Systemic lupus erythematosus (SLE) Testing

What is SLE?

The autoimmune disorder systemic lupus erythematosus (SLE) has a murky pathogenesis: it is characterized by the expression of multiple autoantibodies against multiple organs and systems.

The distinguishing feature of SLE is the profusion of a collection of autoantibodies in the blood that damage organs and systems. In clinical terms, SLE is largely heterogenous in terms of kidneys, blood, musculoskeletal and circulatory involvement, while autoantibody levels are highly variable. The SLE disease cycle can be split into active and remission states. Because of the presence of multiple autoantibodies, the clinical signs and symptoms of SLE vary wildly, varying from milder complaints like rashes or arthritis to life-threatening events like lupus flares or renal artery embolism. This clinical heterogeneity leads to varying treatment outcomes and prognoses in patients. The vast majority of patients during the active phase suffer from severe clinical symptoms and are vulnerable to significant organ destruction.

Of these, the most frequent and most fatal complications of SLE is lupus nephritis (LN). SLE is notoriously sneaky and difficult to spot early. Not only is SLE clinically diverse, but there is also great variability in autoantibody levels, treatment responses, and disease outcomes. Research suggests that SLE is triggered by a complex interaction of at-risk genes and the environment. Genetically susceptible people might get the disease when exposed to environmental triggers like smoking or infection. Further, the immune breakdown in SLE patients triggers activation of T-cells and B-cells, causing multiple autoantibodies.

In SLE patients, disease activity correlates with autoantibody. These antibodies are generally high and their levels tend to be accompanied by damage to other organs such as the blood, kidneys and central nervous system. Therefore, autoantibody measurements are an important factor in determining how SLE starts and progresses. Such autoantibodies attack cells, tissues and organs within the body's cell nucleus, cytoplasm and membranes. Anti-dsDNA antibodies, for example, might attack chromatin chains in the basement membrane of the kidney. These autoantibodies - like the antinuclear antibodies (ANA) and anti-dsDNA antibodies - are central to the pathogenesis of SLE.

Detection Methods We Offer

Creative Diagnostics offers a variety of testing methods, allowing you to choose the best approach for comprehensive results.

1. Enzyme-Linked Immunosorbent Assay (ELISA) - A key method for antibody quantification.

Based on the specific binding between antigens and antibodies, ELISA provides quantitative measurements of antibodies. It is one of the most common methods for detecting ANA, reflecting the autoimmune response in SLE patients. We also provide Elisa Kits able to screening both Sm/RNP.

Example biomarkers detected using ELISA:

• Anti-dsDNA: Gold-standard biomarker for SLE diagnosis and disease activity monitoring.
• Anti-Ro-SSA Antibody: Associated with skin and kidney damage in SLE; the ELISA system allows semi-quantitative detection.
• Anti-La-SSB Antibody: Often appears with Anti-Ro-SSA, also commonly detected via ELISA. In SLE analysis, the ELISA SSA (Ro) test system is a semi-quantitative immune assay for detecting IgG antibodies to SSA in human serum.

2. Indirect Immunofluorescence (IIF) - Widely used to detect antinuclear antibodies (ANA) and more.

IIF uses fluorescent-labeled antibodies to observe reactions with antibodies present in the sample under a fluorescence microscope, helping identify the types and distribution of antibodies.

3. Western Blot - Used for precise confirmation of specific antibodies.

4. Enzyme Immunospot Assay - High sensitivity, suitable for both qualitative and quantitative analysis.

This approach, which is based on individual cells' immunological responses, captures target antibodies or antigens on a solid-phase matrix, producing visible dots. This very sensitive approach enables for accurate quantification of individual antibodies or cytokines released, which is especially valuable for monitoring immunological responses in SLE patients.

5. Immunoturbidimetry - Quick antibody concentration detection, ideal for clinical screening.

This method measures the light scattering generated by immune complexes formed after antigen-antibody reactions, commonly used for rapid antibody screening.

6. Protein Chip - High-throughput, ideal for comprehensive immune system evaluation.

Analysis Services - Related Targets

We have all the SLE-related serological test targets you need:

• Anti-dsDNA: A specific marker for SLE, often used to diagnose and monitor disease activity.
  Anti-dsDNA antibody levels vary significantly. When the disease is highly active or following treatment with steroids or immunosuppressants, levels of anti-dsDNA antibodies tend to be high; subsequently, they may decrease or even disappear. This makes monitoring anti-dsDNA antibodies critical for assessing disease activity in SLE.
• ANA (Antinuclear Antibody): A common initial screening marker for autoimmune diseases, almost all SLE patients test positive.
  In the past century, SLE was the only autoimmune disease known for its connection to ANA, but research has since shown ANA's importance in other conditions like mixed connective tissue disease, rheumatoid arthritis, antiphospholipid syndrome, systemic sclerosis, inflammatory myositis, nephritis, and autoimmune hepatitis.
  HEp-2 cell-based indirect immunofluorescence (IIF) is the gold standard for screening ANA in SARD. If ANA is positive in HEp-2 cells, further testing is needed to identify specific autoantibodies like anti-dsDNA or anti-ENA antibodies. Positive ANA results in HEp-2 cells should be standardized and communicated to clinicians, including endpoint titers, immunofluorescence patterns, and references to associated autoantibodies, to increase diagnostic value and support clinical decision-making.
• Anti-Sm (Anti-Smith Antibody): A highly specific SLE marker, used for diagnosis.
  Anti-Sm antibodies are associated with SLE disease activity. They are a highly specific but less sensitive biomarker for SLE diagnosis. Additionally, anti-Sm antibodies are linked to lupus nephritis, and their presence in SLE patients indicates a risk for developing lupus nephritis in the future. High titers of anti-Sm are considered predictive of asymptomatic lupus nephritis, which can signal early poor prognosis.
• Anti-Ro-SSA/Anti-La-SSB: Antibodies related to SLE and other autoimmune diseases, helping to differentiate between various autoimmune conditions.
  SSB/La is an RNA-binding protein that plays a critical role in RNA metabolism, immune function, and epigenetic regulation. The immune system mistakenly recognizes it, leading to autoimmune diseases such as Sjögren's syndrome and lupus.
• Anti-RNP (Anti-Ribonucleoprotein Antibody): Associated with SLE and mixed connective tissue disease.
  RNP is a combination of RNA and RNA-binding proteins that regulate post-transcriptional gene expression.
• Anti-Nucleosome: An emerging biomarker for SLE, often associated with disease activity.
• Anti-Cardiolipin Antibody (aCL): Related to antiphospholipid syndrome, commonly found in SLE patients.
  Anti-cardiolipin antibodies are linked to recurrent thrombosis, thrombocytopenia, and spontaneous abortion. They can also be seen in patients with SLE, other connective tissue diseases, and individuals receiving chlorpromazine treatment.
• Anti-β2-Glycoprotein 1: Another marker for antiphospholipid syndrome, commonly associated with SLE.

Need a comprehensive set of tests to evaluate SLE status? Or concerned about certain antibodies? Contact us here.