / IFN). Sin embargo, no han logrado un impacto en la supervivencia, que oscila entre 8 y 10 meses, respectivamente. Los pacientes con formas de LLTA crónicas y latentes tienen un mejor pronóstico, pero la supervivencia a largo plazo también es deficiente, tanto cuando estos pacientes se manejan con una política de espera vigilante o con quimioterapia. Aparentemente, las costuras AZT / IFN benefician a estos pacientes. Mientras tanto, la prevención de la diseminación del HTLV-1 es imprescindible en las políticas de salud pública, tanto por tamizaje del virus en bancos de sangre como a mujeres embarazadas para reducir / evitar la transmisión vertical del virus.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive disease of mature activated T cell caused by human T-cell lymphotropic virus type 1 (HTLV-1). ATL carries a bad prognosis due to intrinsic chemoresistance and severe immunosuppression. The aggressive ATL forms, acute and lymphoma, are treated with chemotherapy associated with antiretroviral agents (AZT/IFN) the acute form. However, they have failed to achieve an impact on survival, that ranges from 8-10 months, respectively. Patients with chronic and smoldering ATL forms, have a better prognosis, but long term survival is poor as well, when these patients are managed with a watchfulwaiting policy or with chemotherapy. Apparently, AZT/IFN seams to benefit these patients. Meanwhile, prevention of dissemination of HTLV-1, is a must in public health policies, performing screening in blood banks and a screening to pregnant women to reduce/avoid vertical transmission of the virus.

Una red de biobancos para Chile: investigar hoy, para curar mañana / The implementation of a Biobank network for Chile

The concept "Biobank" is relatively new in the scientific literature, and is not yet consensually defined, even for the World Health Organization (WHO). However, the use of human samples in biomedical research is a very old activity. The organized development of Biobanks in different places has grown in the last decade. The experience in different countries and continents has been diverse. In this special article we intend to summarize, organize and communicate to the national medical and scientific community, (i) the concept of Biobank, (ii) the international experience and a map of the Research Biobanks working in Chile, (iii) the basic biomedical and essential operational aspects to manage a Biobank for Research and (iv) the impact of a National Network of Biobanks implementation in the Chilean Health System. Ethical and regulatory aspects will not be included, given their intrinsic complexity, which should be discussed elsewhere.

Macroglobulinemia de Waldenström: experiencia de 15 años en el Hospital del Salvador, Santiago, Chile / Waldenström macroglobulinemia: experience in 31 patients

Background: Waldenström macroglobulinemia (WM) is an uncommon indolent B-cell lymphoma, due to the proliferation of lymphoplasmacytic cells, and secretion of a monoclonal IgM protein. Aim: To evaluate the clinical characteristics, management and results of treatment of patients with WM at a public hospital in Chile. Patients and Methods: Review of medical records of 31 patients aged 43 to 85 years (16 males) with WM diagnosed between 2002 and 2017. Clinical features and survival were recorded. Results: All patients had bone marrow compromise, and 31%, extranodal involvement. According to the International Prognostic Score System for WM (IPSSWM) 16, 58 and 26% were at low, intermediate and high risk, respectively. Twenty-five patients (81%) were treated, 32% with plasmapheresis and 36% with rituximab. Four cases (16%) achieved complete remission. Median follow up was 35 months (range 6-159). Estimated overall survival (OS) at 5 and 10 years was 74% and 53%, respectively. According to IPSSWM, the estimated five-year OS was 80, 92 and 39%, for low, intermediate and high-risk patients, respectively. Conclusions: OS was similar to that reported abroad, except for low risk patients, probably due to the low number of cases and short follow up. An improved survival should be expected with the routine use of immunochemotherapy.

Leucemia de células plasmáticas primaria: experiencia en un hospital público chileno / Primary plasma cell leukemia: report of five cases

Background: Primary plasma cell leukemia (pPCL) is uncommon, aggressive and has a different biology than multiple myeloma (MM). Aim: To report the features of patients with pPCL. Material and Methods: Review of databases of the Hematology Department and the Hematology laboratory. Results: Of 178 patients with monoclonal gammopathies, five (2.8%) patients aged 33 to 64 years (three females) had a pPCL. The mean hemoglobin was 7.3 g/dL, the mean white blood cell count was 52,500/mm3, with 58% plasma cells, and the mean platelet count was 83,600/mm3. The mean bone marrow infiltration was 89%, LDH was 2,003 IU/L, serum calcium was 13 mg/dL, and creatinine 1.5 mg/dL. Two patients had bone lesions. Three were IgG, one IgA lambda and one lambda light chain. CD20 was positive in one, CD56 was negative in all and CD117 was negative in 3 cases. By conventional cytogenetic analysis, two had a complex karyotype. By Fluorescence in situ Hybridization, one was positive for TP53 and another for t (11; 14). One patient did not receive any treatment, three patients received VTD PACE and one CTD. None underwent transplant. Three patients are alive. The mean survival was 14 months. Conclusions: These patients with pPCL were younger and had a more aggressive clinical outcome than in multiple myeloma.

Aplasia medular adquirida y embarazo. caso clínico / Acquired aplastic anemia during pregnancy. report of one case

Aplastic anemia (AA) or acquired aplastic anemia is an uncommon and potentially fatal disease. It is defined as reduction of at least two peripheral blood series, associated with persistent bone marrow hypocellularity. It's association with pregnancy is even more uncommon, and it may result in high mortality for the mother and the child. We report an adolescent female with aplastic anemia, which worsened during pregnancy. Her hemoglobin was 5.2 g/dl, her leukocytes were 1,833/ul and her platelets were 19,000/ul. She was initially treated with cyclosporine and horse antithymocyte globulin without hematologic improvement. At 36 weeks of pregnancy methylprednisolone and platelet transfusions were used and a cesarean section was performed. Six month later she continues to require red blood cell and platelet transfusions.

Aplasia medular adquirida, experiencia en un hospital público de referencia / Acquired aplastic anemia: experience in a public hospital

Background: The first line treatment for patients < 40 years old with aplastic anemia (AA) is allogeneic HLA-identical sibling donor transplantation (SCT). Immunosuppressive therapy (IST) with a combination of Thymoglobuline (ATG) and cyclosporine is used for older patients or those without a donor. Five year overall survival (OS) for both therapies is > 70%. Aim: To report the experience with SCT and ATG for AA in a public hospital. Patients and Methods: AA was diagnosed in 42 patients between 1998 and 2016, according to Camitta criteria. Thirty eight (90%) received treatment, 7 (18%) under 40 years old received SCT, and 31 (82%) IST. The rest were not treated. OS was calculated from date of diagnosis until last control, death or loss from follow up. Results: Complete or partial hematologic response, was obtained in 71% and 58% of cases with SCT and IS, respectively. Five year OS was 71% and 55% with SCT and IST, respectively. No difference in response was observed between horse and rabbit ATG. Conclusions: SCT from an HLA-identical sibling donor had a high response rate and survival. IST instead, had a lower response and survival, due to an initial high mortality rate.

Leucemia prolinfocítica T variante de células cerebriformes: presentación de un caso y revisión de la literatura / Cerebriform variant type of T cell prolymphocytic leukemia: report of one case

T cell Prolymphocytic Leukemia (T-PLL) is a rare and aggressive mature T cell Lymphocyte Leukemia. Twenty five percent of cases present as a small cell variant, and only 5% as a cerebriform variant. We report a 58 year-old man with rapidly progressive severe leukocytosis, skin lesions, lymphadenopathy, hepatosplenomegaly and pleural effusion. The lymphocytes had a cerebriform type. The diagnosis of T-PLL variant was made by morphology and immunophenotype study of peripheral blood. Karyotype was found to be complex. He was refractory to chemotherapy and died two months later.

Leucemia linfoblástica aguda estirpe B Philadelphia negativa en adolescentes y adultos jóvenes: Resultados del Protocolo Terapéutico LLA 15-30, Programa Nacional de Cáncer del Adulto (PANDA), Ministerio de Salud, Chile / Adolescent and young adult Philadelphia negative B cell acute lymphoblastic leukemia: Results of the Chilean protocol LLA 15-30

Background: Intensified treatment of Philadelphia chromosome negative acute lymphoblastic leukemia (Ph(-)ALL) in adolescents by pediatric teams, with fve years disease free survival (DFS) rate of 65%, encouraged the use of intensified protocols in patients between 15 and 30 years, improving the DFS from 45% to 60-80%. The protocol LLA 15-30 for patients between 15 and 30 years with Ph(-)ALL, based on the Children’s Oncology Group (COG) protocol AALL0232 resulting in a five years DFS of 78%, was started in 2007 by the PANDA national program. Aim: To report the results of the prospective cohort study evaluating the results of this protocol four years after its implementation. Patients and Methods: Between January 2007 and December 2010, 68 Ph(-) ALL patients, aged between 15-30 years (75% males) were incorporated. Survival was evaluated using Kaplan-Meier and log-rank tests. Results: Fifty percent of patients were of high risk. A complete response was achieved in 91%, early death occurred in 6% and induction failure in 3%. Median follow-up was 23 months. Overall survival, disease free survival and relapse rates at 35 months were 61.8, 67.5% and 31% respectively. Conclusions: LLA 15-30 protocol significantly improved three-year overall survival from 31 to 62%. The 20% difference observed with AALL0232 protocol is explained by the high rate of relapse. Improving provider and patient compliance with protocols may eliminate this gap.

Síndrome hemofagocítico secundario: reporte de 5 casos / Secondary hemophagocytic syndrome: report of 5 cases

Secondary hemophagocytic syndrome (HFS) is an uncommon entity with a high mortality rate in adults, if no therapy is given. It is characterized by a severehipercytokinemia due to a highly stimulated but ineffective immune system. Theprincipal causes are infections, malignancy or autoimmune diseases. It appears asa serious illness, similar to a multiorgan failure. Treatment is not well defined. Wereport five patients with HFS, aged 17 to 51 years (three females). The etiology wasonco-hematological in three patients. In two patients, the diagnosis was performedduring necropsy. One case was due to cytomegalovirus (CMV) infection in a hepatictransplant patient and the other, due to parenteral lipid administration. All presentedfever, cytopenia, hepatosplenomegaly and hemophagocytosis. Four of them requiredadmission in an Intensive Care Unit. All received different treatment modalities. Onlyone survived. Median survival time was 75 days. In conclusion, HFS has differentetiologies and a high mortality in adults.

Leucemia promielocítica aguda: Resultados del protocolo terapéutico LPA2000, Programa Nacional de Cáncer del Adulto (PANDA), Ministerio de Salud, Chile / Acute promyelocytic leukemia: Results of the Chilean protocol LPA2000

Background: The current recommendations for treatment of patients with newly diagnosed acute promyelocytic leukemia (APL) include all-trans-retinoic acid (ATRA) and anthracycline based chemotherapy. Aim: To evaluate the results of the Chilean protocol following the LPA99 regimen of the Spanish PETHEMA group, except for the replacement of Idarubicin by Daunorubicin. Patients and Methods: Induction consisted of Daunorubicin 45 mg/m² on days 2, 4, 6 and 8 plus ATRA 45 mg/m² daily until complete remission. Patients in complete remission (CR) received three monthly chemotherapy courses: Daunorubicin 45 mg/m²/d/4days i.v. and ATRA 45 mg/m²/d/15 days p.o. (course no. 1); Mitoxantrone 10 mg/m²/d/5 days i.v. and ATRA 45 mg/m²/d/15 days p.o. (course no. 2); Daunorubicin 60 mg/m²/d/ day 1 i.v. in the low risk group, and 1 and 2 in the intermediate-high risk groups and ATRA 45 mg/m²/d/15 days p.o. (course no. 3). Maintenance therapy consisted of mercaptopurine 90 mg/m²/d p.o., methotrexate 15 mg/m²/wk p.o. and, ATRA intermittently, 45 mg/m²/d p.o. for 15 days every three months. Results: Between January 2000 and December 2005, 56 patients with newly diagnosed APL from 10 centers were enrolled. A total of 46 patients achieved CR (85%), 8 (15%) died of early complications, seven patients relapsed, with a 16% relapse risk at three years. The 5-year Kaplan-Meier estimates of overall survival and relapse-free survival were 64% and 84% respectively. Conclusions: These data indicate that this protocol has a good antileukemic effect but further reduction of early death and relapse, especially in the high risk group is needed.

Síndrome de Good y aplasia pura de la serie roja, reporte de un caso y revisión de la literatura: Report of one case / Association of Good syndrome with pure red cell aplasia

Background: The association between Good's syndrome (hypogammaglobulinemia and thymoma) with pure red aplasia is very uncommon. We report a 70-year-old male, who had a thymoma excised nine years before. Afterwards, he suffered frequent respiratory infections, which were attributed to a humoral immunodeficiency. Nine years later, he developed a pure red cell aplasia. He received prednisone and cyclosporine, resulting in a progressive rise of hemoglobin level, after one month of treatment. The patient died shortly thereafter due to infection, complicating a domestic accident.

Linfoma relacionado a infección por virus de la inmunodeficiencia humana en un hospital público de Santiago, Chile / HIV-related lymphoma in a public hospital in Chile. Analysis of 55 cases

Background: Cancer is the third cause of death in patients infected with human immunodeficiency virus (HIV) and lymphoma is the most common type. Aim: To describe the clinical characteristics, histology, risk factors and prognosis of these patients, in a Chilean public hospital in Chile. Material and Methods: Records of 55 patients (45 males) aged between 23 and 67years with lymphoma and HIV positive serology, diagnosed between 1992-2008, were reviewed. Results: Six patients (11%) had Hodgkin lymphoma (HL) and the rest, non-Hodgkin lymphoma (NHL). B-cell phenotype constituted 83.7% of NHL cases. The most common subtypes of all the lymphoma were diffuse large B cell lymphoma in 24 cases (43.6%), Burkitt lym-phoma in 12 cases (21.8%), andplasmablastic lymphoma in 5 cases (9.1%). Thirty five patients (64%) underwent curative intended chemotherapy (CT) concomitantly with highly active antiretroviral therapy (HAART). Three year survival of the whole cohort was 27%. By multivariate analysis, the most important prognostic factors for long term survival, were complete responses to CT, (p < 0.01) and a low international prognostic index (IPI) score for NHL, (p = 0.01). HAART, histologic subtype and CD4 lymphocyte count at diagnosis, did not influence survival. Conclusions: The most important prognostic factors for HIV patients with lymphoma, were achieving CR with CT and low IPI score. Prognosis remains poor, even with HAART therapy.

T-Cell Lymphomas in South America and Europe

Peripheral T-cell lymphomas are a group of rare neoplasms originating from clonal proliferation of mature post-thymic lymphocytes with different entities having specific biological characteristics and clinical features. As natural killer cells are closely related to T-cells, natural killer-cell lymphomas are also part of the group. The current World Health Organization classification recognizes four categories of T/natural killer-cell lymphomas with respect to their presentation: disseminated (leukemic), nodal, extranodal and cutaneous. Geographic variations in the distribution of these diseases are well documented: nodal subtypes are more frequent in Europe and North America, while extranodal forms, including natural killer-cell lymphomas, occur almost exclusively in Asia and South America. On the whole, T-cell lymphomas are more common in Asia than in western countries, usually affect adults, with a higher tendency in men, and, excluding a few subtypes, usually have an aggressive course and poor prognosis. Apart from anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, that have a good outcome, other nodal and extranodal forms have a 5-year overall survival of about 30 percent. According to the principal prognostic indexes, the majority of patients are allocated to the unfavorable subset. In the past, the rarity of these diseases prevented progress in the understanding of their biology and improvements in the efficaciousness of therapy. Recently, international projects devoted to these diseases created networks promoting investigations on T-cell lymphomas. These projects are the basis of forthcoming cooperative, large scale trials to detail biologic characteristics of each sub-entity and to possibly individuate targets for new therapies.

Normogramas de presión arterial en escolares de 6 a 12 años en la ciudad de Managua, en el mes de noviembre, 2002 / Normogramas of blood pressure in scholars of 6 to 11 years in the city of Managua, in month of november of the 2002

Presión arterial, signo vital modificable en cada una de las etapas del desarrollo del individuo, cambios dados desde el nacimiento hasta la adultez; cada etapa es influenciada por factores ambientales, genéticos, etc., El conocer que la fisiopatología y las complicaciones de la hipertensión arterial inician en edades tempranas y que los valores de presión arterial de las primeras épocas de la vida predicen los valores del adulto ha condicionado que diferentes autores determinen en sus comunidades los valores de presión arterial. Objetivo general: Determinar normogramas de presión Arterial en escolares de 6- 12 años, Managua, noviembre 2002. Metodología: Estudio prospectivo, descriptivo, con universo de 2,287 escolares, de 3 escuelas de Managua; cada escolar se eligió por muestreo al azar con muestreo sistemático, con una muestra de 634 escolares. La información se obtuvo en cada escuela y se registro en una ficha de caso; luego la información se plasmo en una ficha previamente elaborada; se proceso en los programas EPI-INFO y SPSS obteniéndose frecuencias, porcentajes, percentiles, valor de p y coeficiente de correlción de pearson (r). Conclusiones: Existe mayor correlación entre edad y PAS para ambos sexos que para PAD. Existe correlación positiva entre peso y PAS y en menor proporción con PAD. La talla registro menor correlación para ambos componentes. Se encontraron valores de presión Arterial inferiores a los de referencia para ambos sexos, pero sin diferencia estadística significativa. Recomendaciones. Continuar utilizando los normogramas de presión arterial propuestos por la OPS. promover estudios similares incluyendo mediciones como: Indice de masa corporal y relación edad/talla/presión arterial. Conformar esfuerzos con instituciones correspondientes para realizar estudios con poblaciones mayores para construir normogramas de presión arterial de la población pediátrica nicaraguense

Transcriptos de fusión del gen BCR/ABL en pacientes con leucemia mieloide crónica / Fusion transcripts of BCR/ABL gene in patients with chronic myeloid leukemia

La anormalidad citogenética más común en la leucemia mieloide crónica (LMC) es el cromosoma Philadelphia, producida por la t(9;22), cuya expresión molecular es el gen de fusión BCR-ABL, que codifica proteínas con actividad tirosinquinasa. Según el punto de ruptura de los genes BCR o ABL se produce una proteína de fusión de 210-kD(p210) o 190-kD(p190). La presencia de este gen de fusión en pacientes con LMC tiene implicancia diagnóstica. Con el propósito de detectar transcriptos de fusión del gen BCR/ABL en pacientes con leucemia mieloide crónica, procedentes de la IX Región de Chile, se estudiaron 14 muestras de sangre de 11 pacientes con LMC. A 2 de ellos, se les realizó seguimiento durante su tratamiento con Gleevec. Se aplicó la técnica de reacción en cadena de la polimerasa con transcriptasa reversa (RT-PCR), usando una PCR en nido. Para la detección de los transcriptos de fusión p210 y p190 del gen BCR/ABL, se utilizaron 4 pares de iniciadores. En 9/14 muestras se detectó el transcripto de fusión p210 y en 5/14 los transcriptos de fusión p210 y p190. En los 2 pacientes en seguimiento, hubo desaparición del transcripto p190, permaneciendo el transcripto p210. Estos resultados reafirman la importancia de detectar transcriptos de fusión BCR/ABL para el diagnóstico y seguimiento durante el tratamiento de la LMC.