PT  - JOURNAL ARTICLE
AU  - Weisbart, Richard H
AU  - Min, Yoon
AU  - Wong, Andrew L
AU  - Kang, Joanne
AU  - Kwunyeun, Suchada
AU  - Lin, Antony
AU  - Kim, Joon
AU  - Chan, Grace
AU  - Wakelin, Rika
AU  - Sohn, William
AU  - Chang, Sophia S
AU  - Nishimura, Robert N
TI  - Selective IgA immune unresponsiveness to Proteus mirabilis fumarate reductase A-chain in rheumatoid arthritis.
DP  - 2005 Jul 01
TA  - The Journal of Rheumatology
PG  - 1208--1212
VI  - 32
IP  - 7
4099  - http://www.jrheum.org/content/32/7/1208.short
4100  - http://www.jrheum.org/content/32/7/1208.full
SO  - J Rheumatol2005 Jul 01; 32
AB  - OBJECTIVE: To determine if selective immune unresponsiveness to microbial antigens is associated with predisposition to rheumatoid arthritis (RA). METHODS: Proteins from Proteus mirabilis lysate were isolated by SDS-PAGE and examined by Western blotting for antibody responses in sera from patients with RA compared to healthy subjects and patients with psoriatic arthritis (PsA). RESULTS: Although RA patients had marked IgA immune responses to many P. mirabilis proteins compared to healthy subjects, selective unresponsiveness was found in RA to a 66 kDa protein identified as fumarate reductase A-chain (FRD-A) by mass spectroscopy. This was confirmed in Western blots with recombinant FRD-A from P. mirabilis. IgA unresponsiveness to FRD-A was found in 21/59 (35.6%) RA patients compared to 7/63 (11.1%) healthy individuals (p < 0.01) and 6/52 (11.5%) patients with PsA (p < 0.01). IgA unresponsiveness to FRD-A was present in 20/46 (43.5%) RA patients with IgA rheumatoid factors (RF) compared to 1/13 (7.7%) without RF (p < 0.025). CONCLUSION: Our results identify a selective hole in the IgA immune repertoire for P. mirabilis FRD-A in a subset of IgA RF-positive patients with RA.