Peripheral blood and intrathyroidal T cell clones from patients with thyroid autoimmune diseases

For a better understanding of the pathogenesis of thyroid autoimmune diseas es, we have studied morphological and functional properties of T clones fro m peripheral blood Lymphocytes (PBL) and from intrathyroidal lymphocytes (I TL) obtained from 3 patients with Graves' disease or 1 Hashimoto's thyroidi tis, 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 obser ved whatever the origin of the lymphocytes or the autoimmune pathology. Gam ma interferon (IFN-gamma) was detected in the majority (17/19) of the clone s tested. Intracytoplasmic interleukin (IL-4) was secreted in 7/19 clones a nd both cytokines were produced in 5/19 clones, In coculture a proliferativ e response and tumour necrosis factor (TNF-alpha) production were observed with 6 clones (4 from Graves thyrocytes and 2 from thyroiditis), No cytotox ic clone was derived from Graves or thyroiditis tissues. These data demonst rate that the large majority of T clones are principally CD4-T cells; all t he clones secreted TNF-alpha and a large majority produced IFN-gamma, Only a few clones produced IL-4 alone or associated with IFN-gamma, Six T clones induced proliferative response and of TNF-alpha secretion in coculture, Fu rther investigations must be performed on these antigen-reactive T clones t o analyse their role in the pathogenesis of the human thyroid autoimmune di seases.