To compare the HLA-DRB1 shared epitope (SE) alleles in Japanese patients with rheumatoid arthritis (RA) and amyloid A (AA) amyloidosis versus those without AA amyloidosis.
The HLA-DRB1 alleles were genotyped for 91 RA patients without AA amyloidosis, 33 RA patients with AA amyloidosis, and 63 control subjects. HLA-DRB1 typing was performed by polymerase chain reaction, sequence-specific oligonucleotide probe hybridization method.
Although a significant difference was not observed, the frequency of SE genotype was higher in RA patients with AA amyloidosis than in those without AA amyloidosis. All SE-positive RA patients with AA amyloidosis had *04 alleles (*0401, *0405, *0410), and a significant association of the presence of a double dose of *04 SE alleles with AA amyloidosis (OR 4.0, 95% CI 1.91-13.99) was observed.
Our data suggest that presence of double *04 SE is associated with a higher risk of developing AA amyloidosis in Japanese patients with RA.