 Antisera from approximately 8% of humans with the autoimmune disease scleroderma recognize fibrillarin.Fibrillarin is a component of several ribonucleoproteins including a nucleolar small nuclear ribonucleoprotein (SnRNP) and one of the two classes of small nucleolar ribonucleoproteins (snoRNPs).SnRNAs function in RNA splicing while snoRNPs function in ribosomal RNA processing.