| The U1-small nuclear ribonucleoprotein particle
(snRNP) belongs to the most complex autoantigens
known to be recognized in systemic autoimmune
diseases. This particle consists of an RNA backbone
and eleven associated proteins that are immunogenic
in patients suffering from systemic lupus erythematosus
and mixed connective tissue disease. Antibodies directed
against the 70 kDa protein, also called U1-snRNP
(70 kDa), are specific for Sharp´s syndrome. Up to
100 % of all patients suffering from mixed connective
tissue disease exhibit those autoantibodies.
Apart from the 70 kDa protein and the Sm proteins
the U1-snRNP-complex also contains the proteins A and
C. Patients suffering from SLE and MCTD exhibit antibodies
directed against the proteins A, C and 70 kDa.
Autoantibodies against Sm proteins are of pathognomonic
importance for diagnosing SLE. A patient with
a positive anti-Sm finding is confronted with the diagnosis
of SLE. But a negative finding does not exclude
SLE. Anti-Sm is detected in 10% of Caucasian and 30%
of Black and Chinese patients with SLE. The detection
of autoantibodies against Sm belongs to the criteria
for the diagnosis of SLE of the American College of
Rheumatology (ACR) published in 1982. |
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| Tests |
12 x 8 Tests |
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| Calculation |
quantitative |
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| Range |
0 – 200 U/ml |
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| Cut-off |
25 U/ml |
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| Sensitivity |
1 U/ml |
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| Calibration |
CDC |
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| Substrate |
TMB / 450 nm |
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Instruction for Use: ORG 510-0508-01-gb.pdf
Material-Safety-Datasheet: ORG 510.pdf