Atypical neutrophil alkaline phosphatase associated with impaired neutrophil functions

We report the case of a healthy young man presenting with atypical neutrophil alkaline phosphatase (NAP) and reduced neutrophil chemotactic activity, but with no susceptibility to infection. NAP activity was low, kinetic parameters were modified and immunoreactive properties and subcellular distribution were abnormal. Neutrophil morphology was normal. A similar pattern was observed in the patient's healthy brother. The profile of the observed anomalies offers some similarity to that previously described in patients with chronic myelogenous leukaemia. However, in the present case, the NAP deficiency with impaired neutrophil function was present in two brothers with no haematological symptoms and is probably related to a non-acquired neutrophil abnormality. This observation of a primary NAP variant reinforces the hypothesis of a direct link between NAP activity and functional properties of neutrophils.

Evaluation of two markers of cell maturation and proliferation in cultured amniotic cells of trisomic 18 fetuses at the 15th week of gestation

Intensive studies have been conducted so far on biochemical markers available for screening of chromosome defects in obstetrical monitoring. In this paper we report further data on two protein phosphatases: alkaline phosphatase (a marker of cell maturation) and phosphotyrosine phosphatase (a marker of cell proliferation) assayed in cultured amniotic cells from fetuses with trisomy 18 at 15 weeks of gestation. Comparison with normal fetal cells showed a different behaviour for each enzyme: alkaline phosphatase was very significantly lowered while phosphotyrosine phosphatase remained a normal levels. These results provide a further enlargement of the field of biochemical markers used in the screening tests of trisomy 18.

Changes in immunological properties of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Immunoreactivity, cytochemical, immunocytochemical characteristics and subcellular distribution of neutrophil alkaline phosphatase (NAP) were investigated in blood and/or smear samples from 18 women aged 23-46 years (mean 32.5 years) with trisomy 21 fetuses (17-21 weeks) and 28 women aged 20-42 years (mean 31 years) with normal fetuses (17-22 weeks). Immunochemical NAP investigations were carried out in 8 pathological and 8 normal pregnancies; cytochemical and immunocytochemical procedures were carried out in 18 pregnant women with trisomy 21 fetuses and 28 controls. NAP from women with trisomy 21 fetuses is characterized by: (1) a significant decrease in reactivity with anti-liver-type alkaline phosphatase (AP) and anti-NAP antisera; (2) low or very slight reactivity with antiplacental or anti-intestinal antibodies; (3) marked dispersion of NAP lead citrate reaction products or anti-NAP antibody colloidal gold-labelling in neutrophil cytoplasms, as detected by electron microscopy. This subcellular AP distribution (extramembranous) is different from that of normal NAP sites associated with plasma membrane, nuclear membrane and secretory vesicles. The NAP immunochemical and cytochemical characteristics suggest that neutrophils of a woman with a trisomy 21 fetus contain two AP isoenzymes: the liver/bone type and an atypical AP.

Phosphotyrosine phosphatase activity and haematologic changes in Down's syndrome patients

Assays of neutrophil phosphotyrosine phosphatase activity and determination of haematological parameters were performed on 12 trisomic 21 probands without any clinical or biological symptom of other evolutive disease. Haematological studies showed the two main classical abnormalities: the existence of a macrocytosis and an enhanced lymphocyte count. Of interest are the very reduced rates of phosphotyrosine phosphatase activity found in granulocytes from these patients. This defect in protein phosphatase can be considered as an additional enzymatic change extending the list of modified factors recognized at molecular and cellular levels in subjects whose risk of leukaemia is significantly increased.

Alkaline phosphatase and phosphotyrosine phosphatase activities of cultured amniotic cells with trisomy 18

In cultured amniotic cells from fetuses with Edward's syndrome (trisomy 18), the activities of two protein phosphatases, alkaline phosphatase and phosphotyrosine phosphatase, were measured. Comparison with normal fetal cells showed a different behavior for each enzyme. Alkaline phosphatase was significantly lowered while phosphotyrosine phosphatase remained at normal levels. The interest of these enzyme assays in the screening procedure of this severe chromosome defect is discussed.

Difference in activity properties and subcellular distribution of neutrophil alkaline phosphatase between normal individuals and patients with trisomy 21

Biochemical, cytochemical characteristics and electron microscopy subcellular distribution of neutrophil alkaline phosphatase (NAP) were analysed in blood and/or smear samples from 39 trisomy 21 patients (Down's syndrome) aged 11.5-18 years (mean 15.5 years) and 55 normal subjects aged 12-20.5 years (mean 17 years). All patients were karyotyped. NAP cytochemical procedures were carried out on all subjects; biochemical NAP determinations were made in 10 patients and 20 controls; ultrastructural electron microscopy of AP was performed in three patients and four normal subjects. Neutrophil alkaline phosphatase from patients with trisomy 21 displayed the following changes: (1) a significant increase of enzyme activity, (2) a high thermal lability of enzyme. Electron microscope morphology exhibited large deposits of NAP reaction product associated with the plasma membrane and intracellular main organelles, like phosphasomes. The NAP biochemical and cytochemical characteristics suggest that trisomy 21 neutrophils contain a non-specific AP isoenzyme, closely related to the early placental form.

About the presence of a circulating anti-alkaline phosphatase antibody in a trisomy 21 patient's serum

An electrophoretically slow-moving alkaline phosphatase was found in the serum of a 17-year-old patient with Down's syndrome. Immunological and biochemical studies suggested that this abnormal enzyme pattern consisted of a complex of liver/bone isoenzyme with kappa-type immunoglobulins A and G.

New antibody in severe rhesus incompatible pregnancies: IgG-kappa antiplacental alkaline phosphatase

As already found in other various diseases, a macromolecular alkaline phosphatase complex (HMW-AP) was also found in sera of two severe Rhesus-incompatible pregnancies complicated by ascites and fetal hydrops at delivery. This atypical complex was detected and isolated by agarose gel electrophoresis. Immunoelectrophoresis and heat inactivation of this HMW-AP complex revealed that it consisted of IgG of the kappa type and placental AP isoenzyme. The transitory presence of this immuncomplex is discussed. However, in all women with Rh-immunized complicated pregnancies, significant variations of neutrophil and serum AP activities were observed. A fall in AP activity and the presence of an antiplacental AP antibody in serum of women with complicated Rh immunization should be of value in assessing the prognosis of the disease.

Isoelectric focusing of human neutrophil alkaline phosphatase isoenzymes in agarose gel

An isoelectric focusing technique for human neutrophil alkaline phosphatase isoenzymes is described. After sonication with Zwittergent 3-12, butanol extraction and ultracentrifugation, dialysis of cytosols precedes focusing. Focusing patterns show a heterogeneity with two enzymatic activity areas: a main component at pI 6.7-6.8 with a minor component at pI 4.8-5.0 which is difficult to visualize due to its sensitivity to experimental conditions. The addition of 3 mmol/l ZnCl2 to the agarose gel improved the staining of focused bands and in particular the anodic component.

IgG/placental alkaline phosphatase complexes in Rh-incompatible pregnancy with fetal hydrops

In 11 cases with anti-Rh-complicated pregnancies, i.e. ascites at 21/25 weeks and fetal hydrops at delivery, we detected the presence of IgG/placental alkaline phosphatase complexes in the maternal serum.

Thin-layer agarose isoelectric focusing of alkaline phosphatase isoenzymes from human neutrophils

An improved method for thin-layer agarose isoelectric focusing of alkaline phosphatases (AP) from human neutrophils is described. The solubilization of AP isoenzymes was studied with four detergents. The best results were obtained after sonication with Zwittergent 3-12 (1% final concentration), followed by butanol extraction and ultracentrifugation 105,000 x g for 1 h. The cytosol can be stored at 0 degrees C or -80 degrees C, but not at -20 degrees C. Dialysis of the cytosol against a Tris buffer, pH 7.5, was imperative prior to focusing for removal of the detergent. Enzyme visualization is enhanced by incorporation of ZnCl2 (3 mM) into the agarose gel. The focusing patterns consist of two sets of isoenzymes: two main zones with pI 6.4 and 6.8 and minor components with pI 4.2, 4.8 and 5.2.

Heat resistance, immunological and quantitative changes of neutrophil alkaline phosphatase in trisomy 21 pregnancies

Neutrophil alkaline phosphatase (NAP) was analysed in 25 pregnant women with trisomy 21 foetuses whose chromosomal aberration was recognized by cytogenetic study after amniocentesis. Enzyme investigation was performed at 20-22 weeks of gestation using cytochemical and biochemical techniques. Twenty-nine women at the same stage of normal pregnancies were selected as controls. In parallel, each mother was karyotyped. Ten subjects from each series underwent biochemical and immunological investigation: measurement of enzyme levels, thermostability study and immunological tests with alkaline phosphatase isoenzyme antibodies. NAP from pregnant women with trisomy 21 foetuses was characterized by: (1) a lower rate of enzyme activity, (2) a large amount of heat-stable enzyme (T = 56 degrees C for biochemical assays, T = 85 degrees C for cytochemical tests), and (3) a marked loss of liver antigenicity. These findings suggest the presence in trisomy 21 pregnancies of a non-specific alkaline phosphatase isoenzyme which appears as an "enzyme marker" in maternal circulating neutrophils.

An enzymatic marker in mothers of trisomy 21 children: neutrophil alkaline phosphatase

Neutrophil alkaline phosphatase (NAP) from 12 mothers of normal children was investigated and the results compared to those of 7 mothers with trisomy 21 offsprings, in an attempt to determine a parental molecular change in this chromosomal abnormality. The biochemical properties of the enzyme were analyzed by the procedures of isoenzyme characterization, i.e. enzyme assays, thermostability, inhibition patterns and slab gel electrophoresis. Immunological properties were determined on 5 samples from normal mothers and on the same sample number of mothers with affected children. In these latter NAP showed characteristics that were to some extent different from the ones of normal controls. The following changes were observed: highly significant loading of membrane and nucleus pellets in NAP activity, poor effect of inhibitors on thermostable component and immunodepletion measured by a significant decrease of the normal affinity for antiliver and antiplacental alkaline phosphatase antisera. These findings are discussed in the light of our knowledge of alkaline phosphatase isoenzymes.

Haematology and erythrocyte metabolism in man at high altitude: an Aymara-Quechua comparison

In the course of haematological and biological investigations among Aymara and Quechua populations in Bolivia, an anthropological study of the erythrocytary respiratory function was carried out on the two groups at two altitudes: 3,600 m and 450 m. A difference in the intensity of the biological variations of the two populations is observed at high altitude. In the Quechuas, as in any lowland native, the adaptative phenomena are totally and quickly reversible. In the Aymaras, we detected the existence of more marked haematological and biochemical characters: moderate polycythemia, hyperhaemoglobinemia, microcytosis, metabolical hyperactivity with accumulation of 2-3 di-phosphoglycerate and ATP, and methaemoglobinemia with a drop in the activity of the methaemoglobin reductases. The Aymaras preserve some of those characters (methaemoglobinemia excepted) when they settle in lowlands.

Cytochemical and biochemical studies on neutrophil alkaline phosphatase in parents of trisomy 21 children

A study of karyotypes and neutrophil alkaline phosphatase (NAP) was carried out for 66 parents (33 couples) of trisomy 21 children and for 60 control parents (30 couples). Enzyme activity was determined simultaneously by biochemical and cytochemical techniques. In the mothers of trisomy 21 children we found: (a) by biochemical techniques, a significant increase of NAP activity in polymorphonuclear leukocyte (PMN) homogenates (P less than 0.01) and a lower supernatant/pellet ratio (P less than 0.01); (b) by cytochemical techniques (with or without thermal and urea treatments) NAP activity was significantly higher (P less than 0.001) than in control mothers; in the fathers, the two techniques gave normal NAP activity results.