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De Riva, Mestre-Venezia, Italy, found that Na+K+-ATPase activity
in red cells was reduced in 24 patients with untreated Graves' disease.
Upon thionamide treatment ATPase activity was normalized in all patients
after a mean period of 180 days. Antithyroid treatment was stopped after
biochemical and clinical euthyroidism was reached (mean period 304 days)
and at day 450 Na+K+-ATPase activity was again determined. It was reduced
in 8 subjects, who all had a recurrence of Graves' disease, whereas in
the other 16 patients it was normal and none of these patients experience
a relapse (follow-up after treatment 2 yrs.) . It is concluded that determination
of Na+K+-ATPase activity in erythrocytes represents an early marker of
relapse of hyperthyroidism before biochemical and clinical evidence. (Comment:
These are preliminary results in a small number of patients. The findings
however are interesting and studies should be conducted in larger series
of patients.)
Aizawa, Sendai, Japan, studied TBII in Graves' disease at different times after treatment with radioactive iodine. In total 225 patients (158 females) were studied. TBII was detected in 78% of patients. The mean pre-treatment value was 42%, after one year treatment 50%, after two years 19%, after three years 10% and after four years 8%. The longer after 131I treatment the lower was the relapse rate for hyperthyroidism and the higher the incidence of hypothyroidism. The pre-treatment TBII value was significantly higher in those patients who relapsed (46%) as compared to those who became eu- or hypothyroid after treatment (34%). The incidence of relapse hyperthyroidism after 131I treatment in patients with negative TBII was 7% and in patients with positive TBII 29%. No correlation with regard to outcome of treatment was found with regard to antibodies against TG and TPO. A similar study, but then with regard to methimazole treatment, was conducted by Matsubayashi, Kobe, Japan. He reported in 94 thyrotropin receptor antibodies (TRAb) negative patients and in 83 TRAb positive patients after a mean methimazole treatment of 36 months and a mean follow-up of 12 months a remission rate of 66 % and 37 % respectively. Thirteen patients of the TRAb negative group became positive during treatment and only 35 % remained in remission, whereas the patients, who remained TRAb negative, had a remission rate of 77 %. The pre-treatment thyroid volume and free T4 and T3 levels in the TRAb negative patients was significantly lower than in the TRAb positive patients. (Comment: The previous and this communication confirms as in many other studies that measurement of thyroid stimulating immunoglobulins (TSI) has some meaning in the prediction of outcome after treatment in groups of patients. However, it is still questionable if measurements of TBII, TRAb or any other parameter for thyroid stimulating immunoglobulins in individual patients is meaningful in this sense. Patients do still relapse when immunoblobulins cannot be detected and stay in remission in the presence of these immunoblobilins.) Gupta, Cleveland, OH, USA, studied before and after 131I treatment in 18 patients TRAb, TSI and TBII, and assessed ophthalmic Graves' disease (OGD). They found a significant correlation between pre- and post-treatment (2 and 6 months) values of TRAb and TBII, but not with TSI. TRAb and TBII increased after treatment, and TSI decreased but this may be due to interference in the FRTL5 assay by (the increased) TBII. Expression of OGD did not change post treatment. De la Rosa, Providence, RI, USA, prospectively measured body mass index (BMI) in 67 patients (53 female) between 15-88 yrs. after RAI treatment for Graves' disease. They found that BMI increase was maximally between 13-18 months post 131I treatment. It appeared that the greatest increase in BMI occured in patients with lowest baseline BMI and that those patients that did not show posttreatment BMI increase, were most likely overweight at the time of 131I therapy. |
