Increased incidence of autoantibodies to interleukin-1a in rheumatoid arthritis with interstitial lung disease.
OBJECTIVE
To clarify the clinical significance of autoantibodies (auto-Ab) to interleukin-1alpha (IL-1alpha) in rheumatoid arthritis (RA) with interstitial lung disease (ILD), we examined the IL-1alpha auto-Ab level in serum of patients with RA with/without ILD.


METHODS
We investigated the level of IL-1alpha auto-Ab in serum of 70 patients with RA with/without ILD and 40 control patients (CP). Levels of IL-1alpha auto-Ab were measured by radioimmunoassay, and serum was regarded as IL-1alpha auto-Ab positive at an auto-Ab level of more than 5 ng/mL.


RESULTS
Interleukin-1alpha auto-Ab was detected in the serum of 30 out of 70 RA patients (42.9%), and six out of 40 CP (15%) (P < 0.05). Interleukin-1alpha auto-Ab were detected in the serum of 18 out of 32 patients with RA with ILD (56.2%) and 12 out of 38 patients with RA without ILD (31.5%). The positive rate of these autoantibodies in RA with ILD was significantly higher than that in RA without ILD (P < 0.05). Although C-reactive protein, immunoglobulin G, rheumatoid factor and rheumatoid arthritis particle agglutination levels in serum from patients with RA with ILD were not significantly different between the IL-1alpha auto-Ab-positive and -negative groups, the lactate dehydrogenase level (LDH) and AaDO, in the IL-1alpha auto-Ab-positive group were significantly higher than those in the negative group (LDH: P < 0.001, AaDO2: P < 0.05).


CONCLUSIONS
These results suggest that IL-1alpha auto-Ab are generated in response to the immunoinflammatory process of ILD in RA, and these autoantibodies may neutralize and regulate the IL-1alpha activity.
Maniwa
K
K
Third Department of Internal Medicine, School of Medicine, The University of Tokushima, Japan.
Ogushi
F
F
Tani
K
K
Ohmoto
Y
Y
Muraguchi
M
M
Sone
S
S
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000188:drug therapy; D001323:Autoantibodies / Q000097:blood*; D001799:Blood Sedimentation; D002352:Carrier Proteins; D016022:Case-Control Studies; D002373:Cyclic AMP Receptor Protein / Q000097:blood; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000276:immunology*; D007770:L-Lactate Dehydrogenase / Q000097:blood; D017563:Lung Diseases, Interstitial / Q000097:blood / Q000209:etiology* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013256:Steroids
D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D001323:Autoantibodies; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D007375:Interleukin-1; D013256:Steroids; D007770:L-Lactate Dehydrogenase