Antibodies to extracted nuclear antigens in serum

Normally the concentrations of AT to the extracted nuclear Ag RNP / Sm, Sm, SS-A( Ro), SS-B( La) - less than 20 IU / ml, 20-25 IU / ml - boundary values;to Ar Scl-70 AT is normally absent.

This study consists in the quantitative determination of IgG-AT against extractable nuclear Ar-RNP / Sm, Sm, SS-A( Ro) and SS-b( La) in serum. AT to the extracted nuclear Ag( ENA), are complexes of soluble ribonucleoproteins. AT against various nuclear Ar is an important diagnostic feature for monitoring and diagnosis of various rheumatic diseases( Table).

■ AT to Ar RNP / Sm( AT to protein components of U1 - small nuclear ribonucleoprotein - i1RNA) is detected with mixed connective tissue disease, less often with SLE and other rheumatic diseases. The concentration of AT does not correlate with the activity and development of exacerbation. In patients with SLE, in whose blood serum there are ATs to Sm-Ar, antibodies to the ribonucleoprotein are not detected. To avoid false positive results, an immunoblot analysis is used.

■ Sm-Ar consists of five small nuclear RNAs( U1, U2, U4, U5, U6) associated with 11 or more polypeptides( A, B / B, C, D, E, F, G).AT to Ar Sm are specific for SLE and are present in 30-40% of

patients with this disease. These ATs are very rare in other connective tissue diseases( in the latter case, their detection indicates a combination of diseases).The concentration of AT to Arg Sm does not correlate with the activity and clinical subtypes of SLE.AT to Ar Sm is one of the criteria for diagnosing SLE.

Table Frequency of detection of antibodies to various extractable nuclear Ag [Jaeger L. 1990]

Table Frequency of detection of antibodies to various extractable nuclear Ag [Jaeger L. 1990]

■ SS-A( Ro) - polypeptides forming complexes withRo RNA( hY1, hY3 and hY5).AT to Arg SS-A( Ro) are most often found in Sjogren's syndrome / SJ and SLE.With SLE, the production of these ATs is associated with a certain set of clinical manifestations and laboratory disorders: photosensitivity, Sjogre's syndrome, hyperproduction of rheumatoid factor. The presence of these antibodies in the blood of pregnant women increases the risk of developing neonatal wolf-nochnopodobnogo syndrome in newborns. AT to Arg SS-A( Ro) can be increased in 10% of patients with rheumatoid arthritis.

■ SS-B ^ a ^ Ar - nucleocytoplasmic phosphoprotein complex with Ro small nuclear RNA( Ro hY1-hY5), transcriptor of RNA-to-lipase III.АТ to Аг SS-B ^ a) is detected in Sjogren's disease and syndrome( 40-94%).In SLE, SS to SS-B ^) is more often detected at the onset of a disease that develops in the elderly( 9-35%) and is associated with a low incidence of nephritis.

■ Scl-70-Ar - topoisomerase I is a protein with a molecular weight of 100,000 and its fragment has a molecular weight of 67,000. The AT to Scl-70 is more often detected in diffuse( 40%), less often with a limited( 20%) form of systemicscleroderma. They are highly specific for this disease( sensitivity of 20-55% depending on the analytical method) and are a poor prognostic sign. The presence of AT Scl-70 in systemic scleroderma in combination with the carriage of HLA-DR3 / DRw52 genes increases the risk of pulmonary fibrosis 17 times. Detection of AT Scl-70 in blood in patients with isolated Reino phenomenon indicates a high probability of systemic scleroderma.