Fetal hemoglobin in sickle cell disease : relationship to erythrocyte phosphatidylserine exposure and coagulation activation

• Published in: Blood Vol. 96; no. 3; pp. 1119 - 1124
• Main Authors: SETTY, B. N. Y, KULKARNI, S, RAO, A. K, STUART, M. J
• Format: Journal Article
• Language: English
• Published: Washington, DC The Americain Society of Hematology 01.08.2000
• Subjects: Adolescent; Adult; Anemia, Sickle Cell - blood; Anemia, Sickle Cell - etiology; Anemias. Hemoglobinopathies; Biological and medical sciences; Blood Coagulation; Child; Child, Preschool; Diseases of red blood cells; Erythrocytes - metabolism; Fetal Hemoglobin - metabolism; Hematologic and hematopoietic diseases; Humans; Infant; Medical sciences; Phosphatidylserines - blood; Human; Hemoglobinopathy; Blood coagulation; Thrombinogenesis; Sickle cell anemia; F-Cell; Hemopathy; Activation; Homozygosity; Genetic disease; Fetal hemoglobin; Hemolytic anemia; Phosphatidylserine; Cytoplasmic vesicle
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V96.3.1119

In sickle cell disease (SCD), loss of erythrocyte membrane phospholipid asymmetry occurs with the exposure of phosphatidylserine (PS), which provides a docking site for coagulation proteins. In vivo sickling/desickling, with resulting red cell membrane changes and microvesicle formation, appears to be one of the factors responsible for PS exposure. We evaluated children with SCD homozygous for sickle hemoglobin (SS disease) and controls (n = 65) and demonstrate that high levels of fetal hemoglobin (assessed as F cells) are associated with decreased microvesicle formation, PS exposure, and thrombin generation. F cells correlated inversely with both microvesicles and PS positivity (P <.000001) in SS disease. Multiple regression analyses using various hematologic parameters as independent variables, and either microvesicles or PS positivity as the dependent variable, showed a strong relationship only with F cells. Additionally, plasma prothrombin fragment F1.2 levels (a marker for thrombin generation) correlated with both PS positivity (P <.001) and F cells (P <.01). An F-cell level of approximately 70% was associated with normal levels of prothrombin fragment F1.2 and with microvesicle formation indistinguishable from control values. We suggest that the use of such surrogate biologic markers in conjunction with F-cell numbers may provide valuable insights into the biology and consequences of in vivo sickling.