HPRT- mutant T cells in the peripheral blood and synovial tissue of patients with rheumatoid arthritis.
OBJECTIVE
To investigate the frequency and characteristics of hprt- mutant T lymphocytes in the peripheral blood and synovium of rheumatoid arthritis (RA) patients compared with controls, and to correlate these findings with disease parameters.


METHODS
An hprt- T cell assay was performed on blood and synovial samples from 93 RA patients, 8 osteoarthritis (OA) patients, and 19 control subjects. T cell clones were studied by flow cytometry and evaluated for fibronectin adhesion.


RESULTS
RA patients showed a 5-fold increase in the frequency of mutant T cells in the peripheral blood compared with that in control peripheral blood, and a further 10-fold increase in the mutant T cell frequency in synovial tissue. In OA patients, the synovium also had a significantly higher frequency of hprt- mutant T cells compared with the peripheral blood, but at a lower level than in the rheumatoid synovium. RA peripheral blood mutant T cell clones displayed elevated fibronectin adhesion and beta1 integrin expression, similar to that observed in the RA synovial T cell lines.


CONCLUSIONS
The origin of the mutated T cells in the peripheral blood of these patients appears to be the inflamed synovium of RA, and to a lesser extent, of OA, where the cells are exposed to a mitogenic and genotoxic environment.
University of Ottawa, and Ottawa General Hospital, Ontario, Canada.
J L
JL
Cannons
J
J
Karsh
H C
HC
Birnboim
R
R
Goldstein
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000473:pathology; D002448:Cell Adhesion; D002460:Cell Line; D003001:Cloning, Molecular; D005260:Female; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000097:blood* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010003:Osteoarthritis / Q000097:blood; D013583:Synovial Membrane / Q000166:cytology; D013601:T-Lymphocytes / Q000201:enzymology / Q000378:metabolism
D007041:Hypoxanthine Phosphoribosyltransferase