Abstract
Susceptibility to develop Rheumatoid arthritis (RA) maps to a highly conserved amino acid motif (“the shared epitope”) expressed in the third hypervariable region of different HLA-DRB1 alleles. This motif, namely QKRAA, QRRAA or RRRAA helps the development of RA by an unknown mechanism.
However, it is now established that the shared epitope can 1/ Shape the T cell repertoire 2/ Interact with 70 kD heat shock proteins