RESUMEN
Background: Acute myeloid leukemia (AML) is a heterogeneous disease, associated with a high diversity of phenotypes. The study was done with the aim to study about the aberrant phenotypes in acute myeloid leukemia cases and the correlation among the aberrant phenotypes and poor prognostic factors in acute myeloid leukemia.Methods: This cross sectional study was conducted on 35 cases of newly diagnosed AML according to the selection criteria at Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai for a period of 6 months. Immunophenotyping analysis by flow cytometry was done on fresh bone marrow aspirate or peripheral blood sample by applying Acute Leukemia Panel. The co-expression of different antigen markers on lymphocytes was analyzed.Results: Aberrant lymphoid markers were seen in 17 (49%) cases. 5 (14%) cases had lymphoid associated antigen expression alone. 3 (8%) cases had asynchronous antigen expression alone. 9 (27%) cases had both asynchronous antigen expression and lymphoid associated antigen expression which is of cases . In total, lymphoid associated antigen expression is seen in 41% of cases and asynchronous antigen expression in 35% of cases. CD3, CD19 (lymphoid associated antigen) and CD34+ CD15+ (asynchronous aberrant phenotype) were the most common equally expressed aberrant phenotypes, each in 7 cases. CD 3 was significantly more common in males (P=0.021) but in general there were no statistically significant association between adverse prognostic factors and aberrant phenotypic AML.Conclusions: CD19 and CD3 were the most commonly expressed lymphoid associated antigen. Most common asynchronous aberrant phenotype was CD34+CD15+. None of the aberrant phenotypic expression was not associated with poor risk factors in acute myeloid leukemia except for common expression of CD3 in males.
RESUMEN
La citometría de flujo multiparamétrica es el método de elección para la caracterización inmunofenotípica de las células hematopoyéticas clonales presentes en los distintos procesos leucémicos agudos. El objetivo fue analizar la expresión de antígenos de membrana y evaluar la presencia de fenotipos aberrantes en los blastos de pacientes con diagnóstico de leucemia aguda, que permiten el monitoreo de la respuesta al tratamiento. Se revisaron los inmunofenotipos de 364 muestras de pacientes adultos derivadas a nuestro laboratorio en un período de 7 años. El inmunofenotipo se realizó por citometría de flujo con un amplio panel de anticuerpos monoclonales con el que se evaluó la expresión de antígenos de linaje linfoide, mieloide y también antígenos de maduración. De las 364 muestras estudiadas, 60.2% presentaron un fenotipo compatible con leucemia mieloide aguda (LMA), 28.8% con leucemia linfoblástica B (LLA-B), 6.6% con leucemia linfoblástica T (LLA-T) y 4.4% con leucemias agudas poco frecuentes. La presencia de fenotipos aberrantes se observó en 89% de los casos, los fenotipos aberrantes identificados fueron: 1) infidelidad de linaje: LMA (54%), LLA-B (40%), LLA-T (29%); 2) ausencia de expresión antigénica: LMA (21%), LLA-B (35%), LLA-T (70%); 3) alteración de la expresión antigénica: LMA (67%), LLA-B (66%), LLA-T (84%); 4) asincronismo madurativo: LMA (26%), LLA-B (37%) y 5) fenotipo ectópico: LLA-T 96%). El análisis por citometría de flujo multiparamétrica de las leucemias agudas permitió la identificación de fenotipos aberrantes en la mayoría de nuestros pacientes, que son de utilidad para el monitoreo de la respuesta al tratamiento.
Multiparameter flow cytometry (MFC) has become the preferred method for the lineage assignment and maturational analysis of malignant cells in acute leukemias. Multiparametric immunophenotyping analysis allows the detection of aberrant antigen expression and the analysis of heterogeneity and clonality of malignant cells in leukemias. Our objectives were to analyze the membrane antigen expression and to evaluate if the aberrant phenotypes occurrence in blasts cells of patients with acute leukemia is useful in monitoring the response to the treatment. We have retrospectively analyzed the MFC data of 364 samples sent to our laboratory in a 7 years period. For this purpose we have used a large panel of monoclonal antibodies against lymphoid, myeloid and precursors antigens. From the 364 analyzed samples, 60.2% showe d a phenotype compatible with acute myeloid leukemia (AML), 28.8% with B lymphoblastic leukemia (B-LLA), 6.6% with T lymphoblastic leukemia (T-LLA) and 4.4% with rare leukemias. Aberrant phenotypes were found in 86% of the samples. The aberrant phenotypes identified were:1) lineage infidelity AML (54%), B-ALL (40%), T-ALL (29%); 2) absence of antigen expression: AML (21%), B-ALL (35%), T-ALL (70%); 3) altered antigen expression: AML (67%), B-ALL (66%),T-ALL (84%); 4) asynchronous expression: AML (26%), B-ALL (37%) and 5) ectopic phenotype: T-ALL (96%). Multiparameter flow cytometry of acute leukemias allowed identification of aberrant phenotypes in the majority of our patients, that are helpful for monitoring treatment response.