DNA antibodies and complement in SLE patients. A follow-up study

Area of Science:

• Immunology
• Rheumatology
• Clinical Medicine

Background:

• Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with variable clinical manifestations.
• Monitoring SLE activity and distinguishing flares from infections is crucial for patient management.
• Biomarkers such as anti-DNA antibodies and complement levels are potential indicators of disease activity.

Purpose of the Study:

• To prospectively evaluate the correlation between SLE disease activity and levels of anti-DNA antibodies and complement.
• To assess the utility of these biomarkers in differentiating SLE relapses from complicating infections.
• To investigate the role of different antibody classes (IgG, IgM) and complement components (C3, CH50) in SLE activity.

Main Methods:

• Prospective follow-up of 67 patients with SLE for 3-19 months.
• Clinical assessment of SLE activity based on symptoms and signs.
• Measurement of antibodies to native double-stranded (ds) DNA and denatured single-stranded (ss) DNA (IgG and IgM classes).
• Assay of complement components C3 and CH50.

Main Results:

• Significant correlations were found between SLE activity and levels of IgG anti-dsDNA antibodies (P < 0.001), IgG anti-ssDNA antibodies (P < 0.001), and C3 (P < 0.001).
• These markers were not reliable for predicting minor SLE exacerbations.
• IgM class ss-DNA antibodies were higher in SLE patients without nephritis compared to those with nephritis.
• Combined IgG anti-ssDNA antibody and complement (C3, CH50) levels effectively differentiated SLE relapse from infection in most cases.

Conclusions:

• IgG class anti-DNA antibodies and complement levels are valuable indicators of SLE disease activity.
• The combination of IgG anti-ssDNA antibodies and complement assays can aid in distinguishing SLE relapses from infections.
• Further research may refine the predictive value of these biomarkers for SLE exacerbations.