title: Quantitative analysis of the degree of irreversible deformation of F cells and non-F cells and its relationship to cell density in sickle cell disease.
abstract: To study the effect of fetal hemoglobin (Hb F) on the formation of dense and irreversibly deformed cells in patients with sickle cell disease (SCD), we investigated the distribution of Hb F and Hb F cells (FC, cells having HbF) and the difference in the degree of irreversible deformation between FC and non-Hb F cells (NFC) in relation to their cell density. We used immunofluorescence to define FC and image analysis to quantify the degree of deformation. Blood samples from 16 patients with Hb F levels ranging from 4 to 24% were separated into less dense [top (T), d < 1.11 g/mL] and dense [bottom (B), d > or = 1.11 g/mL] fractions. We found higher percentages of Hb F and FC in top fractions, suggesting that FC are hydrated more than NFC. Quantitative shape analysis demonstrated that the irreversible deformation of FC in the top fraction [FC(T)] was not significantly different from that of NFC in the fraction [NFC(T)] (p = 0.163), but rather that the irreversible deformation of FC in the bottom fraction [FC(B)] was much milder than for NFC(B) (p < 0.001). The order of the degree of irreversible deformation was NFC(B) > FC(B) > NFC(T) = FC(T). These results clearly demonstrated that FC are less susceptible to both irreversible deformation and dehydration than NFC, suggesting that in circulation, the sickling process plays a major role in cell dehydration. Additionally, we found that the ratio of NFC(B) to FC(B) decreased as a patient's Hb F increased (r = 0.84) and that NFC(B) = FC(B) when Hb F was about 20%.
authors.affiliation: Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia 19104.
authors.forename: K
authors.initials: K
authors.lastname: Horiuchi
authors.forename: F
authors.initials: F
authors.lastname: Fynn-Thompson
authors.forename: K
authors.initials: K
authors.lastname: Ohene-Frempong
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000473:pathology*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D002648:Child; D002675:Child, Preschool; D004907:Erythrocyte Deformability; D005319:Fetal Hemoglobin / Q000378:metabolism*; D006801:Humans; D007223:Infant
chemical_list: D005319:Fetal Hemoglobin