RESUMO
In thalassemia intermedia (TI), the increase in bone marrow hemopoietic activity frequently leads to extramedullary erythropoeisis (EMH), but its relationship with the soluble form of transferrin receptor (sTfR) which fully reflects the marrow erythropoietic activity, has not yet been explored. From January 2007 to December 2010, all TI patients attending at our center were prospectively enrolled to undergo sTfR assay and MRI or CT (if claustrophobic) scan evaluation for the presence of paraspinal EMH. A total of 59 patients with TI were studied; EMH involved 23 (39%) patients; overall, the concentration of sTfR varied from 2.6 to 20.6 (mean = 8.7) mg/L, but in splenectomized group and in unsplenectomized group, it varied from 4.2 to 17.8 (mean ± SD = 9.86 ± 3.33) mg/L and from 2.6 to 20.6 (mean ± SD = 7.25 ± 3.9) mg/L, respectively with a statistically significant intergroup difference (p < 0.01). The cutoff point at 8.6 mg/L using the ROC curve showed a sensitivity of 78.3% and a specificity of 72.2%, in predicting EMH but, in unsplenectomized subgroup, they raised to 100% and 90.9%, respectively. These data showed that in TI the level of sTfR could represent a predictive factor of EMH particularly in patients with spleen.