Scl-70 Ab ELISA Kit (Scleroderma 70)

INTENDED USE

Scl-70 is an autoantibody that targets the topoisomerase I enzyme, which is involved in DNA replication and repair. The presence of Scl-70 in the blood is strongly associated with diffuse systemic sclerosis, a subtype of the disease characterized by widespread skin involvement and internal organ damage. Studies have shown that up to 60% of patients with diffuse systemic sclerosis have positive Scl-70 antibodies.

Patients with positive Scl-70 antibodies may benefit from more aggressive immunosuppressive therapies to prevent or mitigate organ damage. It is worth noting that Scl-70 testing should always be interpreted in conjunction with a patient’s clinical presentation and other diagnostic findings.

BACKGROUND

Scl-70 (Scleroderma 70)(also called Topoisomerase 1) is a nucleolar and nuclear enzyme which is regarded as being specific for systemic sclerosis (scleroderma) and it can be found in over 60% of patients possessing this connective tissue disease. Anti-Scl-70 and anti-centromere antibodies (ACA) are particularly useful in distinguishing patients having systemic sclerosis (SSc), these antibodies are associated with more severe scleroderma disease.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• Divisible Microplate: Consisting of 12 modules of 8 wells, highly purified Scl-70 antibodies bound to microwells.
• Calibrators (A-F): Concentration 0-200 U/ml, made up from anti-Scl-70 in a serum/buffer matrix.
• Controls Positive and Control Negative: Containing anti-Scl-70 antibodies.
• Sample Buffer (5x).
• Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
• TMB Substrate.
• Stop Solution: Contains acid.
• Wash Buffer (50x Concentrated).
• Instruction Manual.
• Certificate of Analysis.

SENSITIVITY

The minimum detection sensitivity level of human anti-Scl 70 antibody (Scleroderma 70, anti-Scl-70, Scl-70 Ab, topoisomerase 1, anti-topoisomerase 1, topo-1) IgG autoantibodies using current Scl-70 Ab ELISA kit was 1.0 U/ml. The dynamic range for this assay is 12.5 – 200.0 U/ml.

ASSAY CHARACTERISTICS

– Expected Values: Cut-off 25 U/ml.
– Limit Of Detection (LOD): 1 U/ml.
– Measuring Range: 0 – 200 U/ml
– Interference: None.
– Results Interpretation: Negative: < 15 U/ml, Borderline 15-25 U/ml, Positive: ≥ 25 U/ml.
– Intra Assay: 3.2 – 4.0%
– Inter Assay: 2.3 – 2.8%
– Linearity: 97 – 104%
– Clinical Diagnosis: Sensitivity (76.0%), Specificity (99.0%), Overall agreement (94.4%).

REFERENCES

1. An enzyme-linked immunosorbent assay for autoantibodies against the nuclear protein Scl-70. J Immunol Methods. (1985) 80 (2): 211-9. Geisler C. and Høier-Madsen M.
2. Anti-Scl-70 (topo-I) antibodies in SLE: Myth or reality? Autoimmun Rev. (2010) 9 (11): 756-60. Review. Mahler M., et al.
3. Development and comparative evaluation of immunoblot assays for detecting autoantibodies to Scl 70 and Jo 1 antigens in serum. Clin Chem. (1990) 36 (12): 2053-6. Fonong T., et al.
4. High titers of autoantibodies to topoisomerase I (Scl-70) in sera from scleroderma patients. Science. (1986) 231 (4739): 737-40. Shero J.H., et al.
5. Scl 70 autoantibodies from scleroderma patients recognize a 95 kDa protein identified as DNA topoisomerase I. Chromosoma. (1986) 94 (2): 132-8. Guldner H.H., et al.
6. Anti-scl-70. Autoimmunity. (2005) 38 (1): 65-72. Review. Basu D. and Reveille JD.

ADDITIONAL INFORMATION

• Full Name: Scl-70 Ab ELISA Kit (Scleroderma 70)
• Reactivity: Human
• Sample Type: Serum, Plasma
• Sensitivity: 1.0 U/ml

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