title: A hypothesis of target cell formation in sickle cell disease.
abstract: A fraction of erythrocytes appear as target cells in stained blood smears in sickle cell disease, due to a inheritance of the hemoglobin variant Hb S, polymerizing upon deoxygenation. These cells appear in a three dimension as thin cups. A process of their formation in this disease is proposed based on a band 3-based mechanism of the erythrocyte shape control, able to explain the erythrocyte echinocytosis by glucose depletion. It indicates that their formation is due to a stomatocytogenic slow outward transport of the dibasic form of endogenous Pi with an H(+) by band 3, promoted by the decrease of the Donnan ratio, which decreases cell pH and volume, attributed by a decrease of cell KCl concentration by the higher efflux of K(+)Cl(-) cotransport and Ca(2+) activation of the Gardos channel. Its implications are briefly discussed with respect to target cells per se, target cell formation in other hemoglobinopathies, acquired and inherited disorders of the lipid metabolism and dehydrated hereditary stomatocytosis as well as a stomatocyte presence in a double heterozygote of Hb S and Hb C and of an involvement of the process of target cell formation in acanthocytosis in acquired and inherited disorders.
authors.affiliation: Laboratoire de Chimie des Protéines, Montréal, Québec, Canada. Electronic address: pwong_LCP@yahoo.ca.
authors.forename: P
authors.initials: P
authors.lastname: Wong
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000235:genetics; D001692:Biological Transport; D004912:Erythrocytes / Q000166:cytology / Q000648:ultrastructure*; D005947:Glucose / Q000737:chemistry; D006444:Hemoglobin C / Q000235:genetics*; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006453:Hemoglobinopathies; D006579:Heterozygote; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008962:Models, Theoretical; D011189:Potassium Chloride / Q000737:chemistry; D027981:Symporters / Q000378:metabolism; D000096922:K Cl- Cotransporters
chemical_list: D000255:Adenosine Triphosphate; D005947:Glucose; D006444:Hemoglobin C; D006451:Hemoglobin, Sickle; D011189:Potassium Chloride; D027981:Symporters; D000096922:K Cl- Cotransporters
keywords: Band 3; Glucose depletion; Hemoglobinopathies; Sickle cell disease; Target formation