Assessment of iron accumulation in children with transfusion dependent β-thalassemia

Accumulation of excess iron in the organs and tissues significantly increases morbidity and mortality rates in patients with transfusion-dependent forms of anemia. The purpose of the study were to assess the degree of iron overload of the liver, myocardium, pancreas and pituitary gland in children of various ages with transfusion-dependent major form of β-thalassemia and to analyze the adequacy of ongoing chelation and transfusion therapy. 21 patient with β-thalassemia were included in the study. Prior to the study 6 children did not receive chelation therapy. In all children the serum concentrations of ferritin and soluble transferring receptor (rTFR) were examined and T2* mode MRI investigations of pituitary, myocardium, liver and pancreas were performed. For the assessment of the degree of liver fibrosis and hemosiderosis there was performed liver biopsy. There was correlation between the iron content in the myocardium and erythropoiesis activity (r = 0.230). There was revealed the high inverse correlation between the concentration of iron in the liver and the accumulation of iron in the pancreas (r = -0.585), an inverse correlation between the accumulation of iron in the pituitary gland and pancreas (r = -0.430). The most of the children (n = 12) had iron overload as of the pancreas, as well of the pituitary, which corresponds to a T2*MR signal time shortening, 8 patients had iron overload of the pituitary in allowable iron content in the pancreas, and only the one child had iron deposition neither in the pituitary nor in pancreas. Thus, the pituitary gland accumulates excess iron significantly earlier than the pancreas, but before the onset of puberty, the pituitary gland, these changes of the pituitary do not have clinical manifestations. Accumulation of excess iron in the body is accompanied by a damage of the pituitary gland with following involvement of the pancreatic gland and myocardium. The regression analysis revealed a non-linear relationship between the concentration of serum ferritin and iron accumulation in the pituitary gland. These results don’t allow to consider the serum ferritin concentrations as a marker of the accumulation of iron in the pituitary gland.

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