Apoptosis is a physiological type of cell death; it is active, wellcontrolled genetic program of cell death that does not require the participation of the inflammatory process. It is involved in cell turnover in healthy adult tissues and it is responsible for focal elimination of unwanted cells during normal embryonic development, organ homeostasis, immune regulation and defense without causing stress to the neighboring cells. This study was carried on thirty cases of Grave's disease patients. All were females with a mean age of (29.8 ± 8.3) years. The study parameters were considered as: before treatment, after treatment; when the patient
becomes clinically and biochemically euthyroid after 4-6 weeks of starting treatment with antithyroid drug (carbimazole). The immunomodulatory action of this drug is by increasing the rate of apoptosis of both of intrathyroidal and peripheral blood lymphocytes, disruption of mitochondrial transmembrane potential and also by upregulation of Fas ligand expression, thus attenuates the autoimmune reaction of Fas bearing T lymphocytes. The estimated percentage of apoptosis in peripheral blood lymphocytes after treatment was increased significantly (23.9 ± 5.06) than its percentage before treatment (11.1 ± 1.8) with P value < 0.00001, as detected by DNA-binding flourescent stain (acredine orange). There was a significant increase in peripheral blood lymphocytes apoptosis detected by MitoLight kit; which is a mitochondrial activity marker. The results were (6.7 ± 1.7) and (14.1±2.9) before and after treatment respectively with a P value <0.00001.
There was a significant increase of intrathyroidal lymphocytes apoptosis (21.7±4.2) and (34.7±5.6) before and after treatment respectively with a P value < 0.0001, detected by acredine orange and hematoxylin and eosin stains. T3, T4 and thyroid autoantibody levels decreased significantly, while TSH level increase significantly after treatment. In this study, we aimed to detect the apoptosis of peripheral blood lymphocytes and intrathyroidal lymphocytes in Grave's disease patients before and after treatment with carbimazole and the effect of that on the outcome of the disease. In conclusion, Grave's disease is associated with high rate of apoptosis of both peripheral blood lymphocytes and intrathyroidal lymphocytes. The effect of treatment with antithyroid drug to attenuate the autoimmune reaction is achieved by further increasing in the rate of apoptosis of these T lymphocytes to decrease their stimulatory effect on B lumphocytes, thus decreasing the level of the autoantibodies that are the major stimulators for thyroid gland hyperfunction. This in turn decreases the serum levels of thyroid hormones and modifies the course and outcome of this disorder.