Presence of Thyroid-Stimulating Immunoglobulins (TSI) in DR3 Positive Normal Individuals
With the method of thyroid epithelial cell culture (TEC) that we developed in mice , monolayers of human TEC (HTEC) were used to detect thyroid- stimulating immunoglobulins (TSI) in a functional assay of cyclic AMP (cAMP) production. Under these experimental conditions, we previously demonstrated the presence of TSI in 92% of untreated Graves disease (GD) patients and their disappearance 6 months after neomercazole treatment in 55% of the GD patients . In this study, TSI positivity was evaluated as the percentage of response when DEAE-trisacryl-purified IgGs from normal subjects were deposited onto HTEC for cAMP production. Among the 32 samples provided by the blood bank and used as controls, we found four TSI-positive subjects with euthyroid status.