Significance of tissue specific and tissue non specific autoimmune reactions of Graves' disease.

The relationship between the many immunologic abnormalities demonstrated in the peripheral blood of patients with Graves' disease (GD) and the broad spectrum of clinical features with which patients may present has not yet been addressed in detail. In this review we examine the evidence to support the notion that GD could be considered a multi-system autoimmune disorder in which tissue damage is restricted to the thyroid gland, connective tissue of the skin and orbit, extra-ocular and other skeletal muscles and, possibly, the lacrimal glands. Apart from the well recognized reactions of autoantibodies and sensitized T lymphocytes with epitopes on the thyroid specific TSH receptor, thyroid peroxidase and thyroglobulin, in patients with hyperthyroidism, there is also good evidence for autoantibody and, to a lesser extent, T lymphocyte reactivity with several eye muscle, other skeletal muscle and connective tissue, antigens in patients with ophthalmopathy, systemic myopathy, dermopathy and acropachy. There is also some evidence for immunoreactivity against lacrimal gland antigens in patients with ophthalmopathy associated with other features of GD. There are, in addition, a variety of organ non-specific reactions in GD; antinuclear antibodies are detected in serum from about one-third of patients with hyperthyroidism and ophthalmopathy, while from 5% to 10% have antibodies reactive with several other ubiquitous tissue proteins. Cloned proteins which are autoantigenic in some patients with hyperthyroidism or Hashimoto's thyroiditis and ophthalmopathy include collagen XIII, nebulin, the calcium binding protein calmitine, and the Mac-II antigen. All antibodies reactive with eye muscle antigens, except the 64 kDa protein which is also expressed in the thyroid, cross react with the same, or a related, protein in other skeletal muscle. Future research should focus on the underlying mechanisms for this broad loss of tolerance to self antigens and the effect of environmental factors such as stress, radioiodine and viral infection of the thyroid gland and other target tissues, in precipitating disease.