“Packaging” of fetal hemoglobin in sickle cell anemia

Ever since Janet Watson’s astute observation in 1948, the “protective” effect of HbF in persons with sickle cell anemia has been appreciated, and during the last several decades, increasing HbF levels by prescribing hydroxyurea has had salutary clinical effects. HbF has been measured by its overall concentration in the blood or by the percentage of erythrocytes containing fetal hemoglobin (F cells). Now, Steinberg et al elegantly characterize a previously unappreciated third means of expressing the powerful ameliorative effects of HbF in patients with sickle cell anemia: ie, the percentage of erythrocytes containing ≥10 pg of HbF. This amount has been shown to inhibit deoxy sickle hemoglobin (HbS) polymer formation when the oxygen saturation is less than the 40% to 70% encountered in the microcirculation. By preventing polymerization, the beneficial effects for the patient include reduction in intravascular hemolysis, vaso-occlusion–induced pain and tissue damage, and endothelial injury.

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“Packaging” of fetal hemoglobin in sickle cell anemia

Source: Blood
Image credits: ASH image bank


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