Clinical validity of intercellular adhesion molecule-1 (ICAM-1) and TSH receptor antibodies in sera from patients with Graves' disease

Abstract

We compared the concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and the activities of thyroid-stimulating antibodies (TSAb) and thyrotropin-receptor antibodies (TBIAb) as measured with a commercial kit (TRAK). Sera were obtained from patients with Graves' disease (GD) before, during and after therapy with carbimazole (1-methyl-2-thio-3-carbethoxyimidazole). In all the situations, TSAb method was more sensitive than TBIAb. These two parameters dropped during therapy and were not correlated at any stage of measurement. sICAM-1 levels increased in 56.4% of patients before treatment, remained elevated at the beginning of treatment and decreased after twelve months of therapy. TSAb levels were significantly different between patients in relapse (78%) and those in remission (18%) ( Z=−2.250, P = 0.025), with a relapse rate depending on the TSAb positivity ( χ 2 = 7.103, P = 0.0077). Positive sICAM-1 values were found in 3 of the 9 (33.3%) patients who relapsed after discontinuing the drug but were negative in all the patients remaining in remission with a significant difference ( Z = −1.982, P = 0.0475). The relapse rate was also dependent on positive sICAM-1 values ( χ 2 = 3.958, P = 0.0466). No correlation was found between sICAM-1 levels and anti-TSH receptor antibodies TSAb or TBIAb. We conclude that the TBIAb technique is too insensitive to explore GD. TSAb and sICAM-1 assays in patients with GD are good markers of immune process after treatment withdrawal. Because of its rapid implementation, the sICAM-1 assay may advantageously replace TSAb measurement for forming a prognosis of GD.