TSH-receptor autoantibodies in patients with chronic thyroiditis and hypothyroidism.

OBJECTIVES: The reported prevalence of TSH-receptor (TSHR) autoantibodies (TRAb) in patients with chronic thyroiditis (CT) range from 0 to 48%. The objective was to study the prevalence of TRAb in patients with CT and hypothyroidism and to correlate it with gender, age, thyroid dimensions, TSH levels, and autoimmune diseases. METHODS: The study comprised 245 patients with CT and hypothyroidism (median age 42 years, 193 females, 52 males) and 123 Italian healthy subjects matched for sex and age as controls. TRAb were tested with ELISA using a >2.5 IU/L cut off for positivity. TSHR blocking (TBAb) and TSHR stimulating autoantibodies (TSAb) were measured in 12 TRAb-positive patients using bioassays with Chinese hamster ovary (CHO) cells expressing wild-type or R255D-mutated TSHR. RESULTS: TRAb positivity was found in 32/245 (13.1%) patients and significantly correlated (p<0.05) with TSH levels. TRAb positivity was significantly higher in males vs. females (p=0.034), in females 16-45 years of age vs. >45 years of age (p<0.05) and in patients with reduced vs. normal/increased thyroid dimensions (p<0.05). Linear regression analysis showed a correlation between TRAb concentrations with age (p<0.05) and TRAb concentrations with TSH (p<0.01). In bioassay with TSHR-R255D all 12 patients tested were TBAb-positive while 33% were also TSAb-positive suggesting the presence of a mixture of TRAbs with different biological activities in some patients. CONCLUSIONS: TRAb have been found in patients with CT and hypothyroidism. A mixture of TBAb and TSAb was found in some patients and this may contribute to the pathogenesis of thyroid dysfunction during the course of the disease.

The natural history of autoimmune Addison's disease from the detection of autoantibodies to development of the disease: a long-term follow-up study on 143 patients.

BACKGROUND: Adrenal cortex autoantibodies (ACAs) and/or 21-hydroxylase (21OHAb) are markers of autoimmune Addison's disease (AAD) and progression to overt AAD. The reported cumulative risk of developing AAD varies from 0 to 90% in different studies. AIM: To assess the predictive value of different parameters in the progression toward AAD in patients with ACA and/or 21OHAb-positive patients with autoimmune polyendocrine syndromes (APS). MATERIALS AND METHODS: Twenty-nine patients with APS-1 and 114 patients with APS-2 or APS-4 were followed up for a median of 10 years (range 6 months to 33 years) and were assessed using ACTH test. The risk of AAD was estimated according to age, gender, stage of adrenal dysfunction, associated diseases and antibody titer. Univariate and multivariate Cox proportional hazard models were used for statistical analysis. RESULTS: The cumulative risk (CR) of developing AAD was higher in APS-1 patients (94.2%) than in patients with APS-2/APS-4 (38.7%). The CR was high in both male and female APS-1 patients, while in patients with APS-2/APS-4 it was high only in males. Stage 1 (increased plasma renin) for patients with APS-1 and Stage 2 (no response of cortisol to ACTH test) for patients with APS-2/APS-4 were established as the points of no return in the progression to AAD. Adjusted hazard ratio analyses by multivariate Cox model for AAD showed that gender, diseases and adrenal function were independent risk factors for developing clinical AAD. The risk of developing clinical AAD appears to subside after 19 years of follow-up. CONCLUSIONS: A model for estimating the probability to survive free of AAD has been developed and should be a useful tool in designing appropriate follow-up intervals and future therapeutic strategies.

Improved salivary cortisol rhythm with dual-release hydrocortisone

Introduction and Aim: The purpose of replacement therapy in adrenal insufficiency (AI) is mimicking endogenous cortisol levels as closely as possible: dual release hydrocortisone (DR-HC) has been introduced to replicate the circadian cortisol rhythm. Multiple daily saliva collections could be used to assess the cortisol rhythm during real life: our aim was to study the salivary cortisol profile in AI. Materials and Methods: We prospectively evaluated, in an observational study, 18 adult outpatients with AI (11 primary and 7 secondary AI), switched from conventional treatment (conv-HC, 25 mg/day) to the same dose of DR-HC. We collected six samples of saliva in a day, measuring cortisol (F) and cortisone (E) with LC-MS/MS. Forty-three matched healthy subjects served as controls. Results: F levels were similar in the morning (and higher than controls) in patients treated with conv-HC or DR-HC; otherwise F levels and exposure were lower in the afternoon and evening in patients with DR-HC, achieving a cortisol profile closer to healthy controls. Daily cortisol exposure, measured with area under the curve, was lower with DR-HC. Morning F and E presented sensitivity and specificity >90% to diagnose AI (respectively threshold of 3 and 9.45 nmol/L). Total cholesterol and HbA1c levels reduced with DR-HC. Conclusions: Salivary cortisol daily curve could be used as a new tool to assess the cortisol profiles in patients treated with conv-HC and DR-HC. A lower daily cortisol exposure was achieved with DR-HC (despite the same HC dose), especially in the afternoon-evening.