Autoantibodies to the core proteins of hnRNPs.

A novel autoantibody reacting the the core polypeptides of hnRNP particles has been detected in the serum of a patient with systemic lupus erythematosus (SLE) and Sjögren's syndrome manifestations. Immunoblot analysis, using either rat liver or HeLa nuclear extracts as the antigen source, demonstrated that the autoantibody interacts with a specific subgroup of the core polypeptides of hnRNP particles, namely A2, B1 and B2, but not with A1, C1 and C2.