Affinity of tri-iodothyronine(T3) to lymphocytes in thyroid cancer patients

Peripheral blood lymphocytes (PBL) of thyroid cancer patients and 5 normal subjects were studied for their affinity towards 125I labelled tri-iodothyronine (125I-T3). The mean affinity constant K for PBL of normal subjects was 2.94 + 0.47 x 1011 litre/mole and for thyroid cancer patients was 1.75 + 0.44 x 1011 litre/mole. The binding affinity of the PBL of thyroid cancer patients should have been greater because of (a) lack of thyroid hormones resulting from removal of thyroid gland, and (b) higher levels of thyroid stimulating hormone (TSH) which is known to increase the binding of T3 to the cells. The lowered T3 binding of PBL of thyroid cancer patients is explained on the basis of the morphological changes on the lymphocytes of cancer patients. (auth.)