Trace element regulation of immunity and infection

Essential trace elements are required by man in amounts ranging from 50 micrograms to 18 milligrams per day. Acting as catalytic or structural components of larger molecules, they have specific functions and are indispensable for life. Research during the past quarter of a century has identified as essential six trace elements whose functions were previously unknown. In addition to the long-known deficiencies of iron and iodine, signs of deficiency for chromium, copper, zinc, and selenium have been identified in free-living populations. Four trace elements were proved to be essential for two or more animal species during the past decade alone. Marginal or severe trace element imbalances can be considered risk factors for several diseases of public health importance, but proof of cause and effect relationships will depend on a more complete understanding of basic mechanisms of action and on better analytical procedures and functional tests to determine marginal trace element status in man.

Mice fed a purified diet low in copper display anemia, hypoceruloplasminemia, depressed concentrations of liver copper, and elevated concentrations of liver iron. An impaired humoral-mediated immune response (decreased numbers of antibody-producing cells) is observed in mice with severe as well as marginal copper deficiency. The magnitude of this impairment is highly correlated with the degree of functional copper deficiency (hypoceruloplasminemia).