Thyroid autoantibody synthesis by cultures of thyroid and peripheral blood lymphocytes. I. Lymphocyte markers and response to pokeweed mitogen

Thyroid lymphocytes from Graves' and Hashimoto patients have been investigated and compared with lymphocytes from the peripheral blood. Considerably more lymphocytes (20-30 X 10(6)/g) could be isolated from Hashimoto thyroids than from Graves' tissue (1-5 X 10(6)/g) but the cell suspensions extracted from Hashimoto and Graves' glands were similar in terms of cell surface markers and the ability to synthesize immunoglobulin. Thyroid lymphocytes contained a lower proportion of T cells (OKT3+ cells) and in some cases more B cells than the peripheral blood but the ratio of helper to suppressor T cells (OKT4+:OKT8+ cells) was similar to the values obtained for blood lymphocytes. Further, thyroid lymphocytes (unlike blood lymphocytes) synthesized relatively large amounts of microsomal and/or thyroglobulin antibody when cultured in medium only and these levels were significantly decreased by the addition of pokeweed mitogen. The results of this study provide further evidence for the role of the thyroid as a major site of thyroid autoantibody synthesis and emphasize the importance of characterizing the cells infiltrating the gland in autoimmune thyroid disease.