What is a chromatin antibody?
Antibodies to chromatin (DNA complexed with histone proteins) are found in >50% of patients with systemic lupus erythematosus (SLE), and are significantly associated with kidney disease in this patient group. Chromatin antibodies may be found in patients with drug-induced lupus.
What antibodies are involved in lupus?
For example, about 98% of people with lupus possess antinuclear antibodies (ANA), which can attack the nucleic material of your cells. In addition, some individuals may possess anti-phospholipid antibodies, which damage proteins bound to phospholipids in the membranes of your cells.
What is ribonucleoprotein antibody?
The Sm and nuclear ribonucleoprotein (RNP) antigens are a particulate complex composed of small nuclear RNAs (U-RNAs) and proteins. This complex has also been referred to as extractable nuclear antigens (ENA), since it is soluble in saline.
What is U1 nRNP?
The U1 nRNP antibody test is performed through collection of blood. It is usually recommended to people who are suspected of having Mixed Connective Tissue Disease or Systemic Lupus Erythematosus.
What does a high chromatin antibody mean?
The presence of anti-chromatin antibodies may be useful in the diagnosis of systemic lupus erythematosus (SLE) or drug-induced lupus (DIL) and have been reported to be predictive of lupus nephritis, especially when antibody levels are high.
What does high anti-chromatin antibodies mean?
• Anti-chromatin antibodies are a very helpful marker in supporting the diagnosis of SLE in a patient with an unclear systemic autoimmune disorder. • These antibodies have a high sensitivity (50–100%) and a very high specificity (90–99%) for SLE diagnosis.
What is the most specific antibody for SLE?
(Strength of Recommendation: C, based on expert opinion.) The antinuclear antibody (ANA) test is the most commonly used screening test for SLE. The presence of anti-DNA, anti-Sm, and antiphospholipid antibodies is more specific for diagnosing SLE.
What is the function of U1?
U1 snRNP (U1) functions in splicing introns and telescripting, which suppresses premature cleavage and polyadenylation (PCPA). Using U1 inhibition in human cells, we show that U1 telescripting is selectively required for sustaining long-distance transcription elongation in introns of large genes (median 39 kb).
What is an RNP antibody?
RNP (also called nRNP and U1RNP) is a small nuclear ribonucleoprotein that contains 3 protein autoantigens (called A, C, and 68 kD). Sera that contain RNP antibodies react predominately with the A and 68-kD autoantigens.
What is the prevalence of RNP antibodies in lupus?
Antibodies to RNP occur in approximately 50% of patients with lupus erythematosus (LE) and in patients with other connective tissue diseases, notably mixed connective tissue disease (MCTD). MCTD is characterized by high levels of RNP antibodies without detectable Sm or double-stranded DNA (dsDNA) antibodies.
What is the difference between anti-Sm and Anti-U1-RNP antibodies?
Anti–U1-RNP antibodies react to antigens in small nuclear ribonucleoprotein particles distinct from anti-Sm specificities. Both autoantibodies are measured together using the same test system. Different laboratory methods are available; however, the ELISA is probably most commonly used by clinical laboratories.
What is the full form of nRNP?
RNP (also called nRNP and U1RNP) is a small nuclear ribonucleoprotein that contains 3 protein autoantigens (called A, C, and 68 kD).