Anti-dsDNA refers to antibodies directed against double-stranded DNA. These antibodies are highly specific for systemic lupus erythematosus (SLE), an autoimmune disease where the immune system attacks the body's own tissues and organs.

What is Anti-dsDNA?

• Anti-dsDNA antibodies are autoantibodies that bind to the double-stranded DNA found in the nuclei of cells.
• They are a hallmark of SLE and are used as a diagnostic and monitoring tool for the disease.

Clinical Significance of Anti-dsDNA

1. Specificity for SLE:

• Anti-dsDNA is highly specific for SLE, meaning it is rarely present in other diseases.
• It is considered one of the classification criteria for SLE by the American College of Rheumatology (ACR).

1. Association with Disease Activity:

• Elevated anti-dsDNA levels are often correlated with active disease, particularly with lupus nephritis (kidney involvement).
• A rising titer may indicate a flare, especially involving organs like the kidneys.

1. Prognostic Value:

• Persistent high levels can predict complications such as nephritis or systemic inflammation.

Testing for Anti-dsDNA

1. Methods:

• Enzyme-Linked Immunosorbent Assay (ELISA): Commonly used, sensitive, but less specific.
• Farr Assay: More specific, measures high-affinity anti-dsDNA antibodies.
• Immunofluorescence (Crithidia luciliae): Highly specific and considered the gold standard.

1. When It’s Ordered:

• Suspected cases of SLE with symptoms like joint pain, skin rashes (e.g., butterfly rash), and fatigue.
• Monitoring SLE disease activity, especially in patients with renal or systemic involvement.

1. Results Interpretation:

• Positive Test: Strongly supports an SLE diagnosis but must be interpreted alongside clinical symptoms and other tests.
• Negative Test: Does not exclude SLE, as not all SLE patients have anti-dsDNA antibodies.

Symptoms Related to Anti-dsDNA Antibodies

Anti-dsDNA contributes to the development of symptoms by forming immune complexes that deposit in tissues, causing inflammation. Common manifestations include:

1. Renal Symptoms (Lupus Nephritis):

• Proteinuria (protein in urine).
• Hematuria (blood in urine).
• Hypertension.

1. Systemic Symptoms:

• Fever, fatigue, and weight loss.

1. Skin and Mucosal Symptoms:

• Malar rash (butterfly rash on the face).
• Photosensitivity.
• Mouth ulcers.

1. Joint and Muscle Symptoms:

• Polyarthritis (joint pain and swelling).

1. Neurological Symptoms:

• Seizures or psychosis in severe cases.

Management of Elevated Anti-dsDNA Levels

1. Treatment of Active Disease:

• Mild Disease: NSAIDs and hydroxychloroquine for joint and skin symptoms.
• Moderate Disease: Low-dose corticosteroids and immunosuppressants (e.g., azathioprine, methotrexate).
• Severe Disease (Lupus Nephritis or CNS Involvement):
• High-dose corticosteroids.
• Cytotoxic drugs like cyclophosphamide or biologics (e.g., belimumab or rituximab).

1. Monitoring:

• Regular anti-dsDNA titer checks, particularly during flares or when nephritis is suspected.
• Complement levels (C3, C4) are often monitored alongside, as low levels indicate active disease.

1. Lifestyle and Preventive Measures:

• Sun protection to avoid UV-induced flares.
• Avoid smoking, as it exacerbates SLE.
• Regular follow-ups to monitor organ involvement.

Other Conditions Associated with Anti-dsDNA

Although primarily linked to SLE, low levels of anti-dsDNA may sometimes be seen in:

• Chronic hepatitis.
• Other autoimmune diseases (e.g., Sjögren's syndrome, rheumatoid arthritis).
• Drug-induced lupus (rare).