Anticomplementary activity in diffuse and nodular goiters.

The occurrence of anticomplementary activity and its correlation to serum thyroglobulin was investigated in 71 patients with thyroid diseases and 63 age and sex matched control subjects. The patients which were subgrouped according to thyroid function and characteristics of the goiter, were examined at the time of diagnosis. The anticomplementary activity was measured by a complement consumption (CC) assay. Sera from patients with Graves' disease and nontoxic diffuse goiter, showed stronger activity than sera from patients with nontoxic goiter. Seventeen of the patients and one of the controls were positive in the CC-assay. The percentage hemoglobin release in this assay was normally distributed using control sera but not for the patient group. There was no correlation either between CC-activity and serum concentrations of thyroglobulin or CC-activity and antibodies to the O-antigen of Yersinia enterocolitica serotype 3, thyroid cytoplasma, thyroglobulin, nuclear factors, streptolysin O, streptococ hyaluronidase, and parietal cells, respectively. However, correlation between the levels of thyroid stimulating immunoglobulins and CC-activity, was noted (Rho = 0.511, P less than 0.05), which suggests that these immunoglobulins also are present as immune complexes. Thyroglobulin--antithyroglobulin complexes preformed in vitro at high thyroglobulin concentration, gave negative results in the CC-assay.