Cryopreserved human thyroid tissue for TSAb determination: comparison with fresh tissue

A thyroid-stimulating antibody assay using human normal thyroid slices was performed for studying whether the cryopreservation technique produced a sensitive substrate for cyclic-AMP generation. Cryopreservation was carried out in sterile 15% glycerol 0.9% NaCl placed in a hexane-nitrogen bath at -196 degrees C and stored at -80 degrees C for 1-5 weeks. Dose-response curves for untreated Graves' hyperthyroid patients IgG and bovine TSH were similar using fresh and cryopreserved slices. Assay sensibility was 5 mU/ml TSH. A high correlation (r = 0.91; p less than 0.001; n = 41) was found for percentage of cyclic-AMP increase to b-TSH and Graves' IgG comparing both methods. Studying 19 Graves' hyperthyroid patients, positive results were found in 63 and 52% for fresh and cryopreserved slices respectively. The cryopreservation technique used in the study was efficient for TSAb determinations.