ANALYSIS OF THE T-CELL RECEPTOR V-ALPHA REPERTOIRE IN HASHIMOTOS-THYROIDITIS - EVIDENCE FOR THE RESTRICTED ACCUMULATION OF CD8(-CELLS IN THE ABSENCE OF CD4(+) T-CELL RESTRICTION() T)

There has been considerable interest in the possible restriction of th e TCR repertoire in autoimmune disorders, because it would have import ant therapeutic implications. Using ribonucleic acid derived from matc hed peripheral blood lymphocytes (PBL), intrathyroidal lymphocytes (IT L), and CD4- and CD8-selected ITL from three patients with Hashimoto's thyroiditis (HT), we carried out reverse transcription-PCR analysis o f TCR V alpha family usage. No evidence was found for V alpha family r estriction in the PBL, ITL, CD4-selected ITL, or CD8-selected ITL. How ever, restriction was frequent in the CD8-selected ITL after denaturat ion/reannealing of the PCR products followed by nondenaturing PAGE; si milar restriction was uncommon in PBL, CD8-selected PBL, ITL, or CD4-s elected ITL. V alpha 3 and V alpha 6 TCR chains from CD4-selected ITL bands from one patient were cloned and sequenced. There was marked seq uence restriction, particularly within the ITL V alpha 6 TCR chains, i n which 14 of 15 homoduplex band sequences used the J4 segment and had an identical V/N/J junction amino acid (but not nucleotide) sequence. Sequence restriction was not detected in matched CD8-selected PBL mat erial. These data show that there is a marked restriction of V alpha c hain usage in the CD8(+) (but not CD4(+)) T cells in the Hashimoto's t hyroid, with clonal expansion of some sequences.