PCNA

Anti-PCNA antibodies were initially believed to be specific for SLE, but they have now been described in patients with Sjögren's syndrome as well as in a range of other clinical conditions such as hepatitis B, hepatitis C, and malignant disease. Anti-PCNA antibodies in patients with SLE have been reported to correlate with a greater incidence of glomerulonephritis.PCNA is a member of the DNA sliding clamp (ß clamp) family and has an essential role in DNA synthesis. The protein exists as a homotrimer and acts by encircling DNA to serve as a scaffold on which DNA polymerases are tethered. PCNA is also known to interact with a number of other proteins that are involved in DNA replication, repair or methylation or in cell cycle regulation. PCNA deletion mutant studies suggest that autoantibodies in SLE sera are very heterogeneous and can react with a range of different epitopes, whereas autoantibodies present in patients with hepatitis B recognise preferentially the C-terminal of PCNA. Sulfhydryl groups present in PCNA also appear to be essential for autoantibody binding.  PCNA datasheet

Systemic Lupus Erythematosus
SjÓ§gren's syndrome