Introducción:Anemias megaloblásticas secundarias a la deficiencia de vitamina B12 son patologías producidas por una síntesis defectuosa del ADN nuclear. Objetivo:Describir las alteraciones madurativas encontradas en precursores hematopoyéticos de la médula ósea de una serie de pacientes con anemia megaloblástica. Métodos:Se incluyeron pacientes atendidos en el Hospital Regional de Concepción con muestras de médula ósea enviadas para estudio de citopenias por citometría de flujo cuyo diagnóstico fue anemia megaloblástica. El inmunofenotipo se realizó con CD45, CD34, CD117, HLA-DR, marcadores de maduración de serie de neutrófilo (CD13, CD11b, CD10, CD16) y/o eritroblasto (CD105, CD71, CD36). Resultados:Se identificaron 8 pacientes con anemia megaloblástica y como controles se utilizaron síndromes mielodisplásicos (n=9) y médula ósea normal o reactiva (n=10). El 44% eran hombres, con una mediana de edad de 58 años. La anemia megaloblástica se asoció con una mayor proporción de tamaño y complejidad de progenitores eritroides y mieloides con respecto de los linfocitos en comparación a los controles. El porcentaje total de eritroblastos y la proporción de células mieloides CD34+ comprometidas con el linaje eritroide fue mayor en anemia megaloblástica, asociado a una parada madurativa en la etapa de precursor CD105+ (69% vs 19% y 23%, p <0.001). La heterogeneidad de CD36 y CD71 en anemia megaloblástica fue similar a los síndromes mielodisplásicos Conclusiones:La anemia megaloblástica produce una afectación heterogénea de la hematopoyesis, caracterizada por un mayor tamaño y complejidad celulares de precursores de la serie neutrófilo y eritroide y una detención madurativa de los eritroblastos

The diagnosis of blast cell presence in cerebrospinal fluid (CSF) in acute leukemias (AL) is made using techniques such as flow cytometry (FCM) and conventional cytology (CC). This study aims to evaluate CSF blast cell presence frequency in LA using both techniques (CC and FCM) in our center. Methods: We analyzed three hundred and eight CSF samples belonging to 175 patients, 57% male, with a median age of 46 years (1-70 years) were analyzed. Diagnoses were acute B lymphoblastic leukemia (B-ALL, 84%), acute T lymphoblastic leukemia (T-ALL 5%), acute myeloblastic leukemia (AML, 11%). The immunophenotype was performed with an 8-color panel adapted to the diagnosis. Results: The proportion of non-assessable CSF samples in LA was higher for CC (46%) than FCM (4%) (p<0.05). Overall, infiltration was found in 78/308 samples by FCM (25.3%) and in 8/77 by CC (10.4%) (p<0.0001). Seventy of 259 samples were positive in B-ALL (27%) and 6/34 in AML (17%). There were no CC+ cases in AML or T-ALL. The samples that were FCM+/CC+ had more significant infiltration (59.5%) than CMF+/CC- ones (30%) (p<0.0001). Conclusions: CMF detects more than twice as many CSF blast-positive cases in LA as CC and is, therefore, suitable for routine use along with CC.

Background: Inotuzumab Ozogamicin (InO) has shown efficacy in relapsed/refractory acute lymphoblastic leukemia (R/R ALL), but evidence from Latin America is scarce. We evaluated the outcomes of Chilean patients treated with InO in public and private health centers. Methods: We retrospectively analyzed 35 patients with R/R ALL (median age 33 years; 54% male). Twenty percent had BCR::ABL‐positive ALL, 78% expressed CD22, and 91% expressed CD19. Response rates, measurable residual disease (MRD), survival outcomes, and treatment‐related toxicities were assessed. Multivariate analyses explored prognostic factors. Results: Complete remission or remission with incomplete recovery (CR/CRi) was achieved in 74% of patients. Among those evaluated, 82% reached MRD < 0.01%. Patients undergoing allogeneic hematopoietic stem cell transplantation (Allo‐HSCT) after InO had superior overall survival (OS) compared with those who did not (24.2 vs. 5.2 months). Median progression‐free survival (PFS) was 6.9 months and median OS was 8.8 months. Sinusoidal obstruction syndrome occurred in 14% of patients but was generally mild. Multivariate analysis identified comorbidities and high blast counts as adverse prognostic factors, whereas MRD negativity and subsequent Allo‐HSCT were associated with improved outcomes. Conclusions: InO demonstrated high remission and MRD negativity rates in Chilean patients with R/R ALL, with OS and PFS comparable to existing research. Although SOS incidence was higher, it was generally mild. Achieving MRD negativity and proceeding to Allo‐HSCT provided the greatest survival benefit. Study limitations include short follow‐up and limited data.

Palabras clave: Citometría de Flujo; Diagnóstico Diferencial; Inmunofenotipificación

Palabras clave: Citometría de Flujo; Enfermedades Hematológicas; Líquido Cefalorraquídeo