ObjectiveTo investigate Fas,soluble Fas(sFas)and Fas-ligand(Fas-L)gene expression in thyroid tissues and thyrocytes from patients with Graves disease(GD)and to find the interrelationship between apoptosis and pathogenesis of GD.MethodsThyroid tissues were obtained from 7 GD patients and 3 healthy subjects who died accidentally.Thyrocytes were cultured in Eagle′s medium.Total RNA was isolated from thyroid tissues and cultured thyrocytes.The cDNA was prepared by reverse transcription and amplified for Fas,sFas and Fas-L by polymerase chain reaction(PCR).ResultsFas and sFas mRNA were detected in all samples from both GD and normal thyroid tissues and thyrocytes,but Fas-L mRNA was only found in GD thyroid tissues and thyrocytes.Semi-quantitative analysis showed that when compared with those of normal controls,the Fas and sFas mRNA levels were markedly increased in GD thyroid tissues(P<0.01),whereas in GD thyrocytes only the sFas mRNA levels was significantly elevated(P<0.01).ConclusionGene expression of Fas,sFas and Fas-L showed abnormality in both thyroid tissues and thyrocytes from GD.The increased production of sFas might be involved in the hyperplasia of thyroid gland.``