Anti-glucose-6-phosphate isomerase, anti-cyclic citrullinated peptide antibodies and HLA-DRB1 genotypes in Japanese patients with early rheumatoid arthritis.
OBJECTIVE
Our goal was to evaluate the associations of antibodies (Abs) to glucose-6-phosphate isomerase (GPI) with Abs to cyclic citrullinated peptide (CCP) and HLA-DRB1 genotypes in Japanese patients with early rheumatoid arthritis (RA).


METHODS
One hundred and eight patients with early RA (85 female, 23 male) who visited our clinic within 1 year of symptom onset were examined for anti-GPI and anti-CCP Ab levels, and HLA-DRB1 genotype. Anti-GPI and anti-CCP Ab levels, and HLA-DRB1 genotypes were also determined in 63 controls and 265 healthy controls, respectively.


RESULTS
Of the 108 patients with early RA and the 63 controls, 20 (18.5%) and 3 (4.8%) were anti-GPI Ab-positive, respectively. Of the 20 patients with anti-GPI Abs, 17 (85%) were positive for anti-CCP Abs. HLA-DRB1*0405 and shared epitope (SE) carrier frequencies were significantly increased not only in anti-GPI Ab-positive patients (p=0.00057, odds ratio [OR] 4.6, 95% CI 1.8-11.8; p=0.0011, OR 5.0, 95% CI 1.7-14.0), but also in anti-GPI Ab-negative patients (p=0.0017, OR 2.2, 95% CI 1.3-3.7; p=0.00011, OR 2.6, 95% CI 1.6-4.3), when compared with controls. In addition, the carrier frequency of HLA-DRB1*1201 was significantly increased in anti-GPI Ab-positive patients compared with controls (p=0.0056, OR 4.3, 95% CI 1.4-13.2).


CONCLUSIONS
The majority of anti-GPI Ab-positive RA patients constitute a subset of HLA-DRB1* SE-associated, anti-CCP Ab-positive RA patients.
Furuya
T
T
Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan. furuyat@ior.twmu.ac.jp
Matsumoto
I
I
Tsuchiya
N
N
Hakoda
M
M
Ichikawa
N
N
Yago
T
T
Higami
K
K
Nanke
Y
Y
Sumida
T
T
Kamatani
N
N
Kotake
S
S
D000328:Adult; D001172:Arthritis, Rheumatoid / Q000235:genetics* / Q000276:immunology; D001323:Autoantibodies; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D005956:Glucose-6-Phosphate Isomerase / Q000276:immunology*; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010456:Peptides, Cyclic / Q000276:immunology*
D001323:Autoantibodies; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D005956:Glucose-6-Phosphate Isomerase