Related Experiment Video
Updated: Aug 17, 2026

Recognition of Epidermal Transglutaminase by IgA and Tissue Transglutaminase 2 Antibodies in a Rare Case of Rhesus Dermatitis
Published on: December 15, 2011
Selective IgA immune unresponsiveness to Proteus mirabilis fumarate reductase A-chain in rheumatoid arthritis
Richard H Weisbart1, Yoon Min, Andrew L Wong
1Department of Medicine, Veterans Affairs Greater Los Angeles Health Care System, Sepulveda, CA 91343, USA. rweisbar@ucla.edu
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.
Related Concept Videos
Inflammatory Bowel Disease III: Crohn's Disease
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Drugs for Treatment of Crohn's Disease in IBD Using Biologic Agents: Anti-TNF
Inflammatory Bowel Disease II: Ulcerative Colitis
Drugs for Treatment of Crohn's Disease in IBD Using Immunomodulatory Agents
Drugs for Treatment of Ulcerative Colitis in IBD
