A quick method to detect circulating anti-thyroid hormone autoantibodies

The aim of this study was to evaluate the feasibility of a chromatographic method to easily detect circulating anti-thyroid hormone autoantibodies (THBA), to calculate their affinity constant and the total thyroid hormone (TH) levels in presence of THBA. This method was applied to sera from 4 subject with suspected THBA and 20 controls (10 normal subjects and 10 patients with thyroid dysfunctions). After a short incubation with 125I-T3 or T4 tracer solution containing 8-anilino-1-naphthalenesulfonic acid as inhibitor of the binding of TH to plasma proteins without affecting THBA binding, the samples were chromatographied on prepacked Sephadex LH 20 columns and eluted with TRIS buffer to separate free TH from THBA-bound TH. Samples were considered THBA positive when radioactivity values in TRIS eluates were higher than in controls. THBA-bound TH were subsequently eluted with methanol and used to calculate the total TH present in patients with THBA. After a validation test using two standardized methods, we propose this method to quickly detect THBA in samples with suspected spuriously high values of free and total TH.