Serum cytokines in autoimmune and toxic multinodular thyroid diseases

ABSTRACT

Measuring serum cytokine levels in patients with Grave's disease, Hashimoto's thyroiditis, toxic multinodular goiter and compared them to a normal control group, to see if there is any correlation between the level of the serum cytokines and the pathophysiology of autoimmune and toxic multinodular thyroid diseases. Serum INF gamma [Th1], IL-10 and IL-4 [Th2] and IL-6 cytokine levels were studied in 26 patients with Graves thyrotoxicosis, 27 patients with goitrous Hashimoto's thyroiditis, 18 patients with toxic multinodular goiter and 40 normal controls. INF-GAMMA was detected in all Graves' and Hashimoto's patients with mean values of 142.11 +/- 29.53 unit/ml and 85.70 +/- 25.86 unit/ml. The mean levels of INF-gamma in Graves was significantly higher compared to Hashimoto's [P<0.001]. IL-10 was detected in all Graves' patients with a mean value of 583.85 +/- 253.35 pg/ml and 19 out of 27 Hashimoto's patients with a mean value of 332.63 +/- 213.20 pg/ml. The level of IL-10 was significantly higher in Graves' than in Hashimoto's [P<0.001]. Both INF gamma and IL-10 were not detected in toxic multinodular goiter or normal individual. IL-4 was significantly elevated in Graves' with a mean value of 132.4 +/- 44.52 but not in any of the other study groups. IL- 6 was detected in the serum of 25 Graves' with a mean value of 496.80 +/- 180.43 pg/ml, 10 Hashimoto's with a mean value of 293.50 +/- 196.61 pg/ml and 10 toxic multinodular goiter patients with a mean value of 228.75 +/- 73.96 pg/ml but not in the serum of normal individuals. The levels of IL-6 was significantly elevated in autoimmune thyroid disease [Graves and Hashimoto's] compared to toxic multinodular goiter [P<0.001]; also IL-6 level was significantly higher in Graves' than Hashimoto's [P <0.001]. The immunopathology seen in both the Grave's disease and goitrous Hashimoto's thyroiditis groups that we studied are related in part to the presence and interplay of mixed Th1 and Th2 cytokines in which there is a down regulation of cytotoxic effect and production of high levels of autoantibodies. The raised level of IL-6 that we observed in autoimmune [Grave's disease and Hashimoto's thyroiditis] and toxic multinodular goiter could be an indication of a long standing inflammatory and destructive process of the diseases