c-myc expression in the thyroid. II: Thyrocytes and peripheral and intrathyroidal lymphocytes from patients with...

Enhanced oncogene expression observed in lymphocytes from patients with systemic lupus erythematosus has suggested the importance of studying oncogene expression and regulation in the cellular events of autoimmune thyroid diseases (AITD). The present study examines oncogene expression in peripheral and intrathyroidal lymphocytes from patients with Hashimoto's disease (HD) and Graves' disease (GD). Intrathyroidal lymphocytes from a patient with primary thyroid lymphoma were also examined. Lymphocytes were isolated by Ficoll-Hypaque gradients, and total RNA was prepared by extraction with guanididium thiocyanate and ultracentrifugation through a cesium chloride cushion. RNA concentrations were determined by O.D. readings at 260/280 nm and each sample subjected to gel electrophoresis with ethidium bromide staining to assure the integrity of the RNA. 30 micrograms total RNA was size fractionated on a 1% (w/v) agarose/formaldehyde gel and transferred to nylon membranes. These membranes were hybridized with nick-translated 32P labelled c-myc DNA (exon III), washed at high stringency and subjected to autoradiography. Specific bands were quantitated by scanning densitometry. Five RNA samples from GD thyroids had 2.4 Kb bands corresponding to c-myc with a mean O.D. (+/- SD) of 0.76 +/- 0.23, whereas 7 from normal thyroid glands had mean O.D. of 1.0 +/- 0.26. Peripheral lymphocytes from 7 GD patients had a mean O.D. of 1.41 +/- 0.25, 4 HD patients had a mean O.D. of 1.05 +/- 0.10 and 2 normal patients had a mean O.D. of 1.4 +/- 0.14. The readings for a sample obtained from intrathyroidal lymphocytes of a patient with HD and thyroid lymphoma were 1.0 and 1.4, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)