indium-oxine and Anemia--Sickle-Cell

Leukocyte labelling in patients with sickle cell anaemia has been reported as difficult if not impossible due to the slow erythrocyte sedimentation rate (ESR) in these patients. This study investigated standard sedimentation methods in patients with sickle cell disease (n = 16) and compared the results obtained with those following changes in the amount and type of sedimenting agent used. Labelling with either 111In-oxine or 99Tcm-exametazime was attempted in only five patients. Replacement of the commonly used 6% Hetastarch (Hespan) with Dextran or Haemaccel did not improve leukocyte harvesting, even when the proportions used of these agents were increased. In most cases where standard procedures for leukocyte collection did not lead to harvesting of viable samples, it was possible to obtain adequate leukocyte labelling in the majority of sickle cell patients using a minor modification of standard techniques. In this group of patients a ratio of 8 ml of Hespan to 16 ml of blood should be used for cell separation. If this fails then donor cells, anti-granulocyte antibody labelling or HIG should be considered.

Topics: Anemia, Sickle Cell; Blood Sedimentation; Dextrans; Humans; Hydroxyethyl Starch Derivatives; Indium Radioisotopes; Isotope Labeling; Leukapheresis; Leukocytes; Organometallic Compounds; Organotechnetium Compounds; Oximes; Oxyquinoline; Polygeline; Technetium Tc 99m Exametazime

The impaired deformability and heterogeneity of erythrocytes in sickle cell disease endows them with abnormal microvascular flow dynamics. In the sickle cell exchange-transfused rat model, sickle cells exhibit lower volumetric flux and shear rates compared to normal (HbAA) or autologous rat cells. A subpopulation of dense sickle cells and irreversibly sickled cells show a propensity to induce occlusion at precapillary arterioles, residing at such sites for several seconds and causing local rheological disequilibrium. Radionuclide studies with indium-111 demonstrate preferential uptake of labeled HbSS cells in pulmonary microcirculation. These data are relevant to the factors that are involved in the initiation and propagatin of vaso-occlusion resulting in derangement of homeostasis in certain microvascular beds and perhaps painful crisis and selective organ injury.

Topics: Anemia, Sickle Cell; Animals; Blood Flow Velocity; Disease Models, Animal; Erythrocytes; Indium Radioisotopes; Infarction; Male; Mesentery; Microcirculation; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging; Rats; Rats, Inbred Strains