SIGNIFICANCE OF ANTITHYROGLOBULIN AUTOANTIBODIES IN DIFFERENTIATED THYROID-CARCINOMA

The incidence of antithyroglobulin autoantibodies (ATA) was 17.7% in 9 63 patients (who attended the clinic from 1981 to 1990) with different iated thyroid carcinoma (DTC). Another 12 patients developed ATA for a transient period after the treatment with radioiodine. The prevalence of ATA in females (21.5%, 123/572) was significantly higher (p < 0.00 1) than that seen in males (12.0%, 47/391). Age-dependent occurrence o f ATA was not seen for the various age decades. The ATA was more preva lent (p < 0.01) with the papillary type of tumor (118/564) as compared to the follicular variety (51/398). ATA did not influence the metasta tic spread of the tumor at the initial presentation (105/170 for the A TA-positive group and 445/793 for the ATA-negative group). However, wi thin the group with metastases, 82.9% (87/105) of patients had local s pread into the neck in the presence of ATA, which was significantly hi gher (p < 0.01) than that seen for patients without ATA (63.8%, 284/44 5). For assessment of the influence of ATA on the outcome of the disea se, the data from 222 patients (46 positive and 176 negative for ATA), with a minimum follow-up of 5 years (mean follow-up of 7.4 years), wa s considered suitable for analysis. The outcome of the disease was com parable in the presence and the absence of ATA (38/46 and 137/176 pati ents became disease-free in ATA-positive and -negative groups, respect ively). Of the 46 patients with circulating ATA, antibodies disappeare d or decreased in all 38 patients who became disease-free as compared to 8 patients (p < 0.001) with persistent disease; ATA disappeared in 5 but remained unchanged in 3 of these patients. From this study we co nclude (a) ATA is more prevalent in females and in papillary type of t umors, (b) the occurrence of ATA in patients with DTC is not age depen dent, (c) the presence of ATA does not restrict or promote the metasta tic spread of the tumor, (d) there is a tendency for local metastases in the presence of ATA, (e) ATA does not protect or worsen the progres s of the disease, and (f) the persistence of antibodies is indicative of functioning thyroid tissue.