American Board of Internal Medicine (ABIM) Certification Practice Exam

What autoantibody is typically found in drug-induced lupus?

1. Anti-centromere

2. Anti-histone

3. Anti-parietal cell

4. Anti-phospholipase A2 receptor

The correct answer is: Anti-histone

In drug-induced lupus erythematosus (DILE), the autoantibody most commonly associated with the condition is anti-histone antibodies. DILE occurs in response to certain medications, leading to a lupus-like syndrome in patients who are genetically predisposed. Anti-histone antibodies are indicative of a lupus-like reaction due to drug exposure, particularly with medications like procainamide, hydralazine, and isoniazid. Their presence is a hallmark of drug-induced lupus and helps differentiate this condition from other forms of lupus, such as systemic lupus erythematosus (SLE), where other types of autoantibodies might be more prevalent. The other autoantibodies mentioned in the options are associated with different conditions. For instance, anti-centromere antibodies are typically seen in limited scleroderma, anti-parietal cell antibodies are associated with autoimmune gastritis, and anti-phospholipase A2 receptor antibodies are linked to primary membranous nephropathy. Understanding the specific autoantibody profiles can aid in making accurate diagnoses and tailoring appropriate management plans for affected individuals.