Anti-Sm Antibody (Anti-Sm)

LSm proteins(Sm proteins) are a family of RNA-binding proteins found in virtually every cellular organism. LSm proteins are defined by a characteristic three dimensional structure and their assembly into rings of six or seven individual LSm protein molecules. The Sm proteins were first discovered as antigens targeted by so called Anti-Sm antibodies in a patient with a form of systemic lupus erythematosus (SLE), a debilitating autoimmune disease.

Among anti-nuclear antibodies, anti-Sm and anti-RNP antibodies are of the utmost importance in clinical practice. Anti-Sm antibodies are directed against 7 proteins (B/B', D1, D2, D3, E, F, G) that constitute the common core of U1, U2, U4 and U5 small nuclear ribonucleoprotein (snRNP) particles; B/B', D1 and D3 are more frequently targeted.