Lupus Antibodies Explained

Posted by Elaine Moore Dec 1, 2007

Various autoantibodies have been found in systemic lupus erythematosus (SLE) and related connective tissue disorders. Antibody tests help with diagnosis; evaluate flares, disease progression; and determine kidney disease (lupus nephritis), antiphospholipid syndrome (APS).

• Antinuclear Antibody (ANA); Targets Multiple nuclear antigens in cell nuclei ; prevalence in SLE = > 95 percent ; No Correlation with Disease Activity; Clinical Significance= An American College of Rheumatology (ACR) criteria for SLE although this test isn't specific for SLE
• Anti-double-stranded DNA (anti-dsDNA) ; Targets Double-stranded DNA in cells ; prevalence in SLE-=40-80 percent; Positive correlation with disease activity; Significance = Associated with lupus nephritis, severe active disease; also an ACR criteria for SLE
• Anti-Smith (anti-Sm) antibody; Targets antigens comprised of at least 8 polypeptides in the Sm-snRNP complex ; prevalence in SLE= 30-40 percent ; Positive correlation with disease activity; Significance- Often an indication of disease severity independent of anti-dsDNA antibody fluctuations; An ACR criteria for SLE
• Anti-nucleosome antibody; Targets antigens comprised of DNA wrapped around core histones ; prevalence in SLE= 50-90 percent ; Positive correlation with disease activity; Clinical signifcance= IgG3 subtypes associated with lupus nephritis and flares
• Anti-anionic phospholipids antibodies [Mostly anti-cardiolipin (aCL) ] ; Targets phospholipid antigens; Prevalence in SLE= 21-53 percent ; Positive correlation with disease activity; clinical significance= Associated with thrombosis and pregnancy loss [antiphospholipid syndrome (APS)]
• Anti-Beta2 glycoprotein1 antibodies; Targets human plasma protein, B2GP1 ; prevalence in SLE= 17-49 percent ; Correlation with Disease Activity Debated ; Clinical Significance= No correlation with ANA, APS
• Anti-C1Q antibodies; Target Complement Protein ; Prevalence in SLE= 30-50 percent ; Correlates with nephritis activity ; Clinical Significance= Lupus nephritis, correlates with anti-dsDNA antibodies.

Resource:

Richard Hughes and Sarea Ul-Hasan, Searching For Clues, Anti-dsDNA antibodies have a role in detection and monitoring of SLE, Advance for Medical Laboratory Professionals, Nov 5, 2007: 24-27.