Which autoantibody is most specific for systemic lupus erythematosus and often used to confirm the diagnosis?

Which autoantibody is most specific for systemic lupus erythematosus and often used to confirm the diagnosis?

• A. Anti-Sm antibodies
• B. Anti-double-strand DNA antibodies
• C. Anti-Ro antibodies
• D. Anti-La antibodies

Answer: (D)

Autoantibody testing in SLE uses specificity to confirm the diagnosis. The anti-Smith antibodies are the most specific for systemic lupus erythematosus; when they are present, they strongly support the diagnosis because they are rarely seen in other diseases. Anti-dsDNA antibodies are also highly associated with SLE and are useful for monitoring disease activity, especially lupus nephritis, but they are not as universally specific as anti-Smith. Antibodies to Ro/SSA and La/SSB are more common in Sjogren’s syndrome and can occur in SLE but are not specific for lupus, so they are not used to confirm the diagnosis.

Autoantibody testing in SLE uses specificity to confirm the diagnosis. The anti-Smith antibodies are the most specific for systemic lupus erythematosus; when they are present, they strongly support the diagnosis because they are rarely seen in other diseases. Anti-dsDNA antibodies are also highly associated with SLE and are useful for monitoring disease activity, especially lupus nephritis, but they are not as universally specific as anti-Smith. Antibodies to Ro/SSA and La/SSB are more common in Sjogren’s syndrome and can occur in SLE but are not specific for lupus, so they are not used to confirm the diagnosis.