Peripheral Blood and Intrathyroidal T Cell Clones from Patients with Thyroid Autoimmune Diseases

Abstract

For a better understanding of the pathogenesis of thyroid autoimmune diseases, we have studied morphological and functional properties of T clones from peripheral blood lymphocytes (PBL) and from intrathyroidal lymphocytes (ITL) obtained from 3 patients with Graves' disease or 1 Hashimoto's thyroiditis. Investigations were carried out on clones cultured alone or cocultured with autologous thyrocytes. Clonage efficiency ranged from 30% to 33% for PBL and 10% to 36% for ITL. A predominance of CD4-positive clones was observed whatever the origin of the lymphocytes or the autoimmune pathology. Gamma interferon (IFN-y) was detected in the majority (17/19) of the clones tested. Intracytoplasmic inter-leukin (IL-4) was secreted in 7/19 clones and both cytokines were produced in 5/19 clones. In coculture a proliferative response and tumour necrosis factor (TNF-a) production were observed with 6 clones (4 from Graves thyrocytes and 2 from thyroiditis). No cytotoxic clone was derived from Graves or thyroiditis tissues. These data demonstrate that the large majority of T clones are principally CD4-T cells; all the clones secreted TNF-α and a large majority produced IFN-α. Only a few clones produced IL-4 alone or associated with IFN-α. Six T clones induced proliferative response and of TNF-α secretion in coculture. Further investigations must be performed on these antigen-reactive T clones to analyse their role in the pathogenesis of the human thyroid autoimmune diseases

Key Words:

• T lymphocyte clones
• Graves' disease
• Hashimoto's thyroiditis
• Intrathyroidal lymphocytes