INCREASED SERUM NEOPTERIN LEVELS IN PATIENTS WITH GRAVES-DISEASE

Neopterin (NPT) a marker of activation of the T-lymphocyte/monocyte ax is has been measured in serum of 89 patients with autoimmune thyroid d isease (72 patients with Graves' disease and 17 patients with autoimmu ne thyroiditis) and compared to a group of 24 normal controls and 24 p atients with nontoxic goitre. There was a significant correlation betw een NPT levels and age in the patients with nontoxic goitre (r = 0.447 , p<0.001) but not in patients with autoimmune thyroid disease. Signif icantly higher NPT levels were found in all patients with Graves' dise ase (GD) compared to age and sex matched healthy controls, and patient s with nontoxic goitre (5.7 +/- 2.4 vs 4.1 +/- 1.7, and 4.0 +/- 1.5, p < 0.01). However, there was no difference in NPT levels between each group of patients with GD when subdivided in: hyperthyroid newly diagn osed GD, treated GD, GD in remission and relapse. Patients with autoim mune thyroiditis did not have abnormal NPT levels compared to age and sex matched normal controls. Neopterin serum levels were not influence d by hyperthyroidism as no significant differences in NPT levels could be found in 24 patients with hyperthyroid Graves' disease and 13 pati ents with toxic goitre or toxic adenoma when compared to age and sex m atched euthyroid patients with Graves' disease or normal controls. Mor eover, there was no significant difference in mean NPT levels 1. befor e and after restoration of euthyroidism in 10 patients with hyperthyro id Graves' disease and 2. before and under T3 supplementation in 18 pa tients with Graves' disease in remission who underwent a T3 thyroid su ppression test. We conclude that 1. Graves' disease is associated with higher NPT serum levels, however its measurement is not able to diffe rentiate the various clinical states of the disease, 2. thyroid functi on does not affect NPT production in serum and 3. age should be taken into consideration when using NPT serum measurement as marker of immun e activation in thyroid disease.