Assessment of response to therapy with hydroxyurea in patients with functional asplenia

Full text: Functional asplenia is a chronic complication of sickle cell (SC) disease. As the concentration of fetal hemoglobin (hemoglobin F) increases in the re blood cells (RBCs), the polymerization of hemoglobin S declines. This makes it possible for a therapeutic approach with drugs that induce hemoglobin F synthesis, leading to improvement of the acute and chronic consequences of SC disease. Hydroxyurea is a chemotherapeutic agent capable of increasing the levels of hemoglobin F in RBCs. Its long term use as an anti-sicklemic agent has been proposed recently. The purpose of this investigation was to evaluate the long term effects of hydroxyurea on the recovery of splenic function in pts with SC disease. Six pts with the disease (5 males, 1 female; 4 to 22 yrs; 5 with SS hemoglobinopathy, , 1 with Sβo hemoglobinopathy; 4 black, 2 white) were studied. All pts received an intravenous injection of 74-185 MBq of [Tc-99m] sulfur colloid and liver-spleen imaging was performed 10 minutes later in the anterior and posterior views, with and without hepatic shielding. Pts were studied before and immediately after 6 months of treatment with hydroxyurea. All studied were submitted to visual and semi-quantitative analysis. Liver/spleen ratios were obtained before and after 6 months of treatment. Baseline images showed functional asplenia both visually and semi-quantitatively in all 5 SS pts and severely impaired splenic function in the Sβo pt. Follow-up images performed after 6 months of treatment demonstrated significant splenic function improvement in 4 pts while 2 pts did not show any improvement. It was to demonstrate, using liver/spleen scintigraphy, that hydroxyurea is capable of reversing functional asplenia in pts with SC disease. The best results were observed in the youngest pts and in the Sβo pt, probably because the amount of splenic fibrosis was less significant