Improved prediction of relapse of Graves' thyrotoxicosis by combined determination of TSH receptor and thyroperoxidase antibodies.
BACKGROUND
Recently, we and others have demonstrated that high levels of auto-antibodies to the human TSH-receptor (TRAb) predict relapse of hyperthyroidism in Graves' disease (GD). Our objective was to extend the outcome of the prediction by combining TRAb with thyroperoxidase antibody (TPO-Ab) measurement.


METHODS
One hundred and thirty-one GD patients (118 females, 13 males) were analysed, of whom 94 patients (71.8%) had relapse, whereas 37 (28.2%) went into remission. Second generation TRAb and TPO-Ab assays were performed in GD patients with relapse and remission in mean 4.3 months after initial diagnosis.


RESULTS
The mean anti-TPO-Ab levels were similar in all patients with relapse and remission. However, there was a steady decline from 4047 U/ml to 530 U/ml in the remission group that correlated positively with TRAb values (>2 to >10 IU/l). The relapse group remained at consistently high levels. The positive predictive value (PPV) for relapse in patients with TRAbs >6 IU/l and anti-TPO-Abs >5000 U/ml was 100, whereas TRAbs >6 IU/l and anti-TPO-Abs >500 U/ml were associated with a PPV of 93.7 up to 96 (p=0.008). These Ab constellations accounted for about one third of all GD patients. For patients with TRAbs between >2 and <6 IU/l the PPV was 66.7-90.0.


CONCLUSIONS
Our follow-up analysis indicates that the prediction of relapse of GD can be improved by a combined measurement of TRAb and TPO-Ab. In patients with moderately increased Abs, determined about 6 months after initial diagnosis, an ablative therapy can be approached without delay.
Schott
M
M
Department of Endocrinology, Diabetes and Rheumatology, University Hospital Duesseldorf, Duesseldorf, Germany. schottmt@uni-duesseldorf.de
Eckstein
A
A
Willenberg
H S
HS
Nguyen
T-B-T
TB
Morgenthaler
N G
NG
Scherbaum
W A
WA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis*; D005260:Female; D006111:Graves Disease / Q000175:diagnosis*; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011989:Receptors, Thyrotropin / Q000276:immunology*; D012008:Recurrence; D013971:Thyrotoxicosis / Q000175:diagnosis*
D001323:Autoantibodies; D011989:Receptors, Thyrotropin; D007453:Iodide Peroxidase