thymic-factor--circulating and Mediastinal-Neoplasms

Benign thymic hyperplasia (TH) is a known feature of hyperthyroidism. In most cases, thymic enlargement is minimal; however, this syndrome may occasionally appear as an appreciable anterior mediastinal mass. Recognition of the benign nature of TH and its regression following treatment of the hyperthyroidism is important to prevent unnecessary surgical procedures. We present a case of TH associated with hyperthyroidism due to Graves' disease.

Topics: Animals; Antithyroid Agents; Diagnosis, Differential; Female; Graves Disease; Humans; Hyperplasia; Immunoglobulins, Thyroid-Stimulating; Indium Radioisotopes; Magnetic Resonance Imaging; Mediastinal Neoplasms; Methimazole; Radionuclide Imaging; Receptors, Thyrotropin; Somatostatin; Thymic Factor, Circulating; Thymoma; Thymus Gland; Thymus Neoplasms; Young Adult

Lymphoid cells obtained from a mediastinal mass and bone marrow as well as peripheral blood of a patient with poorly differentiated diffuse malignant lymphoma were found to have both E and complement receptors. Addition of the bone marrow lymphoblasts to normal human T-lymphocytes induced a suppression of normal T functional activity as measured by a local xenogeneic graft versus host reaction. Incubation of the same cells with thymic humoral factor (THF), a thymic hormone, reversed their functional activity from suppression to help. Control studies with normal T-suppressor lymphocytes also showed a reversal of function to helper activity upon incubation with THF. In studies of normal T-lymphocytes with monoclonal antibodies, incubation with THF induced no change in phenotype in either theophylline-sensitive (suppressor) cells or theophylline-resistant (helper) cells. The ability of THF to modulate helper and suppressor activities suggests that this or similar agents may provide a useful means of therapy for disorders of immunoregulation.

Topics: Adult; Antibodies, Monoclonal; Bone Marrow; Graft vs Host Reaction; Humans; In Vitro Techniques; Lymph Nodes; Lymphoma; Male; Mediastinal Neoplasms; T-Lymphocytes; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Theophylline; Thymic Factor, Circulating; Thymus Hormones