Extractable Nuclear Antigens

Key points

• Extractable nuclear antigens (ENA) are a group of autoantibodies directed against non-histone nuclear proteins, tested for using an ENA panel
• Anti-Ro (SS-A): associated with Sjogren's syndrome, SLE, and neonatal lupus (congenital heart block)
• Anti-La (SS-B): associated with Sjogren's syndrome, often alongside anti-Ro
• Anti-Sm (Smith): highly specific for SLE, though only moderately sensitive
• Anti-RNP (U1-RNP): associated with mixed connective tissue disease, also seen in SLE
• Anti-Jo-1: associated with polymyositis/dermatomyositis (antisynthetase syndrome)
• Anti-Scl-70 (topoisomerase I): associated with diffuse systemic sclerosis
• Anti-centromere: associated with limited systemic sclerosis (CREST syndrome)