Emergence of RET rearrangement co-existing with activated EGFR mutation in EGFR-mutated NSCLC patients who had progressed on first- or second-generation EGFR TKI.

OBJECTIVES: The gatekeeper mutation T790M mutation is the responsible for the majority of the resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in patients with EGFR-mutated non-small cell lung cancer (NSCLC). Other previously described resistance mechanisms include HER2 amplification, MET amplification, PIK3CA mutation, epithelial-mesenchymal transition (EMT), small cell transformation have also been identified. However other resistance mechanisms remains to be discovered. MATERIALS AND METHODS: Hybrid-capture based comprehensive genomic profiling (CGP) was performed on pre- and post-EGFR TKI progression EGFR-mutated NSCLC tumor samples during routine clinical care. We identify two paired pre- and post-EGFR TKI progression EGFR-mutated NSCLC patient tumor samples where both post EGFR TKI samples harbored in-frame CCDC6-RET rearrangements but not in the pre-EGFR TKI tumor samples. Furthermore analysis of the clinical database revealed one additional NCOA4-RET rearrangement co-existing with activated EGFR mutation in an EGFR-mutated NSCLC patient who had progressed on afatinib. None of the known resistance mechanisms to EGFR TKI including EGFR T790M, EGFR amplification, HER2 amplification, MET amplification, PIK3CA mutation, BRAF mutation, EMT or small cell transformation was identified in the three post progression samples that now harbored RET rearrangements. RESULTS AND CONCLUSIONS: This is the first report of RET rearrangement co-existing with activated EGFR mutations in EGFR-mutated patients who had progressed on either first- or second generation EGFR TKI. As such, RET rearrangement may serve as a potential resistance mechanism to EGFR TKI in EGFR-mutated NSCLC.

[Evidence on the role of HLA and MICA antibodies in renal graft loss]. / Evidencia del impacto de los anticuerpos anti-HLA y anti-MICA en la pérdida del injerto renal.

BACKGROUND: HLA and MICA antibodies are increasingly associated with poorer graft survival. The aim of this study is to report the frequency of graft loss 2 years after the detection of HLA abs and MICA abs among a group of kidney transplant recipients. METHODS: We tested 196 patients with a functioning graft. Sera were screened for HLA and MICA IgG abs by Luminex, using the LABScreen Mixed, and LABScreen PRA. The sera were screened for MICA abs by Luminex. RESULTS: Of 196 kidney transplant recipients (mean age 36.7 years, 42% female), one hundred twenty four (63.3%) were negative to all tested abs, and 72 (36.7%) were positive for: HLA abs alone = 34, MICA abs alone = 29, and HLA+MICA abs = 9. At a median followup of 20.5 (1.2-25.2) months, 8 patients lost their grafts due to biopsy-confirmed chronic allograft injury: 2/124 (1.6%) ab-negative, and 6/72 (8.3%) ab-positive, with a significantly lower survival for the Ab-positive group (p = 0.046, log-rank test). CONCLUSIONS: The presence of circulating abs was associated with an increased risk of graft loss, and the coexistence of HLA and MICA abs increases the risk of graft loss.

Evidencia del impacto de los anticuerpos anti-HLA y anti-MICA en la pérdida del injerto renal / Evidence on the role of HLA and MICA antibodies in renal graft loss

Antecedentes: Los anticuerpos anti-HLA y anti-MICA se han asociado cada vez con mayor frecuencia a menor supervivencia del injerto renal. El objetivo de este estudio es comunicar la frecuencia de pérdida del injerto dos años después de la detección de anticuerpos anti-HLA, anti-MICA, o ambos, en un grupo de receptores de trasplante renal (RTR). Métodos: Estudiamos a 196 RTR con injerto funcional. El suero de los pacientes fue analizado para la presencia de anticuerpos IgG anti-HLA clase I y clase II con Luminex utilizando LABScreen®Mixed y LABScreen® PRA. La presencia de anticuerpos anti-MICA en el mismo suero se analizó por Luminex. Resultados: De 196 RTR (edad promedio 36.7 años, 42% sexo femenino), 124 (63.3%) fueron negativos a todos los anticuerpos estudiados y 72 (36.7%) fueron positivos: 34 para anticuerpos anti-HLA solo, 29 para anticuerpos anti-MICA solo y nueve para anticuerpos anti-HLA+anti-MICA. A una mediana de seguimiento de 20.5 meses (1.2-25.2), ocho pacientes perdieron el injerto por daño crónico del mismo, confirmado por biopsia: 2/124 (1.6%) del grupo de anticuerpos negativos y 6/72 (8.3%) del grupo de anticuerpos positivos, con una supervivencia del injerto significativamente inferior para el grupo de anticuerpos positivos (p=0.046, log-rank test). Conclusiones: La presencia de anticuerpos circulantes estuvo asociados con riesgo incrementado para pérdida del injerto; la coexistencia de anticuerpos anti-HLA y anti-MICA produjo el riesgo más alto para pérdida del injerto en la población analizada.

BACKGROUND: HLA and MICA antibodies are increasingly associated with poorer graft survival. The aim of this study is to report the frequency of graft loss 2 years after the detection of HLA abs and MICA abs among a group of kidney transplant recipients. METHODS: We tested 196 patients with a functioning graft. Sera were screened for HLA and MICA IgG abs by Luminex, using the LABScreen Mixed, and LABScreen PRA. The sera were screened for MICA abs by Luminex. RESULTS: Of 196 kidney transplant recipients (mean age 36.7 years, 42% female), one hundred twenty four (63.3%) were negative to all tested abs, and 72 (36.7%) were positive for: HLA abs alone = 34, MICA abs alone = 29, and HLA+MICA abs = 9. At a median followup of 20.5 (1.2-25.2) months, 8 patients lost their grafts due to biopsy-confirmed chronic allograft injury: 2/124 (1.6%) ab-negative, and 6/72 (8.3%) ab-positive, with a significantly lower survival for the Ab-positive group (p = 0.046, log-rank test). CONCLUSIONS: The presence of circulating abs was associated with an increased risk of graft loss, and the coexistence of HLA and MICA abs increases the risk of graft loss.

The genome project of Taenia solium.

We have constituted a consortium of key laboratories at the National Autonomous University of Mexico to carry out a genomic project for Taenia solium. This project will provide powerful resources for the study of taeniasis/cysticercosis, and, in conjunction with the Echinococcus granulosus and Echinococcus multilocularis genome project of expressed sequence tags (ESTs), will mark the advent of genomics for cestode parasites. Our project is planned in two consecutive stages. The first stage is being carried out to determine some basic parameters of the T. solium genome. Afterwards, we will evaluate the best strategy for the second stage, a full blown genome project. We have estimated the T. solium genome size by two different approaches: cytofluorometry on isolated cyton nuclei, as well as a probabilistic calculation based on approximately 2000 sequenced genomic clones, approximately 3000 ESTs, resulting in size estimates of 270 and 251 Mb, respectively. In terms of sequencing, our goal for the first stage is to characterize several thousand EST's (from adult worm and cysticerci cDNA libraries) and genomic clones. Results obtained so far from about 16,000 sequenced ESTs from the adult stage, show that only about 40% of the T. solium coding sequences have a previously sequenced homologue. Many of the best hits are found with mammalian genes, especially with humans. However, 1.5% of the hits lack homologues in humans, making these genes immediate candidates for investigation on pharmaco-therapy, diagnostics and vaccination. Most T. solium ESTs are related to gene regulation, and signal transduction. Other important functions are housekeeping, metabolism, cell division, cytoskeleton, proteases, vacuolar transport, hormone response, and extracellular matrix activities. Preliminary results also suggest that the genome of T. solium is not highly repetitive.

Pruebas de Histocompatibilidad en el Programa de Trasplantes / Histocompatibility tasting provides data to evaluate the immunological risk for transplantation

The importance of the role of the histocompatibility laboratory in solid organ transplantation is to perform HLA typing and determine the degree of HLA matching between recipient/donor. It is a useful tool to increase graft survival and decrease chronic rejection. HLA matching has a positive effect on kidney transplants and it has variable impact on other organ transplants. The crossmatch procedure is the most important test in a solid organ transplantation to evaluate the presence of recipient antibodies to antigens expressed on donor white cells. This test decreases the risk of hyperacute humoral rejection or early graft loss. Positive crossmatch is a contraindication for transplantation because it represents the existence of IgG recipient antibodies that will reath againts donor antigens. Antibody evaluation is important in donor-recipient selection and the responsability of the histocompatibility laboratory is to identify clinically relevant anti-donor HLA antibodies. This detection is useful to determine the degree of humoral alloimmunization, expressed as a percent panel reactive antibody (96PRA). This test also provides information about the antibody specificity and can be used for evaluate a patient's immune status providing a significant correlation in selecting donors.

La importancia del laboratorio de histocompatibilidad en los programas de trasplante de órganos sólidos es llevar a cabo la tipificación HLA para determinar el grado de compatibilidad que exhibe la pareja receptor/donador para el trasplante. Se tiene conocimiento que el grado de compatibilidad HLA representa un efecto positivo en el trasplante renal y en la disminución de los episodios de rechazo. Su impacto en la sobrevida de los injertos es variable en otros órganos. El procedimiento más importante para evaluar la presencia de anticuerpos preformados presentes en el suero del receptor en contra de los antígenos expresados en los linfocitos del donador es la prueba cruzada. Esta prueba permite disminuir el riesgo de un rechazo hiperagudo o la pérdida temprana del injerto. Una prueba cruzada positiva se considera como contraindicación para el trasplante por presencia de anticuerpos preformados detectables en el suero del receptor del tipo IgG en contra de los antígenos del donador en estudio. Parte de la responsabilidad del laboratorio de histocompatibilidad es la detección en el receptor de anticuerpos anti-HLA clínicamente relevantes dirigidos en contra de las especificidades antigénicas de su potencial donador. Esta evaluación es útil para conocer el grado de aloinmunización humoral del paciente (sensibilización) y se expresa como un porcentaje de reactividad de anticuerpos (%PRA). Esta prueba también permite conocer la especificidad del anticuerpo anti HLA presente, y así evaluar el estatus inmunológico del paciente y la selección del donador.

Estandarización de la prueba cruzada por citometría de flujo y detección del estado de preinmunización en nefrópatas / Standardization of the crossmatch test through flow cytometry and detection of the preimmunization state in patients with renal disease

Varios son los factores de éxito en el transplante de órganos, podemos citar: el parecido de los antígenos de histocompatibilidad entre el donador y el receptor, la eficacia de la terapia inmunosupresora, la tolerancia a la misma, la limpieza de la cirugía, infecciones, presensibilización, etc. Este último factor habitualmente conduce al rechazo temprano del injerto y generalmente de forma irreversible. La sensibilización ocurre por: a) transfusiones (pacientes candidatos a transplante de médula ósea y riñón), b) embarazos y c) transplantes previos, en donde la primera causa es la más importante cuantitativamente. La determinación del grado de sensibilización se realiza mediante la prueba cruzada, que habitualmente es una prueba de microlingocitotoxicidad dependiente de complemento; sin embargo, la citometría de flujo se presenta como una metodología más sensible, pues permite determinar cantidades mínimas de anticuerpos sobre células en forma objetiva, cualitativa y cuantitativa. En este trabajo se comparó la citometría de flujo de 122 pacientes del Registro Nacional de Transplantes, probados contra un panel de células de 22 individuos sanos, valorando también la interferencia de algunos autoanticuerpos, como anticuerpos antinucleares y factor reumatoide. La sensibilidad de la citometría de flujo fue 3.5 veces mayor y con las precauciones necesarias pudiera ser una herramienta muy útil en los programas de transplante investigando estados de presensibilización no conocidos previamente