Modulation of Graves' disease autoantibody stimulation of recombinant human thyrotrophin receptor.

Background: The cAMP response of porcine thyrocytes to the immunoglobulin (Ig) fraction from Graves' sera is increased if these fractions are prepared with higher than usual concentrations of polyethylene glycol (PEG; 22.5% rather than 13.5%), leading to the suggestion that additional factors might exist in serum which influence the ability of autoantibodies to stimulate thyroid cells.