Changes of serum antibody activities to various dietary antigens related to gluten withdrawal or challenge in children with coeliac disease.

IgG, IgA, and IgM serum antibody activities to gluten, a gluten fraction called glyc-gli, and antigens from egg and cow's milk were monitored by an enzyme-linked immunosorbent assay (ELISA) in children with coeliac disease during treatment and gluten challenge. The IgA activity to gluten antigens showed in most patients a rapid and significant reduction after gluten withdrawal, whereas the IgG activity decreased more slowly. During gluten challenge, both these activities rose significantly, and the increases could usually be detected several months before overt clinical relapse. Such determinations, therefore, represent a valuable adjunct in the follow-up of children with coeliac disease. IgA activities to egg and cow's milk antigens likewise tended to decrease after gluten withdrawal and increase during challenge, but the changes were less consistent for individual antigens. Nevertheless, monitoring of IgA activities to a selection of dietary antigens other than gluten may be particularly valuable when it comes to evaluation of intestinal responses in patients on a gluten-free diet.