Statins decrease the aberrant HLA-DR expression on thyrocytes from patients with Hashimoto's thyroiditis

Statins have been found to exert anti-inflammatory and immune modulatory effects. It seems likely that these drugs may improve thyroid function in patients with Hashimoto's thyroiditis (HT). The objective of our study was to investigate the effect of statins on HLA-DR (human leukocyte antigen D-related) expression of thyrocytes from patients with HT hypothyroidism. Thyroid tissues were obtained from surgical specimens. Thyrocytes were cultured in the presence or absence of IFN-gamma (50 ng/ml) with or without statins (simvastatin 10 microM or atorvastatin 10 microM) for 72 hours. HLA-DR expression was detected by flow cytometry. Normal thyrocytes were used for controls. HLA-DR expression of HT thyrocytes was much higher than that of normal thyrocytes (41.2+/-4.5% vs. 2.7+/-2.1%, p<0.01), which could be further increased by IFN-gamma stimulation in both groups (p<0.01). However, simvastatin and atorvastatin could significantly inhibit the "aberrant" HLA-DR expression on HT thyrocytes and decrease IFN-gamma- induced HLA-DR expression in both HT and normal thyroid cells (p<0.01). Statins can repress HLA-DR expression of HT thyrocytes, which might inhibit the subsequent lymphocyte activation and ameliorate the immune disturbance of HT.