A 32-year-old female presents with malar rash, photosensitivity, arthralgias, and pleuritic chest pain. Urinalysis reveals 3+ proteinuria and cellular casts. Serum antinuclear antibody (ANA) is positive at 1:1280. What specific autoantibody has the highest correlation with active lupus nephritis?

Answer and explanation

Correct answer: A. Anti-double-stranded DNA (anti-dsDNA) antibodies

  1. Step 1: Identify systemic lupus erythematosus (SLE) with renal involvement (lupus nephritis).
  2. Step 2: Anti-dsDNA antibodies are highly specific for SLE and their titer levels correlate directly with active renal disease and complement consumption (low C3/C4).
  3. Step 3: Anti-Ro is associated with neonatal lupus and subacute cutaneous lupus; anti-centromere with limited scleroderma; anti-histone with drug-induced lupus.
Answer
Anti-double-stranded DNA (anti-dsDNA) antibodies.
Why not the others: 'Anti-Ro / SSA antibodies' are linked to cutaneous manifestations and Sjogren syndrome; 'Anti-centromere antibodies' are characteristic of CREST syndrome (limited systemic sclerosis); 'Anti-histone antibodies' are classic for drug-induced lupus erythematosus.

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