THE BIASED V-GAMMA GENE USAGE IN THE SYNOVIAL-FLUID OF PATIENTS WITH RHEUMATOID-ARTHRITIS

Taking advantage of the reverse transcriptase-polymerase chain reactio n (RT-PCR), we have analyzed T cell receptor gamma-chain mRNA of synov ial fluid gamma/delta T cells from patients with rheumatoid arthritis (RA) in comparison with those of peripheral blood mononuclear cells (P BMC) from RA patients and healthy individuals. The quantitative RT-PCR method in conjunction with nucleotide sequencing revealed the frequen t usage of the V gamma 3 gene segment in RA synovial fluid mononuclear cells (SFMC) (p < 0.01) which in PBMC of healthy individuals occurred rarely PBMC of most healthy individuals expressed the V gamma 9 gene predominantly (p < 0.01) as expected. However, only half of RB patient s showed elevated levels of the V gamma 9 gene expression in their PBM C The gamma-chain mRNA containing the V gamma 3 gene in RA SFMC showed no conserved junctional sequence (complementarity-determining region 3). To investigate the nature of ligands recognized by the V gamma 3-b earing T cells, we analyzed V gamma gene usage of RA SFMC, RA PBMC, an d normal PBMC stimulated with Mycobacterium tuberculosis (MT) or MT pl us interleukin-2 since there is mounting evidence of high reactivity o f RA SFMC to MT and mycobacterial heat-shock protein 65. However, the V gamma usage appeared to be mostly V gamma 9 in RA SFMC, RA PBMC and normal PBMC. Taken together these results suggest that an as yet unkno wn antigen(s) (other than MT) might select gamma/delta T cells express ing the V gamma 3 gene in RA SFMC.