Autoantibody Profiling in Lupus Patients using Synthetic Nucleic Acids

Martin Klecka,Elizabeth D Mellins,Imelda Maria Balboni,Kira Astakhova,Claudia Macaubas,Christina Thybo,Ilia Solov'Yov,Anne Voss,Julia Simard,Emily Fox

doi:10.1038/s41598-018-23910-5

Abstract

Autoantibodies to nuclear components of cells (antinuclear antibodies, ANA), including DNA (a-DNA), are widely used in the diagnosis and subtyping of certain autoimmune diseases, including systemic lupus erythematosus (SLE). Despite clinical use over decades, precise, reproducible measurement of a-DNA titers remains difficult, likely due to the substantial sequence and length heterogeneity of DNA purified from natural sources. We designed and tested a panel of synthetic nucleic acid molecules composed of native deoxyribonucleotide units to measure a-DNA. ELISA assays using these antigens show specificity and reproducibility. Applying the ELISA tests to serological studies of pediatric and adult SLE, we identified novel clinical correlations. We also observed preferential recognition of a specific synthetic antigen by antibodies in SLE sera. We determined the probable basis for this finding using computational analyses, providing valuable structural information for future development of DNA antigens. Synthetic nucleic acid molecules offer the opportunity to standardize assays and to dissect antibody-antigen interactions.

Highlights

In most patients with systemic lupus erythematosus (SLE), the disease course is characterized by flares and remissions[7]
We report a series of new synthetic DNA antigens and demonstrate their applicability for detection of corresponding antibodies by enzyme-linked immunosorbent assay (ELISA) in patients with pediatric onset SLE or adult-onset SLE
Synthetic antigens described demonstrate high specificity, sensitivity and reproducibility in detection of a-DNAs in SLE, a disease known to be associated with a-DNAs, and for the first time enable a detailed structural study of sequence specificity of these autoantibodies

Summary

Introduction

In most patients with SLE, the disease course is characterized by flares and remissions[7]. Antibodies to dsDNA and to Smith antigen, a non-histone nuclear protein composed of several polypeptides, have validated diagnostic value in SLE, and increased anti-ds DNA titers are associated with disease flare in some patients, but not universally[9]. Structural data on antibody-DNA complexes could be used in the design of antigens with improved specificity, which is of crucial importance to clinical diagnostics[18,19]. We report a series of new synthetic DNA antigens and demonstrate their applicability for detection of corresponding antibodies by ELISA in patients with pediatric onset SLE (pSLE) or adult-onset SLE. Increased antibody titers to synthetic dsDNA correlate with high disease activity, measured by SLEDAI. The a-dsDNA profiles in SLE differ from those in patients with another autoimmune disease, ANA-positive polyarticular juvenile idiopathic arthritis, indicating specificity. Using computational methods, we identify specific interactions between dsDNA and corresponding antibodies

Methods

Results

Discussion

Conclusion