Reactivity of anti-thyroid antibodies to thyroglobulin tryptic fragments: comparison of autoimmune and non-autoimmune thyroid diseases

Abstract

Studies concerning the antigenicity of thyroglobulin fragments allow the characterization of the epitopes but do not consider the role of heavier antigenic fragments that could result in vivo from the action of endoproteases. Here we assess the relative importance of the fragments obtained from thyroglobulin by limited proteolysis with trypsin and compare by immunoblotting their reactivity to serum from patients with autoimmune (Graves disease and Hashimotos thyroiditis) and non-autoimmune (subacute thyroiditis) disease. The results showed no difference in frequency of recognition of any peptide by sera from patients with autoimmune thyroiditis. In contrast, sera from patients with subacute thyroiditis reacted more frequently with a peptide of 80 kDa. These results suggest the presence of antibody subpopulations directed at fragments produced in vivo by enzymatic cleavage of thyroglobulin. This fragment and antibodies to it may represent markers for subacute thyroiditis.

Hashimoto’s Thyroiditis Presents as an Acute Encephalopathy: A Case Report of Unusual Presentation

“…Anxiety, depression, hypersomnia, and difficulty initiating sleep are initial presenting symptoms [ 11 ]. Depression, anxiety, emotional lability, and social withdrawal have been reported as sole symptoms [ 12 ].…”

“…Neuroimaging studies, EEG, and CSF analysis can be supportive but not diagnostic. A detectable level of ATA must be present to consider HE [ 12 ]. Analysis of CSF should be performed; the most common findings are elevated proteins and less commonly pleocytosis [ 13 ].…”

A Case of Steroid-Responsive Encephalopathy

“…Anxiety, depression, hypersomnia, or difficulty initiating sleep can be the initial presenting symptom [ 9 ]. Depression, anxiety, social withdrawal, and emotional lability as sole symptoms have also been reported [ 10 ].…”

“…Variable presentations make an already difficult diagnosis even more difficult. A detectable level of anti-thyroid antibodies must be present for diagnosis [ 10 ]. If high serum levels of these antibodies are found, cerebrospinal fluid should also be evaluated for elevated protein (a nonspecific marker of inflammation that can be observed in patients with underlying endocrine abnormalities).…”