Serum amyloid P component-DNA complexes are decreased in systemic lupus erythematosus. inverse association with anti-dsDNA antibodies.

Abstract

OBJECTIVE:

To study serum levels of serum amyloid P component (SAP) and SAP-DNA complexes in a population-based cohort of patients with systemic lupus erythematosus (SLE).

METHODS:

The study population comprised 82 unselected patients of predominantly Scandinavian ancestry with SLE according to current classification criteria. Serum samples were collected at baseline and serially for up to 2 years. SAP component and SAP-DNA complexes were measured by ELISA. Associations between SAP-DNA and clinical manifestations or serological findings were analyzed. Ninety healthy, age-matched blood donors served as controls.

RESULTS:

SLE patients had normal serum concentrations of SAP, whereas SAP-DNA complexes were decreased. Two-thirds of the SLE patients tested persistently SAP-DNA complex-negative. There was no relationship between the occurrence of SAP-DNA complexes and clinical manifestations. SAP-DNA-negative patients tended to have lower leukocyte counts and complement C3 levels, and higher erythrocyte sedimentation rates and C3d levels versus SAP-DNA-positive patients. There was an inverse association between the occurrence of anti-double-stranded DNA (anti-dsDNA) antibodies and SAP-DNA complexes. Co-occurrence of SAP-DNA complexes and anti-dsDNA antibodies was demonstrated in only one SLE patient, implying that 81/82 patients were discordant for the presence of anti-dsDNA antibodies and SAP-DNA complexes.

CONCLUSION:

The decreased level of SAP-DNA complexes in SLE patients and the inverse relationship between these complexes and anti-dsDNA antibody supports the concept that SAP component is implicated in the clearance of cell nuclear debris.

• Authors: Anne Voss, Ellen Holm Nielsen, Sven Erik Svehag, Peter Junker
• Journal: The Journal of rheumatology (J Rheumatol) Vol. 35 Issue 4 Pg. 625-30 (Apr 2008) ISSN: 0315-162X [Print] Canada
• PMID: 18278838 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Antinuclear
• Serum Amyloid P-Component
• Complement C3d
• DNA

Topics

• Adult
• Antibodies, Antinuclear (immunology)
• Blood Sedimentation
• Complement C3d (analysis)
• DNA (blood, immunology)
• Enzyme-Linked Immunosorbent Assay
• Female
• Humans
• Lupus Erythematosus, Systemic (blood, immunology, physiopathology)
• Male
• Middle Aged
• Serum Amyloid P-Component (metabolism)