Enfermedad mínima residual en leucemia mieloide aguda no promielocítica: Resultados preliminares de un estudio colaborativo internacional / Minimal residual disease in non-myelocytic acute myeloid leukemia: preliminary results of an international collaborative study

A pesar de los avances en los protocolos de tratamiento y en las medidas de soporte en pacientes con Leucemia Mieloide Aguda (LMA), 27% presentan recaídas de la enfermedad. Esto se debe, entre otras causas, a la persistencia de pequeñas cantidades de células malignas (blastos) resistentes a la terapia. Estas pequeñas cantidades de blastos remanentes se denominan Enfermedad Mínima Residual (EMR). La determinación de EMR requiere de técnicas no solo muy sensibles, sino también específicas, y permite evaluar la respuesta individual a la terapia. La introducción de la EMR como parámetro de respuesta y estratificación está bien definida en Leucemia Linfoblástica Aguda (LLA). Por el contrario, aunque existen publicaciones sobre el impacto pronóstico de la EMR en LMA, aún no se encuentra incluida en forma sistemática en los protocolos nacionales actuales, entre otros motivos, por lo laborioso de la determinación y por la necesidad de validación de la misma. Debe tenerse en cuenta que el inmunofenotipo de los blastos mieloides suele ser más heterogéneo que el de los blastos en LLA, presentando, en muchos casos, subpoblaciones diferentes entre sí, lo cual dificulta su detección certera y no hay consenso definido en cuanto a la metodología más eficaz. En este trabajo describimos una nueva estrategia de marcación y análisis estandarizada en un estudio multicéntrico internacional para LMA y la utilidad de la EMR como parámetro de respuesta y de estratificación. Asimismo, detallamos los resultados preliminares de nuestra cohorte de pacientes (AU)

Despite the improvement in treatment and supportive care of patients with Acute Myeloid Leukemia (AML), 27% of them relapse. This is due to the persistence of small amounts of malignant cells (blasts) resistant to therapy, among other causes. These small amounts of blasts are called Minimal Residual Disease (MRD). The determination of MRD requires not only techniques with high sensitivity but also with high specificity, and allows to evaluate the individual response to treatment. The introduction of MRD as a response parameter is well established in Acute Lymphoblastic Leukemia (ALL), and it is used in current stratification protocols. On the other hand, even though there are some reports regarding the prognostic impact of MRD in AML, it is still not included in the current national protocols due to the lack of validation of the determination, among other causes. This is due to the fact that the immunophenotype of myeloid blasts is more heterogeneous than in ALL, presenting different subpopulations, which difficults their accurate detection. Thus, there is still no consensus regarding the most effective approach. In this article, we describe a new staining and analysis strategy standardized by an international multicentric study, and the utility of EMR as a response and stratification parameter. Additionally, we show the preliminary results of our patient cohort. (AU)

In vivo evaluation of three different 99mTc-labelled radiopharmaceuticals for sentinel lymph node identification.

This work was designed to compare sentinel lymph node (SLN) uptake of 99mTc-labelled human serum albumin colloid (99mTc-HSAC), 99mTc-labelled antimony sulphur colloid (99mTc-SC) and a 99mTc-labelled dextran 70 solution (99mTc-Dx) and their selectivity in the identification of this node in the right rear footpad (RRF) of normal mice and tumour bearing mice. Radiopharmaceutical uptake in the SLN (popliteal lymph node) and the lumbar lymph node (LLN), the second lymphatic node station from RRF, were measured at different time points post-intradermal or intratumoural injection into the RRF of NIH normal mice and of Balb/c mice harbouring the murine mammary tumour M2. 99mTc-HSAC uptake in the SLN was significantly higher than LLN uptake. The 99mTc-SC demonstrated high uptake in SLN, but accumulation in LLN was also high. 99mTc-Dx showed low uptakes in both SLN and LLN. The intradermal injection resulted in a more effective radiopharmaceutical accumulation in SLN than did the intratumoural inoculation. Data also show that increments in tumour volume reduced radiopharmaceutical uptake in the SLN. Our results show that 99mTc-HSAC exhibits the highest uptake in the SLN combined with the smallest amounts of radiopharmaceutical passing through to the LLN. Therefore, 99mTc-HSAC appears to be the best radiopharmaceutical for sentinel node detection.