Serum antinuclear antibodies (ANAs) are found in nearly all individuals with active SLE. Antibodies to native double-stranded DNA (dsDNA) are relatively specific for the diagnosis of SLE. Anti-SSA or anti-SSB antibodies are seen in Sjogren's syndrome. Topoisomerase I antibodies (also known as Scl-70), Anticentromere antibodies, Fibrillarin antibodies and antibodies to ribonucleoprotein (RNP) are present in scleroderma. Anti-U1-RNP antibodies, and antibodies against U1-70 kd small nuclear ribonucleoprotein (snRNP) are characteristic of mixed connective tissue disorder (MCTD).