Soluble CD antigen (cytokine) expression in various hyperthyroid states and use in the assessment of propylthiouracil treatment.

The soluble CD antigens sCD8, sCD23, and sCD25 are increased in untreated Graves' hyperthyroidism. These levels remain elevated when euthyroidism is established in response to propylthiouracil (PTU) therapy but decrease to control values after PTU treatment is discontinued, when euthyroidism has been established and maintained. Neither sCD8 nor sCD23 are elevated in patients with euthyroid Graves' ophthalmopathy nor in the hyperthyroid phase of subacute thyroiditis. sCD25 is increased to an intermediate degree in these disorders. Soluble CD8 > or = 450 U/ml is sensitive, specific, and predictive of PTU success as sole therapy or need for definitive therapy in untreated and PTU-treated Graves' hyperthyroidism, exceeding the predictive values of thyroid-stimulating hormone receptor antibody, thyroid peroxidase antibody, and T3 radioimmunoassay.