Serum autoantibodies and thyroid lymphocytic infiltration in endemic goitre.

Patients with thyroid diseases from areas of endemic goitre in Northern Italy were examined for thyroid antibodies by passive haemoagglutination. Of 40 schoolboys with goitre only one had thyroid antibodies (AT) in the blood. Among 182 adults with grade 1-2 goitre, examined within an area of low endemia, the frequency of AT was 7%, not significantly different from that found in the 286 persons with thyroid 'O' living in the same area. Among 181 adults with grade 2-3 goitre, examined within an area of serious endemia, the frequency of AT was 16%; the percentage went up to 24% in 144 patients operated on for goitre. AT frequency was 36% in 87 patients with toxic goitre, more than 70% in 97 patients with Graves' disease and 17% in 60 patients with cancer of the thyroid. AT occurred three times more frequently in women than in men. Microsomal antibodies were more frequently detected than anti-thyroglobulin antibodies: the opposite was true in thyroid cancer. Lymphocytic infiltration (IL) of the gland was observed in 45% of the 464 simple goitres and in 52% of the 60 cancers of the thyroid: it was more frequent and intense in women. Among the 144 patients operated on for goitre the frequency and the titre of AT progressed in parallel with the intensity of the lymphocytic infiltration. Patients with a greater lymphocytic infiltration and higher AT had a higher TSH. Multinodular non-toxic goitre and autoimmune lymphocytic thyroiditis can be present in the same thyroid gland and the clinical expression will depend on which condition predominates.