Thyrotropin receptor antibodies detected by the human recombinant TBII assay--a surrogate marker for autoimmune activity in Graves' ophthalmopathy?
BACKGROUND
Recently a new very sensitive and specific commercial method for detection of TSHR-Ab has become available: TBII assay using human recombinant TSHR. The aim of this study was to assess the potential of this novel TBII assay as a guideline for immunosuppressive therapy in patients with Graves' ophthalmopathy (GO).


METHODS
We detected serum TBII level in three groups of subjects: 17 patients with clinical symptoms of GO, 14 patients with Graves' disease without ophthalmopathy (Gd), and 13 healthy volunteers. Corticosteroid therapy consisted of intravenous infusions of methylprednisolone (MP) and subsequent treatment with oral prednisone (P). Serum samples were collected 24 hours before MP, 24 hours after MP, after 14 days of P treatment and after the end of corticosteroid therapy.


RESULTS
The levels of TBII were significantly increased in both GO and Gd individuals as compared to the controls (p<0.001 and p<0.01 respectively). There was also a significant difference in serum TBII between GO and Gd patients (p<0.01). We observed elevated pretreatment TBII serum levels in corticosteroid-resistant individuals as compared to corticosteroid- responsive patients. Corticosteroids caused a significant decrease in TBII serum levels in GO patients.


CONCLUSIONS
The lack of clinical improvement despite decreased TBII level in our study suggests that the humoral immune response is not crucial in the pathogenesis of early GO. However, measurement of TSHR-Ab by the novel h-TBII assay may have prognostic value in the treatment of patients with severe GO as a surrogate marker of autoimmune activity.
Myśliwiec
Janusz
J
Department of Endocrinology, Diabetology and Internal Diseases, Medical Academy of Białystok, Poland. mysjan@poczta.onet.pl
Kretowski
Adam
A
Stepień
Agnieszka
A
Mirończuk
Katarzyna
K
Kinalska
Ida
I
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000276:immunology*; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use; D011989:Receptors, Thyrotropin / Q000097:blood / Q000276:immunology*; D011994:Recombinant Proteins / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D011989:Receptors, Thyrotropin; D011994:Recombinant Proteins; C094372:thyrotropin-binding inhibitory immunoglobulin; D011241:Prednisone; D008775:Methylprednisolone