Platelet enzyme abnormalities in leukemias.

Aim of the Study: The aim of this study was to evaluate platelet enzyme activity in cases of leukemia. Materials and Methods: Platelet enzymes glucose-6-phosphate dehydrogenase (G6PD), pyruvate kinase (PK) and hexokinase (HK) were studied in 47 patients of acute and chronic leukemia patients, 16 patients with acute myeloid leukemia (AML)(13 relapse, three in remission), 12 patients with acute lymphocytic leukemia (ALL) (five in relapse, seven in remission), 19 patients with chronic myeloid leukemia (CML). Results: The platelet G6PD activity was significantly low in cases of AML, ALL and also in CML. G6PD activity was normalized during AML remission. G6PD activity, although persistently low during ALL remission, increased significantly to near-normal during remission (P < 0.05) as compared with relapse (P < 0.01). Platelet PK activity was high during AML relapse (P < 0.05), which was normalized during remission. Platelet HK however was found to be decreased during all remission (P < 0.05). There was a significant positive correlation between G6PD and PK in cases of AML (P < 0.001) but not in ALL and CML. G6PD activity did not correlate with HK activity in any of the leukemic groups. A significant positive correlation was however seen between PK and HK activity in cases of ALL remission (P < 0.01) and CML (P < 0.05). Conclusions: Both red cell and platelet enzymes were studied in 36 leukemic patients and there was no statistically significant correlation between red cell and platelet enzymes. Platelet enzyme defect in leukemias suggests the inherent abnormality in megakaryopoiesis and would explain the functional platelet defects in leukemias.

Erythrocyte enzyme abnormalities in leukemias.

Red cell enzymes were assayed in a total of 67 patient including 24 patients with AML (19 relapse, 5 remission), 16 patients with ALL (10 relapse, 6 remission), 22 patients with CML and 5 patients with blastic CML. Diagnosis of leukemia was based on clinical presentation, peripheral blood smear and bone marrow examination (as per FAB classification). PK activity was significantly high in case of CML and blastic CML (p<0.01). Red cell HK was high in all leukemia subtypes. There was no alteration in red cell G6PD. Notably there was no PK deficiency in AML or G6PD deficiency in ALL. Activities of G6PD and PK could be correlated in cases of CML, AML, (p<0.05) and ALL (p<0.01) i.e. when there was increased activity of G6PD, PK activity also tended to be higher. HK activity showed a positive correlation with PK and G6PD activity in cases of CML (p<0.05), however in acute leukemia there was no such correlation. Alteration of enzyme activities among red cells in leukemia occurred only during relapse. At the time of remission there has been no significant alteration in any of the enzyme activities. It would therefore, appear that enzyme alterations seen in leukemia patients is due to abnormal pluripotent stem cell that has given to a leukemia cell. The fact that enzyme alterations have primarily occurred at the time of relapse would further substantiate that abnormalities of red cell enzymes may be the result of a derivation some circulating red cells from the abnormal pluripotent stem cell. With the recovery of normal stem cells function during remission, enzyme abnormalities tend to become normal.

Valores de fosfatasa alcalina leucocitaria en leucemia mieloide crónica / Score of leucocyte alkaline phosphatase in chronic myelogenous leukaemia

El objetivo de este estudio fue evaluar los valores de fosfatasa alcalina leucocitaria en pacientes con leucemia mieloide crónica en fase crónica, que concurrieron al Servicio de Hematología del Hospital Central de Mendoza. Se determinó en frotis de sangre periférica el score de la fosfatasa alcalina en los neutrófilos. Se utilizó el método semicuantitativo con hidrólisis enzimática del sustrato naftol fosfato, donde se libera naftol que se acopla a un azocolorante marcando el sitio de actividad de la enzima. Valor normal: 90 ñ 20. Se estudiaron 45 pacientes, 25 hombres y 20 mujeres con edades entre 18 y 75 años; la media y desviación estándar para la edad fue de 45 ñ 16 y para la fosfatasa alcalina 32 ñ 20. A 17 pacientes se les había realizado estudio citogenético, de los mismos resultaron cromosoma Philadelphia positivo el 94,1 por ciento, en éstos la media y desviación estándar fue para la edad 44 ñ 14 y para fosfatasa alcalina, 35 ñ 22, valores similares a los obtenidos en el total de los pacientes. La fosfatasa alcalina leucocitaria resultó mayoritariamente disminuida lo que concuerda con la bibliografía consultada

Leukocyte glucose 6 phosphate dehydrogenase as prognostic indicator in ANLL and CML.

Glucose 6 phosphate dehydrogenase (G6PD) was estimated in the leucocytes of 35 patients with acute non-lymphocytic leukemia (ANLL) and 10 patients with chronic myeloid leukemia (CML). G6PD levels were found to be significantly decreased in majority of the patients with ANLL while it was increased in all CML patients. Variation in G6PD was found to be dependent on the percentage of myelocytes inANLL. Cytogenetic analysis was also carried out in these patients. Correlation analysis of leucocyte G6PD activity and karyotype with prognostic assessment clearly indicated the association of (s) high percentage of chromosomal abnormalities especially translocations, (b) low survival and remission rates, with patients having decreased G6PD activity when compared to patients with normal activity in ANLL. The studies indicate that leucocyte G6PD may be useful as a diagnostic and prognostic tool.

Alteraciones bioquímicas y citoquímicas de hidrolasas ácidas lisosomales en leucemias / Biochemical and citochemical alterations of lisosomal acid hydrolases in leukemias

La actividad enzimática total de ß-galactosidasa (ß-gal), hexosaminidasa (hex) y fosfatasa ácida (Fac) fue determinada bioquímicamente, tanto en suero como en sobrenadantes de homogenatos celulares de sujetos normales y pacientes portadores de leucemias, empleándose sustratos paranitrofenilados específicos. La actividad de ß-gal en leucemias mieloides, tanto agudas (LMA-M1) como crónicas (LMC), sólo mostró un incremento significativo en sobrenadantes de homogenato celulares, respecto a los valores de neutrófilos normales. En leucemias linfoidales agudas (LLA), como crónicas (LLC), su comportamiento no ofreció variaciones. Tanto los sueros como los sobrenadantes de homogenatos celulares de LMA-M1 y LMC mostraron un franco incremento en la actividad de hex, mientras en LLA y LLC esta actividad no mostró variaciones. La actividad sérica de fosfatasa ácida estuvo incrementada en el 86% de las LMC. En los sobrenadantes de homogenatos celulares de LLA y LLC, esta actividad enzimática se mostró significativamente disminuida respecto de los valores de linfocitos normales. En los tres casos de LMA-M4 analizados, fue observado en el contenido celular niveles elevados de ß-gal, hex y Fac (lo que estaría correlacionado con la presencia de monocitos y/o monoblastos normales, con alto contenido de hidrolasas ácidas). Citoquímicamente fue demostrado en médula ósea y sangre periférica de pacientes con LMA-M1 una ligera o nula actividad de hex, en tanto que en LLA la reacción fue localizada asimétricamente en un polo celular o en gránulos citoplasmáticos. Los resultados encontrados demuestran una gran heterogeneidad en el contenido lisosomal de los diferentes tipos de leucemias