Antibodies against ENA (Sm, RNP, SSA, SSB)

Autoantibodies against extractable nuclear antigens (ENAs) describe a subgroup of antinuclear antibodies (ANAs) not reacting with chromatin. They are directed against nuclear proteins that were isolated by salt extraction. ENAs are mainly recognized by sera from patients with systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), systemic sclerosis, myositis, and Sjogren’s. Classical autoantigens are Smith-Protein (Sm), ribonucleoproteins (RNP), Robert-Antigen/Sjögren’s A (Ro/SSA), and Lane-Antigen/Sjögren’s B (La/SSB), which are all detectable in sera from SLE patients. It is recommended that the specific antibody designation be used instead of the global term anti-ENA.