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.
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%.
Horiuchi
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K
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia 19104.
Fynn-Thompson
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F
Ohene-Frempong
K
K
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
D005319:Fetal Hemoglobin