Small nuclear RNA associated proteins: autoantigens in connective tissue diseases.

Small nuclear ribonucleoproteins (smRNPs) are complexes of uridylic acid (U)-rich snRNAs with at least 7 core proteins and a varying number of specific proteins. Most of these proteins act as targets for autoantibodies in autoimmune patients. In the last two years, a number of cDNAs coding for these antigens have been cloned and some specific features of the deduced amino acid sequences of these proteins are discussed. The recombinant antigens, produced in high yields by the microorganism, can be used very efficiently in qualitative and quantitative ELISA tests. It is to be expected that the availability of rather large amounts of pure antigen will be of great help in elucidating the question of why these autoantibodies are generated and what their relation to the disease might be.