The phenotype of Graves' orbitopathy is associated with thyrotropin receptor antibody levels

PURPOSE

Graves' orbitopathy (GO) is a specific inflammatory disorder of the orbit characterized by a highly heterogeneous clinical phenotype. The role of thyrotropin receptor antibodies (TSH-R-Ab) has been widely researched, however there is still no evidence that these antibodies have a direct pathogenic role in this pathology. The aim of this study was to examine their relation to the individual clinical features of GO.

METHODS

Ninety-one consecutive patients with GO were recruited. Total antibody concentration (TSH-R binding inhibitory immunoglobulins, TBII) and their functional activity (stimulating TSH-R-Ab, TSAb) were measured using binding immunoassay and cell-based bioassay, respectively.

RESULTS

Both TSAb and TBII levels were significantly associated to the clinical parameters of GO activity. TSAb was a more sensitive serological marker compared to TBII pertaining to eyelid retraction and edema, proptosis, extra-orbital muscle disorders, diplopia, irritable eye symptoms, and photophobia. TSAb, but not TBII, was a significant predictive marker of conjunctival redness, chemosis, caruncle/plica inflammation, eye irritation, and orbital pain, (odds ratio: 3.096, p = 0.016; 5.833, p = 0.009; 6.443, p = 0.020; 3.167, p = 0.045; 2.893, p = 0.032; versus 2.187, p = 0.093; 2.775, p = 0.081; 3.824, p = 0.055; 0.952, p = 0.930; 2.226, p = 0.099, respectively). Neither TSAb nor TBII correlated with the level of proptosis (ρ = 0.259, p = 0.090, and ρ = 0.254, p = 0.104, respectively), however rising TSAb levels were strongly associated to the level of proptosis.

CONCLUSIONS

TSH-R-Ab were significantly associated with GO's phenotype. Especially TSAb, as a sensitive and predictive serological biomarker, can improve diagnosis and management of GO.

Clinical value of functional thyrotropin receptor antibodies in Serbian patients with Graves' orbitopathy

PURPOSE

Thyrotropin receptor autoantibodies (TSH-R-Ab) are heterogeneous in their biological function and play a significant role in the pathophysiology of both Graves' disease and Graves' orbitopathy (GO). The clinical significance and utility of determining functional TSH-R-Ab in a Serbian collective were evaluated.

METHODS

91 consecutive patients with GO were included in this study. Total TSH-R-Ab concentration, referred to as TSH-R binding inhibitory immunoglobulins (TBII) was detected using a competitive-binding immunoassay. Stimulating and blocking TSH-R-Ab (TSAb and TBAb) were measured with cell-based bioassays.

RESULTS

Stimulating TSAb activity and TBII positivity were detected in 85 of 91 (93.4%) and 65 of 91 (71.4%) patients with GO (P < 0.001). Blocking TBAb activity was observed in only one patient who expressed dual stimulating and blocking TSH-R-Ab activity. The sensitivity rates for differentiating between clinically active versus inactive and mild versus moderate-to-severe GO were 100% and 100% for TSAb, respectively. In contrast, these were 82% and 87% only for TBII. Seven of eight (87.5%) and one of eight (12.5%) euthyroid patients with GO were TSAb and TBII positive, respectively (P < 0.031). TSAb serum levels significantly predicted GO activity compared to TBII (odds ratio, OR, 95%CI: 3.908, 95%CI 1.615-9.457, P = 0.003; versus 2.133, 0.904-5.032, P = 0.084, univariate analysis; and OR 4.341, 95%CI 1.609-11.707, P = 0.004; versus 2.337, 0.889-6.145, P = 0.085 multivariate analysis).

CONCLUSION

Stimulating TSAb are highly prevalent in patients with GO and show superior clinical characteristics and predictive potential compared to the traditionally used TBII.

Changes in the plasma levels of protein C system parameters in pregnancy

Resistance to activated protein C (APC) is a condition that leads to a hypercoagulative state with an increased risk for venous thrombosis. The aim of this study was to test the functionality of the protein C system in normal and complicated pregnancies and APC resistance. A total of 131 patients were tested, including pregnant women with normal and complicated pregnancies at different periods, e.g. from weeks 1 to 20, 21 to 30 and 31 to 38 of gestation. The following hemostatic parameters were determined: protein S, protein C, protein C Global and protein C APC sensitivity. Commercial "Behring" tests were used to determine the parameters of hemostasis. The values for protein C activity were within normal limits. Protein S values were below the lower limits. Significantly lower PC-NR (protein C normalized ratio) and APC-NR (activated protein C normalized ratio) values were found in all three of the gestation periods in pregnant women with a history of repeated miscarriages and hypertension in relation to pregnant women with normal pregnancies. In order to assess the diagnostic accuracy of investigated hemostatic parameters as markers of prethrombotic changes in pregnant women, the obtained values of investigated hemostatic parameters were evaluated by ROC analysis. PC-NR and APC-NR showed satisfactory diagnostic accuracy as markers of prethrombotic changes in pregnant women: more precisely, they were found to be good indicators of resistance to activated protein C in pregnancy.

Reticulocyte haemoglobin content vs. soluble transferrin receptor and ferritin index in iron deficiency anaemia accompanied with inflammation

Ferritin concentration, as a parameter of iron status that is commonly used in the diagnosis of iron deficiency anaemia (IDA), often has limited values if the iron deficiency is accompanied by inflammatory disease. This study evaluated the value of reticulocyte haemoglobin content (CHr) and soluble transferrin receptor-ferritin index (sTfR/F) in the diagnosis of IDA and differential diagnosis of IDA and anaemia of chronic disease. The study included 66 nonanaemic individuals as controls, 86 patients with IDA divided into noninflammatory and inflammatory subgroups, and 32 patients with anaemia of chronic disease. Blood count, iron, transferrin saturation, total iron binding capacity, ferritin, C-reactive protein, sTfR and CHr were determined. Receiver operator characteristic curve analysis showed very high discriminating power for CHr, soluble transferrin receptor (sTfR) and sTfR/F in the diagnosis of IDA. In patients with anaemia of chronic disease these parameters showed no significant difference from the control. CHr and sTfR enabled recognition of iron deficiency and were not affected by acute phase reaction. They are sensitive markers of body iron status with additional value to conventional tests for the detection of iron deficiency.

Biochemical evaluation of patients with acute pancreatitis

In this study we determined the clinical accuracy of alpha2-macroglobulin, alpha-amylase, C-reactive protein, lipase, non-esterified fatty acids, pancreatic alpha-amylase and phospholipase A in the diagnosis and prognosis of acute pancreatitis in a group of patients with acute abdominal pain using receiver operator characteristic curve analysis. We investigated 59 patients with acute pancreatitis and 72 patients with extrapancreatic diseases of gastrointestinal origin. On the basis of initial enzyme activities, at cut-offs of 245 U/l for amylase, 656 U/l for lipase, and 182 U/l for pancreatic alpha-amylase, the diagnostic efficiencies were 0.993, 0.980, and 0.975, respectively. Receiver operator characteristic curve analysis showed the same diagnostic accuracies. We evaluated the accuracy of serum alpha2-macroglobulin, C-reactive protein, non-esterified fatty acids and phospholipase A for differentiation between acute necrotizing pancreatitis and acute oedematous pancreatitis. C-reactive protein had the highest prognostic accuracy of the parameters studied (the area under curve = 0.9082) and at a cut-off value of 126 mg/l, sensitivity and specificity were 0.759 and 0.912, respectively. The role of the clinical laboratory in the investigation of patients with acute pancreatitis continues to evolve and biochemical parameters are a good diagnostic and prognostic option.