Blockade of tumour necrosis factor {alpha} significantly alters the serum level of IgG- and IgA-rheumatoid factor in patients with rheumatoid arthritis.
OBJECTIVE
To determine the effect on the humoral immune system of long term treatment of patients with RA with etanercept.


METHODS
12 consecutive patients with seropositive RA treated with etanercept were studied and followed up for 9 months. Clinical efficacy of treatment was evaluated using the 28 joint count Disease Activity Score (DAS28). Serum samples were collected at baseline and after 9 months and serum immunoglobulin, RF isotypes, and anti-cyclic citrullinated peptide (aCCP), antinuclear, nucleosome, and dsDNA antibodies determined. For comparison 7 patients with seropositive RA treated with adalimumab were studied.


RESULTS
DAS28 decreased significantly after the first month and then was constant for the whole study (5.7 (0.3) v 3.8 (0.2), p< or=0.000). Serum IgA-RF and IgG-RF increased significantly after 9 months' etanercept treatment (mean (SEM) IgA-RF rose from 19.5 (4.8) to 30.5 (5.9) IU/ml, p< or=0.01; IgG-RF from 20.6 (8.1) to 33.8 (11.5) IU/ml, p< or=0.04). Serum levels of total immunoglobulin and specific autoantibodies remained unchanged during the study. In patients treated with adalimumab, no significant changes in serum levels of RF isotypes and aCCP antibodies were seen.


CONCLUSIONS
Etanercept, although effective in treating the clinical symptoms of RA, seems to have a pivotal effect on RF-producing B cells either directly or indirectly.
Yazdani-Biuki
B
B
Division of Rheumatology/Department of Internal Medicine Medical University Graz Auenbruggerplatz 15 A-8036 Graz, Austria.
Stadlmaier
E
E
Mulabecirovic
A
A
Brezinschek
R
R
Tilz
G
G
Demel
U
U
Mueller
T
T
Brickmann
K
K
Graninger
W B
WB
Brezinschek
H-P
HP
D000368:Aged; D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000187:drug effects*; D000068800:Etanercept; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use; D012217:Rheumatoid Factor / Q000097:blood; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
D018501:Antirheumatic Agents; D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D012217:Rheumatoid Factor; D000068800:Etanercept