alpha-chymotrypsin and Anemia--Hemolytic--Congenital

The flow cytometric test measures the fluorescence intensity of intact red cells labelled with the dye eosin-5-maleimide, which reacts covalently with Lys-430 on the first extracellular loop of band 3 protein. In this study, red cells from patients with hereditary spherocytosis (HS), congenital dyserythropoietic anaemia type II, South-east Asian ovalocytosis and cryohydrocytosis have produced a greater degree of reduction of mean channel fluorescence readings than those for other patient groups and normal controls. The predictive value of this test for membrane abnormality was compared with the results obtained from the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method, which is currently the reference laboratory test for the identification of membrane protein deficiencies in hereditary spherocytosis and for the detection of spectrin variants in hereditary elliptocytosis. The dye method is a reliable, speedy diagnostic test (2 h from sample collection to result) for HS with a sensitivity of 92.7% and a specificity of 99.1%. Thus, it will serve well as a first-line screening test for the diagnosis of hereditary spherocytosis in routine haematology.

Topics: Adult; Anemia, Hemolytic, Congenital; Anion Exchange Protein 1, Erythrocyte; Chymotrypsin; Cytoskeleton; Electrophoresis, Polyacrylamide Gel; Eosine Yellowish-(YS); Erythrocyte Membrane; Fetal Blood; Flow Cytometry; Fluorescent Dyes; Humans; Infant, Newborn; Predictive Value of Tests; ROC Curve; Spherocytosis, Hereditary

We report a study of HEMPAS erythrocyte membrane glycoproteins in relation to proteolytic digestion and surface labelling with galactose-oxidase/NaB[3H]4. The proteolytic digestion of band 3, the major intrinsic glycoprotein of the human erythrocyte membrane, reveals an abnormality in the outer glycosylated segment of this protein. 3H incorporation in band 3 and band 4.5 glycoproteins after treatment with galactose-oxidase/NaB[3H]4 is reduced in HEMPAS red cells suggesting a defective glycosylation of these proteins. These findings together with the persistence of i antigen and the normal presence of I antigen lead us to conclude that erythroblastic membrane features may persist in HEMPAS erythrocytes.

Topics: Adult; Anemia, Dyserythropoietic, Congenital; Anemia, Hemolytic, Congenital; Borohydrides; Child; Chymotrypsin; Electrophoresis, Polyacrylamide Gel; Erythrocyte Membrane; Erythrocytes; Galactose Oxidase; Glycoproteins; Humans; Tritium; Trypsin