Novel autoantibodies against 7SL RNA in patients with polymyositis/dermatomyositis.
OBJECTIVE
Autoantibodies against signal recognition particle (SRP) are detected in patients with polymyositis/dermatomyositis (PM/DM). The SRP consists of 7SL RNA and 6 protein components. We examined autoantibodies against deproteinized 7SL RNA in PM/DM patients with anti-SRP antibodies and evaluated the association of anti-7SL RNA antibodies with PM/DM clinically and serologically.


METHODS
Sera from 10 Japanese and 22 North American PM/DM patients with anti-SRP antibodies were tested for the presence of anti-7SL RNA antibodies, using the sera to immunoprecipitate deproteinized RNA extracts derived from HeLa cells.


RESULTS
The immunoprecipitation analysis indicated that 5 Japanese (50%) and one North American (5%) patient with anti-SRP antibodies had novel autoantibodies against deproteinized 7SL RNA. The frequency of anti-7SL RNA antibodies was significantly higher in Japanese than North American patients (p = 0.006). The presence of anti-7SL RNA antibodies appeared to be associated with DM (2 patients) and finger swelling (2 PM patients). The seasonal onset of the disease was different (p = 0.008) for Japanese PM/DM patients with anti-7SL RNA antibodies, who developed the disease between October and January (mean month November; p = 0.01) from that of patients without these antibodies, who developed it between June and August (mean month July; p = 0.01).


CONCLUSIONS
Novel autoantibodies against 7SL RNA were identified in patients with PM/DM, and the presence of these antibodies was correlated to ethnic background, clinical features, and season of disease onset. These findings indicated that autoantibodies against 7SL RNA are a novel serological marker for a subset of PM/DM cases.
Satoh
Takashi
T
Department of Laboratory Medicine, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
Okano
Tetsuroh
T
Matsui
Toshimichi
T
Watabe
Hiroyuki
H
Ogasawara
Takashi
T
Kubo
Kouya
K
Kuwana
Masataka
M
Fertig
Noreen
N
Oddis
Chester V
CV
Kondo
Hirobumi
H
Akahoshi
Tohru
T
D000328:Adult; D044466:Asian People; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology*; D015415:Biomarkers; D015331:Cohort Studies; D003882:Dermatomyositis / Q000097:blood / Q000208:ethnology / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D047468:Immunoprecipitation; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000097:blood / Q000208:ethnology* / Q000276:immunology*; D011336:Probability; D020733:RNA, Small Cytoplasmic / Q000032:analysis / Q000276:immunology*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018271:Signal Recognition Particle / Q000032:analysis / Q000276:immunology*; D044465:White People
C115990:7SL RNA; D001323:Autoantibodies; D015415:Biomarkers; D020733:RNA, Small Cytoplasmic; D018271:Signal Recognition Particle