M. Murakami et al., THYMIC HYPERPLASIA IN PATIENTS WITH GRAVES-DISEASE - IDENTIFICATION OF THYROTROPIN RECEPTORS IN HUMAN THYMUS, The Journal of clinical investigation, 98(10), 1996, pp. 2228-2234
Thymic size and density were studied in 23 untreated patients with Gra
ves' disease and 38 control subjects using computed tomography. Both t
hymic size and density were higher in untreated patients with Graves'
disease than in control subjects in the age-matched group. After treat
ment with antithyroid drugs, both thymic size and density were signifi
cantly reduced, with a concomitant decrease in thyrotropin receptor an
tibodies, PCR of human thymic cDNA using primers for human thyrotropin
receptor amplified a fragment in a size expected for the receptor, an
d its nucleotide sequence was identical to human thyrotropin receptor
cDNA in the thyroid, Northern blot analysis of human thymic poly(A)(+)
RNA demonstrated the presence of the full length form of thyrotropin
receptor mRNA, Western blot analysis of human thymic membrane using an
ti-thyrotropin receptor peptide antibodies demonstrated a band of simi
lar to 100 kD that was also observed in the thyroid membrane, Immunohi
stochemistry of thymic tissue using mouse antihuman thyrotropin recept
or monoclonal antibodies demonstrated the immunostaining of epithelial
cells. These results indicate that thymic hyperplasia is apparently a
ssociated with Graves' disease and suggest that thymic thyrotropin rec
eptor may act as an autoantigen that may be involved in the pathophysi
ology of development of Graves' disease.