Endocrine Abstracts

Background: Abnormal thyroid autoimmunity is often experienced in thyroid clinic. Some of them are associated with hyperthyroidism (HY) or chronic thyoiditis (Hashimoto, HA). The abnormality, however, is observed not only in HY or HA, but nodular goiter (NOD), and seems to be associated with various factors; age, visiting periods, residence, ABO blood type or others. We analyzed long-term (more than 16 years) data of patients who live in northeast Japan, if there is any characteristics in thyroid immunity.

Patients and methods: 6,578 patients (2007-2022), age 54±16 (3-96); female 83.7%), were examined. Observation period: 7.4±7.1 years (median 5). Nodular goiter was 1,442(solid), cyst(513). HY was 577 and HA was 409. Hormonal assay for Tg, anti-thyroglobulin (aTg), thyroid peroxidase antibody (TPO), anti-TSH receptor antibody (TSH-R) and thyroid stimulating antibody (TS), were performed at their visits. Clinical diagnosis was confirmed by ultrasonography(US) and, if necessary, by fine needle aspiration (FNA); classified 0-5(cancer). Signifiance was determined by Kai2 test or student-t test; P< 0.05 significant.

Results: 1) Correlation analysis: TPO was correlated with aTg, TSH-R, TS. Negative correlation was found with AGE, and positive correlation with ABO blood type (A<B<O<AB; A=30%, AB=58%). aTg was correlated with TPO, but not with TSH-R and TS. TPO positive rate decrease with age (78% in 20-29 years old to16% in 60- years old). 2) Changes of autoimmunity during observation years: TPO positive patients showed decreasing of aTg negative rate with years (46% to 3%), whearas aTg positive patients showed increasing of TPO positive rate (82% to 91%). TSH-R and TS in HY patients showed decreasing with period, but remained positive in 60% of patients through observation period. 3)  Autoimmunity in disease: Positive (aTg and TPO) rate in NOD was 29% in solid nodules and 23% in cyst. Positive rate was 86% in HY and 98% in HA. 4)  Residece: There was significant difference in local communities; TPO positive rate was 34% (city area) to 45%(fisher man’s area).

Conclusion: These data suggest that autoimmunity may reflect patients’ life style and genetic back ground. Moreover the immunity seemed long-lasting response in most patients of this area.