Question

Antibodies most commonly seen in drug-induced lupus are:

• A. Anti-ds DNA antibodies
• B. Anti-Sm antibodies
• C. Anti-Ro antibodies
• D. Antihistone antibodies

Hint:

The drug-induced form is anti-dsDNA negative but strongly linked to one nuclear protein antibody.

Answer 1

The Correct Option is D

Step 1: Drug-induced lupus erythematosus (DILE) is triggered by drugs such as procainamide, hydralazine, and isoniazid, and has a distinctive serological profile compared with idiopathic SLE.

Step 2: Almost all patients with DILE are ANA positive, classically in a homogeneous pattern. The antibody most commonly and characteristically associated with DILE is the antihistone antibody, so option d is correct.

Step 3: A key contrast is that antibodies against double-stranded DNA are typically ABSENT in drug-induced lupus. Strongly positive anti-dsDNA instead points toward true SLE, so option a is wrong.

Step 4: Anti-Sm and anti-Ro antibodies are not the usual markers of drug-induced lupus. Note that antihistone antibodies are not fully specific, since they also appear in many idiopathic SLE patients, but among the choices they are the commonest finding in DILE.