Thyrotropin receptor autoantibody measurement following radiometabolic treatment of hyperthyroidism: comparison between different methods.

BACKGROUND: TSH receptor antibodies (TRAb) play a crucial role in the pathogenesis of Graves' disease (GD). The use of human recombinant TSH-receptor far improved the analytical performance of TRAb assays (2nd-generation assays). The 3rd-generation assay is based on the inhibition of binding of a human biotin-labeled monoclonal thyroid- stimulating antibody (M22) to TSH-receptor by the autoantibodies present in the serum. AIM: We aimed to assess the ability of the 2nd- and 3rd-generation assays to detect serum TRAb following radioiodine therapy for hyperthyroidism. METHODS: Sera from 47 hyperthyroid (25 autoimmune, 22 non-autoimmune) patients were tested using the two different assays before and at different time intervals after radioiodine therapy. The modifications of TRAb were evaluated, as well as the correlation between the two methods. RESULTS: The results obtained by the two methods proved to be closely correlated. A rise in TRAb was invariably observed in GD patients following radioiodine, with a median peak at 6 months, irrespective of their initial clinical status, presence of ophthalmopathy, smoking habits or other variables. Such a rise was nearly superimposable using both methods. No TRAb appearance was observed in patients with non-autoimmune hyperthyroidism. CONCLUSIONS: The use of methods of higher sensitivity with respect to that formerly used indicate that nearly all GD patients develop TRAb following radioiodine, and that this phenomenon is transient and not related to baseline conditions and clinical outcome/efficacy of treatment.

Esophageal hyperalgesia in patients with ulcerative colitis: role of experimental stress.

OBJECTIVES: Intestinal inflammation is associated with enteric nervous system alterations, at both inflamed and noninflamed sites. The perception of stimuli from the GI tract is enhanced during inflammatory conditions, but it is unknown whether visceral hypersensitivity is limited to the inflamed area or diffuse throughout the entire GI tract. Moreover, although stress can reactivate inflammatory processes in the gut, it is unknown if this can alter perception from the GI tract. Our aim was to determine if patients with ulcerative colitis (UC) have increased esophageal sensitivity to distention and whether this is modified by experimental stress. METHODS: Ten UC patients and 12 healthy volunteers (HVs) underwent gradual balloon distension of the esophagus to assess their visceral sensitivity. Perceptive and pain thresholds were evaluated in basal conditions and after induction of experimental stress (cold water pressure test) while blood pressure and heart rate were monitored. RESULTS: Patients with UC had perceptive thresholds to distension similar to HVs (14.8+/-2.0 ml of air vs 14.5+/-3.0 ml); in contrast, the volume increment needed to evoke pain was significantly lower in UC patients than in HVs (58.9% vs 149.9%, p < 0.05). Physical stress caused a similar decrease in perceptive thresholds in HVs (-29.1+/-8.4%) and patients (-17.7+/-9.1%), but pain thresholds were significantly decreased only in HVs (-28.3+/-7.1% vs -11.5+/-12.3%). CONCLUSIONS: UC is characterized by increased esophageal sensitivity, indicating the existence of diffuse hyperalgesia during intestinal inflammatory processes. This increased sensitivity may account for the frequent upper GI symptoms these patients complain of when in clinical remission.