Iron overload in children who are treated for acute lymphoblastic leukemia estimated by liver siderosis and serum iron parameters.

OBJECTIVE: To evaluate a secondary liver iron overload and its fate in children who are treated conventionally for acute lymphoblastic leukemia and to assess whether serum soluble transferrin receptor (sTfR) is useful in detecting iron load.

METHODS: Liver siderosis was estimated histologically from liver biopsy specimens of 30 children (aged 2.6-17.6 years) close to or at the end of therapy using total iron score (TIS). Serum iron parameters and sTfR were measured at the same time and in 22 patients 1 to 3 years after therapy.

RESULTS: In 19 (63%) of 30 patients, liver TIS was >15, indicating at least moderate iron overload. Serum ferritin, iron, and transferrin iron saturation levels were highest and transferrin level lowest in the patients with the highest liver iron content. Serum sTfR levels did not differ significantly between the patients with varying amounts of liver iron. TIS correlated most significantly positively with serum ferritin (r(S) = 0.899), transferrin iron saturation (r(S) = 0.764), and the amount of transfused red blood cells (r(S) = 0.783). Serum iron parameters normalized in most patients during the follow-up. In 3 (14%) of 22 patients, serum ferritin level remained high (>1000 microg/L).

CONCLUSIONS: Long-term iron overload is detected in at least 14% of children after therapy for acute lymphoblastic leukemia. Serum sTfR is an inappropriate marker for liver iron overload, whereas ferritin seems to be the most useful serologic marker for it.