Selenium: An Acute-Phase Reactant?

Selenium, an essential micronutrient in man, is not transported on carrier proteins in plasma, but as selenomethionine incorporated into peptides and proteins. The best understood examples of selenoproteins are the glutathione peroxidase enzymes which are part of the antioxidant scavenging system and the enzyme 5'-deiodinase responsible for the conversion of T4 to T3. 1 Because of the anti-oxidant activities of selenium-containing compounds and their proposed role in protecting from oxidative tissue damage, there is currently a lot of interest in the detection and correction of selenium deficiency in patients. We have noted that although the plasma selenium concentration is often very low «0·5 Jlmol/L) in newly admitted, severely ill patients.? the red cell glutathione peroxidase concentration (RBC GSHPx) is relatively normal. Others have proposed that plasma selenoproteins behave as negative acute phase reactants and are redistributed from the plasma pool into the interstitial space in a manner analogous to plasma albumin.t' We now present a case report that further supports the concept.