American Board of Internal Medicine (ABIM) Certification Practice Exam

Which autoantibody is commonly associated with systemic lupus erythematosus?

1. Anti-GAD-65

2. Anti-histone

3. Anti-phospholipase A2 receptor

4. Anti-microsomal

The correct answer is: Anti-histone

The autoantibody commonly associated with systemic lupus erythematosus (SLE) is the anti-histone antibody. This antibody is typically present in SLE patients and serves as a marker for the disease. Anti-histone antibodies are particularly associated with drug-induced lupus erythematosus, but they can also be found in patients with primary SLE. In SLE, a wide range of autoantibodies can be produced, with anti-nuclear antibodies (ANAs) being the hallmark. Among these, anti-histone antibodies are of particular significance due to their association with the disease and their utility in diagnosing SLE, especially in cases where patients may not present with the classic manifestations of the condition at first. The other autoantibodies listed are primarily associated with different disorders or conditions. For instance, anti-GAD-65 is often related to type 1 diabetes, anti-phospholipase A2 receptor is associated with primary membranous nephropathy, and anti-microsomal antibodies are more related to autoimmune thyroid disease. Thus, the specificity of anti-histone antibodies to SLE makes it the correct answer.