Transferrin Receptor, Soluble

Most cells obtain their iron from plasma protein transferrin. Transferrin has a very high affinity for iron at neutral pH and iron release requires a specific membrane receptor. The transferrin receptor is expressed on the surface of human cells that require iron. Transferrin receptor is responsible for internalisation of transferrin-bound iron and its intracellular release.

The expression of transferrin receptor depends on the concentration of Fe in the cellular cytoplasm. The concentration of soluble transferrin receptor(sTfR) has been reported to be proportional to the total amount of cell-associated transferrin receptor.

Measurements of circulating sTfR have been used as an indicator of the rate of erythropoesis (i.e. haemolytic anaemia) and as an indicator of iron deficiency. Increased sTfR concentrations can also be connected to diseases such as sickle cell anaemia and decreased concentrations to chronic renal failure and post bone marrow transplantation.

In iron deficiency the amount of serum soluble transferrin receptor increases. The increase is usually not affected by chronic disease states. The measurement of serum soluble transferrin receptor should be performed in combination with other tests of iron status in order to increase sensitivity and specificity.

Soluble transferrin receptor

Soluble transferrin receptor is purified from human blood. The purity is checked with SDS-PAGE. The immunological activity is confirmed by reaction with monoclonal antibodies, which are specific to soluble transferrin receptor.