THE GAMMA-DELTA T-CELL REPERTOIRE IN GRAVES-DISEASE AND MULTINODULAR GOITER

gamma delta T cells are a subset of T cells with unknown function, and restriction of the gamma delta T cell receptor (TCR) repertoire has b een described in rheumatoid arthritis and multiple sclerosis. Elevated numbers of gamma delta T cells have been reported in the peripheral b lood and thyroids of patients with Graves' disease. We have carried ou t flow cytometric analysis on peripheral blood mononuclear cells (PBMC ) and intrathyroidal lymphocytes (ITL) from 12 patients with Graves' d isease and nine patients with multinodular goitre (MNG), a thyroid dis ease of unknown etiology. There was no significant difference between the proportion of gamma delta T cells in the PBMC of Graves and MNG pa tients, nor between the PBMC and ITL populations in either patient gro up. We have also carried out polymerase chain reaction amplification o n RNA prepared from matched PBMC, ITL and the activated (CD25(+)) subs et of ITL using six TCR V delta-family specific primers. Although ther e were differences in the amounts of each V delta transcript amplified from PBMC and ITL, there was no difference between the two patient gr oups. No consistent differences were therefore found between the gamma delta T cell populations in Graves' and MNG patients, arguing against the direct involvement of this T cell subset in the pathogenesis of G raves' disease.