Obtención de plasma rico en plaquetas (PRP) en el Laboratorio de Terapia Celular para uso como herramienta terapéutica en medicina regenerativa / Obtaining platelet rich plasma (PRP) in the Cell Therapy Laboratory for use as a therapeutic tool in regenerative medicine

Platelet rich plasma (PRP) is used to speed up tissue repair. Despite its widespread use, the therapeutic application of PRP generates controversies in clinical results due to the variability in methods of obtaining the different preparations and differences between the components of different types of PRP, so it's recommended to mention the type of platelet preparation used. In this article, we describe technical and biologics characteristics of our platelet product, and we compare them to different commercial preparations described in order to validate their clinical use. Our results determine that the preparation can be considered a platelet rich plasma with biological activity in vivo and in vitro, which supports its use as a valid therapeutic tool, alternative to products currently available in Regenerative Medicine. (AU)

Estandarización de la técnica Real Time PCR para la detección molecular de la mutación V617F en el gen de JAK-2 en neoplasias mieloproliferativas crónicas / Standardization of the Real Time PCR technique for the molecular detection of the V617F mutation in the JAK-2 gene in chronic myeloproliferative neoplasms

V617F mutation in exon 14 of Janus Kinase 2 gene (jak-2) is used as a molecular marker for the diagnosis of Philadelphia negative myeloproliferative neoplasms (Phi-) such as Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (MFP). To detect this mutation, we used conventional polymerase chain reaction technique (PCR), a simple and inexpensive technique, however, has some drawbacks that current technology allows to solve. During the last years, more sensitive molecular techniques have been incorporated in clinical practice to support the diagnosis, prognosis and follow-up of hematological patients. For its implementation in the clinical routine should be considered technical and economic aspects, so in this work, we evaluate the Real Time PCR technique as a diagnostic method for the detection of the Jak-2-V617F mutation, using in house primers design. Our result show that the technique implemented has a concordance index of 0.87 with the conventional PCR used in the molecular diagnosis of myeloproliferative neoplasms. In addition, it has the same specificity, greater sensitivity and, shorter execution time in relation to conventional PCR. The implementation of this diagnostic method in our Hospital is technically possible and commercially convenient. (AU)

Frecuencia génica de antígenos menores de histocompatibilidad en la población chilena y estimación de sus efectos inmunológicos en el trasplante alogénico de progenitores hematopoyéticos / Frequency of minor histocompatibility antigens among Chilean blood donors

Background: Minor histocompatibility antigens (mHAgs) play a critical role in the immune responses associated with allogeneic stem cell transplantation, such as graft versus host disease (GVHD) and graft-versus-tumor (GVT). Aim: To determine the gene frequencies of the mHAgs HA-1, HA-2 and HA-8 in Chilean Blood Bank donors. Material and Methods: Blood from 192 blood donors was analyzed. The presence of haplotype HLA-A*02 was determined by flow cytometry. The frequency of mHAgs was determined by allele specific polymerase chain reaction in genomic DNA. Results: Sixty one participants were carriers of the haplotype HLA-A*02. The relative allele frequency HA-1H was 45%, HA-Ir 55%, HA-2V 80.6%, HA-2M 19.4%, HA-8R 49.8% and HA-8P was 50.2%. Based on mHAgs disparity between HA-1, HA-2 or HA-8, the probability to generate a GVT response in HLA-A*02 individuals was 40%. Conclusions: The mHAgs frequency in Chilean population is under Hardy-Weinberg equilibrium and they are similar to those of other ethnic populations in the world.

Respuesta inmune contra antígenos menores de histocompatibilidad en el trasplante alogénico de progenitores hematopoyéticos / Immunologycal response under antigens hematopoietic stem cell transplantation

Patients who receive allo hematopoietic stem cell transplantation (SCT) could develop graft versus host disease and/or graft versus tumour effect. These immunological responses can happen even with perfect fully HLA matched haematopoietic stem cells. Moreover, the engraftment of the donor’s cells depends on the immunological conditions of both donor and recipient. The development of alloreactivity occurs in the context of the polymorphisms of the human genome, these genomic differences results in proteins with antigenic properties which trigger immune responses. Considering this, the SCT is a powerful tool to heal the patient disease, because all of them become chimeras. In other words, into individuals with two different genomic sets, which will develop a strong immunological response that cannot exist in natural conditions.

Trasplantes de progenitores hematopoyéticos / Hematopoietic stem cell transplant

The stem cell transplantation (SCT) has improved the disease free survival of a great number of diseases. It began as an experimental procedure, used as last resource in terminally ill patients. Nowadays it is a proved tool that allow the patient receive high dose of chemoradiotherapy, without the bone marrow toxicity being a conditioning step. The haematological recovery follows the same mechanisms that the organisms have designed for this purpose. First, cryopreservation of progenitors stem cells (PSCs) is required, then these cells are re-infused into the blood. The PSCs find their own homing in the bone marrow, proliferate, differentiate and re establish the haematopoietic balance. The present revision gives some information about the different phase or a SCT, physiology background, indications and principals adverse effects.

Estudio de quimerismo: aplicación en pacientes con trasplante de progenitores hematopoyéticos / Chimerism study: application in patients with allogeneic progenitor cell transplantation

El trasplante alogénico de progenitores hematopoyéticos (TAPH) es una técnica que ha cambiado el pronóstico de muchas enfermedades hematológicas malignas y no malignas. En determinados tiempos post trasplante coexisten células hematológicas de receptor y dador, por lo cual el individuo posee dos sistemas hematopoyéticos. El término Quimera se utiliza para indicar el origen dual de las células hematológicas. Este análisis es indispensable para saber si existe prendimiento o rechazo del trasplante. La determinación de quimerismo se realiza mediante la amplificación por PCR de secuencias cortas repetidas tandem (STRs del ingles short tandem repeat sequence). Este examen es fácil de realizar, reproducible, altamente sensible y específico. El resultado del quimerismo es de vital importancia a la hora de tomar decisiones clínicas, sobre todo si se utilizan técnicas no mieloablativas de acondicionamiento, infusión de linfocitos del donante, o modificaciones en los protocolos de inmunosupresión, donde existe una lata variabilidad en el prendimiento del injerto y el desarrollo de enfermedad de injerto contra huésped (EICH) e injerto contra tumor (ICT).

Allogeneic progenitor cell transplantation (ALoPCT) is a procedure that has changed the prognosis of many malignant and non-malignant hematologic diseases. For a period of time post-trasplant, cellular subtypes from the donor and the host coexist, giving the patient two hematopoietic systems. The term Chimera is used to indicate the dual origin of blood cells. This analysis is important to determine whether engrafment or rejection has occurred. The determination of chimerism is based on PCR pf Short Tandem Repeat sequences (STRs). The PCR technique is easy to perform, reproducible, highly sensitive and specific. Chimerism determination helps to improve the clinical approach to the patient, specifically when non-mieloablative conditioning, lymphocyte donor infusion or modification of the immunosuppressive protocols have employed. All of these manipulations produce a high variability in engraftment, development of graft versus host disease (GVHD) and the likelihood to eliminate tumor cells through graft versus tumor (GVT) effects.

Fusariosis diseminada por Fusarium oxysporum en un paciente adulto con leucemia mieloide aguda y neutropenia severa febril / Disseminated fusariosis by Fusarium oxysporum in an adult patient with acute myeloid leukemia and severe febrile neutropenia

Reportamos el primer caso de fusariosis diseminada en un paciente adulto en Chile, con una neoplasia hematológica y tratamiento quimioterápico, quien evolucionó con neutropenia febril prolongada, refractaria, fuera tratado con un amplio esquema antibacteriano y desarrollara una infección multisistémica, con compromiso cutáneo, sinusal y pulmonar por Fusarium oxysporum. Cursó con refractariedad al tratamiento antifúngico con anfotericina B deoxicolato y caspofungina, utilizados en forma secuencial. El desenlace fatal de este paciente se asoció a la persistencia de la neutropenia y a la infección por un hongo filamentoso habitualmente resistente a terapia antifúngica.

Autotrasplante (AT) de progenitores hematopoyéticos en mieloma múltiple: Experiencia clínica / Autologous transplant (AT) with peripheral-blood stem-cell rescue for multiple myeloma: A clinical experience

Background:Multiple myeloma is rarely curable. Advances in high dose chemotherapy and stem cell transplantation have improved overall survival and event-free disease periods, but relapses are inevitable. Aim: To report our experience with AT in multiple myeloma, between 1994 and 2003. Material and Methods: Retrospective analysis of 20 patients (12 women), with a mean age of 51.1 years. VAD (vincristine, doxorubicin and dexamethasone) was used as initial therapy in 19 patients. High dose cyclophosphamide (11 patients) and variations of VAD regimen (7) associated with granulocyte colony stimulating factor were used for peripheral-blood stem cell harvest. The conditioning regimen consisted of melphalan 200 mg/m2 followed by the reinfusion of peripheral-blood stem cells 24 hours later. The median number of CD34 cells infused was 3,3x106/kg. Three patients were subjected to a second auto graft and one to a non-myeloablative transplant. Mean follow up was 35.5 months. Results: Mucositis and febrile neutropenia were common complications. The median number of days for neutrophyl engraftment was 9 (range 8-11) and for platelets, 10 (range 7-13). No patient died. Complete remission was obtained in 60% (12/20), progession-free survival was 30 months and overall median survival, 47 months. Conclusions: The AT with high-dose melphalan is a safe procedure in our hospital, without mortality and engraftment in all the patients. Complete remission and progression free survival were similar to those reported abroad but the overall median survival was lower.

Linfoma intravascular tratado con anticuerpos monoclonales anti CD20: descripción de un caso clínico / Intravascular lymphoma treated with anti CD20 monoclonal antibodies: report of one case

We report a 78 year old male with prostatism, that was subjected to a prostate biopsy. The pathological study showed a microvascular lymphocytic infiltration. Four months later, the patients presentd with reduced alertness, cough, dyspnea, fever and elevation of lactic dehydrogenase and erythrocyte sedimentation rate. Chest and abdominal CAT scans, bone marrow aspirate, protein electrophoresis and prostate specific antigen were normal. A re-evaluation of prostate biopsy showed an intravascular lymphoid infiltration, positive for CD45 and CD20, compatible with the diagnosis of intravascular lymphoma. Chemotherapy was started, but it was not tolerated by the patient and the response was partial. Therefore, treatment with monoclonal antibodies anti CD20 (Rituximab) was started. The tumor had a complete and prolonged (24 months) remission after the treatment.

Intoxicación por rodendicida - superwarfarina: descripción de un caso clínico / Poisoning by rodenticide - superwarfarin: description of a clinical case

Los rodendicidas de uso doméstico están fácilmente disponibles en el comercio y, corresponden en general a superwarfarinas, cuyo mecanismo de acción es semejantea los anticoagulantes de uso clínico, pero difiere en una vida media más prolongada (meses) y una potencia cien veces mayor.Presentamos el caso clínico de una intoxicación con fines suicidas de Rodilon® (difethialone) 10 cajas de 50 g. La paciente ingresa con un tiempo de protrombina(TP) de 6 por ciento con un INR de 12.4, requiriendo administración de vitamina K1 durante varios meses. Las manifestaciones clínicas fueron leves (gingivorragia y petequias) al ingreso.En caso de no contar con el antecedente de ingesta, la intoxicación debe sospecharse en toda hipoprotrombinemia adquirida, sin antecedentes familiares de diátesis hemorrágica y, con función hepática normal.

Coagulación endoscópica con plasma de argón: una opción terapéutica en la ectasia vascular antral / Endoscopic coagulation with argon plasma: a therapeutic option in vascular antral ectasia

Background: Gastric Antral Vascular Ectasia or Watermelon stomach is a rare cause of chronic gastrointestinal bleeding, often presenting as a chronic iron deficiency anemia. This condition can be associated with some other diseases such as cirrhosis, autoimmune diseases and others. We report two patients treated with Argon Plasma Coagulation, a 68 years old male with an ethanol related cirrhosis and a 72 years old female with an idiopathic Gastric Antral Vascular Ectasia. The characteristic endoscopic features were mistaken for many years as gastritis. Both patients presented with severe anemia requiring multiple transfusions as treatment. Due to the poor operative risk, both patients were treated with Argon Plasma Coagulation with good results

Infecciones en el paciente neutropénico / Infections in neutropenic patients

Estudio prospectivo de 74 períodos consecutivos de neutropenia severa (menor o igual a 500 u/L) en 38 pacientes hematológicos del Hospital Clínico de la U. de Chile. La leucemia aguda constituye la principal enfermedad de base y la quimioterapia fue utilizada en el 81 por ciento de los episodios. En 60 períodos (81 por ciento) se logró demostrar infección y 51 de ellos (69 por ciento) cursaron febriles. Destacamos la presencia de 9 episodios de infección de curso afebril por constituir un hecho excepcional en estos pacientes. En los 60 períodos de neutropenia con infección se logró demostrar en el 80 por ciento uno o más focos, destacando el pulmonar, orofaríngeo, mucocutáneo y abdominal. El estudio microbiológico fue positivo en el 45 por ciento de los episodios febriles; se aislaron 34 microorganismos (bacilos Gram (-) 62 por ciento, cocáceas Gram (+) 26,3 por ciento, hongos 8,8 por ciento y virus 2,9 por ciento. Se constataron 11 bacteremias, todas por bacilos Gram (-) predominando K. pneumoniae y E. coli. El esquema ceftazidima-amikacina fue el más utilizado y se modificó en más del 50 por ciento de los casos (se asoció vancomicina, anfotericina B, u otro, o se reemplazó por imipenem, vancomicina y anfotericina B), con éxito terapéutico en el 75 por ciento de los casos. Se produjeron 17 fallecimientos, 13 de causa infecciosa. La mortalidad se asoció al diagnóstico de leucemia aguda, neutropenia prolongada, foco pulmonar y bacteremia por Gram (-). Los episodios febriles sin foco ni bacteriología se asociaron a buen pronóstico

Un caso de neutropenia y agranulocitosis inducidas por clozapina: importancia de un programa de farmacovigilancia para su detección precoz / A case of neutropenia and agranulocytosis due to clozapine: importance of a drug surveillance programme for its early detection

Clozapine is an atypical antipsychotic drug with a very low incidence of extrapyramidal effect, used in the treatment of schozophrenic patients refractory or intolerant to classical neuroleptics. Its use is limited due to the potential risk of producing agranulocytosis in 1 to 2 per cent of patients. Despite the severity of this complication, the Federal Drug Administration allowed its use as long as iots prescription is associated to a drug surveillance program. Two patients had a transitory leukopenia with less than 2000 leukocytes/ml and less than 1000 neutrophyls/ml, that reverted after discontinuing the drug. One patient, whose case is described, had a severe agranulocytosis with less than 500 neutrophyls/ml that required hospital admission