[Transferrine soluble receptors' contribution to the assessment of iron status in homozygous drepanocytic anemia]

Abstract

Sickle cell anemia does not cause martial deprivation per se, but may worsen when iron deficiency exists, notably in tropical zone where infectious diseases and malnutrition are endemic mainly during childhood. This study was aimed to assess iron deficiency prevalence among children with sickle cell disease (SCD) and to determine the best parameters for its diagnosis. In addition to classical parameters, we measured transferrine's soluble receptors which can reveal an iron deficiency, either isolated or associated to another condition since its level is not influenced by chronic anemia. Assays were carried out in 40 homozygous SCD patients, aged 3 to 18 years, having an hemoglobin level < 11 g/dL and in 30 age-paired controls assumed to be healthy and having a negative Emmel test and an hemoglobin level < 11 g/dL. The results showed hyposideremia (serum iron < 60 microg/dL) in 17.5% of the patients. Ferritinemia, transferrinemia as well as total iron fixation capacity were in the normal range for the majority of SCD patients in spite of the frequency of hyposideremia and microcytic anemia (20%). Transferrine's saturation coefficient was low in 22.5% of patients, which can be due to martial deprivation or to inflammatory status. These results confirm the limitations of usual biochemical parameters in the diagnosis of iron deficiency in homozygous drepanocytosis. Soluble receptors' levels were increased in 60% of controls; that proves that iron deficiency prevalence is high in our countries. Higher levels were found in 97.5% of patients. However, receptors' levels are increased during haemolysis, thus it is difficult to ascertain the origin of the increase, but taking into account its index value can reduces misinterpretation. In addition, considering simultaneously microcytosis, hypochromia, transferrine's soluble receptor level and its index, we can speculate that martial deficiency occurs in 20% of SCD patients, a percentage close to the 17.1% obtained by other authors using only the combination of microcytosis and hypochromia. It results from this study that associating microcytosis and hypochromia could validly assess iron deficiency during drepanocytosis.